Vitamin D Deficiency is Common at Breast Cancer Diagnosis and is Associated with a Significantly Higher Risk of Distant Recurrence and Death in a Prospective Cohort Study of T1-3, N0-1, M0 Breast Cancer Goodwin, Pamela J.; Ennis, Marguerite; Pritchard, Kathleen I.; Koo, Jarley; Hood, Nicky Samuel Lunenfeld Research Institute at Mount Sinai Hospital, Sunnybrook Health Sciences Center and St. Michael’s Hospital, University of Toronto I would like to thank the ASCO organizers for allowing me to present our data on vitamin D deficiency in early stage breast cancer. I am presenting this work on behalf of my co-authors at the University of Toronto. I would also like to acknowledge the funding provided by the Breast Cancer research Foundation. Funded by the Breast Cancer Research Foundation

Vitamin D Deficiency in Breast Cancer Metabolism Vitamin D is absorbed in the gut from from dietary sources and supplements. Sun exposure leads to the formation of vitamin D in skin – the amount formed is dependent on latitude, age, skin color and gender. When extensive sun exposure occurs, excess vitamin D is degraded without entering the circulation. Vitamin D circulates protein bound and is converted in the liver to 25-hydroxyvitamin D – this form is inactive but blood levels reflect body stores – it is the form we have measured in this study. 25-hydroxyvitamin D is activated in the kidneys to 1,25-dihydroxyvitamin D – this circulates in an endocrine fashion and is responsible for many effects of vitamin D, including calcium homeostasis and bone formation. Recently, it has been found that many tissues, including the breast, are able to activate 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D in an autocrine or paracrine fashion. Ingraham B et al. Curr Med Res Opin 2006

Vitamin D Deficiency in Breast Cancer Objectives In a cohort of women with newly diagnosed breast cancer: To determine the frequency of vitamin D deficiency To identify factors (patient, tumor) associated with vitamin D deficiency To determine associations of vitamin D deficiency with distant disease-free survival and overall survival To explore factors (patient, tumor) that modify the association of vitamin D with distant disease-free survival and overall survival Our objectives in a cohort of women with newly diagnosed locoregional breast cancer were: To determine the frequency of vitamin D deficiency. To identify patient and tumor related factors associated with vitamin D deficiency. To determine associations of vitamin D deficiency with distant disease-free survival and overall survival. To explore patient and tumor factors that modified the prognostic associations of vitamin D.

Vitamin D Deficiency in Breast Cancer Locoregional Breast Cancer T1-3, N0-1, M0 Dx 1989 to 1996 (Toronto - latitude 43 40) n = 512 women, mean age 50.1 years Blood: frozen at -80C * Diet, Physical Activity, Clinical Data Systemic Treatment (if any) We conducted this research in an existing cohort of 512 early stage breast cancer patients diagnosed in Toronto between 1989 and 1996 – the latitude in Toronto is 43 40. Women underwent surgery and, prior to systemic therapy, provided blood which was frozen at -80C. Blood was drawn an average of 8 weeks postoeratively. Women completed the Block Food Frequency Questionnaire, a Physical Activity Questionnaire and provided information on risk factors and clinical history. They were followed annually to 2007 for a median of 11.6 years for distant recurrence and death. In 2007, the frozen blood specimens were analyzed for 25-hydroxyvitamin D using a radioimmunoassay. Annual Follow-up to 2007 distant recurrence death Mean 11.6 years * Analysed for 25-OH vitamin D in 2007 (RIA Diasorin – Stillwater, Minnesota)

Vitamin D Deficiency in Breast Cancer 25-OH Vitamin D Levels at Diagnosis (Toronto – latitude 43 40) Mean: 58.1 ± 23.4 nmol/L Range: 8-177 nmol/L nmol/L ng/ml # % Deficient < 50 < 20 192 37.5 Insufficient 50-72 20-29 197 38.5 Sufficient > 72-374 30-150 123 24.0 Toxic > 374 >150 Mean vitamin D level at diagnosis was 58 nmol/L with a range of 8-177. On this slide, I have provided standard definitions of vitamin D deficiency in two units – nmol/L and ng/ml – I will use nmol/L in this presentation. Overall 37.5% of our newly diagnosed breast cancer cases had deficient levels of vitamin D, 38.5% had insufficient levels and 24% had sufficient levels.

Vitamin D Deficiency in Breast Cancer Tumor and Treatment Related Factors Associated with Vitamin D Factor # Vitamin D (nmol/L) p-value Type of Surgery Mastectomy Lumpectomy 116 396 54.5 59.1 0.07 Tumor Stage 1 2 3 288 164 24 59.2 56.9 53.7 0.53 Nodal Involvement None ≥ 1 342 98 58.7 56.7 0.41 Tumor Grade 77 212 180 63.4 58.8 55.0 0.03 Estrogen Receptor Positive Negative 57.9 58.3 0.90 Adjuvant CXT No Yes 313 199 60.1 54.9 0.02 Adjuvant Hormone 312 200 57.2 59.5 0.25 Women who had higher grade tumors had significantly lower vitamin D levels than those with lower grade tumors –women who ultimately received adjuvant chemotherapy also had significantly lower vitamin D levels that those who did not receive adjuvant chemotherapy – this was explained, at least in part, by the younger age and higher tumor grade of women who received chemotherapy.

