ESTRO 2020 Abstract Book

S588 ESTRO 2020

Purpose or Objective To assess feasibility and tolerance of a Total Neoadjuvant Therapy (TNT) program with induction chemotherapy (iCT), intensified chemoradiation (CRT), consolidation chemotherapy (cCT) before delayed surgery in high risk locally advanced rectal cancer (LARC) patients (pts). Material and Methods Patients with mid-distal LARC staged as cT3c-d cN2 or T4 N0-2 or involved mesorectal fascia (MRF+) were included. Staging included MRI, PET, CT scans and ecoendoscopy (EUS). Three cycles of capecitabine (CAPE) 2000 mg/mq/die for 2 weeks (wks) and oxaliplatin (OX) 130 mg/mq at day 1 q21 days (XELOX) were planned as induction iCT followed by capecitabine based CRT, IMRT 45 Gy in 25 fractions with SIB to 54 Gy on mesorectum and concomitant capecitabine 1650 mg/mq/die. After CRT, 3 cycles of XELOX were planned as cCT. TME surgery was delayed 15-17 wks after CRT. Restaging with MRI, PET CT and EUS was performed after each step of the program in order to evaluate response (RECIST criteria) and downstaging. We assessed the pts compliance, toxicity (CTC-AE 4.0 scale) and efficacy of this TNT program. Results From April 2016 to April 2019, 23 consecutive pts were prospectively included, 14 (61%) with T3N2 disease, 2 (9) T3N1, 7 (30%) T4N0-2, MRF+ was reported in 21 pts (91%). All pts completed the planned iCT , 2 pts (8%) required a dose modification because of Grade 2 (G2) gastrointestinal (GI) toxicity or G2 neuropathy. No G3 toxicity was reported. After iCT 17 (74%) pts had a partial response (PR), 3 (13%) stable disease (SD) and 3 (13%) local progression (PD). All 23 pts completed the planned IMRT without any break but 7 (30%) required a dose modification of CAPE for persistent G2 hematologic (hem) or GI toxicity. After CRT a PR was reported in 14 pts (60%), SD in 6 (26%), complete response (CR) in 1 (4%); 2 (8%) pts reported distant PD and they underwent to second line chemotherapy. Of the 21 pts who started cCT, 18(85%) completed 3 planned cycles. OX and CAPE doses were reduced in 3 pts (13%) because of G2 hem or GI toxicity. Persistent G2 neuropathy was reported in 1 pt. No G3 toxicity was observed. Surgery was performed in 19/21 pts (2 pts are waiting for surgery) after a median 18 weeks (range 14-23) from CRT. R0 resection was performed in 18 of them (95%) and 2 pts underwent IORT. Major (Grade 3) postoperative complications occurred in 1 pt. Pathologic response is available for 16 pts, pCR was reported in 3 of Our Total Neoadjuvant Therapy program including iCT, intensified CRT and cCT in selected high risk LARC patients demonstrated feasible and well tolerated. Delayed surgery doesn’t increase risk of complications. A prospective phase II multicentric study is planned to confirm these indications. PO-1113 Intensified IMRT-SIB and capecitabine-based chemotherapy in anal cancer:an institutional experience E. Palazzari 1 , O. Schioppa 2 , A. Lauretta 3 , F. Navarria 1 , M. Gigante 1 , A. Caroli 1 , C. Bampo 4 , R. Innocente 1 , J. Polesel 5 , G. Bertola 3 , E. Vaccher 2 , A. De Paoli 1 1 CRO IRCCS Aviano National Cancer Institute, Radiation Oncology Dep, Aviano PN, Italy ; 2 CRO IRCCS Aviano National Cancer Institute, Medical Oncology Dep, Aviano PN, Italy ; 3 CRO IRCCS Aviano National Cancer Institute, Surgical Oncology Dep, Aviano PN, Italy ; 4 CRO IRCCS Aviano National Cancer Institute, Nuclear Medicine Dep, Aviano PN, Italy ; 5 CRO IRCCS Aviano National Cancer Institute, Cancer Epidemiolgy Unit, Aviano PN, Italy Purpose or Objective To assess acute and late toxicity, and efficacy of intensity modulated radiotherapy (IMRT) with simultaneous them (19%) Conclusion

integrated boost (SIB) and concurrent capecitabine-based 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