ESTRO 2023 - Abstract Book

S1131

Digital Posters

ESTRO 2023

Radioterapia Oncologica ed Ematologia, Roma, Italy; 9 Policlinico Umberto I, "Sapienza" University, Department of Radiotherapy, Roma, Italy; 10 IEO European Institute of Oncology, IRCCS, Department of Radiotherapy, Milano, Italy; 11 IRCCS Ospedale Policlinico San Martino, Department of Radiation Oncology, Genova, Italy; 12 University of Eastern Piedmont, Division of Radiation Oncology, Department of Translational Medicine, Novara, Italy; 13 Oncological Referral Center, Radiation Oncology Department, Aviano, Italy; 14 Sant'Andrea Hospital, Sapienza University, Unit of Radiation Oncology, Roma, Italy; 15 Azienda Ospedaliero-Universitaria Pisana, Department of Radiotherapy, Pisa, Italy; 16 IRCCS Multimedica, Radiation Oncology Center, Sesto San Giovanni, Italy; 17 ASST Lariana, Ospedale di Como, Radiation Oncology Unit, Como, Italy; 18 ICS Maugeri, IRCCS, Radiation Oncology Unit, Pavia, Italy; 19 University Hospital, Department of Radiotherapy, Firenze, Italy; 20 University of Perugia and Perugia General Hospital, Radiation Oncology Section, Perugia, Italy; 21 Belcolle Hospital, Radiotherapy Unit, Viterbo, Italy; 22 Azienda Ospedaliera San Gerardo, Radiotherapy Unit, Monza , Italy; 23 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Radiation Oncology, Bologna , Italy; 24 Azienda Ospedaliera SS. Antonio e Biagio e Cesare Arrigo, Radiation Oncology , Alessandria, Italy; 25 Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Radiation Oncology Unit, Campobasso, Italy; 26 Azienda U. S. L. della Valle d'Aosta, Department of Radiotherapy, Aosta , Italy; 27 Veneto Institute of Oncology-IRCCS, Radiotherapy and Nuclear Medicine Unit, Padova, Italy; 28 Ospedale Sanremo-ASL 1 Imperiese, Radiotherapy Unit, Sanremo, Italy; 29 University of Rome Tor Vergata, Department of Biomedicine and Prevention, Radiation Oncology, Roma, Italy; 30 "G. D'Annunzio" University of Chieti-Pescara, Laboratory of Biostatistics, Department of Medical, Oral and Biotechnological Sciences, Chieti, Italy; 31 "G. D'Annunzio" University of Chieti-Pescara, Department of Neuroscience, Imaging and Clinical Sciences, Chieti , Italy Purpose or Objective Concurrent chemo-radiotherapy (CRT) is the standard treatment for anal cancer. Intensity-modulated radiotherapy (IMRT) was proved to reduce severe acute and late toxicities. For elderly patients’ treatment needs often to be modified. Alternative treatment strategies are not described in guidelines and little evidence is available in the literature. Based on these considerations, we have analysed toxicity and treatment outcomes in patients ≥ 70 years with anal cancer treated with curative CRT. Materials and Methods In 2020 a multi-institutional retrospective study on behalf of AIRO gastrointestinal study group was conducted to evaluate the pattern of care and clinical outcomes of anal cancer patients treated with IMRT techniques (RAINSTORM: RAdiotherapy with INtenSiTy mOdulated techniques in the treatment of anal caRcinoMa: a multicenter retrospective observation study). Currently a subgroup analyses according to the distribution of variables in age subgroups (<70 years, n=694 and ≥ 70 years, n= 283) was conducted. The univariate Cox proportional hazards model reports the hazard ratio (HR) and the 95% confidence interval (95% CI) for age (<70 vs. ≥ 70), ECOG PS ( ≥ 1 vs. 0), HIV (Yes vs. No), HPV (Yes vs. No) and baseline Haemoglobin level (Hb <10 vs. ≥ 10) as independent factors impacts on clinical outcomes: Overall Survival (OS) and Disease-Free Survival (DFS). Toxicities were retrospectively graded according to Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0. Results Older patients were more likely to have worse baseline performance status (PS 1 or 2) (35.3% vs. 15.7%, p <0.001), and more HIV+ status (82.7% vs. 72.9%, p <0.001), but otherwise baseline characteristics were similar. Older patients received less concomitant chemotherapy (88.0% vs. 97.4%, p <0.001) with similar compliance in terms of overall treatment times and treatment interruptions. No statistically significant increase has been reported in grade ≥ 3 acute and late toxicities in older patients (Table1). Stratifying by age, the probability of surviving 60 months was 85.6% (SE=1.70%) for age <70 years and 75.7% (SE=3.41%) for age ≥ 70 years (p=0.0001); for DFS was 78.30% (SE=1.93%) for age <70 years and 68.10% (SE=3.91%) for age ≥ 70 years (p= 0.0033). In patients with age ≥ 70 years a statistically significant association was found between HIV positive status and Hb <10 with OS and between Hb <10 and DFS.