From the Guidelines
Estrogen's Impact on Rectal Adenocarcinoma
Estrogen is likely to have a protective effect on rectal adenocarcinoma, with studies suggesting a reduction in risk among women who have used hormone replacement therapy (HRT) [ 1 ].
- The evidence from a meta-analysis of 18 observational studies indicates a 19% reduction in the risk of rectal cancer among women who have ever used HRT [ 1 ].
- This decrease in risk is more pronounced when comparing current users to those who have never used HRT, with a relative risk of 0.66 [ 1 ].
- Key findings from the WHI study and the HERS studies also support the notion that HRT, specifically with conjugated estrogens/medroxyprogesterone acetate (CEE/MPA), may reduce the incidence of colorectal cancer, including rectal adenocarcinoma [ 1 ].
- As a result, patients with rectal adenocarcinoma or those at high risk should discuss their individual risk factors and HRT options with their healthcare provider, considering the benefits and risks of estrogen-based medications.
- Regular screening and surveillance for rectal cancer are crucial for patients with a history of estrogen exposure or those taking estrogen-based medications, to ensure early detection and treatment.
From the Research
Estrogen's Effect on Rectal Adenocarcinoma
- Estrogen has been found to have a protective effect against rectal adenocarcinoma, with studies suggesting that hormone replacement therapy (HRT) is associated with a decreased risk of rectal cancer 2, 3.
- The use of estrogen therapy (ET) and combined estrogen-progestogen therapy (EPT) has been shown to reduce the risk of colorectal cancer, including rectal adenocarcinoma 3.
- Estrogen receptor beta (ERβ) has been identified as a potential target for colorectal cancer prevention, with studies suggesting that activation of ERβ can mediate a protective response against colorectal cancer 4, 5.
- The molecular mechanisms underlying the protective effect of estrogen against rectal adenocarcinoma are not fully understood, but may involve the regulation of gene expression and the suppression of tumor growth 6.
Key Findings
- A case-control study found that ever use of HRT was inversely associated with cancer of the rectum, with an odds ratio (OR) of 0.46 and a 95% confidence interval (CI) of 0.29-0.72 2.
- A meta-analysis found that EPT ever use was associated with a decreased risk of colorectal cancer, with a relative risk (RR) of 0.74 and a 95% CI of 0.68-0.81 3.
- Studies have suggested that estrogen may have a protective effect against rectal adenocarcinoma by reducing the formation of colorectal polyps and promoting apoptosis in preclinical models 4, 5.