Purpose: To evaluate the efficacy and safety of irinotecan as second-line treatment in patients with advanced colorectal cancer (ACC) failing or relapsing after 5-fluorouracil (5-FU) plus leucovorin (LV) standard chemotherapy.
Patients and methods: Irinotecan was randomly administered in two different schedules (once every 3 weeks, and every 10 days) in patients failing prior 5-FU plus LV. Patients were randomized to two treatment groups: group A received irinotecan 350 mg/m2 every 21 days and group B received irinotecan 175 mg/m2 days 1 and 10 every 21 days.
Results: Group A comprised 60 patients: 34 male/26 female, median age 64 years (range 48-70 years), and median Karnofsky performance status (PS) 90. Their metastatic sites included liver (n=47), lymph nodes (n=27), lung (n=14), abdomen (n=14), pelvis (n=8), "other" (n=2), and local recurrence (n=12). Group B comprised 60 patients: 36 male/24 female, median age 62 years (46-70 years), and median PS 90. Their metastatic sites included liver (n=49), lymph nodes (n=29), lung (n=17), abdomen (n=16), pelvis (n=11), "other" (n=2), and local recurrence (n=13). Group A showed the following responses: complete response (CR) 2, partial response (PR) 12, stable disease (SD) 21, progressive disease (PD) 26, overall response rate (ORR) 23%, tumor growth control 58%. Group B showed the following responses: CR 1, PR 14, SD 22, PD 23; ORR 25%; tumor growth control 62%. Toxicities included acute cholinergic syndrome (group A 53%, group B 19%; P<0.0001), late-onset diarrhea grade 1/2 (group A 21%, group B 46%) and grade 3/4 (group A 41%, group B 66%; P<0.0001), nausea and vomiting grade 1/2 (group A 34%, group B 59%) and grade 3/4 (group A 30%, group B 12%; P<0.0001), neutropenia grade 3/4 (group A 27%, group B 28%; P<0.03), with febrile neutropenia seen in only four patients in group A, anemia grade more than 2 (group A 28%, group B 12%; P<0.05), asthenia grade more than 3 (group A 24%, group B 18%; P<0.001), and alopecia grade more than 3 (group A 40%, group B 34%; P<0.2).
Conclusions: . The present study indicates that, in patients with ACC who have relapsed after 5-FU plus LV, the administration of irinotecan fractionated into two doses every 21 days yields a similar efficacy to, but a much lower incidence of toxicity than, the same total dose of irinotecan administered once every 21 days.