Nomograms for predicting survival outcomes in intensity-modulated radiotherapy era of nasopharyngeal carcinoma: A study based on Epstein-Barr virus DNA biological responses

A nomogram based on tumor response to induction chemotherapy may predict survival in locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

To evaluate the clinical significance of tumor response to induction chemotherapy (IC) in locoregionally advanced nasopharyngeal carcinoma (LANPC) patients and further to develop a nomogram for predicting survival prognosis.

METHODS

A total of 498 patients with stage III-IVA NPC applying IC and concurrent chemotherapy were reviewed (training cohort, n = 376; validation cohort, n = 122).

RESULTS

Tumor response was an independent predictor for clinical outcomes. The nomogram included age, N stage, pretreatment Epstein-Barr virus DNA, lymphocyte-to-monocyte ratio, and tumor response achieved an ideal C-index of 0.703 (95% CI 0.655-0.751) in the validation cohort for predicting overall survival (OS), which outperformed than that of the TNM system alone (C-index, 0.670, 95% CI: 0.622-0.718). In addition, the nomogram could successfully classified patients into different risk groups.

CONCLUSIONS

We established and validated a precise and convenient nomogram based on tumor response for predicting the OS of LANPC patients.

A Nomogram for the Determination of the Necessity of Concurrent Chemotherapy in Patients With Stage II-IVa Nasopharyngeal Carcinoma

Background

The efficiency of concurrent chemotherapy (CC) remains controversial for stage II–IVa nasopharyngeal carcinoma (NPC) patients treated with induction chemotherapy (IC) followed by intensity-modulated radiotherapy (IMRT). Therefore, we aimed to propose a nomogram to identify patients who would benefit from CC.

Methods

A total of 434 NPC patients (stage II–IVa) treated with IC followed by IMRT between January 2010 and December 2015 were included. There were 808 dosimetric parameters extracted by the in-house script for each patient. A dosimetric signature was developed with the least absolute shrinkage and selection operator algorithm. A nomogram was built by incorporating clinical factors and dosimetric signature using Cox regression to predict recurrence-free survival (RFS). The C-index was used to evaluate the performance of the nomogram. The patients were stratified into low- and high-risk recurrence according to the optimal cutoff of risk score.

Results

The nomogram incorporating age, TNM stage, and dosimetric signature yielded a C-index of 0.719 (95% confidence interval, 0.658–0.78). In the low-risk group, CC was associated with a 9.4% increase of 5-year locoregional RFS and an 8.8% increase of 5-year overall survival (OS), whereas it was not significantly associated with an improvement of locoregional RFS (LRFS) and OS in the high-risk group. However, in the high-risk group, patients could benefit from adjuvant chemotherapy (AC) by improving 33.6% of the 5-year LRFS.

Conclusions

The nomogram performed an individualized risk quantification of RFS in patients with stage II–IVa NPC treated with IC followed by IMRT. Patients with low risk could benefit from CC, whereas patients with high risk may require additional AC.