Endometrial thickness and risk of breast and endometrial carcinomas in the prostate, lung, colorectal and ovarian cancer screening trial

Cancer Prevention Fellowship Program, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Rockville, Maryland
International Journal of Cancer (Impact Factor: 5.09). 02/2014; 134(4). DOI: 10.1002/ijc.28404
Source: PubMed


Postmenopausal women with higher circulating estrogen levels are at increased risk of developing breast and endometrial carcinomas. In the endometrium, excess estrogen relative to progesterone produces a net proliferative stimulus, which may result in endometrial thickening. Therefore, we tested the hypothesis that endometrial thickness is a biological marker of excess estrogen stimulation that is associated with risk of breast and endometrial carcinomas. Endometrial thickness was measured in 1,272 postmenopausal women, aged 55-74, who underwent transvaginal ultrasound (TVU) screening as part of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. Serial endometrial thickness measurements were available for a subset of women at one (n=1,018), two (n=869) and three years (n=641) after baseline. We evaluated associations between endometrial thickness and breast (n=91) and endometrial (n=14) carcinoma by estimating relative risks (RRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression with age as the time metric. Models incorporating baseline endometrial thickness and as a time-varying covariate using all measurements were examined. Median follow-up among study participants was 12.5 years (range: 0.3-13.8 years). Compared to baseline endometrial thickness of 1.0 - 2.99 mm, women with baseline endometrial thickness greater than or equal to 5.0 mm had an increased risk of breast (RR: 2.00, 95% CI 1.15, 3.48) and endometrial (RR: 5.02, 95% CI 0.96, 26.36) carcinomas in models adjusted for menopausal hormone use and BMI. Our data suggest that increased endometrial thickness as assessed by TVU was associated with increased risk of breast and endometrial carcinomas.

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Available from: Ashley S Felix, Apr 25, 2014