Vitamin D supplementation demonstrated potential benefits for oncology patients, mitigating the side effects of chemotherapy (CT) and radiotherapy (RT) while supporting bone health, according to a study published in Nutrients.
Despite the heterogeneity of methodologies across studies, evidence suggested that vitamin D plays a critical role in reducing treatment-associated adverse events, such as
- peripheral neuropathy,
- nausea,
- and fatigue.
In addition, maintaining adequate levels of vitamin D may help preserve bone density, particularly in patients undergoing preoperative chemoradiotherapy.
A systematic review of 758 articles narrowed the final selection to 5 studies that explored vitamin D’s impact in oncologic settings. One study observed that patients with reduced bone density following chemoradiotherapy exhibited shorter metastasis-free survival times (P <.05). Multivariate analysis identified vitamin D deficiency as a risk factor for loss of bone density (P =.04), reinforcing vitamin D’s role in skeletal integrity.
Similarly, another study reported fewer adverse events, including diarrhea, nausea, vomiting, and neutropenia, in patients receiving a vitamin D-enriched target medical nutrition compared with an isocaloric comparator (64 vs 87 events, respectively), suggesting a protective effect on treatment tolerance.
Vitamin D deficiency appeared highly prevalent among oncology patients. An analysis of 706 patients with cancer found that 72% were deficient in vitamin D. Factors contributing to vitamin D deficiency included low sun exposure (odds ratio [OR], 1.4; P =.045) and palliative care status (OR, 1.5; P =.04).
Interestingly, adjuvant treatment initially emerged as a potential risk factor (OR, 2.6; P=.006), though the small P-value suggested limited statistical robustness. These findings emphasize the need for individualized vitamin D interventions to address patient-specific risk factors.
Chemotherapy-induced peripheral neuropathy, a common and often debilitating side effect, may also be influenced by levels of vitamin D. Analysis revealed an inverse association between baseline concentrations of vitamin D and severity of peripheral neuropathy, with vitamin D-deficient patients experiencing more pronounced neuropathic symptoms.
Vitamin D supplementation appeared to be both effective and safe, though careful monitoring is advised. One study found that in patients with breast cancer undergoing adjuvant chemotherapy, high-dose vitamin D supplementation led to normalization of serum 25-OH vitamin D in 47% of cases. While no clinical toxicity was reported, 29.5% of patients developed grade 1 hypercalciuria, necessitating discontinuation in 10 out of 13 affected patients. These results highlight the importance of regular biochemical monitoring to prevent potential adverse effects.
“[F]ew studies were found that directly link [vitamin D] supplementation with the adverse effects of neoadjuvant treatment. Therefore, further studies are needed on this theme, particularly with more diversified samples regarding the age range and incidence of adverse effects associated with adjuvant and neoadjuvant RT and CT treatment of the oncological patient.”
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