Two-year outcome of concurrent chemoradiation with carboplatin with or without adjuvant carboplatin/fluorouracil in nasopharyngeal cancer: A multicenter randomized trial

BackgroundAccording to the noninferiority result of chemoradiation with carboplatin in our previous nasopharyngeal carcinoma (NPC) study along with the inconclusive data on the efficacy of adjuvant chemotherapy (AC) following concurrent chemoradiotherapy (CCRT), we designed to assess the role of adjuvant carboplatin/fluorouracil following CCRT with carboplatin in locoregionally advanced NPC.Materials and MethodsA multicenter randomized trial was conducted at 5 cancer centers in Thailand. We enrolled in stage T2N0M0-T4N2M0 (American Joint Cancer Committee 7th edition) WHO Type 2 NPC patients. N3 or metastatic disease patients were excluded. Participants were randomized into 2 groups: CCRT plus AC group vs the CCRT alone group. Patients in both groups received weekly carboplatin 100 mg/m² for 6 cycles concurrently with radiotherapy 69.96-70 Gy. Patients in the AC group subsequently received 3 cycles of carboplatin area under curve-5 plus 1000 mg/m²/day of fluorouracil infusion within 96 hours every 3 weeks. We report the 2-year overall survival (OS), disease-free survival (DFS), loco-regional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS). Treatment-related toxicities and compliance were also explored.ResultsOf 175 patients, 82 (46.9%) were assigned to the AC group, and 93 (53.1%) to the CCRT group. The compliance rate during CCRT was 90% and 86% in the AC and CCRT group, whereas 81.7% during adjuvant treatment in the AC group. With a median follow-up time of 24.4 months (interquartile range 17.9-24.4), the 2-year OS rate was 89.6% in the AC group and 81.8% in the CCRT group (P= 0.167). The 2-year DFS rate was 86.8% in the AC group and 74.6% in the CCRT group (P = 0.042). The 2-year LRFS rate was 91.5% in the AC group and 88.2% in the CCRT group (P = 0.443). The 2-year DMFS rate was 85.4% in the AC group and 79.6% in the CCRT group (P = 0.294). The most frequent serious (grade 3/4) nonhematologic toxicity was acute mucositis, which occurred 5% in the AC group vs 4% in the CCRT group (P = 0.498). For hematologic toxicity, grade 3-4 leukopenia were found 10% and 5% in the adjuvant and CCRT groups, respectively (P = 0.003). Multivariate analyses determined stage N2 disease was an adverse prognostic factor associated with shorter OS, DFS, and DMFS. And the adjuvant treatment was a significant protective factor for only DFS.ConclusionsThe addition of adjuvant carboplatin/fluorouracil following CCRT with carboplatin significantly improved 2-year DFS in stage T2N0M0-T4N2M0 NPC albeit there was a nonsignificant trend in favor of a higher 2-year OS, LRFS, and DMFS. Long-term efficacy and late toxicities of AC still require exploration.