Tubal ligation and incidence of 26 site-specific cancers in the Million Women Study

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British Journal of Cancer - Tubal ligation and incidence of 26 site-specific cancers in the Million Women Study

 There were no significant associations between tubal ligation and risk of cancers at the other sites, including cancers of the endometrium, cervix, breast and colorectum.

 We believe that this is the first study to report that tubal ligation is associated with a significant reduction in risk of fallopian tube cancer (Riska et al, 2007; Vicus et al, 2010).

 The large size of the cohort, the individual information on possible confounding factors, and the complete and long follow-up, provided reliable estimates of risks associated with tubal ligation for 26 specific cancer sites, even relatively uncommon ones. We found no association between tubal ligation and the risk of cancers of the endometrium, breast, or cervix. By contrast, tubal ligation is associated with a clear reduction in risk of ovarian cancer, a reduction of similar magnitude of peritoneal cancer, and a reduction of fallopian tube cancer. That tubal ligation is associated with a reduced risk of cancers of the ovary, peritoneum and fallopian tube, but not of other hormonally-related cancers, is consistent with the hypothesis that many of the cancers at these sites have a shared origin in the fallopian tube, and that tubal ligation reduces cancer risk by acting as a barrier to cells, carcinogens or other agents reaching the ovary and peritoneal cavity, rather than by affecting hormone levels.