Enter Your Email Address to Receive a
Copy of MedicExhange Member Demograhpics

NEW YORK (Reuters Health) - Involution of breast lobules as women age appears to be associated with a reduced risk of breast cancer, researchers report in the November 15th issue of Journal of the National Cancer Institute.

"Involution is a natural process whereby the milk-forming lobules are shut down when they're no longer necessary," co-investigator Dr. Lynn C. Hartmann told Reuters Health. "If we can understand how to promote the process, we have a powerful, natural means of reducing risk."

Dr. Hartmann of the Mayo Clinic College of Medicine, Rochester, Minnesota and colleagues came to this conclusion after examining breast biopsy samples taken over a period of 25 years from 8736 women with benign breast disease.

In all, 18.6% of women showed no involution, 59.5% showed partial involution and the remaining 21.9% showed complete involution. Involution was positively associated with older age and inversely associated with parity.

Comparison with a demographically similar cohort of women in Iowa yielded a 1.40 relative risk of cancer in the Mayo Clinic group. The relative risk ranged from 1.88 for those with no involution to 0.91 for those with complete involution.

Moreover, this relationship remained even in high-risk subsets defined by age, atypia, reproductive history or family history.

In addition, apart from the possible benefits of promotion of involution, concluded Dr. Hartmann, "it is quite simple to evaluate the extent of involution in a woman's breast biopsy -- this information can help us to gauge a woman's risk for a later breast cancer."

J Natl Cancer Inst 2006;98:1600-1607.