Electrotherapy in Oncology Rehabilitation: Current Evidence, Safety Considerations, and Future Perspectives

1. Introduction

Continuous advances in cancer prevention, diagnosis, and treatment have transformed many oncological conditions into chronic diseases, leading to substantial improvements in survival worldwide. In several high-income countries, long-term cancer survival rates now exceed 50–60%, reflecting the impact of multidisciplinary and increasingly personalized cancer care [1,2,3].

Consequently, rehabilitation has become an essential component of comprehensive oncology care, requiring early implementation from diagnosis and continuation throughout the disease trajectory to optimize functional outcomes and quality of life [2,4,5].

From a rehabilitation perspective, the management of patients with cancer requires careful consideration of the fundamental ethical principles of non-maleficence and beneficence. While concerns regarding patient safety may discourage the use of certain therapeutic modalities, excessive caution may inadvertently deprive patients of interventions capable of improving function, reducing disability, and enhancing quality of life. In this context, evidence-based guidance is essential to support clinical decision-making and ensure an appropriate balance between therapeutic safety and rehabilitation benefit [6,7].

Cancer and its treatments may result in a broad spectrum of impairments, including pain, fatigue, motor and sensory deficits, dysphagia, sphincter dysfunction, lymphedema, cognitive impairment, mood disorders, and limitations in activities of daily living, ultimately contributing to disability and reduced quality of life [2,8].As the prevention, reduction, and management of disability constitute core objectives of Physical and Rehabilitation Medicine (PRM), the integration of individualized rehabilitation interventions throughout the cancer continuum is both justified and essential. Within this framework, electrotherapy modalities may represent valuable adjunctive interventions for symptom management, functional restoration, and the optimization of quality of life [9].

Despite the growing recognition of rehabilitation as an essential component of comprehensive cancer care, the use of electrotherapy in oncology remains controversial. Historical concerns regarding potential effects on tumor biology, disease progression, and patient safety have contributed to the cautious use of electrotherapy modalities in clinical practice, despite their established or potential role in symptom management and functional recovery [4,10,11,12]. Therefore, a critical appraisal of the available literature is needed to clarify the safety, indications, and clinical utility of electrotherapy interventions in oncology rehabilitation. Accordingly, the aim of this narrative review is to critically evaluate the current evidence regarding safety, clinical applications, contraindications, and therapeutic potential of electrotherapy modalities in oncology rehabilitation.

2. Materials and Methods

2.1. Literature Search Strategy

A structured search was performed in PubMed, Scopus, and Web of Science to identify studies on electrotherapy modalities in oncology rehabilitation. The search combined terms related to cancer rehabilitation and electrotherapy, including therapeutic ultrasound, extracorporeal shock wave therapy, transcutaneous electrical nerve stimulation, neuromuscular and functional electrical stimulation, Deep Oscillation Therapy, photobiomodulation, low-level, multiwave locked system, and high-intensity laser therapies, pulsed electromagnetic field therapy, repetitive peripheral and transcranial magnetic stimulation, the super inductive system, interferential and diadynamic currents, transfer of capacitive and resistive energy therapy, pain, fatigue, neuropathy, and lymphedema. Publications from January 2000 to March 2026 were considered.

2.2. Eligibility and Selection of Evidence

Original studies, randomized controlled trials, systematic reviews, meta-analyses, clinical practice guidelines, consensus statements, and relevant narrative reviews published in English were eligible for inclusion. Preference was given to higher levels of evidence, including randomized controlled trials, systematic reviews, meta-analyses, and evidence-based clinical guidelines. Studies not directly related to oncology rehabilitation, cancer survivorship, or electrotherapy and physical agent modalities were excluded.

2.3. Study Design

This manuscript represents a narrative review based on a structured literature search. The objective was not to perform a quantitative synthesis of the evidence, but rather to provide a clinically oriented overview of the current evidence, safety considerations, contraindications, and practical applications of electrotherapy modalities in oncology rehabilitation. Emphasis was placed on clinical applicability, modality-specific safety considerations, and areas of ongoing controversy or emerging evidence.

