ESTRO 2020 Abstract book

S491 ESTRO 2020

poor LRRFS.

predict the probability of locoregional recurrence (LRR) of MMHN after surgery and PORT. Material and Methods We retrospectively reviewed 111 patients with non- metastatic MMHN who underwent definitive surgical treatment with PORT between January 2008 and December 2018. Clinical characteristics and blood test parameters were analyzed for relationships with treatment outcomes, and a nomogram was created to estimate the risk of LRR using R software. Results The median follow-up was 44.2 months (range, 5.9–111 months), and we identified 17 local recurrence (15.3%), 1 regional lymph node metastasis (0.9%), and 33 distant metastases (29.7%). Relative to later recurrence, early locoregional recurrence (<2 years after surgery and PORT) was associated with poorer overall survival (OS) ( P = 0.001). The multivariate analysis revealed that independent risk factors for better locoregional recurrence-free survival (LRRFS) included age > 56 years, total bile acid (TIB) > 8.5 μmol/L, Mg 2+ > 0.8 mmol/L, mean corpuscular hemoglobin (MCH) < 32.3 pg and mean platelet volume (MPV) <10.0 fL.9 These five factors were used for the nomogram which had a C-index of 0.884 for predicting LRR, and internal validation revealed a good discriminative ability. Conclusion Early locoregional recurrence (<2 years) was associated with poor OS of MMHN after surgery and PORT. Our nomogram may be useful for predicting LRR of MMHN, and internal validation confirmed good discriminative ability. PO-0824 Feasibility and efficacy of radiotherapy in treating recurrent mucosal melanoma of the head and neck D. Dong 1 , S. Li 1 , L. Li 1 , B. Zheng 1 , W. Wang 1 1 Key Laboratory of Carcinogenesis and Translational Research Ministry of Education/Beijing- Department of Radiation Oncology- Peking University Cancer Hospital and Institute- Beijing- China, Radiotherapy Department, Beijing, China Purpose or Objective To investigate the efficacy and side effects of radiotherapy in treating locoregional recurrent mucosal melanoma of the head and neck (MMHN). Material and Methods We retrospectively reviewed 16 patients with locoregional recurrent and none-metastatic MMHN who underwent radiotherapy from January 2008 to December 2018. We used CTCAE 5.0 to evaluate the toxic side effects. Survival was evaluated using the Kaplan-Meier method and the log- rank test. Results The median age of the patients was 54 years old (range, 44-75 years). The tumor originated in the nasal cavity (13, 81.2%), maxillary sinus (2, 12.5%) and buccal mucosa (1, 6.3%). We identified 13 (81.3%) local recurrence (LR), 1 (6.3%) regional lymph node metastasis (LNM), and 2 (12.5%) LR and regional LNM. 12 patients (75.0%) underwent surgery followed by radiotherapy, while 4 (25.0%) received systemic treatment and radiotherapy. The median radiation dose was 62 Gy (range, 31-70 Gy). We observed 3 cases (31.2%) of grade 3 radiation mucositis, 1 case (6.3%) of grade 3 radiation dermatitis, and none grade 4 or higher side effects. The median follow-up time was 64.9 months (range, 13.2-130.5 months). The median locoregional recurrence free survival (LRRFS) time was 25.3 months (range, 2.2-78.1 months). Interruption of radiotherapy decreased LRRFS (P=0.004). Conclusion Radiotherapy with or without surgery could prolong LRRFS with moderate side effects for locoregional recurrent MMHN. Interruption of radiotherapy was associated with

PO-0825 To analyze the feasibility, effectiveness and toxicity of re-irradiation in head and neck cancers. S. Batham 1 , R. Yadav 2 , P. Roy 2 , R. Toprani 3 , K. Jani 1 , M. Gandhi 1 , P. Hirapara 4 1 HCG CANCER CENTRE, RADIATION ONCOLOGY, AHMEDABAD, India ; 2 Sanjay Gandhi Post Graduate Institute of Medical Sciences, Radiation Oncolgy, Lucknow, India ; 3 HCG Cancer Centre, Surgical Oncology, Ahmedabad, India ; 4 HCG Cancer Centre, Radiation Oncology, Bhavnagar, India Purpose or Objective To analyse the feasibility, effectiveness and toxicity of re- irradiation in head and neck cancers. Material and Methods Records were retrospectively analysed of 36 consecutive re-irradiated head and neck cancer patients treated between November 2011 and July 2014 at our center. The data was analysed in December 2018. Results 9 patients with in-field new second head and neck cancers and 27 patients with recurrent head and neck cancers have had high-dose re-irradiation. Re-irradiation was given only to patients with no more than minimal clinical radiation effects from the first radiation course. Dose was 54-59.4Gy in 30-33 fractions in all the patients. 5 patients lost to follow up, analysis of 31 was done. 29/31(93%) patients had history of tobacco /smoking. In 19/31(61%) patients PET Scan was done before re treatment. 26/31(93%) underwent Surgery on recurrence and received post- operative re radiotherapy. 4/26(15%) received post- operative concurrent chemo-radiotherapy. 2/31 received neo adjuvant chemotherapy on re treatment prior to surgery. All 3 patients who died of their disease were treated with definitive chemo-radiation without surgical salvage. 1 with progressive disease developed loco regional recurrence after re surgery and re-irradiation. Disease free interval among failures was < 18 months. Only 1/27 patient in post-op-re-irradiation group had progressive disease. Grade 3 mucositis seen in 11 patients. Four-year locoregional control rates were 39% for patients re-irradiated post operatively versus 17% for patients who underwent re-irradiation as the primary treatment. (p< 0.05). Feeding tube dependency for more than 8 weeks was observed in 3 patients. 25 patients had grade 2 skin toxicity, and 5 had manageable grade 3 skin toxicity. Carotid blow out was not seen in any of the patients. Conclusion We concluded that Re-irradiation for recurrence should be considered for patients with a recurrent or second primary in head and neck cancers, especially post operatively, if indicated and can be given safely in significant proportion of patients. It is associated with acceptable risks in properly selected patients. PO-0826 Hypofractionated radiotherapyfor HNSCC: a retrospective analysis of single Institution F. Sanna 1 , F. Cabras 1 , A. Carai 1 , S. Marogna 1 , A. Musu 1 , E. Orefici 1 , G. Piredda 1 , P. Pittau 1 , C. Sini 1 , M. Urpis 1 , L. Pelagatti 2 , M.C. Santona 2 , M. Giobbe 2 , L. Bandinu 2 , S. Cau 2 , L. Canu 2 , F. Salis 2 , S. Dei 2 , F. Capelli 2 , S. Campoccia 1 1 Ospedale San Francesco Nuoro, Radioterapia Oncologica, Nuoro, Italy ; 2 Ospedale San Francesco Nuoro, Multi Disciplinar Team-Head&Neck, Nuoro, Italy Purpose or Objective This study evaluates retrospectively clinical outcomes of simultaneous integrated boost (SIB-IMRT) hypofractionated radiotherapy for head and neck squamous cell carcinoma (HNSCC). Material and Methods