Estrogen replacement therapy tied to lower risk of gastric, colorectal cancers

The use of estrogen replacement therapy appears to yield a risk-lowering effect on gastric and colorectal cancers, as reported in a retrospective study.

Researchers used data from the National Health Insurance Service–National Sample Cohort 2.0 in South Korea (2002–2015). They examined the medical records of 196,095 women aged ≥40 years, of which 19,063 (9.7 percent) used menopausal hormone therapy and 177,032 (90.3 percent) did not.

The associations were analysed using a time-dependent Cox proportional hazards model, with age as a time scale. Other factors, including income levels based on insurance premiums, region of residence, and comorbidities, were included in the analysis as potential confounders.

There were 1,339 (0.68 percent) incident cases of gastric cancer and 1,428 (0.73 percent) incident cases of colorectal cancer. The risk of both types of cancer appeared to be lower among users of estrogen replacement therapy (estrogen-containing therapy regardless of other regimen types), with the corresponding hazard ratios of 0.68 (95 percent confidence interval [CI], 0.51–0.90) for gastric cancer and 0.57 (95 percent CI, 0.42–0.78) for colorectal cancer, and 0.63 (95 percent CI, 0.51–0.77) for gastrointestinal cancer.

Menopausal hormone therapy has been associated with a reduced risk of gastric and colorectal cancers, and the present data provide support for the protective role of estrogen in both types of cancer in Asians.