516 Background: Bevacizumab into chemoradiotherapy appears safe and active in locally advanced rectal cancer (LARC).This study evaluates whether the addition of bevacizumab to capecitabine-based chemoradiotherapy in the preoperative treatment of LARC improves pathological complete response rate (pCR). Methods: Open-label, unicentric, phase II study in patients with resectable LARC (stage II or III), with or without nodal involvement and no evidence of distant metastases. Treatment schedule of 4-cycles: bevacizumab administered iv on day 1 (10 mg/kg in the first cycle and 5 mg/kg in the following 3 cycles) and capecitabine (900mg/m2/bid) in the 2nd cycle (5 d/wk) concomitantly with radiotherapy 45Gy (25 fractions of 1.8Gy/day) over 5 weeks. Surgical resection was scheduled 6-8 weeks after therapy completion. Preliminary results from ITT analysis are presented. Results: Of the 43 patients included, 41 comprised ITT population. Baseline characteristics: median age 63 (55-67) years; male 76%; ECOG 0/1 49%/51%; stage T3/N1 80.5%/58.5%; nodal metastases 85%. 39 patients underwent surgery, 9 abdominoperineal and 30 anterior resection. No evidence of metastasis after surgery in 97%. Total mesorectal excision was performed in 69% of patients and 85% underwent R0 resection. Sphincter-preservation was achieved in 79.5%. Downstaging occurred in 82%. Among 39 patients evaluable for pathological response, 7.7% experienced pCR, 69.2% partial response and 20.5% stable disease. Grade 3/4 toxicities: 9.8% lymphopenia (all related to capecitabine and 4.9% to bevacizumab), 2.4% neutropenia (capecitabine-related), 2.4% radiodermatitis (related to RT and capecitabine) and 2.4% vasospastic angina (bevacizumab and capecitabine-related). 13 patients had postoperative complications not treatment-related. The most common were wound infection (6), intra-abdominal collection (3), wound dehiscence (2) and paralytic ileus (2). Conclusions: Preoperative regimen with bevacizumab, capecitabine and RT is active for LARC with promising results of R0 resection, sphincter- preservation and tumour downstaging as well as manageable toxicity. Further studies are ongoing to confirm these data. No significant financial relationships to disclose.
Phase II Study of Preoperative Treatment with External Radiotherapy Plus Panitumumab in Low‐Risk, Locally Advanced Rectal Cancer (RaP Study/STAR‐03)
