Feasibility of a randomized controlled trial of vitamin D vs. placebo in women with recently diagnosed breast cancer

Association of Serum Level of Vitamin D at Diagnosis With Breast Cancer Survival: A Case-Cohort Analysis in the Pathways Study

Importance

There are long-standing interests in the potential benefits of vitamin D for preventing breast cancer recurrence and mortality, yet data from prospective cohort studies are limited.

Objective

To investigate a serum biomarker of vitamin D status, 25-hydroxyvitamin D (25OHD) measured at the time of breast cancer diagnosis, to determine the association with prognosis.

Design, Setting, and Participants

The Pathways Study is a prospective cohort study of breast cancer survivors established in 2006. Enrollment was completed in 2013; follow-up is ongoing. The cohort was established in Kaiser Permanente Northern California, a large integrated health care delivery system in northern California. Women with a diagnosis of incident invasive breast cancer were typically consented and enrolled within 2 months of diagnosis. The overall enrollment rate was 46% (4505 of 9820). Participants are followed for health outcomes and comorbidities at 12, 24, 48, 72, and 96 months after baseline interview. A case-cohort design was used for efficiency assay of 25OHD, selecting 1666 cohort members with serum samples and ensuring representation in the subcohort of races and clinical subtypes. The data analysis was performed from January 5, 2014, to March 15, 2015.

Main Outcomes and Measures

Primary outcomes are breast cancer recurrence, second primary cancer, and death.

Results

Mean (SD) age was 58.7 (12.4) years. Serum 25OHD concentrations were lower in women with advanced-stage tumors, and the lowest in premenopausal women with triple-negative cancer. Levels were also inversely associated with hazards of disease progression and death. Compared with the lowest tertile, women with the highest tertile of 25OHD levels had superior overall survival (OS). This association remained after adjustment for clinical prognostic factors (hazard ratio [HR], 0.72; 95% CI, 0.54-0.98). Among premenopausal women, the association with OS was stronger, and there were also associations with breast cancer-specific survival and invasive disease-free survival (OS: HR, 0.45; 95% CI, 0.21-0.96; breast cancer-specific survival: HR, 0.37; 95% CI, 0.15-0.93; invasive disease-free survival: HR, 0.58; 95% CI, 0.34-1.01; all after full adjustment).

Conclusions and Relevance

Serum 25OHD levels were independently associated with breast cancer prognostic characteristics and patient prognosis, most prominently among premenopausal women. Our findings from a large, well-characterized prospective cohort provide compelling observational evidence on associations of vitamin D with lower risk of breast cancer morbidity and mortality.

Randomized, blinded trial of vitamin D3 for treating aromatase inhibitor-associated musculoskeletal symptoms (AIMSS)

The purpose of the study was to evaluate the efficacy and safety of vitamin D3 at 4000 IU/day as a treatment option for aromatase inhibitor-associated musculoskeletal symptoms (AIMSS) when compared with the usual care dose of 600 IU D3. We conducted a single site randomized, double-blind, phase 3 clinical trial in women with AIMSS comparing change in symptoms, reproductive hormones and AI pharmacokinetics. Postmenopausal women ≥18 years with stages I-IIIA breast cancer, taking AI and experiencing AIMSS [breast cancer prevention trial symptom scale-musculoskeletal (BCPT-MS) subscale ≥1.5] were admitted. Following randomization, 116 patients had a run-in period of 1 month on 600 IU D3, then began the randomized assignment to either 600 IU D3 (n = 56) or 4000 IU D3 (n = 57) daily for 6 months. The primary endpoint was a change in AIMSS from baseline (after 1 month run-in) on the BCPT-MS (general MS pain, joint pain, muscle stiffness, range for each question: 0 = not at all to 4 = extremely). Groups had no statistically significant differences demographically or clinically. There were no discernable differences between the randomly allocated treatment groups at 6 months in measures of AIMSS, pharmacokinetics of anastrozole and letrozole, serum levels of reproductive hormones, or adverse events. We found no significant changes in AIMSS measures between women who took 4000 IU D3 daily compared with 600 IU D3. The 4000 IU D3 did not adversely affect reproductive hormone levels or the steady state pharmacokinetics of anastrozole or letrozole. In both groups, serum 25(OH)D remained in the recommended range for bone health (≥30 ng/mL) and safety (<50 ng/mL).

