The Role of Endometrial Biopsy in the Preoperative Detection of Uterine Leiomyosarcoma

Study Objective: To assess the sensitivity of preoperative endometrial biopsy in detection of uterine leiomyosarcoma (ULMS). Study Design: Retrospective analysis of a prospectively collected database (Canadian Task Force III). Setting: Two academic tertiary referral centers. Patients: All cases of ULMS treated at participating institutions between January 2005 and August 2012 were identified following IRB approval. Interventions: Abstracted data included demographics, preoperative evaluation, presenting symptom, surgical management, pathology and clinical outcomes. Chi-square tests were used for statistical analysis. Measurements and Main Results: 329 cases were identified, of which 152 cases had complete pathologic data available for review. Sixty-eight (45%) of 152 patients had endometrial sampling prior to surgery. Patients with postmenopausal bleeding were significantly more likely to be biopsied preoperatively (51.6% vs 9.5%, p = <.0001). Of those sampled, 43 (63%) underwent endometrial pipelle biopsies and 25 (37%) had dilation and curettage. Endometrial sampling was significantly more likely to detect a concern for malignancy in patients who presented with postmenopausal bleeding (72.7% vs 32.3%, p = 0.002), however it was less likely to detect malignancy in patients with abnormal premenopausal bleeding (31.8% vs 64.3%, p = .02), compared to other presenting symptoms. Overall, 51.5% of patients with ULMS on final pathology had preoperative endometrial biopsies in which leiomyosarcoma or atypical spindle cell proliferation were diagnosed, whereas 35.5% of the pre-operative biopsies identified ULMS specifically. Conclusions: The sensitivity of an endometrial biopsy to detect ULMS is low, illustrating the difficulty of diagnosing ULMS preoperatively. As expected, the probability that an endometrial biopsy will detect ULMS or a related worrisome pathological finding is higher for patients with post-menopausal bleeding. Thus, benign endometrial biopsy results, particularly in pre-menopausal patients, should be interpreted with caution if there is suspicion for leiomyosarcoma. However, a positive or suspicious result can play an important role in the subsequent management of patients with ULMS, even if the absolute numbers of affected patients are small.