3. Results

3.1. Contraindications and Current Challenges of Electrotherapy in Oncology Rehabilitation

Electrotherapy includes a wide range of therapeutic interventions that use electrical currents, electromagnetic fields, electromagnetic radiation, or other electrically generated physical energies to induce biological and clinical effects in target tissues [13,14,15]. Because these modalities differ in mechanisms, parameters, and tissue effects, appropriate prescription requires a clear understanding of their mechanisms of action, indications, contraindications, biological effects, and dosimetry principles [12]. In PRM, electrotherapy is typically integrated into individualized rehabilitation programs. Like pharmacological interventions, these modalities produce dose-dependent effects and may be beneficial when correctly prescribed, but they may also cause adverse effects if used with inappropriate indications or treatment parameters [13,14,15].

As oncology rehabilitation evolves, contraindications and precautions for physical interventions in cancer patients are increasingly defined, supporting a transition from historically based restrictions to individualized, evidence-based clinical decision-making [2,4,12]. In this context, it is important to distinguish general contraindications to electrotherapy from cancer-specific considerations. As in the general population, electrotherapy may be contraindicated in patients with acute illness, severe clinical decompensation, uncontrolled cardiovascular disease, implanted electronic devices, active thrombosis, or other modality-specific contraindications [16,17].

In patients with cancer, two additional concerns have historically influenced clinical decision-making regarding electrotherapy interventions: the theoretical risk of influencing tumor biology and the possibility of destabilizing an already medically vulnerable patient. These concerns have contributed to the cautious application of electrotherapy in oncology rehabilitation and continue to influence contemporary clinical practice, despite the growing body of evidence supporting the safety and clinical utility of several modalities when appropriately prescribed [2,12,15].

Table 1 summarizes the general contraindications commonly considered when prescribing electrotherapy, together with the additional cancer-specific factors that may influence clinical decision-making in oncology rehabilitation.

3.2. Oscillatory Electro-Mechanotherapy: Therapeutic Ultrasound and Extracorporeal Shock Wave Therapy

Oscillatory electro-mechanotherapy comprises therapeutic modalities in which electrical energy is transformed into mechanical energy through electromechanical transduction mechanisms. In therapeutic ultrasound, alternating electrical current induces oscillation of a piezoelectric crystal, generating high-frequency mechanical waves that propagate through biological tissues. Similarly, extracorporeal shock wave therapy (ESWT) generates acoustic pressure waves through electrohydraulic, electromagnetic, or piezoelectric mechanisms. Although both modalities are generally classified as mechanical physical agents, their generation fundamentally relies on electrically driven electromechanical processes.

Beyond their common physical origin, therapeutic ultrasound and ESWT exert their biological effects through the propagation of mechanical waves within tissues and share several mechanotransductive and therapeutic mechanisms, including pain modulation, stimulation of tissue repair, and promotion of regenerative responses. Consequently, within the conceptual framework adopted in this review and from a PRM perspective, these modalities may be considered related forms of oscillatory electromechanotherapy [18,19,20,21].

3.2.1. Therapeutic Ultrasound

Therapeutic ultrasound exerts a series of physical, chemical and biological effects resulting from the propagation of high-frequency mechanical waves through biological tissues [22,23].

Physical and chemical effects include deep tissue heating, modulation of oxidation–reduction processes, phonophoresis, increased membrane permeability, enhanced diffusion phenomena, thixotropic changes in soft tissues, and cavitation-related effects [18,23].

The therapeutic effects of ultrasound are dose-dependent. Low intensities (0.2–0.3 W/cm²) are mainly associated with analgesic and reflexogenic effects, whereas intermediate intensities (0.4–0.6 W/cm²) may produce myorelaxant and fibrinolytic responses. Higher intensities (>0.8 W/cm²) generate stronger mechanical tissue stimulation and may support tissue remodeling and repair [18,24].

