Objectives: Exposures during early life may affect risk of breast cancer. History of tonsillectomy has recently been associated with risk of several cancers, including cancer of the breast.
Methods: We conducted a population-based case-control study of women living in Western New York from 1986 to 1991. Cases had incident, primary, pathologically confirmed breast cancer and were recruited through all major hospitals in the region (n = 740). Population-based controls (n = 810) were randomly sampled from among drivers' license holders from Department of Motor Vehicles records (<65 yrs) and from Health Care Finance Administration records (> or =65 yrs). Participants were interviewed with regard to diet, anthropometrics, demographics, medical, and reproductive history. Unconditional logistic regression models stratified by menopausal status were used to estimate multivariate odds ratios (OR) and 95% confidence intervals (95% CI).
Results: A history of tonsillectomy was associated with increased breast cancer risk among premenopausal (OR 1.50, 95% CI: 1.08-2.08) but not postmenopausal women (OR 1.05, 95% CI: 0.79-1.38).
Conclusions: Our findings add to accumulating data implicating tonsillectomy in risk of cancer. Tonsillectomy may be an indicator for conditions of chronic inflammation and/or reduced efficiency of immune function. Our study also provides additional evidence that early life exposures may affect premenopausal breast cancer risk.