Lynch syndrome increases risk for endometrial cancers in women
Study shows association between genetic conditions, hormonal factors and risk of endometrial cancer
For women with Lynch syndrome, an association was found between the risk of endometrial cancer and the age of first menstrual cycle, having given birth and hormonal contraceptive use, according to a study published in JAMA. Lynch syndrome is a genetic condition that increases the risk for various cancers.
Endometrial cancer is the most common type of gynecologic cancer in developed countries, and between 2 and 5 per cent of all cases are associated with a hereditary susceptibility to cancer, mainly Lynch syndrome, which is caused by a germline mutation in one of the DNA mismatch repair (MMR) genes. Depending on the mutated gene, the cumulative risk of developing endometrial cancer by age 70 years for women is thought to be between 15 and 30 per cent. Apart from hysterectomy, there is no consensus recommendation for reducing endometrial cancer risk for women with an MMR gene mutation. Studies in the general population have shown that hormonal factors are also associated with endometrial cancer risk.
For Lynch syndrome, the association between hormonal factors and endometrial cancer risk has not been clear. Aung Ko Win, from the University of Melbourne, and colleagues conducted a study that included 1128 women with an MMR gene mutation identified from the Colon Cancer Family Registry. Participants were recruited between 1997 and 2012 from centres across the USA, Australia, Canada and New Zealand.
Endometrial cancer was diagnosed in 133 women. The researchers found that later age at menarche (first menstrual cycle, age 13 or older), parity (has had one or more live births) and hormonal contraceptive use (for one year or longer) were associated with a lower risk of endometrial cancer. There was no statistically significant association between endometrial cancer and age at first and last live birth, age at menopause and postmenopausal hormone use.
“In this study, an inverse association was observed between the risk of endometrial cancer for women with an MMR gene mutation and later age of menarche, increased parity, and use of hormonal contraceptives. The directions of the observed associations are similar to those that have been reported for the general population, suggesting a possible protective effect of these factors,” wrote the authors.
“If replicated, these findings suggest that women with an MMR gene mutation may be counseled like the general population in regard to hormonal influences on endometrial cancer risk.”
Dashti, S.G., Chau, R., Ouakrim, D.A., et al. (2015) Female hormonal factors and the risk of endometrial cancer in Lynch syndrome. JAMA 314(1), 61. doi: 10.1001/jama.2015.6789