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Journal of Clinical Oncology, 2008 ASCO Annual Meeting Proceedings (Post-Meeting Edition).
Vol 26, No 15S (May 20 Supplement), 2008: 511
© 2008 American Society of Clinical Oncology
Frequency of vitamin D (Vit D) deficiency at breast cancer (BC) diagnosis and association with risk of distant recurrence and death in a prospective cohort study of T1–3, N0–1, M0 B
P. J. Goodwin,
M. Ennis,
K. I. Pritchard,
J. Koo and
N. Hood
Samuel Lunenfeld Research Institute, Toronto, ON, Canada; University of Toronto, Toronto, ON, Canada; Sunnybrook Health Sciences Center, Toronto, ON, Canada; St. Michael's Hospital, Toronto, ON, Canada
511
Background: Vit D acts through a nuclear transcription factor to regulate many aspects of cellular growth and differentiation. Low levels have been associated with increased BC risk. We examined Vit D levels and prognostic effects in an existing BC cohort. Methods: 512 consecutive women with newly diagnosed BC were enrolled at 3 U of Toronto hospitals between 1989 and 1995. A blood specimen obtained at diagnosis was stored at –80°C. The Block questionnaire was used to measure diet intake. Clinical and pathology data were obtained from medical and pathology records. 25-OH Vit D was measured by radioimmunoassay. Women were followed prospectively to 2006. Results: Mean age was 50.4±9.7 yrs. 288 women had T1 tumors, 164 T2 and 24 T3/4. 356 tumors were N0. 342 were estrogen receptor (ER) positive. 73 tumors were grade 1, 202 grade 2 and 173 grade 3. 199 women received adjuvant chemotherapy (CXT) and 200 received tamoxifen. 116 women (22.7%) had distant recurrences and 106 (20.7%) died during a median follow-up of 11.6 yrs. Mean 25-OH Vit D was 58.1±23.4 nmol/L. Vit D levels were deficient (<50 nmol/L) in 192 (37.5%), insufficient (50–72 nmol/L) in 197 (38.5%) and adequate (>72 nmol/L) in 123 (24.0%). Low Vit D levels were associated with premenopausal status, high body mass index (BMI), high insulin and high tumor grade (all p 0.03). Low Vit D levels were associated with low dietary intake of retinol, Vitamin E, grains and alcohol (all p<0.02). Vit D was marginally lower when drawn in winter (Oct-Mar) vs summer (Apr-Sept) months (56.7 vs 59.5 nmol/L, p=0.07). Distant disease-free survival (DDFS) was significantly worse in women with deficient (vs adequate) Vit D levels (HR 1.94, 95% CI 1.16–3.24, p=0.02) as was overall survival (OS) (HR 1.73, 95% CI 1.05–2.86, p=0.02). Vit D associations with DDFS were independent of age, BMI, insulin, T and N stage, ER and grade (all HR  1.55 Q1 vs Q4, all p 0.04); they were not significantly modified by ER, adjuvant CXT or tamoxifen. Vit D associations with OS were attenuated by grade and were absent in ER negative BC. Conclusions: Vit D deficiency is common at BC diagnosis and is associated with poor prognosis. This research was funded by the Breast Cancer Research Foundation.
No significant financial relationships to disclose.
Abstract presentation from the 2008 ASCO Annual Meeting
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