Aspirin, other NSAIDs at standard doses may lower endometrial cancer risk in obese women
Use of standard-dose aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) appears to confer protection against the risk of endometrial cancer in overweight and obese women, according to a meta-analysis.
The findings provide further evidence of the chemopreventive role of aspirin or other NSAIDs in endometrial cancer, the investigators said.
“If confirmed, clinicians could consider [the said drugs] as an option to reduce the greatly increased risk of endometrial cancer among obese women who have an intact uterus,” they added.
The meta-analysis included seven cohort and five case-control studies participating in the Epidemiology of Endometrial Cancer Consortium, with the total population comprising 7,120 women with endometrial cancer and 16,069 controls. These studies provided data on the effect of different analgesics on the risk of endometrial cancer.
Pooled data revealed that using aspirin and nonaspirin NSAIDs at least weekly yielded about a 15-percent reduction in the risk of endometrial cancer in both overweight and obese women. The respective odds ratios (ORs) were 0.86 (95 percent CI, 0.76–0.98) and 0.86 (0.76–0.97) with aspirin (p=0.04 for heterogeneity), and 0.87 (0.76–1.00) and 0.84 (0.74–0.96) with nonaspirin NSAIDs (p=0.003 for heterogeneity). [Ann Oncol 2018;doi:10.1093/annonc/mdy541]
There was no apparent benefit from such drugs in women of normal weight (body mass index <25 kg/m2).
The risk reduction observed with aspirin in overweight and obese women was greatest for 2–6 times/week of use (OR, 0.81; 0.68–0.96) than for daily use (OR, 0.91; 0.80–1.03). This was probably due to a high number of daily users taking low-dose formulations, as the investigators noted.
Meanwhile, acetaminophen showed no association with endometrial cancer risk.
“The results [for aspirin and nonaspirin NSAIDs] did not differ significantly between type 1 and type 2 cancers, although the associations with type 2 cancers were slightly stronger,” the investigators said.
“[Moreover], although the potential risk reduction with aspirin is modest (10–20 percent), if this association is causal and all overweight/obese women used standard-dose aspirin at least once a week, this could translate into up to 4,600 fewer endometrial cancers per year in the US,” they added.
Anti-inflammatory medications are plausibly chemopreventive in endometrial cancer because several risk factors for such cancer type, including obesity, are associated with systemic chronic low-grade inflammation, the investigators explained.
“In vitro studies suggest [that] aspirin and NSAIDs also have antiproliferative and antineoplastic effects that … can inhibit the proliferation of endometrial cancer cells,” they added.
While the present data is consistent with two previous meta-analyses, the investigators highlighted the need for additional research to clarify the relationship between low-dose aspirin and endometrial cancer. [Gynecol Oncol 2016;140:352-358; Int J Gynecol Cancer 2016;26:1111-1120]
Future studies “should include regularly updated measures of medication use (dose, frequency), ideally in a well-powered randomized trial to minimize bias and confounding,” they said.