ESTRO 2020 Abstract book

S636 ESTRO 2020

assess the physician and patient reported short-course radiotherapy-induced acute toxicity in the waiting period before surgery for rectal cancer. Material and Methods All rectal cancer patients referred to the Radiotherapy Department of UMC Utrecht for neoadjuvant SCRT-delay (5 times 5 Gy without immediate surgery) were asked to score low anterior resection syndrome (LARS) symptoms before, during and weekly after radiotherapy. Every week, participating patients were contacted by telephone by the physician or researcher to assess toxicity (dermatitis, diarrhea, fatigue, cystitis and urine incontinence according to CTCAE 4.0). Only descriptive statistics were applied. Results 20 patients (9 female, 11 male) were included. Median age was 61.5 years (IQR 53.0-69.7). 13 patients received SCRT- delay for intermediate risk rectal cancer, one patient for locally advanced rectal cancer unable to undergo neoadjuvant chemoradiation and 6 patients for oligometastatic disease (M1-scheme). Median interval to surgery was 8 weeks. The majority of patients did not experience dermatitis, fatigue, cystitis or urine incontinence during or after radiotherapy. A transient increase in CTCAE grade 2 or 3 diarrhea was seen 2-3 weeks after SCRT. LARS scores of 16 patients were available for analysis. 88% of patients experienced major LARS within 2 weeks following radiotherapy. Most reported complaints were frequency, urgency and re-evacuation within 1 hour. The majority of patients was free of complaints before they proceeded to surgery. No hospital admissions were recorded during the study period.

chemotherapy in an HIV negative (HIV-) and HIV positive (HIV+) anal cancer (AC) patient population. Material and Methods We retrospectively analyzed the records of patients (pts) with histologically confirmed AC treated with IMRT 45 Gy/25 fractions on low-risk volume and SIB on intermediate risk (positive nodes<3cm) and high risk volume (Tumor and positive nosed>3cm). Concomitant chemotherapy was Capecitabine given orally (650 mg/m2 twice daily) seven days a week with either Mitomycin-C (10 mg/m2) on day 1 or weekly Carboplatin (AUC2). Acute and late toxicities were evaluated according to the CTC-AE 4.0 scale. Disease evaluation after chemo- radiotherapy (CRT) was performed by MRI, PET , CT scan and endoscopy. Efficacy was evaluated in terms of clinical response (CR) at 8 and 24 weeks from CRT, local control, colostomy free survival (CFS), PFS and OS. Results From January 2011 and June 2018, 51 pts were included. Median age was 60 years (range 41-85). Eight pts (16%) were HIV+ in cART. All pts had normal sphincter function before treatment. Forty-six (90%) pts had squamous and 5 (10) adenocarcinoma AC. Thirty-four pts (66%) had stage III disease, 8 (16%) stage II, 3 (7%) stage I and 6 (11%) stage IV (paraortic lymph nodes involvement), respectively. All 51 pts, including HIV+, received Capecitabine at plenned dose, 44 pts (86%) received Mitomycin-C and 7 (14%) Carboplatin. Median SIB dose to high risk volume was 54 Gy (range 52.5-55) in 25 fractions. Median SIB dose intermediate risk volume was 52.5 Gy (range 52.5-54). Fifty pts (98%) completed the planned IMRT-SIB. Grade 3 hematologic or gastrointestinal toxicity was reported in 4 (7.8%) pts , and grade 3 dermatitis in 20 (39%). A break in CRT was needed in 10 pts (19.6%) because of toxicity. Grade 3 toxicity was reported in 4 (50%) HIV+ pts. Late grade 2 proctitis occurred in 3 pt (6%), no grade 3 late toxicity was reported. After 8 weeks from CRT 50/51 pts were evaluated for response, 34 of them (68%) showed a clinical complete response (cCR) and 15 (30%) a partial response (cPR). After 24 weeks, 47 pts were evaluable, 37 of them (80%) had a cCR, 8 cPR and 2 progressive disease. Surgical salvage was performed in 6 pts with cPR. With a median follow up of 32 months, 2 years (yrs) LC,CFS, PFS and OS were 90%, 85%, 88% and 92% respectively. Five yrs LC, CFS, PFS and OS were 84%, 78%, 57% and 62% respectively. HIV+ pts showe the same LC and survival. Conclusion IMRT-SIB and concurrent Capecitabine plus Mitomycin-C or Carboplatin chemotherapy appears feasible and safe in AC pts. Also HIV+ pts can safely receive this intensified treatment. LC, CFS, PFS and OS results are well comparable with the available data of current standard treatment. PO-1114 Patient reported toxicity of short course radiotherapy with interval to surgery for rectal cancer. S. Hoendervangers 1 , H. Van Grevenstein 2 , H. Verkooijen 1 , M. Intven 1 1 UMC Utrecht, Radiotherapy, Utrecht, The Netherlands ; 2 UMC Utrecht, Surgical Oncology, Utrecht, The Netherlands Purpose or Objective Previous trials suggest that short-course radiotherapy with a prolonged interval to surgery (SCRT-delay) could serve as an adequate neoadjuvant treatment for intermediate to high risk rectal cancer, with decreased postoperative complications compared to SCRT and immediate surgery. Furthermore, introduction of an interval after neoadjuvant radiotherapy gives the opportunity for organ-sparing treatment strategies if a clinical complete response is achieved. However, an interval to surgery also introduces radiotherapy-induced toxicity in the interval period. Structured patient reported data on the toxicity during this interval is still lacking. Therefore, in this study we

Conclusion Diarrhea and LARS symptoms are most reported within 2-3 weeks following short course radiotherapy for rectal cancer, but these complaints recover before surgery. No grade >3 toxicity was seen in this limited patient group. These results indicate that the SCRT-delay strategy is safe and well tolerated by patients.