Abstract
TPS196
Background: Different treatment strategies may be indicated for intermediate-risk (T1–2N1, T3N0) versus moderately high- (T1–2N2, T3N1,T4N0) or high-risk patients (T3N2, T4N1–2) based on differential survival rates and rates of relapse (Gunderson et al JCO 22: 1785-1796, 2004). T3 tumors are prognostically inhomogeneous and patients with extramural penetration > 5 mms and extramural venous invasion (EMVI) are associated with increased risk of local relapse but especially with distant failure. Thin-slice high-resolution MRI can identify those patients accurately (Smith NJ. Br J Surg. 2008 95:229-36). Bevacizumab monotherapy has significant antivascular and vascular normalizing effects in rectal cancer (Willett et al. J Clin Oncol 27:3020-3026, 2009) and in combination with capecitabine and oxaliplatin (CAPOX) is a standard treatment for metastatic disease. Purpose: To evaluate the efficacy of induction CAPOX/bevacizumab with selective chemo/radiotherapy (CT/RT) in patients with intermediate-risk (T3) rectal adenocarcinoma.
Methods: Main eligibility criteria: 1. Patient with measurable disease at the baseline visit. 2. Tumor that meets all the following criteria in MRI (3-mm slices) of the pelvis: Distal border of tumor > 5 cm from the external edge of the anus and below the sacral promontory and tumor ≥2 mm from the mesorectal fascia and one or both of the following: T3 > 5 mm extramural penetration or presence of EMVI. 3. Candidate for R0 surgery with sphincter preservation surgery. All pre- and post-treatment MRI scans are reviewed independently by one radiologist (G.B.). Treatment: Induction CAPOX with bevacizumab are given for 3 cycles over 9 weeks and one additional cycle without bevacizumab. Patients undergo re-staging within 3 weeks of their 4th cycle with MRI. Those who respond (i.e. complete or partial response) proceed to surgery between 4-6 weeks from the last chemotherapy dose. Patients with stable or progressive disease receive capecitabine/radiation. Design: Simon 2-stage: α=0.1 β=0.1; 28 evaluable pts 1st stage and 41 evaluable pts for 2nd stage. Primary Endpoint: Response rate (RECIST). To date 12 patients have been registered.
No significant financial relationships to disclose.
© 2010 by American Society of Clinical Oncology
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