Another way to estimate outcome of advanced nasopharyngeal carcinoma--is concurrent chemoradiotherapy adequate?

Abstract

Purpose: To evaluate a simple risk grouping system and determine whether concurrent chemoradiotherapy (CCRT) is adequate for patients with advanced nasopharyngeal carcinoma (NPC).

Methods and materials: A total of 284 patients with 1992 American Joint Committee on Cancer (AJCC) Stage III to IV (M0) NPC were analyzed retrospectively. They were treated by either radiotherapy (RT) alone or CCRT. We divided patients into high-risk and low-risk subgroups according to our experience. High-risk patients met at least one of the following criteria: (1) nodal size >6 cm, (2) supraclavicular node metastases, (3) 1992 AJCC stage T4N2, (4) multiple neck node metastases with 1 node >4 cm. The disease extent of each patient was stratified by our risk grouping system, AJCC 1992 and 1997 staging systems. Survival analyses-including nasopharynx disease free (TS), neck disease free (NS), distant metastasis disease free (MS), overall survival (OS), and progression-free (PFS) survival curves-were compared between these three different classifications.

Results: According to the 1992 AJCC staging system, 80.3% (228/284) of NPC patients are Stage IV, whereas only 19.7% are Stage III. Most patients are downstaged by the 1997 AJCC staging system with 28.5% (81/284) Stage IV and 71.5% (203/284) Stage III/II. Our risk criteria stratify more even patient distribution, because 119 patients (41.9%) are assigned to the high-risk group and 165 patients (58.1%) to the low-risk group. Log-rank test of Kaplan-Meier survival curves, multivariate comparison of the Cox proportional hazards model, and 3 goodness-of-fit indices validated that our risk grouping system seemed to be at least as efficacious as, or slightly superior to, the 1992 and 1997 AJCC systems. The 5-year TS (95.1% vs. 76.8%, p = 0.0012), NS (100% vs. 95.7%, p = 0.0974), MS (90.5% vs. 78.1%, p = 0.0282), OS (83.2% vs. 59.7%, p = 0.0041), and PFS (87.3% vs. 61.5%, p = 0.0003) were significantly better in patients receiving CCRT than RT alone for the low-risk group. However, the corresponding survival rates between CCRT and RT for high-risk patients were 74.9% vs. 67.6% (p = 0.2545) for TS, 92.1% vs. 86.8% (p = 0.4744) for NS, 59.7% vs. 60.0% (p = 0.5537) for MS, 55.8% vs. 46.3% (p = 0.1761) for OS, and 44.5% vs. 43.1% (p = 0.3911) for PFS, respectively.

Conclusions: Concurrent chemoradiotherapy is superior to RT alone for low-risk patients but inadequate for high-risk patients. Adding neoadjuvant and/or adjuvant chemotherapy would be a reasonable approach for high-risk patients. Our risk grouping criteria are a simple and useful guide that will have important implications in the design of future therapeutic trials.