Improvement of survival after addition of induction chemotherapy to radiotherapy in patients with early-stage nasopharyngeal carcinoma: Subgroup analysis of two Phase III trials

Purpose: Induction chemotherapy has not been shown to improve survival in nasopharyngeal carcinoma (NPC) in Phase III trials. To evaluate the effect of induction chemotherapy in NPC further, we performed subgroup analysis of two Phase III trials according to the T and N stage. Methods and Materials: Data from two phase III trials comparing cisplatin/epirubicin or cisplatin/bleomycin/5-fluorouracil followed by radiotherapy (RT) vs. RT alone in NPC were pooled together for analysis. Patients were stratified into four subgroups according to the 1997 American Joint Committee on Cancer T and N stage: T1-T2N0-N1, Group 1 (early-stage disease); T1-T2N2-N3, Group 2 (advanced N disease); T3-T4N0-N1, Group 3 (advanced T stage); and T3-T4N2-N3, Group 4 (advanced T and N disease). Group 1 consisted entirely of patients with Stage IIB disease. A total of 784 patients were included for analysis on an intent-to-treat basis. The median follow-up for the surviving patients was 67 months. Results: No significant differences in overall survival, locoregional failure-free, or distant metastasis-free rates were observed between the combined and RT arms in Groups 2 to 4. Significant differences in the overall survival and distant metastasis-free rates were observed only in Group 1, favoring the combined chemotherapy and RT arm. The 5-year overall survival rate was 79% in the combined arm and 67% in the RT-alone arm (p 0.048). The corresponding 5-year distant metastasis-free rates were 86% and 74% (p = 0.0053). Conclusions: Our results have shown that patients in Group 1, with early-stage NPC treated by RT alone, had relatively poor survival because of distant metastases. The observation of improved outcomes in this subgroup after the addition of induction chemotherapy has not been previously reported and warrants additional investigation