ESTRO 2022 - Abstract Book

S1237

Abstract book

ESTRO 2022

The aim of this study was to evaluate survival rates as well as acute and late toxicity after hypofractionated palliative radiotherapy (RT) in patients (pts) with low performance status and elderly patients, unfit of standard RT treatment. Materials and Methods Between December 2010 and June 2020, 211 pts underwent hypofractionated palliative RT treatment were evaluated retrospectively. The prescribed dose was 36,75 - 42 Gy in 7-8 fractions given one fraction of 5,25 Gy weekly. Of them 104 pts (49,3%) were male and 107 (50,7%) female. Mean age was 79 years old (range 42-100 years). Majority of pts were elderly with 2 or more comorbidity (88 % pts were aged more than 70 years old). The primary treated consisted in head and neck cancer (31 %), lung cancer (19 %), gynecological cancer (17 %), gastrointestinal cancer (8 %), breast cancer (7 %), prostate cancer (7%), skin cancer (7 %), sarcomas (2 %) and other metastatic disease (2 %). A 3DCRT technique was used in 88 (pts) (41,7 %) and a VMAT or IMRT technique in 123 (pts) (58,3 %). Concomitant systemic chemotherapy (OT, CT or immunotherapy) was administered in only 41 pts (19,4 %). At the moment of RT start the median KPS was 70 (range 40-90). Results After a mean follow-up of 14 months the median overall survival was 11 months. Overall, 74,5 % of patients completed radiotherapy at the prescribed dose and 25,5 % interrupt it due to PD, clinical worsening or lost motivation A clinical or radiological examination response was observed in 56 % of patients; CR 24 %, PR 32 %. A SD was obtained in 6 %, a PD 17 % of pts and in reaming 21 % was not possible to evaluate the response. In pts receiving the prescribed the response rate was 75 %, of them 35 % had a CR. Patients that completed RT treatment at the prescribed (RT 36,75 Gy-42 Gy in 7-8 ff) had a higher survival rate compared to patients which interrupt RT treatment (median 14 mths vs 3 mths; p-value 0,0001). Moreover, KPS > 70, PTV < 250 cc, systemic therapy during RT treatment and clinical or radiological response were prognostic factors regarding OS (p- value < 0,05). Radiotherapy delivered technique did not influence survival rate or local response, however pts treated with 3DCRT had higher rates of ≥ G2 acute or late toxicity compared to patients treated with IMRT-VMAT technique with a trend toward statistically significant (p-value < 0,067). A G3 or higher acute toxicity was observed in only 1,8 % of patients. A late toxicity ≥ G3 was observed in 8 patients (4,7 %). Conclusion Weekly hypofractionated radiotherapy 36,75-42 Gy in 7-8 fractions appears acceptable in poor performants status and elderly patients unit of standard RT treatment with a response rate of 75 %. Total dose, KPS > 70, PTV < 259 cc, systemic therapy during RT resulted prognostic factors regarding overall survival. IMRT-VMAT technique is recommended to be used for this schedule of hypofractionated palliative treatment due to reduce G2 or higher toxicity. 1 UO Radioterapia Oncologica, Sapienza Università di Roma, AOU Sant'Andrea Roma, Radiation Oncology, Rome, Italy; 2 UO Radioterapia Oncologica, Sapienza Università di Roma, AOU Sant'Andrea Roma , Radiation Oncology, Rome, Italy; 3 UO Radioterapia Oncologica, Sapienza Università di Roma, AOU Sant'Andrea Roma, Radiation Oncology, Rome, Italy Purpose or Objective The role of postoperative adjuvant radiation therapy (PORT) remains controversial. The purpose of this study was to evaluate outcomes and toxicities of PORT in a series of patients with thymoma or thymic carcinoma. Materials and Methods We retrospectively analysed 27 consecutive patients (17 thymomas, 8 thymic carcinomas) who underwent surgery with a curative intent and PORT to the mediastinal surgical bed and microscopic/macroscopic disease, if present, from 2006 to 2020 at our institution. Eight patients received neo-adjuvant chemotherapy prior to surgery. Surgical margins status was reported as follow: R0 resection (microscopic negative margin) was achieved in 14 patients, R1 (microscopic positive margin) in 11 patients and R2 (macroscopic positive margin) in 2 patients. According to Masaoka-Koga staging system 4, 6, 13 and 4 patients were stage I, II, III and IV of disease, respectively. Acute toxicities were graded according to the RTOG/EORTC scoring system and late toxicities where scored according to the SOMA (symptoms, objective, management, analytic) scoring system. The Kaplan Meier method was used to assess overall survival (OS), relapse-free survival (RFS) and metastases-free survival (MFS). Sub-group analysis was performed stratifying patients with R0 vs R1-2 resection margins, patients staged I-II vs III-IV stages and patients with A-AB-B1 vs B2-B3-0 histologies. PO-1458 The impact of post-operative radiotherapy (PORT) in patients with thymomas and thymic carcinomas G. Vullo 1 , G. Facondo 1 , R.C. Sigillo 1 , A. Priore 1 , M. Rotondi 2 , M. Valeriani 3 , V. De Sanctis 1 , M.F. Osti 1