Summary:
Breast cancer is one of the most common cancers affecting women and represents a major cause of cancer-related morbidity and mortality. It is typically treated with a combination of surgery, chemotherapy, radiotherapy, and hormonal therapy. Vitamin D is a fat-soluble vitamin involved in calcium regulation and also plays a role in cell growth, immune function, and inflammation. It acts through the vitamin D receptor, which is present in many tissues including breast tissue. Low vitamin D levels are common in people with cancer and have been associated in some studies with poorer outcomes, although evidence is still evolving. This study is a randomised clinical trial that examined whether vitamin D supplementation influences treatment response in women with breast cancer undergoing chemotherapy. Eighty women aged 45 and older were included and randomly assigned to receive either daily vitamin D (2,000 IU) or a placebo for six months during chemotherapy. Serum vitamin D levels were measured at diagnosis and after treatment. Most participants had low vitamin D levels at the start of the study. After six months, vitamin D levels increased in the supplementation group compared with the placebo group. A higher proportion of women in the vitamin D group achieved a complete pathological response following chemotherapy, which means there was no detectable cancer remaining in tissue samples after treatment. Overall, the findings suggest that vitamin D supplementation during chemotherapy may be associated with improved treatment response in women with breast cancer. However, further research is needed to confirm these results and better understand the underlying mechanisms.
Abstract:
This study aimed to evaluate the effect of vitamin D (VD) supplementation on the pathological complete response (pCR) rate in women with breast cancer (BC) undergoing neoadjuvant chemotherapy (NCT). A randomized clinical trial was conducted with 80 women aged ≥45years with BC who were eligible for NCT. Women were randomized into two groups: VD group, daily supplementation with 2,000IU of cholecalciferol (n = 40) or placebo (n = 40), for 6 months. The primary outcome measure was the pCR rate. Serum 25-hydroxyvitamin-D [25(OH)D] levels were measured after BC diagnosis and the end of NCT. Of the 80 randomized women, 75 completed the NCT and underwent surgery. Baseline 25(OH)D values indicated hypovitaminosis D in both groups (VD: 19.6 ± 5.8 ng/mL and placebo: 21 ± 7.9 ng/mL, p = 0.33). After 6 months, 25(OH)D levels increased in the VD group compared to the placebo group (28 ± 8.7 vs. 20.2 ± 6.1 ng/mL, p = 0.03). The pCR rate was higher in women supplemented with VD when compared than the placebo (43% vs. 24%, p = 0.04). Adjusted logistic regression showed that women with 25(OH)D levels ≥20ng/mL were more likely to achieve pCR (OR3.65, 95%CI 1.09-12.8, p = 0.04). Women with BC undergoing NCT who received supplementation with 2,000IU of VD were more likely to achieve a pathological complete response than women in the placebo group.
Article Publication Date: 17/03/2025
DOI: 10.1080/01635581.2025.2480854
