Abstract Book

S809

ESTRO 37

EP-1492 Bowel and anal sphincter function after neoadjuvant chemoradiotherapy in rectal cancer patients. C. ROSA 1 , L. Caravatta 1 , M. Di Tommaso 1 , L.A. Ursini 1 , A. Allajbej 1 , I.A. Zecca 2 , M. Di Nicola 2 , D. Genovesi 1 1 SS. Annunziata Hospital- “G. D’Annunzio” University, Department of Radiation Oncology, Chieti, Italy 2 “G. D’Annunzio” University, Laboratory of Biostatistics- Department of Medical- Oral and Biotechnological Sciences, Chieti, Italy Purpose or Objective Currently, neoadjuvant chemoradiotherapy (CRT) or short-course radiotherapy (RT) has become the standard of care in locally advanced rectal cancer patients, resulting in an improvement in local control and long- term survival and in an increased number of sphincter preserving surgery. On the other hand, complications represented by bowel dysfunction, fecal urgency and/or incontinence, urinary and sexual disorders, could adversely affect quality of life (QoL), and need to be taken into account, especially in long-term surviving patients. The aim of this study was to evaluate long-term effects of preoperative long-course CRT on anorectal functions and late toxicity in locally advanced rectal cancer patients treated in our Institution. Material and Methods Between 2000 and 2016, 201 patients treated with different neoadjuvant schedules of chemotherapy and radiotherapy doses were retrospectively analysed. The Memorial Sloan-Kettering Cancer Centre score was used for the evaluation of anal sphincter function. Patients presenting stoma or poor sphincter function were evaluated to assess the impact of bowel function on QoL, using indexes by cancer linear analog scales (CLAS). Results Patients, tumor and treatments characteristics are reported in Table 1. Mean length tumor was 49.3 mm (SD=17.7 mm), sited at a distance from the anorectal ring shorter than 30 mm, between 31 and 50 mm and longer than 50 mm in 43 (21.4%), 66 (32.8%) and 77 (38.3%) patients, respectively. Sixty-six patients (32.8%) received a RT schedule using concomitant boost with a total dose of 5500 cGy. Concomitant chemotherapy, based on 5-FU or Capecitabine, was administered to 79 patients (39.3%). The addition of Cisplatin or Oxaliplatin was given to 104 (51.7%) and 18 (9%), respectively. Radical resection was performed in 188 (93.5%) patients, with a pathological complete response rate of 26.4%. With a median follow- up time of 68 months (IQR = 35-113 months), overall sphincter function resulted excellent in 105 (52.2%) patients, good in 13 (6.5%), fair in 10 (5.0%) and poor (incontinence) in 40 (19.9%), with a persistent stoma rate of 16.4%. A further evaluation on 194 patients showed an improvement on sphincter function after 2 years in 11.9% of them. Seventy-three patients presenting stoma or poor sphincter function were re-evaluated for Quality of Life (QoL) indexes. Twenty-one (29%), 19 (26%) and 24 (33%) of them declared some variations concerning well-being, fatigue and ability to perform daily activities.

Department of Radiation Oncology, Chieti, Italy 2 “G. D’Annunzio” University, Laboratory of Biostatistics- Department of Medical- Oral and Biotechnological Sciences, Chieti, Italy Purpose or Objective Pathological complete response (pCR= the absence of pathological cells in surgical resection) was reported in about 12-15% of patients treated with neoadjuvant fluoropyrimidine chemo-radiotherapy (CRT). Aiming to improve pCR rate and other clinical outcomes, many studies have been conducted to evaluate the impact of treatment intensification, in terms of dose escalation and/or drug combination with different results. Following these evidences, different schedules of CRT were performed also in our Institution. A retrospective analysis of our 15-year single institutional experience was conducted looking at pCR, long-term oncological outcomes as disease free survival (DFS), overall survival (OS) and loco-regional control (LC) rates. Material and Methods From 2000 to 2016, 289 patients with T2-T4 and/or N0/N+ rectal cancer were treated with preoperative CRT at our Radiotherapy Department and retrospectively analysed. Toxicity was assessed according to the RTOG- EORTC criteria; pCR was evaluated on the basis tumor regression grade (TRG) according to Mandard classification. The Kaplan–Meier method was used to estimate OS, DFS and LC. Results The mean patient age was 64.1 years (range, 32-88 years); M: 189 (65.4%), W: 100 (34.6%). Most patients (80.7%) had cT3 tumors. Eighty-two patients (28.4%) received a RT schedule using concomitant boost (total dose: 5500 cGy). Concomitant fluoropyrimidine was administered to 121 patients (41.9%). An intensification with the addition of Cisplatin or Oxaliplatin was given to 143 (49.4%) and 19 (6.6%), respectively. Six patients (2.1%) received the Tomox schedule. The median follow- up was 60 months. Late bowel dysfunction in terms of severe bleeding (G3 toxicity) was reported in 3 patients (1%). Mild and moderate diarrhea were reported in 59 (20.4 %) and 25 (8.7%) patients, respectively. No other severe late toxicities were recorded, except for 2 (0.6%) patients with severe dysuria and one (0.3%) case with gross telangiectasia. Two hundred seventy one (93.8%) patients underwent surgery. One hundred and seventy patients (62.7%) showed tumor down-staging. pCR was observed in 68 patients (25.1%) and residual tumor cells in 39 patients (14.5%); overall, the TRG1-2 rate was: 39.6 %. The 5- and 10-year OS, DFS and LC rates were 76.9%±2.8% and 58.3%±4.1%, 64.6%±3.1% and 51.1% ±3.9%, 92.1%±2.0% and 90.2%±2.3%, respectively. TRG 1-2 was significantly associated with a better 5- and 10-years OS (p=0.012) and DFS (p=0.001). Furthermore, multidrug chemotherapy was associated to a better 5- and 10-year OS (p=0.002) and DFS (p=0.009) whereas the higher distance from the anorectal ring was significantly associated with a better 5- and 10-year DFS (p=0.050). Conclusion Neoadjuvant CRT in rectal cancer resulted in favorable long-term oncologic outcomes with high pCR rate, tumor and nodal-status down-staging, with acceptable toxicity. The rate of pCR was confirmed as an independent prognostic factor.