Cisplatin-based concurrent chemoradiotherapy improved the survival of locoregionally advanced nasopharyngeal carcinoma after induction chemotherapy by reducing early treatment failure

PURPOSE

The aims of this study focusing on Locoregionally advanced nasopharyngeal carcinoma (LANPC) were mainly two-fold: on the one hand, to establish a cut-off value to differentiate early and late failure based on prognosis after recurrence or metastasis; and on the other hand, to investigate the duration of concurrent cisplatin benefit over follow-up time. The results of our study have the potential to guide clinical practice and follow-up.

METHODS

In total, 3123 patients with stage III-IVa NPC receiving Induction chemotherapy followed by concurrent cisplatin or not were analysed. The cut-off value of treatment failure was calculated using the minimum P-value approach. Random survival forest (RSF) model was to simulate the cumulative probabilities of treatment failure (locoregional recurrence and /or distant metastasis) over-time, as well as the monthly time-specific, event-occurring probabilities, for patients at different treatment groups.

RESULTS

Based on subsequent prognosis, early locoregional failure (ELRF) should be defined as recurrence within 14 months (P = 1.47 × 10 - 3), and early distant failure (EDF) should be defined as recurrence within 20 months (P = 1.95 × 10 - 4). A cumulative cisplatin dose (CCD) > 200 mg/m² independently reduced the risk of EDF (hazard ratio, 0.351; 95% confidence interval (CI), 0.169-0.732; P = 0.005). Better failure-free survival (FFS) and overall survival (OS) were observed in concurrent chemotherapy settings ([0 mg/m² vs. 1-200 mg/m² vs. >200 mg/m²]: FFS: 70.4% vs. 74.4% vs. 82.6%, all P < 0.03; OS: 79.5% vs. 83.8% vs. 90.8%, all P < 0.01). In the monthly analysis, treatment failure mainly occurred during the first 4 years, and the risk of distant failure in patients treated with concurrent chemotherapy never exceeded that of patients without concurrent chemotherapy.

CONCLUSION

Locoregional failure that developed within 14 months and/or distant failure within 20 months had poorer subsequent survival. Concurrent chemotherapy provides a significant FFS benefit, primarily by reducing EDF, translating into a long-term OS benefit.

Impact of cumulative cisplatin dose and adjuvant chemotherapy in locally-advanced nasopharyngeal carcinoma treated with definitive chemoradiotherapy

BACKGROUND

Both adjuvant chemotherapy and higher cumulative cisplatin dose (CDDP-D) given as part of multimodality therapy for locally-advanced nasopharyngeal carcinoma (LA-NPC) have improved survival in Asian series. We evaluated their impact in a contemporary single-institution Canadian cohort of LA-NPC.

METHODS

Patients with EBV-related stage II-IV LA-NPC by 7th edition TNM (TNM-7) treated with IMRT plus high-dose CDDP followed by adjuvant chemotherapy with CDDP/Carboplatin - 5-FU (maximum total/adjuvant CDDP-D = 540/240 mg/m²) between 2003 and 2016 were analyzed. 5-year overall survival (OS) and recurrence-free survival (RFS) were calculated and compared using log-rank test by stage, adjuvant chemotherapy (yes/no) and total CDDP-D (>300 vs ≤300 mg/m²). Multivariable analysis (MVA) was performed to identify survival predictors.

RESULTS

A total of 312 patients were evaluated: TNM-7 stage II/III/IV = 2%/51%/47%; T4 = 36%; N3 = 17%; adjuvant chemotherapy = 83% (79% 21% CDDP/carboplatin); median total/adjuvant CDDP-D = 380/160 mg/m²; median follow-up 76 years (range 06-149). 5-year OS differed by stage II-III vs IV (95% vs 80%, p < 0.001) and by total CDDP-D >300 (n = 210) vs ≤300 (n = 102) mg/m² (89% vs 83%, p = 0.02). Adjuvant chemotherapy and total CDDP-D impacted on 5-year OS in stage IV but not stage II-III. 5-year RFS was higher in stage IV patients with total CDDP-D >300 vs ≤300 mg/m² (74% vs 59%, p = 0.03), with a trend seen in locoregional (LRC) (91% vs 80%, p = 0.05) but not distant control (DC) (78% vs 72%, p = 0.36).

CONCLUSIONS

Adjuvant chemotherapy and total CDDP-D >300 mg/m² improved OS and RFS in stage IV but not stage II-III LA-NPC, mainly due to effect on LRC rather than DC.