Development and Internal Validation of a Prediction Model for Nasopharyngeal Carcinoma: Using BMI and Inflammatory Response for Deciding Sequence of Chemotherapy

PURPOSE

Concurrent chemoradiotherapy followed by adjuvant chemotherapy (CRT-AC) and induction chemotherapy followed by concurrent chemoradiotherapy (IC-CRT) are among the best treatments in nasopharyngeal carcinoma (NPC). This study aimed to develop a model for deciding the sequence of chemotherapy in NPC.

METHODS

Data were separated into two cohorts. The CRT-AC cohort had 295 patients, while the IC-CRT cohort had 112. The predictors were standard factors with BMI and neutrophil-lymphocyte ratio (NLR) to predict overall survival (OS). A flexible parametric survival model was used.

RESULTS

A total of 132 (44.7%) and 72 patients (64.3%) died in the CRT-AC and IC-CRT cohorts, respectively. The predictors in the final models were age, sex, T, N, NLR, and BMI. The models of OS for CRT-AC and IC-CRT had concordance indices of 0.689 and 0.712, respectively, with good calibration curves. When changing the burden of disease along with NLR and BMI, we found that CRT-AC was not significantly different OS from IC-CRT when low NLR (<3) and high burden of disease (T3N3). By contrast, CRT-AC was remarkably more effective when there were high levels of NLR (≥3) and BMI (≥25) with any burden of disease (anyT anyN).

CONCLUSION

With additional BMI and NLR in model, it could be easier to decide between CRT-AC and IC-CRT in countries with limited health care resources.

Added value of metastatic cervical lymph node group V in nodal staging of nasopharyngeal cancer

BACKGROUND

Prognostic significance of posterior cervical lymph node metastasis in nasopharyngeal cancer is largely unknown. This study aims to determine the added prognostic significance of cervical lymph node group V to the standard American Joint Committee on Cancer (AJCC) staging system (eighth edition AJCC) of nasopharyngeal patients with cancer treated with intensity-modulated radiation therapy (IMRT) in terms of overall survival (OS), distant metastatic-free survival (DMFS), and disease-free survival (DFS).

METHODS AND MATERIALS

A retrospective cohort of 199 consecutively diagnosed nasopharyngeal patients with cancer treated with definitive radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) in the era of IMRT in a large university hospital in endemic area of Southeast Asia. Pre-treatment imaging studies were thoroughly re-evaluated and re-staged by a board-certified radiologist using radiographic criteria for cervical lymph node metastasis. T and N classifications were reclassified according to the eighth AJCC staging system. Group V (Va and Vb) cervical node was evaluated for its added prognostic significance. Cox's proportional hazard model was used to retrieve hazard ratio (HR), 95% confidence interval and P value for N classification. Harrell's C-statistic (concordance index) was used for test of discrimination and internal validation was calculated by bootstrap method.

RESULTS

This study demonstrated greater separation of OS with HR of 6.75 (95%CI 1.94-23.51, P = .003) by using group Vb only as N3 compared to HR of 4.70 (95%CI 1.37-16.13, P = .014) by using current standard N3 disease (groups IV and Vb). Similarly, N2 with presence of Va shows worsened DFS with HR of 8.70 (95%CI 1.08-69.67, P = .042) compared to N2 without Va with HR of 5.93 (95%CI 0.76-46.00, P = .089). After incorporating cervical group V into nodal staging, the HR and 95%CI among each group was better separated than the eighth AJCC staging system but without significant improvement in C-index.

CONCLUSION

Cervical lymph node group V is a potentially added prognostic factor to standard TNM staging.