Study supports link between PCOS, endometrial cancer

Key takeaways:

• Regardless of age, women with PCOS had an increased risk for endometrial cancer.
• Women with PCOS aged 45 years and older had higher risks for endometrial, breast and ovarian cancers vs. younger women with PCOS.

MINNEAPOLIS — Women with vs. without PCOS had a significantly increased risk for endometrial cancer, confirming findings from previous research, according to data presented at the ACOG Annual Clinical & Scientific Meeting.

PCOS did not appear to increase the risk for breast or ovarian cancer, Amani R. Patterson, MBS, BA, a third-year medical student at the University of Texas Medical Branch John Sealy School of Medicine, and colleagues reported.

Patterson and colleagues conducted a retrospective analysis using data from 196,478 women with (n = 98,239) and without PCOS (n = 98,239) from the TriNetX database. The researchers first examined the relative risk for breast, endometrial and ovarian cancer in women with vs. without PCOS. They then stratified women with PCOS by age to compare the risk among those of reproductive age (15 to 44 years) vs. post-reproductive age (45 years and older).

Compared with women without PCOS, Patterson and colleagues observed a significantly higher risk for endometrial cancer (RR = 2.39; 95% CI, 1.95-2.93) and a significantly lower risk for breast cancer (RR = 0.85; 95% CI, 0.74-0.98) among those with PCOS. There was no significant difference in risk for ovarian cancer between women with or without PCOS.

After stratifying women by age, the researchers found that post-reproductive-aged women with PCOS had significantly higher risks for endometrial (RR = 0.42; 95% CI, 0.34-0.53), breast (RR = 0.26; 95% CI, 0.18-0.39) and ovarian (RR = 0.17; 95% CI, 0.13-0.23) cancers compared with reproductive-aged women with PCOS.

“This study is consistent with current literature. It corroborates that women with PCOS may be at increased risk of endometrial cancer,” Patterson said. “Interestingly, women of reproductive age with PCOS are not. We found that they’re not at increased risk of cancers across the board.”

Patterson highlighted several limitations to the study, including the retrospective design and reliance on diagnostic and procedural codes. She further noted that past research is mixed on a link between PCOS and breast cancer. While one study showed a lower breast cancer risk in women with PCOS and infertility, another study found that PCOS may increase the risk for estrogen receptor-positive breast cancer.

“For next steps, my colleagues and I discussed the continued use of TriNetX studies. We think this is a really good start; however, we discussed narrowing the scope to specific types of ovarian cancers or breast cancers, and then propensity matching based on treated PCOS with combined oral contraceptives or any other hormonal modality when it comes to contraception,” Patterson said. “The anovulation component of PCOS is quite known, but in removing that, we could potentially unveil some sort of genetic component.”