Background: This study aimed to establish an effective prognostic nomogram with or without plasma Epstein-Barr virus DNA (EBV DNA) for nondisseminated nasopharyngeal carcinoma (NPC).
Methods: The nomogram was based on a retrospective study of 4630 patients who underwent radiotherapy with or without chemotherapy at Sun Yat-sen University Cancer Center from 2007 to 2009. The predictive accuracy and discriminative ability of the nomogram were determined by a concordance index (C-index) and calibration curve and were compared with EBV DNA and the current staging system. The results were validated using bootstrap resampling and a prospective cohort study on 1819 patients consecutively enrolled from 2011 to 2012 at the same institution. All statistical tests were two-sided.
Results: Independent factors derived from multivariable analysis of the primary cohort to predict recurrence were age, sex, body mass index (BMI), T stage, N stage, plasma EBV DNA, pretreatment high sensitivity C-reactive protein (hs-CRP), lactate dehydrogenase (LDH), and hemoglobin level (HGB), which were all assembled into the nomogram with (nomogram B) or without EBV DNA (nomogram A). The calibration curve for the probability of recurrence showed that the nomogram-based predictions were in good agreement with actual observations. The C-index of nomogram B for predicting recurrence was 0.728 (P < .001), which was statistically higher than the C-index values for nomogram A (0.690), EBV DNA (0.680), and the current staging system (0.609). The C-index of nomogram B (0.730) and nomogram A (0.681) remained higher for predicting recurrence among patients treated with intensity-modulated radiotherapy (P < .001). The results were confirmed in the validation cohort.
Conclusions: The proposed nomogram with or without plasma EBV DNA resulted in more accurate prognostic prediction for NPC patients.
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