Measuring endometrial thickness (ET) with transvaginal ultrasound (TVU) and endometrial sampling with cytological examination have been proposed as possible screening modalities for endometrial cancer. The Papanicolaou (Pap) test, used successfully for screening for cervical cancer, is too insensitive to be used as a screening technique for the detection of endometrial cancer, although occasionally the Pap test may fortuitously identify endometrial abnormalities, such as endometrial cancer.
Routine screening of asymptomatic women for endometrial cancer has not been evaluated for its impact on endometrial cancer mortality.[2,3] Although high-risk groups can be identified, the benefit of screening in reducing endometrial cancer mortality in these high-risk groups has not been evaluated. Using the same cutoffs to define an abnormal ET in asymptomatic women  as used in symptomatic women  would result in large numbers of false-positive test results and larger numbers of unnecessary referrals for cytological evaluations. Published recommendations for screening certain groups of women at high risk for endometrial carcinoma are based on opinion regarding presumptive benefit.
Cervical cancer is a disease in which malignant (cancer) cells form in the cervix.
The cervix is the lower, narrow end of the uterus (the hollow, pear-shaped organ where a fetus grows). The cervix connects the uterus to the vagina (birth canal).
Anatomy of the female reproductive system. The organs in the female reproductive system include the uterus, ovaries, fallopian tubes, cervix, and vagina. The uterus has a muscular outer layer called the myometrium and an inner lining called...
TVU is used as a diagnostic tool to evaluate symptomatic women with vaginal bleeding. Among women with postmenopausal uterine bleeding and cancer, 96% will have an abnormal ET (>6 mm). The specificity varies by whether women used hormone therapy. Among nonusers, the specificity was 92%. Much less work has been done to evaluate the accuracy of TVU among asymptomatic women. If the same endometrial thickness cutoff is used among asymptomatic women, the false positives will be extremely high, resulting in a very low positive predictive value. No studies have evaluated the efficacy of screening with TVU in reducing mortality from endometrial cancer.
A group of researchers used dilation and curettage (D&C) as a gold standard, to evaluate TVU measurement of ET as a predictor of endometrial cancer in women reporting postmenopausal bleeding (estrogen-progestin therapy [hormone therapy] and nonhormone therapy users). Of the 339 participants, 39 (11.5%) were diagnosed with endometrial cancer (four had an ET of 5–7 mm and 35 had an ET > 8 mm) based on histopathology from curettage. No cancers were detected in women with an ET of less than 4 mm. Using a cutoff point of 4 mm, TVU has 100% sensitivity and 60% specificity. In this population, 46% (156) of the women had an ET greater than 4 mm.
Ultrasonography in women without vaginal bleeding
A comparison of TVU and endometrial aspiration was conducted among asymptomatic postmenopausal women potentially eligible for an osteoporosis prevention trial  as part of determination of eligibility for randomization. TVU was performed on 1,926 women. Of these, 93 women had ET greater than 6 mm. Among the 93 women with abnormal ET, 42 had endometrial aspiration with one finding of abnormal pathology (defined as adenocarcinoma or atypical hyperplasia). Of the 1,833 women with ET measuring 6 mm or less, 1,750 women had endometrial aspiration and five of these women had an abnormal pathologic biopsy. Among this population of asymptomatic postmenopausal women, the estimated sensitivity for TVU with a threshold value of 6 mm was 17% and 33% for a threshold value of 5 mm.