Distant Metastases in Uterine Leiomyosarcomas: The Wide Variety of Body Sites and Time Intervals to Metastatic Relapse

Uterine leiomyosarcoma (U-LMS) is the most frequent malignant gynecologic mesenchymal tumor, often develops distant metastases and has a dismal prognosis. In this study we aim to characterize the body sites and time to metastasis in women with U-LMS. We evaluated 130 U-LMSs with distant metastases including a series of patients diagnosed at 2 tertiary centers, as well as cases published in the literature, found using a PubMed query. Data collected included clinic-pathologic features, time to first metastasis, and survival. Survival analysis was performed using univariable and multivariable Cox regression model. The most frequent metastatic sites were: lung (67.7%), cranial/intracranial (16.2%), skin/soft tissues (15.3%), and bone (13.8%). Other sites included thyroid, salivary gland, heart, liver, pancreas, adrenal gland, bowel, and breast. Metastases were histologically identical to primary tumors. Median time to first metastasis was highly variable (median: 24 mo; range, 1 mo to 26 y). Lung and peritoneum were the earlier metastatic sites; 21.4% of patients with U-LMS limited to the pelvis develop metastasis > 5 yr after diagnosis. Lung metastases significantly associated with other distant metastases. Regarding treatment, only resection of metastases significantly influenced postmetastasis survival in multivariable analysis (hazard ratio: 0.49, P = 0.015). In conclusion, U-LMS display highly variable sites of distant metastases. Metastases in unusual locations are sometimes the first to be detected, and not uncommonly, single and prone to surgical resection. There is also a wide range of time intervals to first metastasis, highlighting the need of long-term follow-up, high level of suspicion, and appropriate diagnostic confirmation.