3.2.1.1. Safety Considerations of Therapeutic Ultrasound in Oncology Rehabilitation

Therapeutic ultrasound may be considered in selected cancer patients for soft-tissue dysfunction, pain, and muscle-related disorders, provided significant bone involvement has been excluded. Low- to moderate-intensity applications (0.2–0.6 W/cm²) are generally preferred. Particular caution is required in patients with skeletal metastases or marked cortical bone destruction because of the increased risk of pathological fracture, especially when higher intensities (>0.8 W/cm²) are used. Treatment decisions should therefore be guided by lesion location, skeletal integrity, and the patient’s overall clinical status [12,16,25,26].

Historically, therapeutic ultrasound has been regarded as contraindicated over malignant tissues because of concerns regarding potential tumor stimulation. Nevertheless, growing evidence indicates that ultrasound–tumor interactions are multifactorial and may involve thermal, mechanical, and cellular responses that are not yet fully understood. These effects include acoustic pressure changes, mechanotransduction pathways, microstreaming, and cavitation-related phenomena, the biological significance of which may vary according to treatment parameters and tissue characteristics. Importantly, evidence derived from focused ultrasound and ultrasound-guided oncological therapies should not be directly extrapolated to conventional therapeutic ultrasound used in rehabilitation medicine. Therapeutic ultrasound should therefore be prescribed individually, based on tumor location, tissue involvement, rehabilitation goals, skeletal stability, and the patient’s overall clinical status. In practice, skeletal stability is a key consideration, particularly in patients with bone metastases, osteolytic lesions, cortical destruction, or increased risk of pathological fracture. In many oncological contexts, these biomechanical factors may be more clinically relevant than theoretical concerns about direct tumor stimulation [12,16,27].

3.2.2. Extracorporeal Shock Wave Therapy

ESWT consists of the therapeutic application of high-pressure acoustic waves, delivered as focused or radial shock waves, which require a material medium for propagation. The biological effects of ESWT are primarily mediated through mechanical stimulation and controlled microtrauma, leading to modulation of inflammatory processes, tissue remodeling, neovascularization, and activation of cellular signaling pathways involved in tissue repair and regeneration [19,20,21].

3.2.2.1. Safety Considerations of ESWT in Oncology Rehabilitation

Because ESWT acts primarily through mechanotransduction and controlled microtrauma, careful patient selection is required in oncology rehabilitation [12]. Current evidence suggests that ESWT may represent a useful supportive modality in selected cancer patients and, contrary to historical assumptions, available data do not indicate tumor-promoting effects [28]. Therefore, malignancy itself should not be considered an absolute contraindication.

The principal safety concern relates to structural tissue integrity rather than tumor stimulation. Consequently, ESWT should be avoided in areas with extensive bone metastases, significant cortical destruction, pathological fractures or high fracture risk, active tumor masses within the treatment field, and other conditions associated with mechanical fragility. Clinical decisions should be guided primarily by skeletal stability, local tissue involvement, rehabilitation goals, and the patient's overall condition [12,28].

3.3. Transcutaneous Electrical Nerve Stimulation

Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive electrotherapy modality primarily used for pain management. Its analgesic effects are mainly explained by the gate control theory, whereby stimulation of large-diameter sensory afferent fibers inhibits nociceptive transmission at the level of the dorsal horn of the spinal cord. Additional mechanisms include activation of descending inhibitory pathways and modulation of endogenous opioid release [29].

TENS can be delivered using various stimulation patterns, including conventional, symmetrical biphasic, and asymmetrical biphasic waveforms. Owing to its favorable safety profile, ease of application, low cost, and established analgesic efficacy, TENS remains one of the most widely used electrotherapy modalities in clinical practice [30].

3.3.1. Evidence for TENS in Oncology

Current evidence has primarily focused on the use of TENS for cancer-related pain, chemotherapy-induced peripheral neuropathy (CIPN), post-surgical pain, and symptom management in palliative and supportive cancer care, indicating a favorable safety profile and potential clinical benefits, particularly for pain control, although the available evidence remains limited by methodological heterogeneity and insufficient high-quality randomized controlled trials [31,32,33,34,35].

