Effect of vitamin D supplementation on the pathological complete response to neoadjuvant chemotherapy in women with breast cancer: a randomized clinical trial

Resumo

Objective: The objective of this study was 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).
Methodology: A randomized clinical trial was conducted on 80 women aged ≥45 years with a histological diagnosis of
BC, who were eligible for NCT. Women were randomized to one of two groups that received either daily supplementation
with 2,000 IU of cholecalciferol (VD, n=40) or placebo (n=40) during the chemotherapy period (6 months). The primary
outcome measure was pCR. Serum 25-hydroxyvitamin-D [25(OH)D] was measured at two time points, after BC diagnosis and at the end of chemotherapy. Clinical, anatomopathological, immunohistochemical, and chemotherapy data were
collected. A per-protocol analysis was performed using Student’s t-test, χ2
test, ANOVA, and logistic regression (OR, odds
ratio). Study registration: RBR-10k4gqdg. Results: Out of the 80 randomized women, 75 completed chemotherapy and
underwent surgery. Mean baseline 25(OH)D values indicated hypovitaminosis D in both groups (VD group: 19.6±5.8 ng/mL
and placebo: 21.0±7.9 ng/mL, p=0.331). After 6 months of intervention, there was a significant increase in 25(OH)D values
in the VD group compared with the placebo (28.0±8.7 vs. 20.2±6.1 ng/mL, p=0.032). The pCR rate was higher in women
supplemented with VD when compared with the placebo (55.3% vs. 32.4%, p=0.046). In logistic regression analysis adjusted for variables that interfere with pCR (anatomopathological, immunohistochemical, and chemotherapy regimens),
women with 25(OH)D values ≥20 ng/mL were more likely to achieve pCR than women with VD deficiency (OR 0.10,
95%CI 0.02–0.61, p=0.013). Conclusion: In this study, women with BC undergoing NCT and receiving supplementation
with 2,000 IU of VD had a higher pCR rate than women in the placebo group. Women with 25(OH)D values >20 ng/mL
were more likely to achieve a pCR than women with VD deficiency. Our results support the evidence that serum VD levels
should be assessed during NCT and supplementation may be beneficial for attaining pCR in women with BC. Further studies are needed to validate these results because confirmation of this finding is of direct clinical relevance and has possible therapeutic implications.