ESTRO 2020 Abstract Book

S561 ESTRO 2020

Material and Methods We included patients with lung or liver metastases. Patients were candidate to SBRT if a maximum of 5 metastases were diagnosed in up to 2 sites. End points of the present analysis were LC, PFS, and OS. The binary classification tree approach with RPA was applied in order to stratify the patients into risk groups based on OS and PFS. Results 218 patients were treated with SBRT on 371 metastases. Majority of patients (56%) was treated on single lesion, followed by 2 (26.1%) and 3 lesions (14.7%). Median follow- up was 22.7 months. Rates of LC were 84.2% at 1 year and 73.8% at 3 years. Rates of PFS at 1 and 3 years were 42.2% and 14.9%, respectively. RPA identified 3 classes for PFS, according to age and number of metastases with 3 years PFS of 30.6%, 13.5% and 8.4%. Overall survival was 87.2% at 1 year, 51.9% at 3 years, and 36.8% at 5 years. RPA identified 3 nodes. Class 1 included patients with liver metastases (3y OS 35.2%). Class 2 included patients with lung metastases and DFI ≤ 48 months (3y OS 65%). Class 3 included patients with lung metastases and DFI > 48 months (3y OS 73.5%). Conclusion Stereotactic body radiation therapy can be considered an effective treatment for the management of liver and lung metastases from CRC. With RPA we identified prognostic risk class in order to define patients who could benefit the most from SBRT. PO-1056 Chemoradiation for esophageal cancer using carboplatin and paclitaxel: A single centre experience S. Gomberg 1 , A. Gaya 1 , K. Owczarczyk 1 , A. Qureshi 1 1 Guy's and St Thomas' NHS Foundation trust, Clinical Oncology, London, United Kingdom Purpose or Objective Definitive chemoradiation (CRT) remains the non- operative treatment of choice for patients with localized carcinoma of the esophagus. Cisplatin with fluorouracil (CF) or capecitabine, has been considered the standard chemotherapy combination for these patients. However, this combination is often considered too toxic for many patients and precludes them from receiving chemoradiotherapy. In 2012 the CROSS trial showed efficacy of carboplatin and paclitaxel (CT) in combination with radiotherapy in the neoadjuvant setting, with minimal toxicity. This has resulted in interest in this combination for definitive CRT. We introduced this chemotherapy regimen in May 2015 as an alternative to CF. Here we present our experience of definitive CRT with concurrent CT. Material and Methods Data was collected retrospectively on all patients who received CRT for oesophageal cancer between May 2015 and January 2018 at Guy’s and St Thomas’ NHS Foundation Trust, London. Results Between May 2015 and January 2018 74 patients received definitive CRT for oesophageal cancer. 39 patients received CF and 35 received CT. Patient characteristics were similar for the two groups (see table). Median follow- up was 17.9 months. The majority of patients in both groups received 50Gy in 25#, 71.8% vs 82.9%). More patients in the CF group received some form of chemotherapy prior to receiving chemoradiation (28.2% vs 14.3%). Similar numbers of patients in each group completed the prescribed course of both radiotherapy and chemotherapy without deviation from the clinical protocol (53.8% vs 51.4%). Although admission to hospital during definitive CRT was higher in the CF group (56.4% vs 37.1%), mean number of inpatients days was lower (11.1 days vs 15.8 days). During this period a greater proportion of patients receiving CF had a good radiological response (PR 66.7% vs 48.6%) and endoscopic response (cCR 92.3% vs

68.6%, p=0.008) following treatment. More patients receiving CF had relapsed at a distant site (50.0% vs 14.3%), whereas those receiving CT were more likely to have local relapse (16.7% vs 50.0%, p=0.06). Median OS was not significantly different between the two groups (not reached vs. 33.6 months). No significant difference in median PFS was observed (18.0 months vs. 21.2 months). Subgroup analysis based on histological subtype showed no significant differences (median OS; adeno-CT = 24.8 months, adeno-CF = 14 months, SCC-CT = 33.6 months, SCC-CF = not reached).

CF CT

Age 66 75 PS 0-1 94.9% 85.7% T3 61.5% 62.9% N+ 78.9 57.1

Conclusion In our cohort of patients receiving definitive CRT with CT, treatment was well tolerated with lower admission rates compared to those receiving CF. Treatment outcomes were similar with no significant difference between median PFS and OS. Although not significant a trend towards improved median OS was observed for patients with adenocarcinoma receiving CT. Our findings suggest CT with definitive radiotherapy is a suitable alternative to treat oesophageal cancer in patients in who cannot receive CF. PO-1057 Influence of brachytherapy on local control of locally advanced esophageal carcinomas D. Scepanovic 1 , M. Lukacovicova - Kolarcikova 1 , M. Pobijakova 1 , M. Dzongov 1 1 National Cancer Institute, Radiation Oncology, Bratislava, Slovakia Purpose or Objective Despite developments in the treatment of esophageal carcinoma, the outcomes remain poor. Retrospective and single institution trials suggest that there is no advantage of adding brachytherapy to external beam radiation. However, the aim of our analysis is to show the influence of brachytherapy on local control in patients with locally advanced esophageal carcinomas. Material and Methods Seventy patients (66 men and 4 women, median age of 64 years) with locally advanced esophageal cancer were treated with chemoradiotherapy between 2008 to 2012 in our institute. Fifty-four patients had squamous cell carcinomas and 16 had adenocarcinomas. External beam radiotherapy (EBRT) combined with chemotherapy (ChT), EBRT/ChT followed by surgery and combined EBRT/intraluminal brachytherapy (ILBT) were performed in 31, 19 and 20 patients (pts), respectively. Patients with definitive EBRT/ChT received 50-60 Gy over 5-6 weeks with cisplatin and fluorouracil-based ChT, neoadjuvant group of patients received 41.4-50.4 Gy over 4.5-5.5 weeks with the same ChT as the EBRT/ChT group or combined paclitaxel and carboplatine. ILBT with high dose-rate Ir- 192 source was applied after pts completed EBRT as a boost therapy. Brachytherapy was given 2 weeks after the last fraction of EBRT with a fractional dose of 500 cGy, with interval of 1 week between fractions to the total dose of the 1000 cGy. Results At a median follow-up of 16 months, the incidence of local recurrence was 4% in pts with ILBT, but 24% of pts without ILBT (p = 0.0268). There was no statistically significant difference between the two groups of pts regarding strictures as a late toxicity (p=0.0941). However, among pts with ILBT one had esophagobronchial fistula. The two-