Prospective Cohort Study Indicates No Association Between Migraine and Breast Cancer Risk
Some data suggest that migraine is associated with reduced risk of breast cancer. In a prospective cohort study reported in the Journal of the National Cancer Institute, Winter et al found no association between migraine and breast cancer risk or endogenous sex hormone levels. A meta-analysis showed a lower risk of breast cancer in women with history of migraine, with the association being limited to case-control studies included in the meta-analysis.
Study Details
The prospective cohort study assessed the association of migraine and breast cancer risk among 115,378 Nurses’ Health Study II participants and differences in endogenous sex hormone levels according to migraine status in 2,034 premenopausal women. A meta-analysis was also performed using five studies investigating the association between migraine and invasive breast cancer risk published through October 2013; the analysis included three prospective cohort studies, including the current study, and two case-control studies.
No Associations
In total, 17,696 women (15.3%) had physician diagnosis of migraine at baseline. Over 20 years of follow-up, 833 in situ and 3,091 invasive breast cancers occurred. On multivariate analysis, migraine was not associated with risk of breast cancer overall (hazard ratio [HR] = 0.96, 95% confidence interval [CI] = 0.88–1.04), in situ breast cancer (HR = 0.97, 95% CI = 0.82–1.15), or invasive breast cancer (HR = 0.95, 95% CI = 0.87–1.04). No significant associations with migraine were observed for risk of estrogen receptor–positive/progesterone receptor–positive (HR = 0.99, P = .88), estrogen receptor–positive/progesterone receptor–negative (HR = 0.78, P = .15), or estrogen receptor–negative/progesterone receptor–negative cancers (HR = 0.93, P = .51) or for ductal cancers (HR = 0.92, P = .11) or lobular cancers (HR = 0.74, P = .10), but increased risk of cancers defined as both ductal and lobular was observed (HR = 1.54, P = .02). There were no differences in endogenous sex hormone levels according to migraine status.
Meta-Analysis
In the meta-analysis, migraine was associated with a lower risk of breast cancer overall (pooled risk ratio [RR] = 0.84, 95% CI = 0.73–0.98), including among the pooled case-control studies (pooled RR = 0.72, 95% CI = 0.66–0.79) but not among the pooled cohort studies (pooled RR = 0.98, 95% CI = 0.87–1.10).
The investigators concluded: “In this large cohort study, migraine was not associated with breast cancer risk or differences in endogenous sex hormone levels. While case-control studies suggest an inverse association between migraine and breast cancer risk, prospective cohort studies do not support an association in pooled analyses.”
Rulla M. Tamimi, ScD, Channing Division of Network Medicine, is the corresponding author for the Journal of the National Cancer Institute article.
The study was supported by the National Institutes of Health, Washington University School of Medicine, Barnes-Jewish Hospital Foundation, and Siteman Cancer Center. For full disclosures of the study authors, visit jnci.oxfordjournals.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
