Postoperative irradiation in patients with pT3-4N0 laryngeal cancer: results and prognostic factors.

Approximately 60 % of patients with locally advanced laryngeal cancer (LALC) treated primarily with surgery require adjuvant radiotherapy. In the available literature predominate series of patients were with pathologically confirmed node-positive status. Subgroups of pN0 patients with LALC are scarce. The aim of the study is to evaluate the efficacy of postoperative radiotherapy in patients with pathological stage T3-4N0M0 and identification of prognostic factors in this group. Between 1975 and 2005, 138 patients with squamous pT3-4N0 laryngeal cancer were irradiated postoperatively. Primary surgical treatment consisted of total laryngectomy and cervical lymphadenectomy. The median time between surgery and the implementation of radiotherapy was 56 days. The median total dose was 60 Gy (range 40-70 Gy). Five-year disease-free survival (DFS5) was achieved in 76 % of patients. Cancer recurrence was observed in 34 patients. In 28 (82 %) cases it was locoregional failure. DFS5 rates for pT3 and pT4 were 92 and 69 %, for margin status R0, R1 and R2 were 82, 72 and 67 %, respectively. The pharyngeal invasion was related to a decrease in DFS5 from 80 to 59 %. Postoperative irradiation in patients with pT3-4N0 LALC is an effective treatment method. The main reason of the failure is local recurrence. The following independent prognostic factors were identified in this group of patients: pT stage, surgical margin status and pharyngeal invasion.