Prognostic associations of 25 hydroxy vitamin D in NCIC CTG MA.21, a phase III adjuvant randomized clinical trial of three chemotherapy regimens in high-risk breast cancer

Low vitamin D levels have been associated with poor breast cancer outcomes in observational studies. We examined the association of vitamin D blood levels with relapse-free survival (RFS), breast cancer-specific survival (BCSS), and overall survival (OS) in the MA.21 randomized clinical trial. Fasting blood was collected pre-chemotherapy in 934/2104 (44.4 %) of subjects; 25 hydroxy vitamin D was measured (radioimmunoassay, Diasorin) in one batch. Vitamin D was assessed as a transformed continuous factor, and categorically (quartiles and clinical classifications). Univariate and multivariate prognostic analyses (adjusted for treatment, stratification factors, and baseline imbalances) were performed using Cox models. Most patients were young (median 47.8 years), white (91.6 %) and premenopausal (69.4 %) with grade III (52 %), HER2 negative or missing (89.5 %), ER positive (61.9 %), T1-2 (89.4 %), N + (72.7 %) breast cancer. Compared to the full population, those with vitamin D levels were more likely to be white, PS 1 or 2, to have undergone mastectomy, and to have an ER + tumor. Mean vitamin D was 69.7 nmol/L (27.9 ng/ml) and did not vary by tumor subtype. The majority (80.5 %) had levels >50 nmol/L (20 ng/ml), considered adequate by Institute of Medicine. Continuous vitamin D was not multivariately associated with RFS, BCSS, or OS (p = 0.36, 0.26, 0.33, respectively); categorical vitamin D was also not associated with outcome. Vitamin D associations with RFS did not differ within ER/HER2 subgroups. There was no evidence that vitamin D blood level was associated with RFS, BCSS, and OS in MA.21; the majority of subjects had adequate vitamin D levels at study entry.

Safety, Feasibility, and Biomarker Effects of High-Dose Vitamin D Supplementation Among Women at High Risk for Breast Cancer

Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer prevention. We examined the safety, feasibility, and biomarker effects of high-dose vitamin D among women at high risk for breast cancer. Forty high-risk women, defined as a 5-year breast cancer risk ≥1.67% per the Gail model, lobular or ductal carcinoma in situ, were assigned to a 1-year intervention of vitamin D3 20,000 IU or 30,000 IU weekly. Participants were monitored for toxicity every 3 months, underwent serial blood draws at baseline, 6 and 12 months, and a digital mammogram at baseline and 12 months. Biomarker endpoints included serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D], parathyroid hormone (PTH), insulin-like growth factor (IGF-1), IGF binding protein (IGFBP-3), and mammographic density (MD) using Cumulus software. From November 2007 to January 2011, we enrolled 40 women; 37 were evaluable at 6 months and 30 at 12 months. One patient was taken off study for hypercalciuria; otherwise, the intervention was well tolerated. From baseline to 12 months, mean serum 25(OH)D and 1,25(OH)₂D rose from 20.0 to 46.9 ng/ml and 69.7 to 98.1 pg/ml, respectively (p<0.01). Serum PTH decreased by 12% at 6 months and IGF-1/IGFBP-3 ratio decreased by 4.3% at 12 months (p<0.05). There was no significant change in MD regardless of menopausal status or dose level. We demonstrated that 1 year of high-dose vitamin D3 was associated with a significant increase in circulating vitamin D levels and favorable effects on IGF signaling, but no significant change in MD.

Nutrition and physical activity influence on breast cancer incidence and outcome

INTRODUCTION AND AIMS

To provide a current perspective on nutrition and physical activity influence on breast cancer.

METHODS AND RESULTS

A comprehensive literature review was conducted and selective presentation of findings follows. While some observational studies have associated higher dietary fat intake with higher breast cancer incidence, two full-scale randomized, clinical trials of dietary fat intake reduction programs were negative. However, a lifestyle intervention targeting fat intake reduction in the Women's Intervention Nutrition Study (WINS), resulted in weight loss and also reduced breast cancer recurrences in women with early stage disease. Observational studies evaluating specific nutrient intakes and dietary supplements have provided mixed results. Several observational studies find women with early stage breast cancer with lower 25-hydroxyvitamin D levels at higher recurrence risk, a finding requiring cautious interpretation. The lifestyle factor most strongly and consistently associated with both breast cancer incidence and breast cancer recurrence risk is physical activity. A meta-analyses of observational studies supports the concept that moderate recreational physical activity (about 3-4 h walking per week) may reduce breast cancer incidence and that women with early stage breast cancer who increased or maintain their physical activity may have lower recurrence risk as well. Feasibility of achieving increased physical activity and weight loss in women with early-stage breast cancer has been established. Two full-scale randomized clinical trials are evaluating weight loss/maintenance and increased physical activity in relation to recurrence risk in women with early-stage, resected breast cancer.

