Dados do Trabalho

Título

SABR reirradiation for high volume head and neck cancer

Introdução

The management of reirradiation of advanced head and neck (AHNC) has been quite a challenge over decades.

Objetivo

The present study aims to evaluate the role of stereotactic ablative body radiotherapy (SABR) as a strategy to the worst group of palliative patients when there are no other local treatment options.

Método

We conducted an institutional retrospective review of patients who underwent reirradiation with SABR for AHNC at a single institution from January 2017 to December 2019. All patients were classified as unresectable/inoperable by tumor board with at least one experienced H&N surgeon and unsuitable to receive chemotherapy due to poor performance status (PS) and/or significant comorbidities. The planning target volume was restricted to the gross tumor volume plus a 5mm uniform expansion, SABR was delivered with 40 Gy in 5 fractions every other day. The Kaplan-Meier method was used to estimate locoregional control (LRC),progression free survival (PFS), and OS endpoints.

Resultados

Sixty two patients were considered eligible for this retrospective analysis. The mean and median GTV volume were 125.5cc and 75.5cc, respectively. The mean follow up was 9.26 months and a median of 6.75 months. The 1 and 2-year OS was 24.0% and 13.3%, respectively, with a median survival time of 6.8 months. The 1-year PFS was 33.6% with a median PFS of 7.7 months. The 1-year LRC was 46.4% with a median LRC of 8.9 months. Considering tumor volume of V<30cc, the 1-year OS was 55.6% versus 18.6% (p= 0.038); PS≤1, the 1-year OS was 32.7% versus 4.8% (p=0.006); N staging ≤N1, the 1-year OS was 35.4% versus 8.5% (p= 0.044). With a cut point of 2 years for the reirradiation, the 1-year OS was 13.3% versus 30.3% (p= 0.022).
An univariate analysis for PFS demonstrated that mean volume (125.5cc) and an advanced N staging grouping (N≥3) were potential prognostic factors. The statistical significance was sustained after a multivariate analysis for N status (p=0.001) and tumor volume (p=0.031).
Only 3 patients developed grade 4 skin necrosis (all with tumors involving skin), no other grade 4 toxicity was assessed.

Conclusão

Our data shows that 5 fractions SABR is an interesting and feasible strategy for last line AHNC reirradiation. Small tumor volume was strongly associated with overall survival but even larger tumors can be well controlled with this palliative SABR treatment. Toxicity seems to be acceptable. Future prospective studies are needed to better understand who will benefit the most from this treatment.

Palavras-chave

Palliative SABR, head and neck cancer, reirradiation