ESTRO 2020 Abstract book

S492 ESTRO 2020

We analyzed 70 HNSCC ECOG PS 0-2 pts treated with hypofractionated SIB-IMRT between 2011 and 2017. The median age was 60 years (range 43-86), 83% males and 17% females,. The primary tumor were 40% oropharynx, 23% larynx, 17% hypopharynx, 7% oral cavity, 6% unknown primary, 4% nasopharynx, 3% others. Patients were staged with TC scan and PET/TC. Stage (AJCC-7 th edition) was 67% IV a-b, 19% III, 10% II, 4% I. All patients received SIB-IMRT consisted in 67.5 Gy/2.25 Gy /fr in high risk CTV, 60Gy/ 2.0 Gy/fr in medium risk CTV and 54Gy/1.8 Gy/fr in low risk CTV, given in 30 fractions. 51 pts (73%) received concurrent CDDP-based chemotherapy (CRT). Pts were examined once a week during radiation therapy, after 1, 3, 6 and 9 months, then every 6 months up to 5 years. Acute and late toxicities were graded using CTCAE 4.0 and LENT SOMA respectively. Response was assessed according to the RECIST criteria. Survival data were up-dated from regional database system The median follow-up of patients still alive was 4.98 years (range 1.9-8). Results 67 pts completed the planned schedule (compliance 96%). The median overall treatment time was 46 days (range 40- 62). The following severe acute toxicities were observed: 17% G3 skin reactions, 9% G3 mucositis, 14% G3 dysphagia, 16% G3 hematological toxicity (all with concurrent chemotherapy). Four G3 in RT alone and 35 G3 in CRT group respectively. One patient died because of fatal bleeding during radiotherapy. The following late severe toxicities were observed: 1% G3 xerostomia, 3% G3 and 7% G4 dysphagia. One patient died 10 months after the end of RT of epidural abscess in low-dose field. No chondronecrosis of the larynx was observed. Response was assessed in 66 pts (94%). A complete response (CR) was observed in 60% of pts, a partial response (PR) in 21%, stable disease (SD) 1% and 10% experienced a progression disease (PD).15/41 pts with CR had a progressive disease: 7 locoregional recurrences (4/7 underwent salvage surgery/radiotherapy), 8 distant recurrences. For all pts, the median OS was 2.46 years and the 3-years OS resulted 47%. The median PFS was 2.2 years and the 3-years PFS resulted 41%. The 3-years OS were 69% in larynx, 67% nasopharynx, 58% hypopharynx, 36% oropharynx and 25% oral cavity. The 3-years survival were 100% and 41% for stage I-II and III-IV respectively. At the time of data analysis (October 2019), 33/70 pts were alive. No differences statistically significant were found in Multivariate analysis considering Stage, primary, overall treatment time.

Conclusion Hypofractionated SIB-IMRT for locally advanced HNSCC not selected pts with or without chemotherapy is feasible and produced good results in term of response rate, PFS, OS. Hypopharynx and larynx primary tumor showed superior overall survival over the current standard