RÉSUMÉ
ObjectiveTo determine the maximal tolerated dose and the dose-limiting toxicity of hydroxycamptothecin (HCPT)concurrently combined with three-dimensional conformal radiotherapy (3DCRT) for unresectable or locally relapsed rectal cancer.Methods Twenty-two patients with rectal cancer were enrolled into phase Ⅰstudy between 2004 -2007. HCPT was intravenously administered concurrently with 3DCRT weekly,dose given from 6,8,10 mg/m2 or twice a week,dose given from 4,6,8,10 mg/m2,respectively.Total radiation dose of 50 Gy was delivered to the whole pelvis at a fraction of 2 Gy per day for 5 weeks,with 10 - 16 Gy subsequent boost to tumor area.Dose-limiting toxicities (DLT) were defined as grade 3 or higher non-hematologic toxicity or grade 4 hematologic toxicity.ResultsIn the twice a week group,DLTs of grade 3 diarrhea were observed in 2 patient treated at dose of 6 mg/m2.In the weekly group,DLTs of grade 3 diarrhea and radiation-induced dermatitis were observed in Ⅰ patient at dose of 8mg/m2,and were not observed in the next 3 patients at the same dose level.However,at dose of 10 mg/m2,2 patients had grade 3 diarrhea or nausea.The 5-year overall survival rate was 23％ and the median survival time was 18 months.ConclusionsHCPT given concurrently with 3DCRT is safe and tolerable for patients with unresectable or locally relapsed rectal cancer.Either 8 mg/m2 weekly or 4 mg/m2 twice a week can be recommended for further study.The dose-limiting toxicities are grade 3 diarrhea,nausea and radiation-induced dermatitis.