Reirradiation for Recurrent Nasopharyngeal Carcinomas Experience from an Academic Tertiary Center in a Low-Middle-Income Country

Abstract

Objectives

The objective of this study is to present the oncologic outcomes and the treatment-related toxicities after reirradiation (re-RT) for recurrent nasopharyngeal carcinoma (rNPC) at our institution.

Methods

Thirty-two cases of rNPC treated at our institution with re-RT (2006 to 2017) were retrospectively reviewed. Treatment modalities for re-RT were: IMRT (n=14), 3DCRT (n=9), single fraction SRS (n=6), fractionated SRT (n=2), and HDR intracavitary brachytherapy (n=1). Twenty-seven patients had re-RT with curative intent, while 5 were treated for palliation.

Results

Median follow-up for the entire group was 14.5 months (range, 1 -123 months). Median LRRFS was 14 months (range, 3.9 – 22.0 months), with actuarial 1-year, 2-year, and 5-year LRFS estimate of 67.5%, 44.0%, and 44.0%, respectively. Median OS for the entire group was 38 months (range, 14.6 – 61.4 months) with actuarial 1-year, 2-year, and 5-year OS estimate of 74.2%, 57.2%, and 33.0%, respectively. With a median follow-up of 16 months (range 3-123 months), median LRRFS was not reached for patients treated with curative intent only. Actuarial 1-year, 2-year, and 5-year LRRFS estimates for these patients (curative intent treatment) were 68.2%, 54.5%, and 54.5%, respectively. Median OS for patients treated with curative intent was 42 months, with actuarial 1-year, 2-year, and 5-year OS estimates of 75.4%, 63.8%, 40.5%, respectively. Patients treated with palliative intent had a median OS of 6 months, with 3-month, 6-month and 1-year actuarial OS estimates 60%, 30%, and 30%, respectively. On univariate analysis, center of primary RT and risk classification were significantly associated with LRRFS, while recurrent T-stage category was associated with OS. Three (9.4%) patients developed symptomatic brain necrosis. There was no reported grade 5 treatment-related toxicity.

Conclusion

Results of the study report that re-RT may be an effective salvage strategy for rNPC. Re-RT to 60 Gy maximum EQD2 may yield acceptable LRRFS and translate to prolonged OS, with minimal risk for treatment-related mortality.

Advances in Knowledge

This is the first report of re-RT outcomes from the authors’ country, which is a low-middle-income country endemic for NPC. This study also reports early application of a recently published prognostic model for OS in rNPC.