Outcome and toxicity of intensity-modulated radiotherapy with simultaneous integrated boost in patients with pharyngo-laryngeal cancer.

PURPOSE: The present work aims at evaluating intensity-modulated radiation therapy with simultaneous integrated boost (IMRT-SIB) in squamous cell carcinomas (SCC) of the larynx and hypopharynx.

METHODS/PATIENTS: We performed a single institutional retrospective analysis on 116 pharyngo (29%)-laryngeal (71%) SCC patients (93% male) treated with IMRT-SIB to 66-69.96 Gy in 33 fractions between 2008 and 2016. Those who underwent surgery (54%) received adjuvant radiation of 66 Gy at 2 Gy/fraction to the surgical bed. 16 patients (14%) were treated for a local recurrence after prior surgery. High-risk lymph node regions received 59.4 Gy at 1.8 Gy/fraction and low risk regions 54.12 Gy at 1.64 Gy/fraction. The median age was 60 years and 95% of patients had an ECOG performance status 0-2. Most had advanced stage disease (III 22%, IV 74%). Chemotherapy was delivered in 74% of cases.

RESULTS: Median follow-up was 32 months. Two and three-year overall survival for all patients was 87% and 82%, respectively. There were 28 (24%) locoregional recurrences and 19 (16%) distant failures. Grade 3 mucositis, dermatitis, and xerostomy were observed in 12%, 10%, and 3%, respectively. A longer IMRT-SIB overall treatment time was associated with a higher risk of mortality (HR 1.09, CI 1.01-1.17, P = 0.02). Postoperative IMRT-SIB associated with a significantly lower risk of any recurrence (HR 0.34, CI 0.18-0.64, P = 0.001) and higher local control (HR 0.06, CI 0.01-0.24, P < 0.01). Additionally, it associated with a lower risk of mucositis (P = 0.029) compared with definitive radio (chemo) therapy.

CONCLUSIONS: IMRT-SIB is a safe and feasible radiation treatment technique for pharyngo-laryngeal SCC patients with a tolerable acute toxicity profile.