ESTRO 2023 - Abstract Book

S811

Monday 15 May 2023

ESTRO 2023

An history of heart disease was found to be significantly correlated with both pulmonary acute (p:0,016) and late toxicity (p:0,008). A correlation with dosimetric parameters was found between V30-Lung and late lung toxicity (p:0,007, cut-off V30-bil>15%) and between V5-Heart and acute cardiac one (p:0,043, cut-off V5>32%). With a median follow up of 54 months, 48 patients (22,6%) showed a locoregional relapse, while 106 patients (50%) developed distant metastases. Finally, 64 patients (30,2%) showed no evidence of disease and 55 patients (25,9%) were dead for disease. The number of positive nodes (p:0,015) was the only parameter correlated with distant metastases, while the total number of removed nodes (p:0,034) was related with locoregional relapse. Conclusion RAC-TAC retrospective study confirmed the low incidence of severe toxicities after PORT when delivered with more advanced technologies. At the same time, most of the patients develop distant metastases. The total number of removed nodes and the number of positive ones e significantly correlated with the pattern of recurrence. PD-0962 Second PFS after post-PACIFIC relapse in the Blue Sky observational study on stage 3 NSCLC. A.R. Filippi 1 , J. Saddi 2 , F. Agustoni 3 , G. Galli 4 , S. La Mattina 5 , G. Facheris 6 , G. Stella 7 , C. Bortolotto 8 , A. Ferrari 9 , P. Pedrazzoli 10 , L. Preda 11 , P. Borghetti 12 1 University of Pavia, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences and Fondazione IRCCS Policlinico San Matteo, Radiation Oncology, Pavia, Italy; 2 University of Milano Bicocca, Radiation Oncology, Milan, Italy; 3 University of Pavia,Department of Internal Medicine and Medical Therapeutics and Fondazione IRCCS Policlinico San Matteo, Medical Oncology, Pavia, Italy; 4 Fondazione IRCCS Policlinico San Matteo , Medical Oncology, Pavia, Italy; 5 Spedali Civili and University of Brescia, Brescia, Italy, Radiation Oncology, Brescia, Italy; 6 Spedali Civili and University of Brescia, Brescia, Italy, Radiation Oncology, Brescia, Italy; 7 University of Pavia, Department of Internal Medicine and Medical Therapeutics and Fondazione IRCCS Policlinico San Matteo , Respiratory Medicine, Pavia, Italy; 8 University of Pavia, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences and Fondazione IRCCS Policlinico San Matteo , Radiology, Pavia, Italy; 9 Oncology Clinical Trials Office, Fondazione IRCCS Policlinico San Matteo, Medical Oncology, Pavia, Italy; 10 University of Pavia, Department of Internal Medicine and Medical Therapeutics and Fondazione IRCCS Policlinico San Matteo , Medical Oncology, Pavia, Italy; 11 University of Pavia, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences and Fondazione IRCCS Policlinico San Matteo, Radiology, Pavia, Italy; 12 Spedali Civili and University of Brescia, Brescia, Italy, Radiation Oncology , Brescia, Italy Purpose or Objective The Blue Sky Radiomic trial is a multicenter, observational study started in 2020, enrolling a sample of 100 patients affected with unresectable stage 3A-C NSCLC treated with the PACIFIC regimen (clinicaltrial.gov identifier: NCT04364776, active, recruiting). We here report an exploratory analysis of PFS-2 after the first relapse in a cohort of 65 patients enrolled by 2 of 5 participating Centres. Materials and Methods All patients received at least one durvalumab dose after chemoradiation (25 sequential, 38%, and 40 concurrent, 62%). Median age was 69 years old; median radiation dose was 60 Gy. All tumors were PD-L1 positive (TPS>1%). Twenty-seven had squamous (42%) and 38 (58%) non-squamous histology. The median follow-up time for the whole cohort was 18.2 months (range of 4.1-42 months). Results The median time of durvalumab administration for the whole cohort was 11.2 months (corresponding to an average of 22 doses). We recorded 4 deaths and 35 events of progression (local, distant, or both). Fourteen occurred <6 months from the first durvalumab administration (36%) and 25 >6 months (64%), respectively. Global PFS rate (progression at any site or death, whichever occurred first) was 59.8% at 12 months and 41% at 24 months, respectively. Median PFS was 18.3 months. Twenty-nine/35 patients (83%) received an active treatment after the first progression (20 chemotherapy, 5 radiotherapy alone, 2 chemotherapy and local treatment, one surgery, and 1 TKI, respectively), and 6 best supportive care. Among 29 patients who received an active treatment, 22 (76%) experienced a second progression at a median time of 5.3 months from the first relapse (range 1.0-25.7 months). Conclusion Very few reports explored PFS2 after failure of the PACIFIC regimen. In this observational study, 83% of patients did receive an active treatment at first progression, achieving a median PFS2 of 5.3 months after very heterogeneous regimens. Prospective trials are needed to improve PFS2 in this sub-group of patients, and these findings may serve as a benchmark for comparison of future experimental strategies. PD-0963 Lung re-irradiation with SBRT: outcomes and predictive factors of response in the recurrent setting I. Angelicone 1 , M. Rotondi 1 , R.C. Sigillo 1 , P. Bonome 2 , D. Caivano 3 , M. Valeriani 1 , M.F. Osti 1 1 Università degli Studi di Roma "La Sapienza", A.O.U. Sant'Andrea M-P, Radiation Oncology, Rome, Italy; 2 Gemelli Molise Hospital Department of Laboratories and Services, Radiation Oncology, Campobasso, Italy; 3 Santa Maria Goretti Hospital, Radiation Oncology, Latina, Italy Purpose or Objective Patients (pts) with primary or secondary lung lesions previously irradiated can experience a locoregional failure or the appearance of new lung lesions, thus requiring a thoracic re-irradiation. In this setting Stereotactic Body Radiation Therapy (SBRT) represents an optimal treatment modality due to its high local control rate with acceptable risk of complications. Aim of this monoinstitutional retrospective study is to evaluate outcomes and predictive factors of response of SBRT in the recurrent setting. Materials and Methods From April 2011 to October 2021, 42 pts (29 males, 13 females) received re-irradiation of lung lesions by SBRT. Median time between the two treatment was 24.6 months (range: 3-92). Median age was 73 years (range: 47-88). All pts had an Eastern