ESTRO 38 Abstract book

S780 ESTRO 38

model, diabetes did not independently affect OS. After nCRT and surgery 25% (no DTM2) and 38% (DTM2) of patients had a pathologic complete tumor response (p=0.721). When stratifying patients by therapy, higher rates of anemia were seen in patients with DTM2 after nCRT (≥II° 60% vs. 34%, p=0.0001). However, this difference was not confirmed in patients undergoing nCRT. In addition, no significant differences were seen for the rates of leukopenia and thrombocytopenia between both groups. Conclusion While there was a small trend towards an increased OS in patients without DTM2, DTM2 did not affect PFS or histopathologic tumor response in patients undergoing neoadjuvant or definite chemoradiation for esophageal squamous cell carcinoma. However, higher rates of anemia were seen in diabetic patients undergoing nCRT. EP-1436 SBRT for large hepatocellular cancer unsuitable for other therapies: Results from a clinical audit K. George 1 , S. Chopra 1 , R. Engineer 1 , K. Rajamanickam 1 , S. Mechanery 2 , K. Joshi 2 , J. Swamidas 2 , S. Patkar 3 , P. Patil 4 , V. Ostwal 5 , S. Mehta 4 , M. Goel 3 1 Tata Memorial Hospital, Radiation Oncology, Mumbai, India ; 2 Tata Memorial Hospital, Radiation Physics, Mumbai, India ; 3 Tata Memorial Hospital, Surgical Oncology, Mumbai, India ; 4 Tata Memorial Hospital, Gastroenterology- Department of digestive diseases and clinical nutrition, Mumbai, India ; 5 Tata Memorial Hospital, Medical Oncology, Mumbai, India Purpose or Objective To evaluate the outcomes of liver stereotactic radiotherapy (SBRT) in the treatment of large hepatocellular carcinomas (HCC) that are unsuitable for, or refractory to prior liver-directed therapies. Material and Methods Between March 2015 and June 2018, patients with primary HCCs refractory or progressive to or unsuitable for treatment with loco-regional therapies were treated with SBRT. Only patients of Child status A5-B7 and with adequate normal liver reserve of 700 cc or higher were eligible. SBRT was delivered using IMRT or VMAT using video bio-feedback based deep inspiration breath-hold technique to a total dose of 25-54 Gy in 5-6 fractions. Overall survival (OS) and progression free survival (PFS) were determined by Kaplan-Meier analysis. In-field, out- of field recurrences and toxicities were also assessed. Univariate and multivariate analysis was performed to assess impact of various prognostic factors on outcome. Results Twenty one patients with large HCCs were treated. The median tumour diameter was 9.6 cm (5-21) and median GTV volume was 350 cc (32.9-2541.5 cc). Overall, 57.1 % patients were BCLC B and 42.9 % patients were BCLC C. Majority of the patients (80.9%) had some form of previous therapy (TACE, Sorafenib, RFA, PVE). The median SBRT dose prescription was 42Gy/6 fractions (24-54 Gy). The median normal liver volume was 1080 cc (423-1979 cc) and median normal liver dose was 15.3 Gy. At a median follow up of 9 months (1-26 mths), only 9.5% patients (n=2) had in-field tumour progression, 14.3% (n=3) had out of field new lesions and 33.3% (n=7) had extra-hepatic distant failure. The 1 year and 2 year local control rate was 88% and 43% respectively. The median overall survival for the entire cohort was 13 months (3-36) respectively. The 1- and 2 - year overall survival rates were 51% and 15% respectively. Overall rate of grade ≥ III toxicity attributable to SBRT was 14%. Patients with Child A 5 liver function status had a better overall survival (21 months) than Child A 6 and Child B7 patients (11 months and 8 months respectively) [p value = 0.01]. BCLC class B patients had a better overall survival (17 months) than BCLC C (8 months), however this was not significant [p

