ESTRO 38 Abstract book

S861 ESTRO 38

were compared between patients receiving concurrent RT (CIR) or no concurrent irradiation (NCIR). Patients who received RT before immunotherapy were secondly pooled in the analysis. Results Sixty-three patients received Ipilimumab between June 2007 and May 2017 at our institution. Among these, 50.8% (n=32) received RT before immunotherapy (at least four weeks before immunotherapy) and 20.6% (n=13) received RT concurrently to immunotherapy. Sixty-six % (n=42) received RT both before and/or concurrently to immunotherapy (RT group). RT schedules were heterogeneous. After a 12.0 months median follow-up, median Progression-free survival (PFS) after initiation of immunotherapy for the NCIR group was 3.2 months versus 3.1 months for the CIR group (P=0.863). Overall Survival (OS) was also non-significant between these groups (P=0.141). For RT group (n=42), median PFS were 3.2 months compare to 3.0 months for unirradiated patients (P= 0,802). OS was also non-significant between RT Group and unirradiated patients (P=0.080). Acute and late “in- field” or “out-of-field” immunologic toxicity profiles were similar in the two groups. Conclusion Despite the homogeneity of our series (we selected exclusively all patients receiving Ipilimumab as first-line immunotherapy after chemotherapy), we failed to show that combination of RT and Ipilimumab increase PFS or OS. These results could be explained by the heterogeneity of the RT schedules in our series. However, combination of RT and Ipilimumab were well tolerated and did not increase toxicities rates within and outside the irradiated field. EP-1597 Radiotherapy of monstrous squamous cell carcinoma of the head and scalp in elderly: our series G. Lazzari 1 , A. Terlizzi 2 , G. Silvano 1 1 Azienda Ospedaliera SS. Annunziata Presidio Osped, Radiology, Taranto, Italy ; 2 Azienda Ospedaliera SS. Annunziata Presidio Osped, Physics, Taranto, Italy Purpose or Objective Squamous cell carcinoma of scalp and skin head is a common clinical tumor in elderly population, mainly complicated by bleeding, necrotic masses with tissue loss. Most of them are very difficult to treat and little has been documented regarding treatment or outcomes due to low survival of these patients (pts). Herein we present our retrospective cases treated with customized electron beam radiotherapy analyzing factors impacting on local control . Material and Methods Fifty pts entered into this analysis. Elderly pts treated for giant and necrotic T3-T4 squamous skin lesions of the scalp and other skin regions of the head (occipital, face, nasal, retroauricolar) between 2005-2015 were retrospectively studied. Age, sex, comorbidity, extension of the lesions, site , deep tissue involvement, necrosis, electron energies and radiation doses were analysed with t-test for univariate analysis assuming p< 0.05 for statistical significance. The Pearsons covariance test was adopted for multivariate analyses. The patients were primarily male (60%) with a median age of 83 years (75-93 years). A total of 60 lesions were treated. There were an high proportion of tumours of the scalp ( 55 %) and lesions with a maximum diameter over mean 6 cm (5- 9 cm) mainly showing a deep tissue involvement with bleeding (40%). Treatment consisted of one field with a customized electron beam. Energies ranged within 8- 15 MeV with or without a customized bolus according to deep involvement which was assessed by a simulation CT scan. The clinical target volume (CTV) was created adding 10 to 20 mm margins around the lesions. The dose schedules were 60 Gy in 30 fractions for lesions over 8 cm maximum diameter and 50 Gy in 20 fractions for the others.

Radiotherapy is an optimal option for unoperable SSCC (Skin Squamous Cell Cancer) with excellent local control and good cosmetic outcomes. A lot of different fractionation and total doses had been used to treat SSCC, according to several clinical and histological parameters. Dermoscopically, these kind of lesion are characterized, by atypical vascular pattern and/or deep ulceration that some authors correlate with the severity of the neoplasm. In our study, we decide to use different radiotherapy schedules for our patients with SSCC, performing a “dose escalation” in those who had negative dermoscopic features. Material and Methods 28 patients (age> 60yo) with unoperable SSCC were enrolled in this study. Based on negative dermoscopic features (ulceration, bleeding, irregular vessels), signed by a skilled dermoscopist, we divided them in two groups: those with no negative dermoscopic features (15 patients) and those with negative one (13 patients). All the lesions were on the trunk or on upper/lower limbs. None of these lesions had nodal involvment (N0). No lesions were >4cm. In the first group we use an electron beam schedule of 2 Gy/30fx (60Gy) while in the second group we prescribe 2Gy/33fx (66Gy). Results All the patients ended treatment. In the group A (standard) the LC was observed (at 1 year follow up) in 13 patients (86%) and in 11 patients (73%) at 2 years follow up. Skin toxicity > grade 3 was not seen in these patients. No late toxicity was registered, with good cosmetical outcome. In the group B (negative features) the LC was observed in 12 patients (92%) at 1 year follow up and in 10 patients (77%) at 2 years follow up. 3 patients had grade 3 skin toxicity in this group with 2 cases of hypopigmentation. Conclusion Dermoscopic examination could be used to perform a dose excalation schedule in unoperable SSCC, with similar LC and accettable toxicity. More patients and a longer follow up are the main future topics to enhance this kind of approach. EP-1596 Radiotherapy and Ipilimumab as first-line immunotherapy: A comparative study on 63 patients N. Benziane 1 , V. Atallah 1 , F. Amestoy 1 , E. Gerard 2 , N. Leduc 1 , A. Huchet 1 , M. Beylot Barry 2 , C. Dupin 1 , S. Prey 2 , L. Dousset 2 , N. Ouabrache 1 , M. Martin 1 , P. Gillon 1 , C. Dutriaux 2 , R. Trouette 1 , V. Vendrely 1 1 University Hospital Bordeaux, Radiation Oncology, Bordeaux, France ; 2 University Hospital Bordeaux, Dermatology, Bordeaux, France Purpose or Objective A combination of immune-checkpoint inhibitors and radiation therapy (RT) represents a promising therapeutic strategy in part mediated by the abscopal effect, but clinical experience related to this combination remains scarce (1). Abscopal effects have been observed with association of radiotherapy concomitantly to Ipilimumab (2). Shaverdian et al. showed that patients receiving radiotherapy before immunotherapy presented better survival rates (3). Radiotherapy used concomitantly to immunotherapy showed better survival outcomes. But all of series pooled heterogeneous cancer types or lines of treatment (1). Our study evaluated clinical outcomes for patients treated by radiotherapy or not concomitantly to cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) inhibitor ipilimumab in a homogeneous cohort of patients. Material and Methods Clinical data and patterns of treatment were retrospectively collected from all consecutive patients with metastatic melanoma and receiving ipilimumab after one line of chemotherapy exclusively. Patients receiving Tyrosine Kinase inhibitor or other immunotherapies before Ipilimumab were excluded. Survival data and toxicities