[Timing and duration of postoperative radiotherapy in patients with laryngeal cancer]

Aim of this was an evaluation of the impact of prolongation of combined treatment time on the local-regional control laryngeal cancer patients treated with surgery and postoperative radiotherapy. Study was based on retrospective analysis of 254 patients with T3/T4 and N0-N2 laryngeal cancer who were treated between January 1993 and December 1996 with surgery and postoperative radiotherapy (RT). Median age of investigated group was 56.3 years. Surgery consisted of total laryngectomy in all cases and with selective neck dissection. RT began 22 to 78 days postoperatively (median 45 days) and continued for a median of 47 days (range, 40-74 days). The primary tumor bed and all lymph neck nodes were treated in all patients. The total dose to the primary tumor bed was about 60 Gy, fraction dose was 2 Gy. All lymph nodes were irradiated with a dose of 50 Gy. The factors studied for prognostic importance for a local-regional failure included: overall combined treatment time, interval between surgery and the start of radiotherapy, radiotherapy treatment time, age, sex, T and N categories. The 5-year actuarial disease-free local-regional survival was 50%. On univariate analysis, using log rank test, only N status, sex were predicted for the locoregional control of postoperative radiotherapy. Overall treatment time longer than 90 days and especially 100 days was correlated with worse locoregional results of combined treatment respectively (p = 0.003 and p = 0.0007). Also prolongation of interval time between surgery and postoperative radiotherapy beyond 50 days was connected with higher rate of failures (p = 0.02). The same trend was observed when time of irradiation was longer than 47 days (p = 0.01). This analysis indicated that the prolongation of the overall treatment time of combined modality, the the time between surgery, and radiotherapy and time of postoperative radiotherapy were correlated with increased of local regional failures.