3.4. Deep Oscillation

Deep Oscillation Therapy is an electrokinetic modality that combines the effects of pulsed electrostatic fields with mechanically induced tissue oscillations. Its proposed mechanisms of action include analgesic, anti-edematous, vasculotrophic, and tissue-mobilizing effects, making it a potential therapeutic option for the management of lymphedema, post-surgical edema, pain, and soft-tissue dysfunction. Owing to its minimal mechanical loading and favorable safety profile, Deep Oscillation Therapy has been investigated as a supportive intervention in rehabilitation, including cancer-related lymphedema and oncology rehabilitation [36,37,38].

3.4.1. Evidence for Deep Oscillation in Oncology

Current evidence has primarily evaluated Deep Oscillation Therapy for cancer-related lymphedema, post-surgical edema, pain, and soft-tissue dysfunction. Available studies suggest favorable effects on edema reduction, symptom control, pain, and quality of life, particularly in patients with breast cancer-related lymphedema. However, despite its favorable safety profile, the current evidence remains limited and further high-quality studies are required to define its role in oncology rehabilitation [36,39,40].

3.5. Electrical Stimulation in Oncology Rehabilitation

Electrical stimulation comprises a group of electrotherapy modalities designed to elicit neuromuscular responses through the application of electrical impulses. Depending on the degree of innervation, different stimulation parameters may be required, with denervated muscle responding preferentially to long-duration impulses, such as exponential or trapezoidal waveforms, whereas normally innervated muscle responds to short-duration rectangular pulses. Consequently, stimulation parameters should be individualized according to the underlying neurological impairment and the degree of muscle denervation [13,41].

In oncology rehabilitation, electrical stimulation may be considered for the management of motor deficits resulting from cancer itself or its treatment, including chemotherapy-induced peripheral neuropathy, radiation-induced neuropathy, post-radiation myelopathy, cancer-related weakness, and functional impairment associated with prolonged immobilization. Emerging evidence supports the feasibility and safety of neuromuscular electrical stimulation in selected cancer populations, particularly for improving muscle function, mobility, and sensorimotor deficits [12,42,43].

3.5.1. Evidence for Electrical Stimulation in Oncology

Current evidence suggests that electrical stimulation may represent a safe and feasible intervention for selected cancer patients with sensory or motor deficits. Beneficial effects have been reported in chemotherapy-induced peripheral neuropathy, cancer-related muscle weakness, and functional impairment in hematological malignancies. Furthermore, the routine use of electrical stimulation techniques in neuro-oncology, including intraoperative cortical mapping during glioblastoma surgery, illustrates that electrical stimulation per se is not universally avoided in patients with cancer. Although these applications differ substantially from rehabilitation electrotherapy, they further challenge the concept of electrical stimulation as an absolute contraindication in oncology. Nevertheless, treatment indications and stimulation parameters should be individualized according to tumor location, neurological status, and rehabilitation goals [42,43,44].

3.6. Neuromuscular and Functional Electrical Stimulation (NMES/FES)

Neuromuscular electrical stimulation (NMES) and functional electrical stimulation (FES) are electrotherapy modalities that elicit muscle contractions through the electrical activation of intact peripheral motor nerves. Their main therapeutic objectives include the preservation of muscle mass, prevention of atrophy, improvement of muscle strength, and enhancement of functional performance [45,46].

Both modalities generally use short-duration rectangular pulses, whereas denervated muscle requires specific protocols based on long-duration impulses, such as exponential or trapezoidal waveforms [13,41].

More recently, whole-body electromyostimulation (WB-EMS) has emerged as a complementary approach for improving muscle function and physical performance through simultaneous stimulation of multiple muscle groups. Although evidence regarding WB-EMS in oncology remains limited, its potential role in addressing cancer-related muscle loss and physical deconditioning warrants further investigation [17,47].

Owing to their potential to counteract muscle weakness and functional decline, NMES and FES have gained increasing attention as supportive interventions in oncology rehabilitation [12,48].

