Long-term results of weekly/daily cisplatin-based chemoradiation for locally advanced squamous cell carcinoma of the anal canal.

BACKGROUND: Weekly or daily cisplatin and 5-fluorouracil (5-FU)-based chemoradiation was evaluated for patients with locally advanced squamous cell carcinoma (SCC) of the anal canal treated at a single institution over a 20-year period. METHODS: A retrospective, single-institution analysis was conducted of patients receiving concurrent 5-FU/cisplatin and radiotherapy for locally advanced SCC from 1989 to 2009. Endpoints included clinical complete response rate, local recurrence rate, colostomy-free survival, disease-free survival (DFS), overall survival, and treatment-related toxicity. RESULTS: A total of 197 patients were evaluable. The majority had American Joint Committee on Cancer stage II (41%) or stage III (46%) disease; most were T2 (44%) or T3 (27%); bulky nodal disease (N2-N3) was noted in 24% of patients. Patients received weekly (20 mg/m2) or daily (4 mg/m2) cisplatin during radiotherapy. Median radiation dose was 55 Gy. Clinical complete response was observed in 185 patients (94%). After a median follow-up of 8.6 years, local recurrence rate was 11%. Sixteen patients (8%) developed distant metastases. The 5-year DFS was 81%, the 5-year overall survival was 86%, and the 5-year colostomy-free survival was 88%. By univariate analysis, N-stage was a poor prognostic indicator for 5-year DFS (P = .02, 95% confidence interval = 1.17-2.01) and distant metastases (P = .046, 95% confidence interval = 1.09-2.13). Increased T-stage correlated with the necessity for salvage surgery (P = .01). CONCLUSIONS: The combination of weekly/daily cisplatin and 5-FU-based chemotherapy with concurrent radiotherapy is an effective regimen, and our long-term results indicate that cisplatin is an alternative to mitomycin C and may be considered for the treatment of locally advanced SCC of the anal canal.

The optimization of dose delivery for intraoperative high-dose-rate radiation therapy using curved HAM applicators.

BACKGROUND AND PURPOSE: To determine the effect of the curvature of Harrison-Anderson-Mick applicators on the dose distribution in high-dose-rate intraoperative radiation therapy (HDR-IORT). MATERIAL AND METHODS: Treatment planning was performed with flat applicators using (192)Ir as the radioactive source, and dwell times were optimized using dose-point optimization techniques. These optimized dwell times were then used for the curved applicators, and the dose distributions that would actually be delivered to patients were determined. RESULTS: The dose directly below the central catheter was strongly dependent on the curvature of the applicator. Steep parabolic curves caused underdoses of as much as 19% at a point 1cm from the convex side of the applicator. The rate of dose reduction with increasing distance from the applicator surface was also a function of the curvature of the applicator. CONCLUSIONS: The curvature of the applicator profoundly affects dosimetry and can be exploited to optimize coverage of the target during HDR-IORT procedures. To ensure accurate dose delivery, these dose perturbations must be accounted for in the planning process. We recommend maintaining a dosimetry atlas of various applicator sizes and curvatures in addition to one for flat applicators.