ESTRO 36 Abstract Book

S595 ESTRO 36 _______________________________________________________________________________________________

histologically classified as squamous cells carcinoma. At the time of the diagnosis, 86.8% of the patients had stage IV disease. Mean Karnofksy Performance Status (KPS) was 68%. RT palliative schemes chosen were 50Gy delivered in 20 fractions during 4 weeks (50Gy/20fr/4w) in 35% of our patients, 30Gy/10fr/2w in 32%, 37.5Gy/15fr/3w in 18.9% and 40Gy/20fr/4w in 13.2% of our patients. After the analysis of cervical and chest CT, 61.2% of the patients had partial response while 10.2% had complete imagiologic response, 18.4% had imagiologic progression and 8.2% had stabilised disease. After a mean follow-up period of 27.2 months (±8,3), overall survival was 9.55 months (±9,3). The group with better tumor response on CT was the group that underwent for the 50Gy/20fr/4w scheme (in which 89.4% had partial/complete response) with no need for interruption of the treatment due to toxicity. The group with longer overall survival was the group that underwent for the 30Gy/10fr/2w (11.8 months) and the shortest overall survival was verified after the 37.5Gy/15fr/3w scheme (5.2 months). Despite these results, there were no statistically significant differences between the four RT schemes delivered to our patients and overall survival (p=0.41). Patients who had better tumor response on CT (partial or complete response) had longer overall survival comparing to patients who had stabilised disease or progression (11.6 months vs. 6.65 months; p=0,011).

5 Instituto Português de Oncologia de Lisboa Francisco Gentil- EPE, Clinical Research Unit, Lisboa, Portugal Purpose or Objective To review the outcomes of early-stage oropharyngeal squamous cell carcinoma (OSCC) submitted to primary surgery or primary radiotherapy (RT). Material and Methods Retrospective study of patients diagnosed with OSCC between January 2009 and December 2014, clinically staged cT1 to cT2 cN0/cN1, who underwent primary surgery or primary RT. Cases surgically upstaged were excluded. We analyzed patient charts, imaging and clinical data regarding primary therapy, adjuvant treatment and side effects. Toxicity was graded according to Common Terminology Criteria for Adverse Events (v4.0). Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method and log-rank test for group comparison. Time-to-event endpoints were calculated from the date of first treatment. Results We found 61 patients with cT1 to cT2 cN0/cN1 OSCC treated with primary surgery or primary RT. Ten were excluded after surgical upstage. From the remaining 51, 45 were male, with a median age of 56 years. The majority was treated with surgical resection (n=35), followed by RT (n=30) with or without (n=21) chemotherapy (high-dose cisplatin), due to positive (n=9), close (<5mm, n=20) or non-evaluable (n=3) margins. Sixteen were submitted to primary RT, with or without (n=13) concomitant chemotherapy. Disease was in stage I in 10 patients, stage II in 24 and stage III in 17. Patients were treated with IMRT using simultaneous integrated boost (n=33) or 3D-CRT. Prescribed dose was 60-70Gy to the high-risk PTV and 50- 54Gy to the low/intermediate-risk PTV. Median follow-up time in patients alive was 5 years. Three patients had tumor persistence, 4 had local failure and no one developed distant metastasis. In both groups, median OS and PFS were not reached. In the primary surgery group, 3-year and 5-year OS were 80% and 62%, and 3-year and 5-year PFS were 74% and 50%, respectively. In the primary RT group, both 3-year and 5-year OS were 81%, and 3-year and 5-year PFS were 81% and 70%, respectively. There was no significant difference in the two groups (OS p value = 0,4; PFS p value = 0,3). Acute grade 3 toxicity was reported by 15 patients (mucositis, dysphagia, dermatitis, xerostomia). Late side effects were grade 1 xerostomia (n=10) and mandibular osteoradionecrosis (ORN, n=6). ORN occurred in patients submitted to primary (n=3) or adjuvant RT, who had been given 66-70Gy with 3D-CRT (n=4) or concomitant cisplatin (n=2). Fourteen died due to disease progression (n=3), treatment complications (sepsis, n=1) or other unrelated causes. Conclusion In our study, there was no significant difference in the OS and PFS between primary surgery vs. primary RT. Although surgery was the most frequent primary approach, almost all patients required adjuvant treatment due to close margins. Our toxicity profile reminds us that careful patient selection is necessary as well as further surgical margins studies are warranted to identify subgroups where treatments can be safely avoided. EP-1083 HPV as an etiological and prognostic factor for the Polish patients with HNC. A. Brewczyński 1 , T. Rutkowski 2 , A. Mazurek 3 , M. Snietura 4 , Z. Kołosza 5 , A. Wygoda 2 , K. Składowski 2 , A. Celejewska 1 , E. Małusecka 3 , A. Fiszer-Kierzkowska 3 , U. Bojko 3 , W. Pigłowski 4 , A. Hajduk 2 , P. Polanowski 2 , U. Dworzecka 2 , I. Gawron 2 , M. Kentnowski 2 , B. Pilecki 2 , T. Stępień 2 , I. Domińczyk 2 , E. Nadolska 2 , A. Tatar 2 , P.

Conclusion There is no consensus regarding the choice of the optimal RT fractionation scheme used in palliative care of H&N cancer patients and careful patient selection. Patients with advanced incurable H&N cancer have a poor prognosis but the addition of palliative RT provides better local-regional control of the disease with the possibility of longer survival rates. More studies should be carried out in order to evaluate predictive factors of tumor response as a mean of improving patient’s outcomes and quality of life. EP-1082 Primary surgery vs. radiotherapy in early- stage oropharyngeal cancer: a single centre experience C. Pedro 1 , B. Mira 2 , P. Silva 1 , E. Netto 3 , R. Pocinho 1 , A. Mota 1 , P. Pereira 1 , M. Ferreira 2 , T. Alexandre 2 , I. Sargento 2 , P. Montalvão 4 , M. Magalhães 4 , S. Esteves 5 , F. Santos 1 1 Instituto Português de Oncologia de Lisboa Francisco Gentil- EPE, Radiotherapy Department, Lisboa, Portugal 2 Instituto Português de Oncologia de Lisboa Francisco Gentil- EPE, Oncology Department, Lisboa, Portugal 3 NOVA Medical School UNL, Radiation Oncology, Lisboa, Portugal 4 Instituto Português de Oncologia de Lisboa Francisco Gentil- EPE, Otorhinolaryngology Department, Lisboa, Portugal