3.6.1. Evidence for NMES/FES in Oncology

Current evidence has evaluated NMES and FES primarily in patients with CIPN, cancer-related weakness, sarcopenia, hematological malignancies, and neurological impairments resulting from cancer or its treatment. Available studies indicate that electrical stimulation may enhance muscle strength, physical function, mobility, and selected sensory and motor deficits, while maintaining a favorable safety profile.Furthermore, the routine use of electrical stimulation techniques in neuro-oncology and neurosurgery, including cortical stimulation procedures performed during glioblastoma surgery, further illustrates that electrical stimulation per se is not universally avoided in patients with cancer. Although these applications differ substantially from rehabilitation electrotherapy, they challenge the historical concept of electrical stimulation as an absolute contraindication in oncology. Nevertheless, treatment indications and stimulation parameters should be individualized according to the underlying pathology, neurological status, and rehabilitation goals [43,44,48].

3.7. Diadynamic Currents

Diadynamic currents (DDC) are low-frequency pulsed currents generated by rectification of sinusoidal alternating current. Their biological effects are frequency-dependent and include neuromuscular stimulation, vasotrophic effects, and pain modulation. Lower frequencies are associated predominantly with excitomotor responses, whereas higher frequencies exert mainly analgesic effects. Consequently, DDC have traditionally been used for pain management, neuromuscular stimulation, and functional rehabilitation [13,49,50].

3.7.1. Evidence for DDC in Oncology

Direct evidence on the use of DDC in oncology rehabilitation is limited. Although current data do not indicate tumor-promoting effects, oncology-specific evidence remains insufficient to support definitive recommendations. Therefore, DDC should be prescribed only after individualized risk–benefit assessment, considering clinical objectives and standard electrotherapy precautions [12,16].

3.8. Interferential Current Therapy

Interferential current therapy (IFC) is an electrotherapy modality generated by the interaction of two medium-frequency alternating currents, producing an amplitude-modulated low-frequency current within the target tissues. Compared with conventional low-frequency stimulation, IFC is generally associated with greater patient comfort and a greater capacity to influence deeper tissues due to reduced skin impedance [30,51].

Its biological effects are frequency-dependent and include neuromuscular stimulation, vasotrophic effects, and pain modulation. Consequently, IFC has traditionally been used for pain management, edema reduction, functional rehabilitation, and selected neurorehabilitation applications [51,52].

3.8.1. Evidence for IFC in Oncology

Evidence on IFC therapy in oncology rehabilitation remains limited. Few studies have directly assessed its efficacy or safety in cancer populations; therefore, current oncology-specific recommendations rely mainly on general electrotherapy principles rather than direct clinical evidence. Although available data do not indicate tumor-promoting effects, they are insufficient to support definitive recommendations. Consequently, IFC should be prescribed individually, considering tumor location, clinical status, rehabilitation goals, and standard electrotherapy precautions [12,16].

3.9. Photobiomodulation and Laser Therapy

Photobiomodulation (PBM) refers to the therapeutic use of non-ionizing light sources, including low-level laser therapy (LLLT), high-intensity laser therapy (HILT), and multiwave locked system laser therapy (MLS). These modalities deliver light energy to biological tissues, where photon absorption by intracellular chromophores, particularly within the mitochondrial respiratory chain, initiates a cascade of photochemical and photobiological responses, including increased mitochondrial activity, ATP synthesis, and modulation of cellular signaling pathways [53,54,55].

The biological effects of PBM include modulation of cellular metabolism, regulation of inflammatory processes, promotion of tissue repair and regeneration, and pain modulation. Depending on the wavelength, power output, and energy density delivered, laser therapies may produce predominantly photobiomodulatory effects (LLLT), combined photobiomodulatory and thermal effects (MLS), or photomechanical, photothermal, and photobiomodulatory effects (HILT) [53,55,56].

