The 7th Joint Session between JDDW-KDDW-TDDW1(JDDW)
Thu. November 2nd   9:00 - 12:00   Room 9: Portopia Hotel Main Building Kairaku 3
JKT1-3
 Adding bevacizumab to neoadjuvant chemoradiotherapy increases pathological complete remission and survival in patients with locally advanced rectal cancer
Jason Chia-Hsien Cheng1, Yun Chiang1, Jin-Tung Liang1
1Department of Oncology, National Taiwan University Hospital
Purpose: This retrospective study investigated the impact of adding bevacizumab to neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced rectal cancer (LARC).
Methods: This retrospective study enrolled patients with LARC undergoing NCRT with or without bevacizumab followed by curative resection at National Taiwan University Hospital from 2009 to 2021. Locoregional recurrence was defined as recurrence within the irradiated field and distant metastasis as outside the irradiated field. Associations between clinical factors and pathological complete remission (pCR), overall survival (OS), locoregional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were analyzed using ANOVA and Cox proportional hazards model. Propensity score matching (PSM) analysis was used to evaluate the effects of adding bevacizumab. Programmed death-ligand 1 (PD-L1) immunostaining on rectal tumor biopsies taken at diagnosis was conducted to assess the correlation between PD-L1 expression level and treatment response.
Results: A total of 200 patients were enrolled. Of these, 39 patients (18/54 vs. 21/146 without bevacizumab, p=0.004) achieved pCR. Patients receiving bevacizumab had more T4 disease (p=0.005), low-lying rectal tumor (p=0.047), concurrent oxaliplatin use (p<0.001), but less frequent adjuvant chemotherapy (p=0.005). With a median follow-up of 71 months, 5-year OS, LRFS, and DMFS were 86%, 84%, and 79%, respectively. Factors associated with pCR in univariate analysis were clinical N0 (cN0), gross tumor volume ≤70 ml, and adding bevacizumab. In multivariate analyses, cN0 and adding bevacizumab remained significantly associated with pCR, and pCR was the only independent factor for OS (HR=0.32, p=0.004), DMFS (HR=0.29, p<0.0001), and LRFS (HR=0.32, p=0.002). In PSM cohort, adding bevacizumab was associated with better OS (p=0.034) and DMFS (p=0.045). A high PD-L1 expression, as determined by the VENTANA PD-L1 (SP263) assay, was associated with pCR rate only in patients receiving the additional bevacizumab.
Conclusions: Adding bevacizumab to NCRT in LARC patients contributes to improved survival by increasing pCR with tolerable toxicities. A correlation might exist between immunochemical PD-L1 expression level and the response to bevacizumab.
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