Chemoradiation as definitive therapy is the preferred primary therapy for patients with anal canal carcinoma.
However, the 5-year disease-free survival rate from concurrent fluorouracil/mitomycin and radiation is only approximately 65%.
|The cumulative rate of colostomy was 10% for mitomycin-based treatment|
|Journal of American Medical Association |
Dr Jaffer Ajani and colleagues from the USA compared the efficacy of cisplatin-based (experimental) therapy vs mitomycin-based (standard) therapy in treatment of anal canal carcinoma.
The research team reports the results of the US Gastrointestinal Intergroup trial RTOG 98-11, a multicenter, phase 3, randomized controlled trial.
The trial compares treatment with fluorouracil plus mitomycin and radiotherapy vs treatment with fluorouracil plus cisplatin and radiotherapy in 682 patients with anal canal carcinoma.
The patients were enrolled between 1998 and 2005, stratified by sex, clinical nodal status, and tumor diameter.
The team assigned participants to 1 of 2 intervention groups.
Group 1 was the mitomycin-based group including 341 patients who received fluorouracil 1000 mg/m2 on days 1 to 4 and 29 to 32 plus mitomycin 10 mg/m2 on days 1 and 29, and radiotherapy 45 to 59 Gy.
Group 2, termed the cisplatin-based group, included 341 patients received fluorouracil 1000 mg/m2 on days 1 to 4, 29 to 32, 57 to 60, and 85 to 88 plus cisplatin 75 mg/m2 on days 1, 29, 57, and 85, and radiotherapy 45-59 Gy.
The team's primary end point was 5-year disease-free survival; and secondary end points were overall survival and time to relapse.
The researchers reported that a total of 644 patients were assessable.
The researchers noted that the median follow-up for all patients was 3 years.
Median age of the patients was 55 years, of whom 69% were women, 27% had a tumor diameter greater than 5 cm, and 26% had clinically positive nodes.
The 5-year disease-free survival rate was 60% in the mitomycin-based group, and 54% in the cisplatin-based group.
The team found the 5-year overall survival rate was 75% in the mitomycin-based group, and 70% in the cisplatin-based group.
The 5-year local-regional recurrence and distant metastasis rates were 25%, and 15%, respectively for mitomycin-based treatment.
For cisplatin-based treatment, the 5-year local-regional recurrence and distant metastasis rates were 33%, and 19%, respectively.
The cumulative rate of colostomy was significantly better for mitomycin-based than cisplatin-based treatment, at 10% vs 19%.
The researchers observed that severe hematologic toxicity was worse with mitomycin-based treatment.
Dr Ajani's team concluded, "In this population of patients with anal canal carcinoma, cisplatin-based therapy failed to improve disease-free-survival compared with mitomycin-based therapy."
"However, cisplatin-based therapy resulted in a significantly worse colostomy rate."
"These findings do not support the use of cisplatin in place of mitomycin in combination with fluorouracil and radiotherapy in the treatment of anal canal carcinoma."