ESTRO 37 Abstract book

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ESTRO 37

Results Primary end point was pCR (pathologic Complete Response: absence of viable tumor at the primary site or locoregional lymph nodes). A pPR was defined as >50% tumor mass regression in the histology specimen. Overall down staging occurred to all pts. Group B experienced a pCR in 3/15 pts (20%), while no pCR was observed in pts with KRAS mutation (Group A).The most common grade 3 adverse events were skin reaction (acneiform rash) in 5/15 pts (33%) of group B , while grade 3 mucositis and diarrhea occurred in 2 (14%) and 4 (26%) pts of Group A & B respectively Conclusion C etuximab monotherapy on a weekly basis after completion of CCRT with capecitabine & 3D-CRT is feasible , well tolerated and has demonstrated efficacy as better outcome , compared to capecitabine & 3D-CRT alone, regarding upfront preoperative tx of pts with locally advanced rectal cancer. EP-1467 Cetuximab,Capecitabine ,3D-CRT vs capecitabine ,3D-CRT as preoperative treatment in rectal cancer P. Mavroeidi 1 , A. Varveris 1 , A. Spanakis 1 , C. Varveris 1 1 Heraklion University Hospital, Radiotherapy-Oncology, Heraklion- Crete, Greece Purpose or Objective To compare treatment outcome of 2 preoperative chemoradiotherapy regimen for rectal cancer. Material and Methods From September 2010 to September 2017 ,30 pts with histology confirmed staged T2-4N0-2M0 rectum adenocarcinoma were enrolled and divided according to their KRAS mutation status in 2 groups of 15 pts each (Group A: KRAS mut+, Group B :KRAS mut-). KRAS status was correlated to tumor down staging and pathological response. All pts had ECOG performance status 0-1 and the median age was 64 years (range 52-76 yrs). 3D-CRT (three dimensional conformal radiotherapy) of 50.4 Gy in 28 daily fraction with 18 MV Photons was given. Capecitabine was administered daily during RT at a dose of 1600mgr/m 2 /day. One more cycle was given at week 4 and 5 after RT (for 14 consecutive days). Group B patients were treated with Cetuximab with a loading dose of 400mgr/m 2 on day 1, followed by 250 mgr/m 2 on days 8,15,22,29 of treatment , continued by weekly administration (after completion of CCRT) for 8 weeks until surgery. The infusion was withheld or discontinued for defined adverse events , as grade 3 skin toxicity or hypersensitivity reactions. Surgery followed 8 wks after CCRT completion, to remove the primary tumor according to the principles of total mesorectal excision, either by low anterior resection, abdominoperineal excision or intersphincteric resection. Results Primary end point was pCR (pathologic Complete Response: absence of viable tumor at the primary site or locoregional lymph nodes). A pPR was defined as >50% tumor mass regression in the histology specimen. Overall down staging occurred to all pts. Group B experienced a pCR in 3/15 pts (20%), while no pCR was observed in pts with KRAS mutation (Group A).The most common grade 3 adverse events were skin reaction (acneiform rash) in 5/15 pts (33%) of group B , while grade 3 mucositis and diarrhea occurred in 2 (14%) and 4 (26%) pts of Group A & B respectively.

Demographic data (e.g. age, sex), data of main and co- diagnoss (e.g. coronary heart diseases, strokes, diabetes), previous and current treatments (e.g. previous RT, systemic therapy), clinical status before RT (e.g. status of pain, shortness of breath, Karnofsky Performance Status, BMI, medication), laboratory findings and the clinical timeline of RT (e.g. duration, volume, dose, fraction) were analysed. The median follow-up time was 11.0 months. To determine specific risk groups depending on their status of survival (alive or dead) and their individual results in a constructed score formula we generated a survival tree by using “R”. Results A multivariate Cox regression analysis identified status of pain (p<0.001), hospitalization during the last 6 months (p=0.004), the Karnofsky Performance Score (p=0.045) and the Body Mass Index (p=0.043) as influencing factors for life expectancy of the analysed patients. These factors were used to create a score formula. In connection three prognostic groups were defined: The group “low risk“ (X ≤ 0.188), „intermediate risk“ (0.188< X ≥0.66) and „high risk“ (X>0.66). The 1-year-survivals vary between 60.3% for „low risk“, 30.4% for „medium risk“ and 0% for „high risk“. Conclusion By using the proposed new score ( TUM -Score) derived from individual patient and treatment parameters, we intend to better estimate the individual patient prognosis. Risk stratification in low, intermediate or high risk groups will further help to tailor RT treatment schedules in a more adequate manner EP-1466 Cetuximab,Capecitabine ,3D-CRT vs capecitabine ,3D-CRT as preoperative treatment in rectal cancer. P. Mavroeidi 1 1 Heraklion University Hospital, Radiotherapy-Oncology, Heraklion- Crete, Greece Purpose or Objective Purpose/Objective; To compare treatment outcome of 2 preoperative chemoradiotherapy regimen for rectal cancer. Material and Methods From September 2010 to September 2017 ,30 pts with histology confirmed staged T2-4N0-2M0 rectum adenocarcinoma were enrolled and divided according to their KRAS mutation status in 2 groups of 15 pts each (Group A: KRAS mut+, Group B :KRAS mut-). KRAS status was correlated to tumor down staging and pathological response. All pts had ECOG performance status 0-1 and the median age was 64 years (range 52-76 yrs). 3D-CRT (three dimensional conformal radiotherapy) of 50.4 Gy in 28 daily fraction with 18 MV Photons was given. Capecitabine was administered daily during RT at a dose of 1600mgr/m 2 /day. One more cycle was given at week 4 and 5 after RT (for 14 consecutive days). Group B patients were treated with Cetuximab with a loading dose of 400mgr/m 2 on day 1, followed by 250 mgr/m 2 on days 8,15,22,29 of treatment , continued by weekly administration (after completion of CCRT) for 8 weeks until surgery. The infusion was withheld or discontinued for defined adverse events , as grade 3 skin toxicity or hypersensitivity reactions. Surgery followed 8 wks after CCRT completion, to remove the primary tumor according to the principles of total mesorectal excision, either by low anterior resection, abdominoperineal excision or intersphincteric resection.