Owing to their analgesic, anti-inflammatory, and regenerative properties, laser-based therapies have been increasingly investigated in oncology rehabilitation, particularly for the prevention and management of treatment-related toxicities and functional impairments.

3.9.1. Evidence for Laser Therapy in Oncology

Among laser-based modalities, LLLT and PBM currently have the strongest evidence base in oncology supportive care. Clinical studies and international guidelines support their use for the prevention and management of oral mucositis associated with chemotherapy and radiotherapy, particularly in patients with head and neck cancer [57,58]. In a clinical series of 415 patients receiving chemoradiotherapy for head and neck malignancies, low-dose laser therapy (1–6 J/cm²) was successfully used for oral mucositis prevention [59].

Additional studies suggest that PBM may support tissue repair and help manage cancer therapy–related toxicities [61]. Experimental findings also indicate that PBM may reduce pain and promote tissue healing without causing additional tissue damage [60].

However, the interaction between PMB and tumor biology remains a subject of ongoing debate. While clinical studies and current supportive care protocols have not demonstrated increased tumor progression, recurrence, or reduced oncological outcomes associated with PBM when applied according to established clinical guidelines, experimental investigations have reported increased proliferation and viability of certain isolated cancer cell lines under specific irradiation conditions. These findings suggest that biological responses may depend on multiple factors, including wavelength, power output, energy density, irradiation time, treatment frequency, and tumor type. Although PBM shows a favorable safety profile for selected oncological indications, laser therapy should be applied near active malignant tissues only with caution and according to validated protocols, pending further clarification of PBM–tumor interactions [62].

3.10. Electromagnetic Field Therapy

Electromagnetic field therapies utilize time-varying magnetic fields that induce endogenous electric fields within biological tissues through electromagnetic induction. In physical and rehabilitation medicine, these modalities may be classified according to magnetic induction (B), a fundamental physical parameter governing electromagnetic energy delivery and the magnitude of the induced electric field. Accordingly, electromagnetic therapies encompass low-intensity magnetotherapy (μT–mT), pulsed electromagnetic field therapies (PEMF/rPMS; mT), transcranial magnetic stimulation (rTMS; 1–3 T), and high-intensity peripheral stimulation systems such as the Super Inductive System (SIS; up to 3 T). Their biological effects include analgesic, neuromodulatory, electrostimulatory, osteogenic, and regenerative responses [63,64].

3.10.1. Evidence for Electromagnetic Field Therapies in Oncology

Clinical evidence indicates that electromagnetic field therapies may benefit cancer-related pain, chemotherapy-induced peripheral neuropathy (CIPN), postoperative recovery, and supportive cancer care, while maintaining a favorable safety profile [65,66,67,68].

In parallel, a growing body of experimental evidence indicates that pulsed electromagnetic fields (PEMF) may influence tumor biology through modulation of cellular proliferation, apoptosis, senescence, immune responses, and signaling pathways involved in cancer progression. Several preclinical studies have reported reduced tumor cell viability, induction of apoptosis and senescence, modulation of antitumor immune activity, and enhanced sensitivity to anticancer therapies, suggesting that electromagnetic stimulation may exert biologically relevant effects on tumor biology, some of which appear to be antitumoral in experimental models [69,70,71,72,73,74].

Although these findings are promising, current evidence remains insufficient to establish electromagnetic field therapies as antineoplastic treatments. Further translational and clinical studies are required to define optimal treatment parameters, clarify underlying mechanisms, and determine their role within contemporary oncology rehabilitation and supportive cancer care.

3.11. Shortwave and TECAR Diathermy

Shortwave diathermy and transfer of capacitive and resistive energy (TECAR) are electromagnetic diathermy modalities that deliver radiofrequency energy to biological tissues. Shortwave diathermy utilizes electromagnetic waves at a standardized frequency of 27.12 MHz, whereas TECAR therapy operates at lower radiofrequencies, typically between 0.3 and 1 MHz (most commonly 448–500 kHz). Their therapeutic effects are mediated primarily through deep endogenous heating (diathermy), resulting in increased tissue metabolism, vasodilation, pain relief, muscle relaxation, and facilitation of tissue repair processes [75,76,77,78].

