Radiotherapy alone in patients with advanced nasopharyngeal cancer: comparison with an intergroup study. Is combined modality treatment really necessary?

Purpose: To examine the outcome of radiotherapy (RT) alone in patients with advanced nasopharyngeal cancer (NPC) and to compare the results with those reported by the Intergroup study 0099 (IGS) comparing RT to combined modality therapy (CMT).

Materials and methods: During the period 1985-1992, 198 NPC patients presenting without distant metastatic disease were treated for cure. Of these, 172 had stage III/IV (UICC 1987, 1992). Planned RT was 2 Gy/day fraction to 60-66 Gy to the primary tumor, with 50 and 60 Gy to the node negative and to palpable nodes, respectively. Outcomes included overall survival (OS) and disease-free survival (DFS), defined from the time of registration at our institution.

Results: The TNM categories and other prognostic factors were similar to the IGS, though 80% had stage IV compared to 91% in IGS. The 5 year OS and DFS for the 172 patients with stage III/IV disease were 62 and 48%, respectively, as compared to the IGS results of OS 37% and DFS 29% for RT alone, and OS 67% and DFS 58% for the CMT arm of IGS. When the distribution of adverse prognostic factors was balanced between both studies the comparative results were unchanged.

Conclusions: The early results for RT alone of this single institution experience are superior to those of the IGS control arm (RT), while somewhat inferior to those reported in the chemo-radiotherapy arm. The surprisingly poor outcome of the IGS/RT control arm may have resulted by chance, suggesting the need for a confirmatory randomized trial to fully establish the role of combined chemotherapy and radiation, as used in the IGS.