Abstract Book

S16

ESTRO 37

Purpose or Objective To compare patterns of care for elderly patients versus younger patients with stage III non-small cell lung cancer (NSCLC) not treated surgically using the National Cancer Database (NCDB). We hypothesize that elderly patients are less likely to receive curative treatments, including concurrent chemoradiation (CCRT), compared to younger patients. Material and Methods We identified patients from the NCDB between 2003 and 2014 with non-surgically treated stage III NSCLC. We defined elderly as ≥70 years old and non-elderly as <70 years old. We categorized patients as having no treatment, palliative treatment (chemotherapy alone, radiation therapy (RT) alone<59.4 Gy or chemoradiation (CRT)<59.4 Gy), or definitive treatment (RT alone≥59.4 Gy or CRT≥59.4 Gy). Patients treated with CRT were further subdivided into those receiving CCRT vs. those treated with sequential CRT (SCRT). CCRT was defined as chemotherapy delivered within 30 days prior to or after initiation of RT while SCRT was defined as RT delivered >30 days after initiation of chemotherapy. Differences in treatment between the elderly and non-elderly were tested using the χ 2 test. Results We identified 57,602 elderly and 55,928 non-elderly patients. The mean age was 77.5 years (SD=5.3) in the elderly and 60.2 years (SD=7.0) in the non-elderly. The elderly were less likely (1) to have no comorbidities (57.7% vs. 62.9%, p<.0001), (2) to be treated at academic centers (25.5% vs. 30.3%, p<.0001), and (3) to have stage IIIB disease (44.5% vs. 50.0%, p<.0001) compared to non- elderly patients. More elderly patients received no treatment (24.5% vs. 13.2%, p<.0001) and the elderly were less likely to receive definitive treatment (51.1% vs. 59.7%, p<.0001). Chemotherapy as part of a definitive treatment course was included less often in the elderly: 21.1% of the elderly received definitive RT alone compared to 6.5% for the non-elderly, p<.0001. In patients receiving definitive CRT, a higher proportion of the elderly received SCRT compared to the non-elderly (16.3% vs. 15.4%, p=.016). Overall, CCRT was delivered in a significantly smaller proportion of elderly vs. non- elderly patients (66.0% vs. 78.9%, p<.0001 in patients treated with definitive intent; 32.0% vs. 44.5%, p<.0001 in patients receiving any treatment; and 24.2% vs. 38.6%, p<.0001 amongst all patients). Conclusion In this large study of patients with stage III NSCLC not treated surgically, elderly patients were less likely to receive any treatment or treatment with definitive intent compared to the non-elderly. When a definitive treatment course was delivered, more than 20% of elderly patients received RT alone. The lack of use of concurrent or sequential chemotherapy in the elderly with stage III NSCLC suggests that the optimal treatment approach for this vulnerable population remains undefined. PV-0041 Hand grip strength: independent prognostic selection test for OS in stage I NSCLC treated with SBRT S. Peeters 1 , B. Chris 2 , B. Jacques 1 , S. Martijn 3 , D.R. Dirk 4 1 MAASTRO Clinic, Radiation Oncology, Maastricht, The Netherlands 2 Hasselt University, Faculty of Medicine and Life Sciences, Hasselt, Belgium 3 University Maastricht, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands 4 Maastricht University Medical Center, Radiation Oncology, Maastricht, The Netherlands Purpose or objective Medically inoperable stage I non-small cell lung cancer (NSCLC) patients treated with stereotactic body

Purpose or Objective Previous study by our group showed that increasing the radiotherapy (RT) dose in an overall treatment time (OTT) of less than 6 weeks on basis of the isotoxic principle is feasible and could potentially increase the overall survival (OS) with without increasing the toxicity. No data were yet available for IMRT treated patients. Here we report on the results of elderly patients (≥ 75 years) treated within the study with IMRT. Material and Methods From 04-05-2009 until 26-04-2012, 300 patients with stage III NSCLC, of whom 76 ≥ 75 years (25.3%), treated with either RT alone (RT), sequential (sCRT) or concurrent (cCRT) chemo-RT were included in this phase II trial. An OS update was done in October 2017. The primary endpoint of the study was OS, with toxicity as a secondary endpoint. Patients in the concurrent arm received 1 cycle of cisplatin-etoposide followed by two cycles of the same chemotherapy with concurrent radiotherapy (IMRT, 45 Gy BID followed by 2 Gy daily fractions to the maximal organ at risk constraints), while patients in the sequential arm received 3 cycles of cisplatin-etoposide followed by the same RT regimen. Results 32% of patients ≥ 75 years received cCHRT, 29% sCHRT and 39% RT. The mean total tumor dose was 66.7 +/- 5.5 in the sCRT and 66.2 +/- 27.6 Gy in the cCRT group. 96% of the elderly patients treated with cCRT had a WHO PS ≤ 1. OS was significantly worse compared to the younger population (median OS 15.6 vs 19.8 months, 5 yr OS 13.2% vs 24.1%, p=0.013). The worse OS was confined to the patient group treated with cCRT, while OS was comparable for sCHRT and RT compared to patients < 75 years treated with the same regimen. No difference in toxicity scores as scored by the physician were found between the older and younger patientpopulation. Conclusion Although relatively fit elderly patients were assigned to cCHRT, survival was worse compared to the younger patient population, and worse compared to patients ≥ 75 yrs treated with sCRT. A recent retrospective study in unselected stage III NSCLC patients ≥ 70 years did not show a survival benefit with cCRT compared to sCRT or RT either (Driessen et al, RTO 2016). In contrast to the results with 3D conformal RT, isotoxic dose escalation was not feasible with IMRT. These findings underscore the need for prospective studies including geriatric assessment in this understudied patient population to identify predictive factors for treatment outcome, including quality of life and patient reported outcome measures. PV-0040 Patterns of care for the elderly with non- surgically treated stage III non-small cell lung cancer E.D. Miller 1 , J.L. Fisher 2 , K.E. Haglund 1 , J.C. Gre cula 1 , M. Xu-Welliver 1 , E.M. Bertino 3 , K. He 3 , P.G. Shields 3 , D.P. Carbone 3 , T.M. Williams 1 , G.A. Otterson 3 , J.G. Bazan 1 1 Ohio State University Wexner Medical Center, Department of Radiation Oncology, Columbus, USA 2 Ohio State University, College of Public Health, Columbus, USA 3 Ohio State University Wexner Medical Center, Department of Internal Medicine- Division of Medical Oncology, Columbus, USA