3.11.1. Evidence for Diathermy in Oncology

Shortwave diathermy and TECAR therapy have historically been regarded as contraindicated in the presence of active malignancy because of concerns related to deep tissue heating, increased local blood flow, and the theoretical possibility of tumor stimulation. However, these precautions are based largely on theoretical considerations and historical clinical practice rather than on direct clinical evidence demonstrating tumor-promoting effects. To date, the available literature has not provided convincing evidence that therapeutic diathermy promotes tumor growth or cancer progression when applied under standard rehabilitation conditions. Nevertheless, clinical evidence remains limited, and the number of studies specifically investigating the safety and efficacy of shortwave diathermy and TECAR therapy in oncology rehabilitation is insufficient to support routine clinical use, particularly in regions containing active tumor tissue. Therefore, treatment decisions should be individualized according to tumor location, disease status, therapeutic objectives, and overall patient condition, while adhering to established safety precautions until further high-quality clinical studies become available [12].

3.12. Summary of the Available Evidence and Clinical Considerations for Electrotherapy Modalities in Oncology Rehabilitation

Table 2 summarizes the principal electrotherapy modalities discussed in this review and integrates the available evidence regarding their potential role in oncology rehabilitation.

4. Discussion

The available evidence indicates that electrotherapy modalities should not be considered a homogeneous therapeutic category in oncology rehabilitation. Their safety profile, biological effects, and clinical applicability differ substantially according to the type of physical energy delivered, treatment parameters, mechanism of action, anatomical site, tumor status, and patient-specific factors. Consequently, the use of electrotherapy in cancer patients should be guided by modality-specific evidence and individualized risk–benefit assessment rather than by generalized historical contraindications [4,10,12].

Several important trends emerge from the available literature. First, modalities such as TENS, neuromuscular and functional electrical stimulation (NMES/FES), and Deep Oscillation Therapy have reached a relatively mature stage of development within oncology rehabilitation. Their use is supported by an expanding evidence base demonstrating benefits in pain management, lymphedema, cancer-related weakness, sarcopenia, functional impairment, and selected manifestations of CIPN [12,36,42,43].

For these interventions, the principal challenge is no longer whether they may be used in oncology patients, but rather how they can be optimally prescribed and integrated into individualized rehabilitation programs.

In contrast, PBM and LLLT represent one of the most intriguing paradoxes in contemporary oncology rehabilitation. The same biological mechanisms responsible for their regenerative, anti-inflammatory, and analgesic effects—including modulation of cellular metabolism, tissue repair, and angiogenesis—have also raised theoretical concerns regarding potential tumor stimulation [53,54,62]. Nevertheless, PBM has become an evidence-supported intervention for selected treatment-related complications, particularly oral mucositis [59,67]. This apparent contradiction highlights the complexity of balancing theoretical biological concerns against demonstrated clinical benefits in supportive cancer care.

Electromagnetic field therapies, including pulsed electromagnetic field therapy (PEMF), repetitive peripheral magnetic stimulation (rPMS), and repetitive transcranial magnetic stimulation (rTMS), may represent a promising area for future research in oncology rehabilitation. Beyond their established or emerging roles in pain management, neuromodulation, and rehabilitation of chemotherapy-induced peripheral neuropathy, recent experimental studies suggest that electromagnetic stimulation may influence tumor biology through mechanisms involving apoptosis, senescence, immune modulation, and altered cellular signaling [65,66,69,70,71,72,74]. Although these observations remain predominantly preclinical, they challenge traditional assumptions that electromagnetic stimulation is inherently undesirable in oncology and suggest that such interventions may have broader biological and therapeutic implications than previously recognized. [65,66,69,70,71,72,74].

The situation is different for therapeutic ultrasound and ESWT. Current concerns regarding these modalities relate less to potential tumor stimulation and more to the structural fragility frequently encountered in cancer patients, particularly in the presence of bone metastases, cortical destruction, or an increased risk of pathological fracture. Current concerns regarding these modalities appear to be related predominantly to skeletal integrity and fracture risk rather than to direct evidence of tumor stimulation [12,25,26].

