Dataset Information

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival.

ABSTRACT:

Background

Breastfeeding is associated with decreased breast cancer risk, yet associations with prognosis and survival by tumor subtype are largely unknown.

Methods

We conducted a cohort study of 1636 women from two prospective breast cancer cohorts. Intrinsic tumor subtype (luminal A, luminal B, human epidermal growth factor receptor 2 [HER2]-enriched, basal-like) was determined by the PAM50 gene expression assay. Breastfeeding history was obtained from participant questionnaires. Questionnaires and medical record reviews documented 383 recurrences and 290 breast cancer deaths during a median follow-up of nine years. Multinomial logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between breastfeeding and tumor subtype. Cox regression was used to estimate hazard ratios (HRs) for breast cancer recurrence or death. Statistical significance tests were two-sided.

Results

Breast cancer patients with basal-like tumors were less likely to have previously breastfed than those with luminal A tumors (OR = 0.56, 95% CI = 0.39 to 0.80). Among all patients, ever breastfeeding was associated with decreased risk of recurrence (HR = 0.70, 95% CI = 0.53 to 0.93), especially breastfeeding for six months or more (HR = 0.63, 95% CI = 0.46 to 0.87, P trend = .01). Similar associations were observed for breast cancer death. Among women with luminal A subtype, ever breastfeeding was associated with decreased risks of recurrence (HR = 0.52, 95% CI = 0.31 to 0.89) and breast cancer death (HR = 0.52, 95% CI = 0.29 to 0.93), yet no statistically significant associations were observed among the other subtypes. Effects appeared to be limited to tumors with lower expression of proliferation genes.

Conclusions

History of breastfeeding might affect prognosis and survival by establishing a luminal tumor environment with lower proliferative activity.

SUBMITTER: Kwan ML

PROVIDER: S-EPMC4554253 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature

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Publications

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival.

Kwan Marilyn L ML Bernard Philip S PS Kroenke Candyce H CH Factor Rachel E RE Habel Laurel A LA Weltzien Erin K EK Castillo Adrienne A Gunderson Erica P EP Maxfield Kaylynn S KS Stijleman Inge J IJ Langholz Bryan M BM Quesenberry Charles P CP Kushi Lawrence H LH Sweeney Carol C Caan Bette J BJ

Journal of the National Cancer Institute 20150428 7

<h4>Background</h4>Breastfeeding is associated with decreased breast cancer risk, yet associations with prognosis and survival by tumor subtype are largely unknown.<h4>Methods</h4>We conducted a cohort study of 1636 women from two prospective breast cancer cohorts. Intrinsic tumor subtype (luminal A, luminal B, human epidermal growth factor receptor 2 [HER2]-enriched, basal-like) was determined by the PAM50 gene expression assay. Breastfeeding history was obtained from participant questionnaires ...[more]

PMID: 25921910

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Dataset Information

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival.

Background

Methods

Results

Conclusions

Publications

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival.

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