WHI database: increased ca rates seen in women with infertility Hx; Ovarian, endometrial, and breast cancer.(News)

EDMONTON, ALTA. -- Women with at least a 1-year history of infertility appear to be at significantly elevated risk of developing hormonal cancers, according to data extracted from the Women's Health Initiative database of nearly 162,000 subjects.

Participants reporting a history of infertility were nearly 40% more likely to be diagnosed with ovarian cancer, nearly 20% more likely to have endometrial cancer, and about 14% more likely than other women in the Women's Health Initiative (WHI) to have breast cancer, Dr. Rahi Victory reported at the annual meeting of the Society of Obstetricians and Gynaecologists of Canada.

The 26,148 women who said they spent at least a year trying, unsuccessfully, to become pregnant also had an increased overall cancer risk. (See table on next page.)

To minimize the chance that the findings were coincidental, Dr. Victory and his associates at Wayne State University, Detroit, set a high statistical bar for determining significance: P

No significant relationship was found between prior infertility and cancer of the colon, bladder, or cervix.

Dr. Victory noted that questions have long been raised about the potential link between infertility and certain health outcomes, including polycystic ovarian syndrome, diabetes, cardiovascular disease, and endometrial cancer. Whether infertility itself or medications used to treat the condition may contribute to cancer risk is not clear; most major studies on the issue have been hampered by small sample sizes or limited to specific subgroups or conditions. For example, an elevated risk of ovarian cancer among women with idiopathic infertility has been reported (Best Pract. Res. Clin. Obstet. Gynaecol. 17[2]:343-67, 2003).

The WHI database offers a much larger look at the epidemiologic question, although it does not have sufficient data on infertility-related diagnoses to clarify the potential reasons for elevated risk. He noted that it is impossible from the data to determine whether infertility placed women at risk--through hormonal or inflammatory effects--or whether they received hormones for infertility that increased their chances of developing cancer later.