Reproductive factors and risk of pancreatic cancer in women: a review of the literature.

PURPOSE: Pancreatic cancer (PCA) is the fourth leading cause of cancer death in the United States. The male-to-female incidence and mortality ratio of PCA is 1.1-2.0. One possible explanation for this difference is that female hormone exposure is protective for the development of PCA. Several hypotheses were investigated in this systematic review: (1) increased exposure to estrogen through early menarche and later menopause is associated with a decreased risk of PCA; (2) increased exposure to pregnancy is associated with decreased risk of PCA; and (3) increased exposure to oral contraceptives and/or hormone replacement therapy is associated with decreased risk of PCA.

METHODS: Of 371 articles identified, 10 case-control and 5 cohort studies met the criteria for our review. Odds ratios for case-control studies and hazard ratios for cohort studies and their accompanying 95% confidence intervals for analyses relevant to our hypotheses were considered in the review.

RESULTS: For all 3 hypotheses, studies displayed inconsistent results, and this may have been due to the diversity of study populations, exposure quantification, analysis approach, confounding and other limitations, and biases across studies.

CONCLUSIONS: As there was no strong support for any of the 3 hypotheses, it appears that reproductive factors are not associated with the development of PCA in women.