gastrointestinal toxicity occurred in 14.2% (8 pts). Three pts (5.3%) had bacterial pneumonia (1 pt G5). Responses: 55/56 pts were available (1 pt early lost). Median time to restaging was 42 days (14-87 d). CT/PET showed local RP in 27 pts, SD 9 pts, RC 18 pts, PD in 1pt. Median time from CT/RT to surgery was 61 days (15-148). Forty-three pts (75%) underwent surgery, 13 excluded (7 for PD, 3 for worsening clinical condition, 1died, 1 lost, 1 pt had cCR). One pt underwent urgent surgery 15 days after CT/RT because of aorto-esophageal fistula. Post-surgery stage was T0: 7pts (16%), T1: 9 pts (22%), T2: 12 pts (28%), T3: 14 pts (32%), T4: 1 pt (2%); N0: 25 pts (58%), N+: 18 pts (42%). Forty-one/ 43 pts (95.3%) had R0. Mandard TRG was: TRG1: 7 pts (16.5%), TRG2: 8 pts (18.5%), TRG3: 22 pts (51%), TRG4: 6 pts (14%). At a median follow up of 17.4 months (4.1-49.4 m): 25/43 pts (58%) are free from disease, and 18/43 pts (42%) had a progression disease (2 of them had a local relapse concomitant to distant progression). Median time to progression was 20 months (1.5-96.9 m). Median OS of all pts was 17.4 months (3-49.4 m). Conclusion Our data seems to be comparable to CROSS data in term of R0 and toxicity profile. In patients treated with IG-IMRT and chemotherapy, lymphopenia was the major cause of not optimal tolerability of treatment and could explain the onset of pneumonia and the difference between TRG responses. EP-1435 Impact of diabetes on outcome and toxicity of chemoradiation for esophageal squamous cell carcinoma D. Bierbaumer 1 , S. Muench 1 , B. Haller 2 , D. Habermehl 1 , P.T. Pfluger 3 , K. Stemmer 3 , S.E. Combs 1 1 Klinikum rechts der Isar- Technical University Munich- Ismaninger Str. 22, Department of Radiation Oncology, 81675 Munich, Germany ; 2 Klinikum rechts der Isar- Technical University Munich- Grillparzerstr. 18, Insitute of Medical Informatics- Statistics and Epidemiology- Medical School, 81675 Munich, Germany ; 3 Helmholtz Zentrum München- Ingolstädter Landstraße 1, Insitue for Diabetes and Obesity, 85764 Neuherberg, Germany Purpose or Objective For patients with locally advanced squamous cell carcinoma of the esophagus (SCC), international guidelines recommend neoadjuvant chemoradiation (nCRT) with subsequent surgery or definite chemoradiation (dCRT) for patients unsuitable for surgery. Until now, there are conflicting data regarding the impact of diabetes on the effectiveness and toxicity of chemoradiation in these patients. Aim of this study was to compare oncologic outcome and toxicity between patients with and without diabetes mellitus type 2 (DTM2) undergoing nCRT or dCRT for locally advanced SCC. Material and Methods In total, 108 patients with locally advanced SCC were included in this analysis. Within this cohort, we identified 25 patients with DMT2 with a median haemoglobin A1c (HbA1c) of 6.7%. Baseline and tumor characteristics, oncologic outcome and toxicity of these patients were compared to 83 patients without diabetes. For the analysis of toxicity, patients were stratified by therapy. Results Patients with DTM2 were had a significantly higher body mass index (BMI) than patients without DTM2 (median BMI 27.2 vs. 22.7 Kg/m², p=0.001). However, no further differences regarding baseline and tumor characteristics were seen between both patient groups. In addition, there was no significant difference in terms of progression-free survival (median PFS 14.0 months (DTM2) vs 13.9 months (no DTM2), p=0.147). Concerning OS, there was a trend towards an increased OS in patients without DTM2 (median OS 23.3 months (DTM2) vs. 25.6 months (no DTM2), p=0.095). However, within a multivariable Cox regression