ESTRO 38 Abstract book

S795 ESTRO 38

or neoadjuvant short-course radiotherapy, were included in this analysis. Within this cohort, we identified 20 patients with diabetes mellitus type 2 (DMT2) with a median haemoglobin A1c (HbA1c) of 6.2%. Baseline and tumor characteristics, oncologic outcome and toxicity of these patients were compared to 53 patients without diabetes. Results Patients with DMT2 were significantly older than patients without diabetes (median age 68 vs. 60 years; p=0.006). In addition there was a strong trend towards an increased body mass index (BMI) in patients with DTM2 (median BMI 26.8 vs. 24.6 Kg/m², p=0.09). After a median follow-up of 49.7 months, there were no significant differences regarding progression-free survival (PFS) between both groups. In contrast, median overall survival (OS) was significantly higher in patients without DTM2 (median OS not reached), compared to patients with DTM2 (45.2 months, p=0.006). DTM2 was also confirmed to independently affect OS in a multivariable Cox regression model (p=0.029). After nCRT, pathologic complete response was seen in 10% of patients with DTM2 and in 7% of patients without DTM2, (p=0.944). Regarding toxicity, diabetic patients had a higher rate of anemia than patients without diabetes (≥II° 43% vs. 10%, p=0.004). However, no significant differences were seen for the rates of leukopenia (≥II° 21% (DTM2) vs. 14% (no DMT2), p=0.377) and thrombocytopaenia (≥II° 0% (DTM2) vs. 0% While there were no significant differences for PFS or the rate of complete pathologic remission after nCRT, median OS was significantly higher in patients without DMT2 than in diabetic patients. A significant difference was also seen for the rate of anemia after nCRT, but not for leukopenia or thrombocytopenia. EP-1466 Preoperative chemoradiation with raltitrexed in locally advanced rectal cancer: a systematic review E. Galofaro 1 , V. Panni 1 , M. Buwenge 1 , A. Guido 1 , G. Macchia 2 , F. Deodato 2 , V. Picardi 2 , M. Boccardi 2 , S. Mignogna 3 , C. Pozzo 3 , F. Di Fabio 4 , A.G. Morganti 1 , S. Cammelli 1 1 Policlinico Universitario S. Orsola Malpighi, Radiation Oncology Center- Department of Experimental- Diagnostic and Specialty Medicine - DIMES, Bologna, Italy ; 2 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Radiotherapy Unit, Campobasso, Italy ; 3 Fondazione di Ricerca e Cura “Giovanni Paolo II”, Medical Oncology Unit, Campobasso, Italy ; 4 Policlinico Universitario S. Orsola Malpighi, Department of Medical Oncology, Bologna, Italy Purpose or Objective Neoadjuvant chemoradiotherapy with capecitabine followed by surgery is the standard therapy in patients with locally advanced rectal cancer (LARC). Raltitrexed (RTX) is a specific TS inhibitor with a radiosensitizing effect. No systematic reviews have been performed to analyze the efficacy of RTX based chemoradiotherapy in LARC. The aim of this study was to systematically review available literature to analyze the safety and efficacy of RTX based chemoradiation in terms of pathological CR. Material and Methods A systematic review of literature published from the earliest date possible to May 2018, using PubMed electronic database was conducted. Only articles reporting at least one of the following patients’ outcome: toxicity and/or pathological complete response (pCR) or tumor downstaging were analyzed. Only studies of patients with diagnosis of locally advanced rectal cancer treated with neoadjuvant RTX based chemoradiotherapy alone or combined with other drugs were considered. (no DMT2). Conclusion

Results Fourteen studies were included. All the studies had prospective study design. Median follow up was 40.3 months (range 15-91). Median G3/G4 toxicity and pCR were: 24,8% (range: 16.4-44.4%) and 34.8% (range: 27.7- 50.0%), respectively. Moreover, tumor downstaging was reported in nine articles ranging between 53% and 85%. Conclusion Neoadjuvant chemoradiation with RTX in the preoperative treatment of LARC is reasonably tolerated and able to achieve high pCR rates. EP-1467 KRAS mutation status as predictor factor in locally advanced rectal cancer M. Campo 1 , S. Flamarique 1 , A. Gemma 1 , L. Alejandra 2 , G. David 3 , M. Fernando 4 , M. Ainara 1 , R. Maitane 1 , R. Lombardo 1 , A. Fernando 1 1 Hospital of Navarra, Radiation Oncology, Pamplona, Spain ; 2 Hospital of Navarra, Medical Oncology, Pamplona, Spain ; 3 Hospital of Navarra, Pathology, Pamplona, Spain ; 4 Hospital of Navarra, Physics, Pamplona, Spain Purpose or Objective Standard treatment of locally advanced rectal cancer (LARC) includes neoadjuvant chemo-radiotherapy followed by total mesorectal excision (TME). However, some patients have poor tumor response and long-term oncologic outcomes, indicating a lack of benefit from preoperative CRT. The mutation of Kirsten RAS (KRAS) is a molecular transducer and important component of the EGFR pathway and is now widely accept as a predictor of poor response to anti-EGFR monoclonal antibodies in metastatic colorectal cancer. Nevertheless, few trials have investigated the KRAS status and clinical outcomes in LARC patients treated with neoadjuvant CRT followed by TME. Therefore, we evaluate the Tumor Regression Grade (TRG), Relapse-Free Survival (RFS) and Overall Survival (OS) according to the KRAS oncogene status in LARC. Material and Methods We evaluated retrospectively 23 patients with LARC treated at our Hospital between January 2013 and August 2018. Tumor DNA was obtained from pretreatment biopsy tissues. Standard polymerase chain reaction analysis was executed to detect specific mutations in KRAS using established primers. All patients received preoperative irradiation of 45Gy in 25 fractions to the whole pelvis al 1.8 Gy/day and 5,4 Gy in 3 fractions to the primary tumor and visible nodes, daily of 5 consecutive days per week. Concurrent chemotherapy was administrated as oral Capecitabine (825mg/m 2 twice daily during radiation time). All patients underwent TME 6-8 weeks after the end of preoperative completation CRT. Tumor regression grade after CRT was classified according to the Mandard grading system; good responders were defined as Mandard TRG1 and TRG2 and bad responders as Mandard TRG3, TRG4 or TRG5. Kaplan-Meier method and the log-rank test were used to compare survival distributions. The significance of correlations between mutation status and tumor regression was assessed by the Chi-square test. All statistical test were 2-sided, and p -values <0.05 were considered statistically significant. Results The clinicopathological characteristics of the patients are summearized in Table1. KRAS mutation was found in 30,4% of the patients. TRG (1-2) after CRT were 56,2% and 42,8% (p= NS), for wild-type and mutant KRAS groups (image1). After a median follow-up of 31 months, there was no difference in RFS (47,7 vs 23,3 months) or OS (51,5 vs 30 months) between wild-type and mutant-type KRAS groups, respectively (image2).