Concurrent-Adjuvant Chemoradiation Therapy for Stage III-IVB Nasopharyngeal Carcinoma-Exploration for Achieving Optimal 10-Year Therapeutic Ratio

Purpose: This is an updated combined analysis of 2 randomized studies (NPC-9901 and NPC-9902 trials) to evaluate the 10-year outcome attributed to the addition of concurrent-adjuvant chemotherapy for advanced locoregional nasopharyngeal carcinoma (NPC).

Patients and methods: Eligible patients with stage III-IVB nonkeratinizing NPC were randomly assigned to radiation therapy alone (RT: 218 patients) or chemoradiation therapy (CRT: 223 patients) using 3 cycles of cisplatin (100 mg/m²) concurrent with RT, followed by 3 cycles of cisplatin (80 mg/m²) and fluorouracil (1000 mg/m²/day for 4 days). All of the patients were irradiated with conventional fractionation to ≥66 Gy. The median follow-up was 13.9 years.

Results: Intention-to-treat analysis confirmed that the CRT group achieved significant improvement in 10-year failure-free rate (FFR: 62% vs 52%, P = .016), progression-free survival rate (PFS: 56% vs 44%, P = .008), and overall survival rate (OS: 60% vs 50%, P = .044). There was no significant increase in overall late toxicity rate (51% vs 48%, P = .34) or noncancer deaths (19% vs 16%, P = .52). Exploratory studies showed no difference in disease control between 2 or 3 cycles of concurrent cisplatin; however, patients given 3 concurrent cycles had a significant increase in hearing impairment (40% vs 24%, P = .017). Only those who continued to receive 2 or more cycles of adjuvant cisplatin-fluorouracil achieved significant improvement in distant control (73% vs 65%, P = .037) and maximal survival gain.

Conclusion: The addition of concurrent cisplatin plus adjuvant cisplatin-fluorouracil could significantly improve overall survival and disease control without incurring a significant increase in late toxicity or noncancer deaths. Exploratory analyses suggested that both the concurrent and the adjuvant phases contributed to tumor control. Furthermore, the number of concurrent cycles could be reduced from 3 to 2 cycles in order to achieve a similar survival benefit without incurring an excessive increase in hearing impairment. This is a useful hypothesis that warrants further validation.