Vitamin D Deficiency in Breast Cancer Distant Disease-Free Survival Proportion distant disease free Years since diagnosis 2 4 6 8 10 12 0.0 0.2 0.4 0.6 0.8 1.0 Deficient Insufficient Sufficient p=0.02 Women with sufficient levels of vitamin D had significantly better distant disease-free survival than women with deficient levels. Those with insufficient levels had intermediate outcomes. Women with deficient vitamin D had a hazard ratio for distant recurrence of 1.94 compared to women with sufficient vitamin D. There as a 14% absolute difference in 10-year survival rates in women with deficient versus sufficient levels of vitamin D. Deficient < 50 nmol/L Insufficient ≥ 50-72 nmol/L Sufficient > 72 nmol/L HR (95% CI) 1.94 (1.16-3.25) 1.37 (0.80-2.33) 1.0 5 year 82% 85% 88% 10 Year 69% 79% 83%

Vitamin D Deficiency in Breast Cancer Overall Survival Years since diagnosis Proportion survived 2 4 6 8 10 12 0.0 0.2 0.4 0.6 0.8 1.0 Deficient Insufficient Sufficient p=0.02 Turning to overall survival, women with deficient vitamin D had significantly worse survival than women with insufficient or sufficient levels of vitamin D. The overall survival of the latter two groups was similar. The hazard ratio for death in women with deficient, as compared to sufficient, vitamin D was 1.73 – 10-year survival rates are shown on the slide – they were 11% lower in women with deficient vitamin D. Deficient < 50 nmol/L Insufficient ≥ 50-72 nmol/L Sufficient > 72 nmol/L HR (95% CI) 1.73 (1.05-2.86) 1.01 (0.59-1.73) 1.0 5 year 87% 93% 92% 10 Year 74% 85%

Vitamin D Deficiency in Breast Cancer Overall Survival Smoothed Log Hazard 25-Hydroxyvitamin D (nmol/L) Log hazard of death 50 100 150 -1 1 2 Because we saw no survival difference between women with insufficient or sufficient levels of vitamin D, we modelled a smoothed log hazard of death across the observed range of vitamin D levels. The solid yellow line represents the point estimate of the log hazard and the dotted lines represent 95% confidence intervals. The log hazard is curvilinear with the lowest hazard being seen in women with vitamin D levels in the range of 80 to 110 – there is a non-significant trend towards increasing risk of death in women with vitamin D levels above 110. A similar pattern at similar levels of vitamin D has been reported by Wang et al. for risk of cardiac events and a recent review by Bischoff-Ferrari et al found a similar range was optimal for general health outcomes including fracture prevention, lower extremity strength, periodontal disease and possibly colorectal cancer risk.

Vitamin D Deficiency in Breast Cancer Conclusions Vitamin D deficiency/insufficiency was common at breast cancer diagnosis. Only 24% had levels considered sufficient. Vitamin D deficiency was associated with higher grade tumors. Vitamin D deficiency was associated with an increased risk of distant recurrence and death. Replication is recommended; an RCT of vitamin D supplementation may be indicated if results are replicated. Caution is recommended in applying these results in the clinical situation – it is premature to advise breast cancer patients to use vitamin D supplementation in doses higher than recommended for bone health. Consideration should be given to measuring vitamin D levels in blood to ensure they are in a healthy range. In conclusion, vitamin D deficiency or insufficiency was common at breast cancer diagnosis. Vitamin D deficiency was associated with higher grade tumors and a significantly increased risk of distant recurrence and death. We recommend that this association be examined in additional observational studies. Ifour results are replicated, a randomized adjuvant trial may be indicated to address the potential benefits of administering vitamin D after breast cancer diagnosis. Prior to initiating such a trial, surveys are needed of women currently diagnosed with breast cancer to confirm that vitamin D deficiency/insufficiency remains a problem in the current era when vitamin D supplementation is more commonly used. Finally, caution is recommended in applying these results in the clinical situation. I believe it is premature to advise breast cancer patients to use vitamin D supplementation in doses higher than those recommended for bone health in the hopes of improving their breast cancer outcomes. Consideration should be given to measuring vitamin D levels in women with breast cancer to ensure they are in a healthy range (ie: 80 to 110 nmol/L or 32-44 ng/ml)), particularly if women are considering taking high doses of vitamin D. If measurement of blood levels is not possible, I would recommend doses of 400 to 800 IU per day. I would be happy to review the data that are available to support this recommendation in the question period.

! VITAMIN D ! Natural History of the Disease ASCO 2008 Take Home Messages for Clinical Practice ! VITAMIN D ! There is “nothing to lose” in measuring/correcting vitamin D levels at BC diagnosis