Dataset Information

Breast cancer survival and season of surgery: an ecological open cohort study.

ABSTRACT: Background Vitamin D has been suggested to influence the incidence and prognosis of breast cancer, and studies have found better overall survival (OS) after diagnosis for breast cancer in summer-autumn, where the vitamin D level are expected to be highest. Objective To compare the prognostic outcome for early breast cancer patients operated at different seasons of the year. Design Open population-based cohort study. Setting Danish women operated 1978-2010. Cases 79?658 adjusted for age at surgery, period of surgery, tumour size, axillary lymph node status and hormone receptor status. Statistical analysis The association between OS and season of surgery was analysed by Cox proportional hazards regression models, at survival periods 0-1, 0-2, 0-5 and 0-10 years after surgery. A two-sided p value <0.05 was considered statistical significant. Results Only after adjustment for prognostic factors that may be influenced by vitamin D, 1-year survival was close to significantly associated season of surgery. 2, 5 and 10 years after surgery, the association between OS and season of surgery was not significant. Limitations Season is a surrogate measure of vitamin D. Conclusions The authors found no evidence of a seasonal variation in the survival after surgery for early breast cancer. Lack of seasonal variation in this study does not necessarily mean that vitamin D is of no importance for the outcome for breast cancer patients.

SUBMITTER: Teilum D

PROVIDER: S-EPMC3253416 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Breast cancer survival and season of surgery: an ecological open cohort study.

Teilum Dorthe D Bjerre Karsten D KD Tjønneland Anne M AM Kroman Niels N

BMJ open 20120105

Background Vitamin D has been suggested to influence the incidence and prognosis of breast cancer, and studies have found better overall survival (OS) after diagnosis for breast cancer in summer-autumn, where the vitamin D level are expected to be highest. Objective To compare the prognostic outcome for early breast cancer patients operated at different seasons of the year. Design Open population-based cohort study. Setting Danish women operated 1978-2010. Cases 79 658 adjusted for age at su ...[more]

PMID: 22223841

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Project description:BackgroundThe aim of this study was to examine breast density in relation to breast cancer specific survival and to assess if this potential association was modified by mode of detection. An additional aim was to study whether the established association between mode of detection and survival is modified by breast density.MethodsThe study included 619 cases from a prospective cohort, The Malmö Diet and Cancer Study. Breast density estimated qualitatively, was analyzed in relation to breast cancer death, in non-symptomatic and symptomatic women, using Cox regression calculating hazard ratios (HR) with 95% confidence intervals. Adjustments were made in several steps for; diagnostic age, tumour size, axillary lymph node involvement, grade, hormone receptor status, body mass index (baseline), diagnostic period, use of hormone replacement therapy at diagnosis and mode of detection. Detection mode in relation to survival was analyzed stratified for breast density. Differences in HR following different adjustments were analyzed by Freedmans%.ResultsAfter adjustment for age and other prognostic factors, women with dense, as compared to fatty breasts, had an increased risk of breast cancer death, HR 2.56:1.07-6.11, with a statistically significant trend over density categories, p = 0.04. In the stratified analysis, the effect was less pronounced in non-symptomatic women, HR 2.04:0.49-8.49 as compared to symptomatic, HR 3.40:1.06-10.90. In the unadjusted model, symptomatic women had a higher risk of breast cancer death, regardless of breast density. Analyzed by Freedmans%, age, tumour size, lymph nodes, grade, diagnostic period, ER and PgR explained 55.5% of the observed differences in mortality between non-symptomatic and symptomatic cases. Additional adjustment for breast density caused only a minor change.ConclusionsHigh breast density at diagnosis may be associated with decreased breast cancer survival. This association appears to be stronger in women with symptomatic cancers but breast density could not explain differences in survival according to detection mode.

Dataset Information

Breast cancer survival and season of surgery: an ecological open cohort study.

Publications

Breast cancer survival and season of surgery: an ecological open cohort study.

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