Vitamin D deficiency is associated with the inability to reach pathologic complete response (pCR) in patients with breast cancer undergoing neoadjuvant systemic chemotherapy (NAC), and a trend for worse survival was seen in patients with triple negative tumors. Results from an analysis were presented on Thursday, December 7, during a poster session at the San Antonio Breast Cancer Symposium (SABCS).

At the SABCS in 2016, Marie Viala from the Institut Régional du Cancer de Montpellier Val d'Aurelle in Montpellier, France, and colleagues from Wake Forest University School of Medicine in Winston-Salem, NC, and Holden Comprehensive Cancer Center in Iowa City, IA, reported that low serum vitamin D were associated with not attaining pCR following breast cancer NAC; this is a further analysis of the impact on survival.

Vitamin D deficiency was defined as less than 20 ng/ml. pCR was defined as no residual invasive disease in breast and lymph nodes. Survival was defined from the date of diagnosis to the date of relapse or date of death (OR). A total of 327 women were enrolled from two Iowa registries and a French study. Patients presented with human epidermal growth factor receptor 2, hormone receptor positive/HER2-negative and triple negative (TN) tumors in 28.5%, 43.9%, and 27.6% of the cases, respectively. In this expanded cohort, vitamin D deficiency remained associated with the odds of not attaining pCR (OR = 1.64; 95%CI = 1.02–2.66, p = 0.04). During the median follow-up of 5.33 years (range = 0.5–9.5 years), 54 relapses and 52 deaths occurred. Table 1 shows the multivariate outcomes independently associated with a worse survival.

Table 1. Multivariate Outcomes Associated With Worse Survival

	PFS (Hazard Ratio, 95%CI)	p	OS (Hazard Ratio, 95%CI)	p
Stage
I–II	1		1
III	2.78 (1.56–4.95)	0.001	2.82 (1.57–5.05)	0.001
Tumor phenotype
HR+/HER2-	1		1
HER2+	3.00 (1.28 – 7.06)	0.012	1.78 (0.76–4.08)	0.174
TN	7.37 (3.26 – 16.69)	< 0.001	6.50 (3.07–13.76)	< 0.001
NAC response
Non-pCR	1		1
pCR	0.19 (0.08 – 0.45)	< 0.001	0.22 (0.09–0.55)	< 0.001
Vitamin D
< 20 ng/ml	1		1
≥ 20 ng/ml	1.01 (0.57–1.78)	0.97	1.03 (0.58–1.84)	0.92

PFS–progression free survival; OS–overall survival; HR+/HER2-–hormone receptor positive/human epidermal growth factor 2 negative; HER2+–hormone receptor positive/human epidermal growth factor 2 positive; TN–triple negative; NAC–neoadjuvant chemotherapy; pCR–pathologic complete response

The researchers concluded that the “strong association between vitamin D deficiency and the inability to reach pCR warrant further evaluation in the TN subgroup,” and suggested that prospective interventional studies might be warranted to determine if maintaining vitamin D levels during NAC would positively affect outcomes in TN breast cancers.

Topics: