ESTRO 2020 Abstract book

S626 ESTRO 2020

patients). A reduced or poor contraction or inhibition of the pubo-rectal muscle in DRE performed within 2 years was reported in the 73% whereas it resulted of 45% in DRE performed after 2 years (8 patients for each group). Regarding functional assessment, incontinence at rest was showed in 5 (45%) and 7 (39%) patients, at DRE performed within or after 2 years, respectively. Globally, MSKCC score seemed to overestimate functional assessments in 5 (17%) patients. Table 1 reported DRE characteristics and the MSKCC score for each patient.

Material and Methods Retrospective analysis of 59 patients who received 74 Gy (RBE) / 37 fr between March 2004 to March 2014 was performed. There were 42 males and 17 females, with a median age of 63 years (range, 37-79). Proton and carbon ion therapy were used for 48 and 11 patients, respectively. Seven patients had the history of distant metastasis prior to particle therapy, and all metastasis were under control by local therapies. Median serum CEA and CA19-9 level at the end of irradiation were 5.7 ng/ml (range, 0.8-465.0) and 16.9 U/ml (range, 0.2-334.3), respectively. Results The median follow-up period was 26.7 months (range, 4.6- 104.7 months). The 2-year overall survival (OS), progression-free survival (PFS), and local control (LC) rates were 83.0%, 35.2%, and 64.4%, respectively. In multivariate analysis using the Cox proportional hazards model, lower serum CEA and CA19-9 level at the end of irradiation and no history of distant metastasis were significantly favorable factors for OS and PFS. Lower serum CA19-9 level at end of irradiation was a significantly favorable factor for LC. There were no differences between carbon ions and protons on OS, PFS, LC. The late adverse effects of ≥Grade 3 were observed in 9 patients. Conclusion Particle therapy using protons or carbon ion has shown to achieve survival benefit not inferior to surgery. PO-1093 Defecography for sphincter evaluation in rectal cancer patients irradiated with dose intensification C. Rosa 1 , M. Di Tommaso 1 , B. Seccia 2 , A. Delli Pizzi 2 , R. Cianci 2 , R. Basilico 2 , A. Di Pilla 1 , M. Taraborrelli 1 , L. Caravatta 1 , D. Genovesi 1 1 Ospedale Clinicizzato S.S. Annunziata, Radiotherapy Oncology- Chieti, Chieti, Italy ; 2 Ospedale Clinicizzato S.S. Annunziata, Department of Radiology, Chieti, Italy Purpose or Objective Sphincter disorders and dysfunctions could be possible in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT) and sphincter saving surgery, followed by recanalization. Defecography (DRE) evaluates the transport of a semi-solid barium column to the outside during a simulated defecation, investigating the two components of this process, both anatomically and functionally. We performed this study with the aim to evaluate the sphincter functionality by DRE. Material and Methods Twenty-nine LARC patients (M:W=18:11) underwent neoadjuvant CRT with dose intensification treatment up to 5500 cGy (220 cGy/die) and sphincter saving surgery. DRE was performed evaluating the characteristics of contraction or inhibition of the pubo-rectal muscle and the type of incontinence (at rest/during Valsalva). The number of evacuations per day, including incontinence, was evaluated using the Memorial Sloan Kettering Cancer Center (MSKCC) Score. Furthermore, we performed a comparison of both methods. Results All patients completed the prescribed treatment. The median patients age was 66 years (range, 44-79 years). The mean length tumor was 45 mm, sited at a distance from the anorectal ring shorter than 30 mm, between 31 and 50 mm, and longer than 50 mm in 10 (34.5%), 11 (37.9%), and 8 (27.6%) patients, respectively. The majority of patients (22 patients, 75.9%) had cT3 tumors. All patients underwent anterior rectal resection with complete pathological response rate of 51%. With a median follow- up of 3.4 years, all patients had a local control, with distant metastases reported in 6 (21%). Twenty-nine patients underwent DRE: 11 patients within 2 years, 18 after 2 years from the end of CRT. Mostly women reported an anterior rectocele (9 women vs 6 men, in a total of 15

Conclusion Despite the small number of analysed patients, sphincter dysfunctions rate in our patients treated with a dose intensification schedule was in line with literature. DRE resulted to be a valid tool to evaluate anorectal function, giving information regarding both sphincter morphology and functionality. DRE is advantageous to evaluate incontinence during Valsalva, completing a qualitative evaluation of the MSKCC score. Both DRE and MSKCC could be considered for an accurate sphincter evaluation. PO-1094 Pathological complete response and outcomes in rectal cancer patients with treatment intensification C. Rosa 1 , M. Di Tommaso 1 , L. Caravatta 1 , M. Taraborrelli 1 , D. Fasciolo 1 , A. Augurio 1 , R. Cianci 2 , M. Di Nicola 3 , D. Genovesi 1 1 Ospedale Clinicizzato S.S. Annunziata, Radiotherapy Oncology- Chieti, Chieti, Italy ; 2 Ospedale Clinicizzato S.S. Annunziata, Department of Radiology, Chieti, Italy ; 3 G. D’Annunzio University, Laboratory of Biostatistics- Department of Medical- Oral and Biotechnological Sciences, Chieti, Italy Purpose or Objective Preoperative long-course chemoradiotherapy (CRT) followed by total mesorectal excision (TME) is a standard of care for locally advanced rectal cancer (LARC) patients, aiming to reduce locoregional recurrences and increase pathological complete response (pCR). To improve clinical outcomes, we retrospectively evaluated pCR, disease free survival (DFS), overall survival (OS) and loco-regional control (LC) rates in patients with treatment intensification strategies, according to the different CRT schedules used as dose escalation and/or drug combination. Material and Methods We analyzed 322 LARC patients (M: 209; W: 113). RT was performed by 3D conformal technique, with a total dose of 4500 cGy (180 cGy/die) followed by a sequential boost of 540 cGy (180 cGy/die; total dose 5040 cGy), or a concomitant boost of 1000 cGy (100 cGy/die, 2 times/week; total dose 5500 cGy) with a 3D-CRT technique or with a simultaneous integrated boost with intensity