For diadynamic and interferential currents, the principal limitation is the scarcity of contemporary evidence rather than the presence of demonstrated risks. These modalities have received relatively little attention in modern oncology rehabilitation research, making it difficult to draw firm conclusions regarding their efficacy, safety, or optimal indications. Their future role will depend largely on the availability of high-quality clinical studies capable of establishing evidence-based recommendations [10,12].

A particularly interesting area of ongoing debate concerns shortwave and TECAR diathermy. Historically, these modalities were considered contraindicated in patients with active malignancy because of their ability to increase local blood flow, tissue metabolism, and deep tissue temperature. However, advances in cancer biology have highlighted the complex relationship between tissue perfusion, tumor hypoxia, and treatment responsiveness [79,80]. Emerging concepts from hyperthermia research suggest that improved local perfusion may, under specific circumstances, enhance the effectiveness of anticancer therapies rather than simply promote tumor growth [79,81]. Importantly, these concepts derive primarily from hyperthermia and tumor biology research and should not be interpreted as evidence supporting the routine use of rehabilitation diathermy in patients with active malignancy. Nevertheless, they challenge traditional assumptions and suggest that the role of therapeutic heating in oncology may deserve renewed scientific investigation.

Overall, the evolution of electrotherapy in oncology rehabilitation reflects a broader transition from historically based contraindications toward individualized, evidence-based clinical decision-making [4,10,12]. While several modalities have already established a role in supportive cancer care, others remain controversial or insufficiently studied. At the same time, emerging experimental and clinical evidence indicates that certain physical agent modalities may exert biological effects extending beyond symptom control, opening new avenues for research and potentially broadening the scope of oncology rehabilitation [69,70,71,82].

4.1. Limitations

Several limitations should be acknowledged. First, this review is narrative in nature and does not follow a formal systematic review methodology; therefore, study selection and interpretation may have been influenced by selection bias.

Second, the quality and quantity of available evidence vary considerably among electrotherapy modalities. While some interventions, such as TENS, NMES/FES, Deep Oscillation Therapy, and PMB, are supported by an expanding body of clinical evidence, others—including IFC, DDC, HILT, SIS, and certain electromagnetic field therapies—remain supported primarily by limited clinical data or emerging experimental evidence.

Third, many studies in this field are heterogeneous with respect to patient populations, cancer types, treatment parameters, outcome measures, and follow-up duration, limiting direct comparisons and the formulation of definitive clinical recommendations.

Finally, several promising findings discussed in this review, particularly those related to electromagnetic field therapies and their interactions with tumor biology, are derived predominantly from preclinical studies and therefore require confirmation in well-designed clinical trials before definitive conclusions can be drawn.

5. Conclusions

Current evidence suggests that electrotherapy modalities differ substantially in their mechanisms of action, biological effects, safety profiles, and clinical applicability in oncology rehabilitation. While several interventions, including TENS, NMES/FES, Deep Oscillation Therapy, and PMB, have established or emerging roles in supportive cancer care, other modalities remain insufficiently investigated and require further clinical evaluation.

The findings of this narrative review indicate that electrotherapy in oncology should not be regarded as a homogeneous therapeutic category. Rather than relying on generalized historical contraindications, clinical decision-making should be guided by modality-specific evidence, biological plausibility, treatment objectives, tumor characteristics, and individualized risk–benefit assessment.

Although important uncertainties remain, particularly regarding electromagnetic field therapies, laser–tumor interactions, and diathermy-based interventions, the available evidence supports a gradual transition from historically based restrictions toward evidence-informed, patient-centered rehabilitation practice.

Future research should prioritize high-quality clinical studies capable of establishing modality-specific recommendations, defining optimal treatment parameters, and clarifying the complex interactions between physical agent modalities, tumor biology, rehabilitation outcomes, and quality of life in cancer survivors.