Discussion
The RBAC-QoL study aims to determine the potential effect of RBAC compared to placebo on the QoL of cancer patients undergoing active treatment. This interim analysis showed encouraging results, with RBAC showing a statistically significant difference in increasing QoL over placebo during the trial with a large effect size in the primary analysis (F[1,8] = 8.6,
p = 0.019, eta2[g] = 0.267). Specifically, the global QoL scores of the patients taking RBAC were higher than those taking placebos at week 6 and marginally higher at week 12 during the trial. The placebo group had a drop in global QoL at week 6 before experiencing some recovery after that (
Figure 2). Since the participants were starting active treatment at baseline, a decline in QoL was expected since antitumour treatment, especially chemotherapy with unwanted side effects, could negatively affect their well-being (Chagani et al., 2017; Sibeoni et al., 2018). The RBAC group, however, maintained their QoL throughout the trial while on active treatment, revealing the effectiveness of RBAC in QoL maintenance. Notably, the reported effect size (eta2[g] = 0.267) is considered large for ANOVA (Lakens, 2013), and Cohen’s
d measuring the differences in mean QL2 between groups at weeks 6 and 12 were large and thus clinically significant (Cocks et al., 2010). The treatment effects of RBAC appeared more pronounced after adjusting for the age differences between groups (
Figure 5). Such favourable observation is thus consistent with the results of Tan and Flores (2020), whereby there was a statistically significant difference in the mean QoL scores (
p = 0.019) between the RBAC and placebo groups two months after radiation treatment for participants with head and neck cancers.
Other RCTs have reported RBAC’s benefits in reducing cancer treatment’s side effects. Masood et al. (2013) studied the incidents of side effects in breast cancer patients taking RBAC compared to those who did not during six cycles of chemotherapy using a self-reporting questionnaire. Reductions in the proportions of patients experiencing anorexia/tiredness (RBAC vs. control: 20% vs. 88%), nausea/vomiting (40% vs. 100%), hair loss (28% vs. 100%), and weight loss (0% vs. 84%) were reported. Another study by Petrovics et al. (2016) also reported significant alleviation of fatigue symptoms (p<0.001) in cancer patients with chronic fatigue syndrome after 24 weeks of RBAC plus oncothermia interventions during active treatment compared to control patients who received only conventional oncological treatment. The fatigue measurement was based on the Chalder fatigue questionnaire and Patients’ Global Impression of Change (PGIC) scales.
In the present study, fatigue was also one of the treatment side effects experienced by the participants. However, no statistically significant differences between the groups were detected in fatigue and other treatment side-effects, such as nausea and vomiting or pain, based on QLQ-C30. Such discrepancy could be due to the lack of sensitivity in the symptom scores of QLQ-C30, based on 4-point Likert scales. Finstad (2010) found that 7-point Likert items could provide a more accurate measure of a participant’s evaluation than a 5-point scale (let alone 4) in electronic questionnaires. Moreover, the lack of sensitivity in the symptom scales could also be compounded by the small sample size in this interim analysis, which may not have enough power. Therefore, to assess treatment side effects, future studies should consider augmenting the QLQ-C30 with a more specific self-evaluated adverse effects questionnaire, such as the 10-item instrument proposed by Montemurro et al. (2016) and the Chalder fatigue questionnaire.
While RBAC was hypothesised to impact the QoL of cancer patients via the inflammatory and nutritional pathways, none of the secondary and exploratory outcome measures, including BMI, INI, NLR, and cytokine profile, showed significant differences between groups. Notwithstanding, this interim analysis detected substantial between-group differences in WBC and TP from the routine safety assessment of participants with considerably large effect sizes, albeit not being the pre-established outcome measures of interest. The analysis found relatively higher WBC and TP in the RBAC group compared to the placebo group at visits 2 and 3 (
Figure 3). In particular, the rise in WBC resulted from rising neutrophil count in the RBAC group based on the age-adjusted analysis (
Figure 6).
Two other RBAC RCTs also examined WBC. Itoh et al. (2015) compared RBAC to placebo in patients with cervical cancer undergoing chemoradiotherapy. Depletion of WBC was reported in all patients after three weeks of treatment due to radiation side effects. However, no significant difference between groups was found, although the study authors commented that the control group tended to have lower WBC than the RBAC group. Radiation therapy also caused head and neck cancer patients to have lower posttreatment WBC in the RCT by Tan and Flores (2020). Similarly, there was no significant difference between the RBAC and placebo groups in this study. Therefore, RBAC was not known to affect WBC. The current study is the first to demonstrate that RBAC could potentially preserve and improve the WBC profiles of cancer patients during active treatment with chemotherapy or immunotherapy.
The potential effects of RBAC on cancer patients’ neutrophil count were previously reported by Golombick et al. (2016) in a single-arm before and after study in patients with monoclonal gammopathy of undetermined significance (MGUS)/smouldering multiple myeloma (SMM). Combining RBAC with curcumin improved the neutrophil count of eight out of 10 MGUS/SMM patients after six months. In another case series by Tsunekawa (2004) with 16 cancer patients who had recently completed oncological treatment, the proportion of patients who had increased, unchanged, and decreased neutrophil categorisation after six months of RBAC treatment were 5/16, 5/16, and 6/16, respectively. Hence, RBAC appeared to maintain or increase the neutrophil count 10/16 of these patients. Many cancer patients develop neutropenia due to chemotherapy, thus increasing the risk of infection (Lustberg, 2012). Hence, the findings of this interim analysis are consistent with these earlier reports. RBAC’s immunomodulatory effect appeared to help maintain adequate neutrophil count in cancer patients during and after treatment.
TP measures the concentration of proteins dissolved in the plasma, which consists mainly of albumins and globulins (Rahman & Begum, 2005). Older cancer patients, those with gastrointestinal cancer, and malnutrition were found to be significantly associated with hypoproteinemia (Enkobahry et al., 2023). As a marker for protein-energy malnutrition, TP has been found to correlate well with nutritional screening based on the subjective global assessment tool in cancer patients (Enkobahry et al., 2023). The current analysis found that the participants’ TP strongly correlated with their WBC level (r = 0.539), and a moderate correlation with their QoL scores (r = 0.338) was also detected. The RBAC group demonstrated better QoL at weeks 6 and 12 of active treatment than the placebo group, coinciding with their higher TP and WBC. These preliminary findings support that RBAC could improve QoL via the immuno-nutrition pathway by interacting with the immune system and nutritional status. However, the lower TP levels in the placebo group may also result from the overrepresentation of colorectal cancer patients with an increased risk of malnutrition (Lewandowska et al., 2022). Therefore, further validation in the final analysis with a larger sample size and a more balanced group is needed.
Physical activity is recommended for all cancer patients at all stages of their treatment (Misiąg et al., 2022), and many oncologists routinely advise patients to be physically active (Hardcastle et al., 2018). The pattern of changing physical activity levels among the participants in this analysis is intriguing, albeit not directly related to the study objectives. The inverted V curve (
Figure 4) depicted a scenario in which the generally sedentary participants at baseline complied with the advice and were more physically active during the treatment. However, they appeared to be lowering their physical activity level near the end of the treatment. Such behaviour warrants further investigation to inform the design of interventional exercise programmes as supportive care for cancer patients during and after treatment to improve outcomes and QoL.