Nomograms incorporating primary tumor response at mid-radiotherapy to predict survival in locoregionally advanced nasopharyngeal carcinoma

Abstract

Background: A nomogram that incorporates tumor response at mid-radiotherapy (mid-RT) to predict the prognosis of locoregionally advanced nasopharyngeal carcinoma (LA-NPC) has not been established.

Methods: This study retrospectively reviewed 583 patients with LA-NPC who underwent magnetic resonance imaging scans at mid-RT (the fourth week of RT) between 2015 and 2019.

Results: Primary tumor (PT) response at mid-RT was found to predict disease-free survival (DFS) and overall survival (OS). Independent factors from multivariable analysis to predict DFS and OS were assembled into nomograms with (nomograms A_mid-RT and B_mid-RT ) or without (nomograms A_baseline and B_baseline ) PT response. Internal validation revealed good performance of these nomograms in discrimination: C-statistics = 0.761 for nomogram A_mid-RT and 0.809 for nomogram B_mid-RT , which showed better discrimination performance than (C-statistics: 0.755) nomogram A_baseline and (C-statistics: 0.798) nomogram B_baseline (Z-statistic = 2.476, p < 0.05; Z-statistic = 1.971, p < 0.05).

Conclusion: The nomograms based on PT response at mid-RT showed favorable predictive accuracy for DFS and OS in patients with LA-NPC.

Keywords: nasopharyngeal carcinoma; nomogram; prognosis; radiotherapy; tumor response.