ESTRO 37 Abstract book

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ESTRO 37

EP-1417 SBRT for liver oligometastases:predictive factors of local responce response by 18F-FDG-PET/CT S. Fersino 1 , R. Mazzola 1 , D. Aiello 1,2 , F. Gregucci 1 , N. Giaj-Levra 1 , A. Fiorentino 1 , F. Ricchetti 1 , R. Ruggieri 1 , F. Alongi 1,3 1 Sacro Cuore Don Calabria Cancer Care Center, Radiation Oncology, Negrar, Italy 2 University of Palermo, Radiation Oncology School, Palermo, Italy 3 University of Brescia, Radiation Oncology, Brescia, Italy Purpose or Objective To investigate metabolic parameters as predictive of local response after Stereotactic Body Radiation Therapy (SBRT) for liver-oligometastases Material and Methods Inclusion criteria of the present retrospective study were: a) metachronous liver oligometastases; b) absence of progressive disease≥6months (mo); c) metastases≤3; d) BED > 100Gy; e) evaluation of SBRT-response by means of 18-FDG-PET/CT for at least two subsequent evaluations; f) Karnofsky performance status >80; g) life-expectancy>6 mo. The following metabolic parameters were defined semi-quantitatively for each metastases: 1) SUV-max; 2) SUV-mean; 3) Metabolic Tumor Volume (MTV)-total tumor volume with a SUV ≥ 2.5; 4) Total Lesional Glycolysis (TLG)-SUV mean × MTV. Local control was defined as absence of recurrence in the field of irradiation. Results Between October 2014 and February 2017, twenty-two patients for a total of forty-one liver metastatic lesions met the inclusion criteria of the study. At the time of the analysis, the median follow up was 16.3 mo (range, 6-32 mo). The most frequent primary tumor sites were colorectal (31%) and lung (24%). Pre-SBRT, median SUV- max was 8.74 (range, 4.49 – 23.59), median SUV-mean was 4.6 (range, 3 – 7.46), median MTV was 5.74 cc (range, 0.9-80.64) and median TLG was 24.1 (range, 3.6 - 601.5). High values of SUV-mean and SUV-max pre-SBRT related to local failure. In detail, at the time of the analysis, the rate of in-field failure was 66.7% in case of pre-SBRT SUV-mean>5 and 61.1% for pre-SBRT SUV- max>10. At statistical analysis, metastases with SUV- mean>5 (p 0.04; OR 4.75, Sensitivity = 50%, Specificity = 82.6%, AUC 0.66) and SUV-max>10 (p 0.02; OR 5.03, Sensitivity = 69%, Specificity = 70%, AUC = 0.69) showed higher rates of in field-failure compared to the remaining lesions. Conclusion According to current findings, pre-SBRT SUV max and SUV mean could predict response in liver oligometastases. To date, biological equivalent dose represents a predictive parameter of local control for liver metastases submitted to SBRT. The present results could be integrated in SBRT strategy in order to customize dose prescription taking into account the single-metastases metabolic profile. EP-1418 SBRT for unresectable locally advanced pancreatic cancer: clinical outcomes on 100 patients T. Comito 1 , C. Franzese 1 , E. Clerici 1 , L. Di Brina 1 , A. Tozzi 1 , C. Iftode 1 , D. Franceschini 1 , G. Carta 1 , S. Tomatis 1 , M. Scorsetti 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgey, Rozzano Milan, Italy Purpose or Objective Pancreatic adenocarcinoma is characterized by a poor prognosis. Surgery is the gold standard of care, however more than 50% of patients are unresectable at the time of diagnosis. In patients with locally advanced pancreatic cancer (LAPC), the integration of chemotherapy (CT) and chemo-radiation treatment (CRT) is the current therapeutic option, associated with a significant toxicity rate and with a disappointing overall survival (OS). In the last years, the role of stereotactic body radiotherapy

(SBRT) in the treatment of LAPC was investigated. Higher local control related to the high doses employed, short overall treatment time and sequential integration with systemic therapy, represent the crucial advantages of SBRT over conventional CRT. Objective of this prospective study is to assess the efficacy of SBRT in patients with inoperable LAPC. Material and Methods Patients with unresectable LAPC with maximum tumor diameter ≤ 5cm, without limph node disease and without distant metastasis were treated with SBRT, after multidisciplinary board evaluation. Prescription dose was 45Gy in 6 fractions. Primary end-point was freedom from local progression (FFLP). Secondary end-points were overall survival (OS), progression-free survival (PFS), and toxicity. Local control (LC) was defined according to RECIST v1.1 criteria. Acute and late toxicity was scored according to the NCI Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Results Between January 2011 and December 2016, 100 patients (44 male-56 female) with LAPC were treated with SBRT at Humanitas cancer Center. Median age was 71 years (range 41-88 years). 57 patients (57%) received CT before SBRT, for a median time of 5 months (range 3 - 10 months). In 44 patients (77%) gemcitabine-based CT was administered ( 4 gemcitabine alone, 21 GEMOX, 9 PEX-G, 10 gemcitabine-nab paclitaxel), whereas 13 patients (33%) received FOLFIRINOX. Median follow-up was 86 months (range 2-88 months). FFLP was 82% and 76% at 1 and 2 years, respectively. At univariate (p<0.03) and multivariate analysis (p<0.001), lesion size was significant for LC. Median PFS was 7 months (95% CI 4.76-8.23). Median OS was 13 months (95% CI 8.76-13.21). CT administered before SBRT (p< 0.005) and FFLP (p<0.002) were significantly correlated with OS. Grade 3 gastrointestinal toxicity was detected in 2% of patients. Conclusion SBRT is an effective and safe local therapy for selected patients with LAPC. Our results suggest that the stereotactic treatment may be a promising therapeutic option in the multi-modality treatment of these patients. EP-1419 Outcomes according to radiation fields of neoadjuvant chemoradiotherapy for esophageal cancer N. Choi 1 , W. Jeon 1 , H.C. Kang 1 , H.J. Kim 1 , S. Kim 2 1 Seoul National University Hospital- Seoul National University College of Medicine, Radiation Oncology, Seoul, Korea Republic of 2 Seoul Metropolitan Government Boramae Medical Center- Seoul National University College of Medicine, Radiation Oncology, Seoul, Korea Republic of Purpose or Objective The purpose of this study is to analyze the treatment outcomes and patterns of failure after neoadjuvant concurrent chemoradiotherapy (CCRT) and surgery for esophageal cancer. Material and Methods Medical records of 62 esophageal squamous cell carcinoma patients treated with neoadjuvant CCRT from 2005 to 2014 were retrospectively reviewed. The median follow-up duration was 12.8 months (range 1.3-141.7). Results Of the 62 patients who fully completed neoadjuvant CCRT, 77.4% underwent subsequent surgery. The most common cause rendering patients to be unsuitable for surgery was disease progression. Failure occurred in 25 (52.1%) patients, of which distant failure was most common. Locoregional failure was observed in 13 (27.1%) patients, of which 8 and 5 patients had in-field and out- of-field recurrences, respectively. The 2-year progression-free survival (PFS) rate was 48.6% and 2-year overall survival (OS) rate was 53.8%. On multivariate analysis, clinical stage III-IV before surgery (HR 6.8, 95%