Phase 1/2 study of concurrent chemoradiotherapy with weekly irinotecan hydrochloride for advanced/recurrence uterine cancer: A multi-institutional study of Kansai Clinical Oncology Group.

Concurrent chemoradiotherapy using cisplatin was thought to be standard treatment for squamous cell carcinoma of cervix, but it had not been effective for adenocarcinoma. Concurrent chemoradiotherapy using irinotecan hydrochloride (CPT-11) had been effective for colorectal cancer, thus, we chose CPT-11 as a candidate for gynecologic adenocarcinoma. To evaluate the maximum tolerated dose (MTD) of weekly CPT-11 with external pelvic radiotherapy, a phase 1/2 study was conducted according to modified Fibonacci method.

Eligible patients were advanced uterine cancer with measurable diseases [performance score (PS): 0-2]. Study period was from August 1st, 2002 to December 31st, 2008. The starting dose level (DL) of CPT-11 was 30 mg/m² (DL1) given weekly for 4 weeks. Subsequently, dose escalation was scheduled in 10 mg/m² increments to 60 mg/m² (DL4). The fixed radiotherapy consisted of whole pelvic 1.8 Gy/d, once a day in weekday for five weeks and it amounted to 45 Gy (25 fractions) in total.

Seventeen patients were enrolled. As for toxicities, one (1/17: 5.9%) grade (G) 4 neutropenia lasting 7 days had been seen in DL4. G2 diarrhea was identified in 35.3% (6/17) of the patients, and 11.8% (2/17) G3 diarrhea was observed in DL3 and DL4. Thus, the MTD of CPT-11 was defined as dose of 60 mg/m². The recommended dose was decided as 50 mg/m². The response rate was 88.2% [9 complete response (CR), 3 partial response (PR), 3 stable disease (SD), 2 not evaluable (NE)]. Disease control rate at 1 month after treatment completion was 100% but distant metastases were found in 24% (4/17) in longer outcome.

MTD was 60 mg/m² and recommended dose was set as 50 mg/m². This concurrent chemoradiation using weekly CPT-11 was feasible at 50 mg/m², and it might be effective even in adenocarcinoma of the uterus.