Session Item

Despite the constant improvement of techniques, locoregional recurrences (LR) after radiation therapy (RT) for head and neck cancer (HNC) remain frequent. In a curative context, in case of inoperability or incomplete resection, reirradiation (reRT) can be discussed. The objective of this study was to retrospectively analyze the outcomes and toxicities of patients treated with curative reRT (either by intensity-modulated radiation therapy [IMRT], or by proton therapy [PT]) for recurrent HNC.

This is a retrospective review of patients who underwent curative-intent reRT for nonresectable recurrent or second primary HNC from 30/08/2012 to 08/04/2019. All patients included received curative reRT for HNC LR. CTCAEv5 was used to assess acute and late toxicities. Follow-up was considered as the time between the end of reRT and the date of last follow-up. Survival times were defined between date of the end of reRT and the event date. Patient free of event have been censored to their last known contact date.

Twenty-three patients were re-irradiated (47.8% with IMRT and 52.2% with PT) with curative intent for advanced HNC. The patients were mostly men (73.9%) and WHO 0 (87%). Locations at the time of reRT were mainly the nasopharynx, cervical nodes, oropharynx, nasal fossae and maxillary sinus. Nine patients underwent surgery prior to reRT, seven had neoadjuvant chemotherapy, and six had concomitant chemoradiotherapy. The median interval time between the two irradiations was: 23.9 months (IQR: 15.3–37.2 months). The median maximum dose prescribed to the CTV was: 66 Gy EBR (55.8-70.2 Gy), median overall treatment time: 54 days (45-66 days), median CTV and PTV volumes: 49.8 cc (IQR: 32.4–88.8 cc) and 124.3 cc (IQR: 76.9– 208.6 cc), respectively. After a median follow-up of 15 months from the end of reRT, a total number of 18 patients (78.2%) developed LR. Nine LR (39%) occurred inside previously irradiated targets. The local control (LC) rate and survival without LR at 18 months were: 29.3 CI95%[15-57] and 26.1%[13.1-51.9]. Most patients (74%) did not have grade 2 toxicity before the start of reRT. Acute toxicities of grade ≥ 2 were radiomucositis (43.5%), dysgeusia (27.3%), dysphagia (26%), and radiodermatitis (13%). Main late grade ≥ 2 toxicities were: dysphagia (34.8%), trismus (30.4%), xerostomia (26.1%), dysgeusia (26.1%), cranial nerve deficit (17.4%), osteoradionecrosis (13.4%), and temporal radionecrosis (8.7%). Carotid blowout occurred in three patients (13.4%). Dysgeusia was significantly more frequent in the photon than in the proton group (p=0.017).

Curative reRT in HNC is possible for selected cases, but the LR rate in the irradiated field and the risk of toxicity grade ≥ 2 remain high. Improved selection criteria and definition of target volumes may improve the outcome of these patients.