DISCUSSION/CONCLUSIONS

Dietary intake may influence breast cancer but influence is difficult to separate from influence of body weight. A consistent body of observational study evidence suggests higher physical activity has favorable influence on breast cancer incidence and outcome. While awaiting definitive evidence from ongoing randomized trials, breast cancer patients can reasonably be counseled to avoid weight gain and reduce body weight if overweight or obese and increase or maintain a moderate level of physical activity.

The role of vitamin D in reducing cancer risk and progression

Vitamin D is not really a vitamin but the precursor to the potent steroid hormone calcitriol, which has widespread actions throughout the body. Calcitriol regulates numerous cellular pathways that could have a role in determining cancer risk and prognosis. Although epidemiological and early clinical trials are inconsistent, and randomized control trials in humans do not yet exist to conclusively support a beneficial role for vitamin D, accumulating results from preclinical and some clinical studies strongly suggest that vitamin D deficiency increases the risk of developing cancer and that avoiding deficiency and adding vitamin D supplements might be an economical and safe way to reduce cancer incidence and improve cancer prognosis and outcome.

Serum 25-hydroxyvitamin D levels and survival in colorectal and breast cancer patients: systematic review and meta-analysis of prospective cohort studies

AIM

To estimate the association between serum 25-hydroxyvitamin D (25(OH)D) levels and survival among colorectal and breast cancer patients.

METHODS

We performed a comprehensive literature search of prospective cohort studies assessing the association of serum 25(OH)D levels with survival in colorectal and breast cancer patients. Study characteristics and results were extracted and dose-response relationships were graphically displayed in a standardised manner. Meta-analyses using random effects models were performed to estimate pooled hazard ratios.

RESULTS

The systematic search yielded five studies including 2330 colorectal cancer patients and five studies including 4413 breast cancer patients all of which compared mortality across two to five categories of 25(OH)D levels. Among colorectal cancer patients, pooled hazard ratios (95% confidence intervals) comparing highest with lowest categories were 0.71 (0.55-0.91) and 0.65 (0.49-0.86) for overall and disease-specific mortality, respectively. For breast cancer patients, the corresponding pooled estimates were 0.62 (0.49-0.78) and 0.58 (0.38-0.84), respectively. No significant evidence of heterogeneity between studies was observed.

CONCLUSION

Higher 25(OH)D levels (>75nmol/L) were associated with significantly reduced mortality in patients with colorectal and breast cancer. Randomised controlled trials are needed to evaluate whether vitamin D supplementation can improve survival in colorectal and breast cancer patients with low vitamin D status (25(OH)D<50nmol/L) at diagnosis and before treatment.

Vitamin d: are we ready to supplement for breast cancer prevention and treatment?

Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer prevention and treatment. Preclinical studies support various antitumor effects of vitamin D in breast cancer. Numerous observational studies have reported an inverse association between vitamin D status, including circulating 25-hydroxyvitamin D (25(OH)D) levels, and breast cancer risk. The relationship between vitamin D and mammographic density, a strong predictor of breast cancer risk, remains unclear. Studies analyzing the link between genetic polymorphisms in vitamin D pathway genes and breast cancer incidence and prognosis have yielded inconsistent results. Vitamin D deficiency among breast cancer patients has been associated with poorer clinical outcomes and increased mortality. Despite a number of clinical trials of vitamin D supplementation, the efficacy, optimal dosage of vitamin D, and target blood level of 25(OH)D for breast cancer prevention have yet to be determined. Even with substantial literature on vitamin D and breast cancer, future studies need to focus on gaining a better understanding of the biologic effects of vitamin D in breast tissue. Despite compelling data from experimental and observational studies, there is still insufficient data from clinical trials to make recommendations for vitamin D supplementation for breast cancer prevention or treatment.