Impact of adjuvant therapy on recurrence patterns in stage I uterine carcinosarcoma

BACKGROUND: To examine recurrence patterns in women with stage I uterine carcinosarcoma (UCS) stratified by adjuvant therapy pattern. METHODS: We examined 443 cases of stage I UCS derived from a retrospective cohort of 1192 UCS cases from 26 institutions. Adjuvant therapy patterns after primary hysterectomy-based surgery were correlated to recurrence patterns. RESULTS: The most common adjuvant therapy was chemotherapy alone (41.5%) followed by chemotherapy/radiotherapy (15.8%) and radiotherapy alone (8.4%). Distant-recurrence was the most common recurrence pattern (5-year cumulative rate, 28.1%) followed by local-recurrence (13.3%). On multivariate analysis, chemotherapy but not radiotherapy remained an independent prognostic factor for decreased risk of local-recurrence (5-year cumulative rates 8.7% versus 19.8%, adjusted-hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.25–0.83, P = 0.01) and distant-recurrence (21.2% versus 38.0%, adjusted-HR 0.41, 95%CI 0.27–0.62, P < 0.001). The chemotherapy/radiotherapy group had a lower 5-year cumulative local-recurrence rate compared to the chemotherapy alone group but it did not reach statistical significance (5.1% versus 10.1%, adjusted-HR 0.46, 95%CI 0.13–1.58, P = 0.22). Radiotherapy significantly decreased local-recurrence when tumors had high-grade carcinoma, sarcoma component dominance, and deep myometrial tumor invasion (all, P < 0.05); and combining radiotherapy with chemotherapy was significantly associated with decreased local-recurrence compared to chemotherapy alone in the presence of multiple risk factors (5-year cumulative rates, 2.5% versus 21.8%, HR 0.12, 95%CI 0.02–0.90; P = 0.013) but not in none/single factor (P = 0.36). CONCLUSION: Adjuvant chemotherapy appears to be effective to control both local- and distant-recurrences in stage I UCS; adding radiotherapy to chemotherapy may be effective to control local-recurrence when the tumor exhibits multiple risk factors.