ESTRO 2020 Abstract book

S635 ESTRO 2020

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 integrated boost (SIB) and concurrent capecitabine-based them (19%) Conclusion

Figure 2 shows the mean AUCs and confidence intervals of the trees discriminating abilities on the mesorectum, tumor, and clinical data are 0.62 (0.61-0.64), 0.59 (0.58- 0.60), and 0.58 (0.57-0.60) respectively.

Conclusion We observed that mesorectum radiomics features have a statistically significant higher discriminating ability compared to the tumor (p-value = 0.004) and clinical (p- value = 0.003) informations despite the lower than optimal prediction accuracy. However, there was no difference between the tumor and clinical data (p-value = 0.429). Our study highlights the potential benefit of a non-invasive and cost-effective radiomics for precision medicine, which could enhance the efficiency and efficacy of cancer care. The optimal performance of these models with further research and increased sample size is the next step for this project in addition to external validation. PO-1112 Total neoadjuvant therapy in high risk rectal cancer: a feasibility pilot study E. Palazzari 1 , A. Buonadonna 2 , A. Lauretta 3 , F. Navarria 4 , E. Ongaro 2 , L. Foltran 2 , R. Innocente 4 , C. Belluco 3 , P. Ubiali 5 , V. Canzonieri 6 , M. Urbani 7 , C. Colombo 8 , G. Bertola 3 , A. De Paoli 4 1 CRO IRCCS Aviano National Cancer Institute, Radiation Oncology Dept, Aviano PN, Italy ; 2 CRO IRCCS Aviano National Cancer Institute, Medical Oncology Dept, Aviano PN, Italy ; 3 CRO IRCCS Aviano National Cancer Institute, Surgical Oncology Dept, Aviano PN, Italy ; 4 CRO IRCCS Aviano National Cancer Institute, Radiation Oncology Dept, Aviano PN, Italy ; 5 Santa Maria degli Angeli Hospital, Surgery Dept, Pordenone, Italy ; 6 CRO IRCCS Aviano National Cancer Institute, Oncologic Pathology Dept, Aviano PN, Italy ; 7 CRO IRCCS Aviano National Cancer Institute, Oncologic Radiology Dept, Aviano PN, Italy ; 8 CRO IRCCS Aviano National Cancer Institute, Nuclear Medicine Dept, Aviano PN, Italy

Purpose or Objective