226MO - Is induction chemotherapy beneficial in locally recurrent nasopharyngeal carcinoma before re-irradiation? A multicenter retrospective analysis

Background

To evaluate the role of induction chemotherapy (IC) in salvage treatment for locally recurrent nasopharyngeal carcinoma (lrNPC) and identify optimal subsets of patients who may benefit from IC prior to re-irradiation based on a prognostic risk stratification model.

Methods

Patients with lrNPC following salvage radiotherapy (sRT) from three cancer institutions were enrolled as discovery cohort (n=267) (Fudan University Shanghai Cancer Center) and validation cohort (n=211) (Sun Yat-sen University Cancer Center and National Cancer Center Beijing). Multivariate analysis using Cox proportional hazards regression method identified the predictors of OS in the discovery set. Patients were divided into three subgroups by the sum of coefficients and role of re-IC was assessed in each of the subgroups. The risk stratification model and re-IC were evaluated in the validation cohort respectively.

Results

In the discovery cohort, significant prognostic predictors including males (P=0.007), age≥60 (P<0.001), volume of rGTV≥17cc (P=0.014), and LDH-ratio≥0.5 (P=0.018) were revealed. The intermediate-risk group was defined as the sum of coefficients between 0.8 to 1.4, while lower score (0-0.7) as the low-risk group and higher score(1.5-2.4) being the high-risk group. The 5-year OS for the three subgroups in the discovery cohort were 34.3%, 40.1% and 67.9%, respectively (P<0.001). Similar outcome was found in the validation cohort (24.3%, 39.3%, and 46.4%, P=0.007). Survival was significantly improved with the administration of re-IC in the intermediate-risk subsets of patients in the discovery set (P=0.03) which was verified in the validation set (P=0.008).

Conclusions

A validated risk stratification model was established to discriminate OS for patients with lrNPC after salvage radiotherapy. The re-IC appeared to significantly improve survival of patients at intermediate risk while offering no survival advantages for the low- and high-risk cohort.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.