Citations

446 Background: MutKRAS and mutBRAF are important predictive and prognostic markers, respectively, in colorectal cancer (CRC). However, little is known about why some tumors harbor these mutations. N0147 is a phase III adjuvant trial for stage III CRC patients (N=3397) in which patients completed questionnaires and tumor variables and KRAS/BRAF mutation status was assessed. Methods: 2,323/3,397 patients who were enrolled prior to a 2008 amendment requiring KRAS testing completed a Patient Questionnaire. Primary tumors were assessed for mutKRAS and mutBRAF using standard methods; MMR status was determined using IHC. Multivariate analysis was performed to identify predictors of mutation status. Results: 60% and 86% of mutKRAS and mutBRAF tumors were right-sided, respectively. MutKRAS was less likely if there was a family history of CRC and in ever-smokers, and was nearly mutually exclusive with mutBRAF. MutBRAF was associated with deficient MMR (dMMR), high grade histology, and 4+ positive lymph nodes at surgery. MutBRAF was more likely in patients age > 70, retired persons, ever-smokers, but was less likely in non-whites and men. Conclusions: Smoking, family history of CRC, and dMMR status are associated with lower frequency of mutKRAS , but higher mutBRAF. Both mutations tend to be right sided, and mutBRAF is more common in the elderly, females, and non-Hispanic whites. [Table: see text]

111 Background: Trastuzumab in combination with chemotherapy is recommended for advanced gastric cancer positive for human epidermal growth factor receptor 2 (HER2) overexpression. Despite this recommendation, an informal pilot survey suggested that many oncologists do not include HER2 testing as part of routine practice to identify patients most likely to benefit from adding trastuzumab to chemotherapy. Methods: An interactive online educational activity was developed to provide expert guidance on HER2 testing and use of HER2-targeted agents in gastric or GE cancer. Pre- and post-education surveys were administered as part of the activity to measure changes in participant competence. In addition, 3 months after completing the educational activity, participants were sent another follow-up survey by email to assess changes in practice. Results: To date, pre-and post-education surveys have been obtained for 122 oncologists and 3-month follow-up surveys obtained from 14 oncologists. In the pre-education survey, only 46% said they were testing all of their patients with advanced gastric or GE cancer for HER2 overexpression. However, immediately after participating in the educational intervention, this proportion increased to 93%. Importantly, a follow-up survey indicated that HER2 testing of all patients with advanced gastric or GE cancer was now part of routine practice for 79% of those surveyed. A final analysis of pre- and post-education and 3-month follow-up surveys will be presented. Conclusions: Expert guidance on HER2 testing and use of HER2-targeted agents in gastric or GE cancer provided through an interactive online educational intervention substantially improved oncologist competence and practice patterns.

In the past decade, significant advances have been made in the treatment of advanced colorectal cancer. Multiple cytotoxic agents and targeted therapies have been approved for management of metastatic colorectal cancer, leading to improvement of median overall survival in clinical trials to more than 30 months. Of note, before the introduction of biologics into treatment algorithms for metastatic colorectal cancer, median survival in phase III trials never exceeded 24 months. In 2016, the most common treatment approach in first line is a combination of chemotherapy with a biologic agent. The choice of therapy is influenced by patient factors (eg, age, comorbidities), tumor characteristics (eg, overall tumor burden, pattern of metastatic spread, mutation signature), potential adverse effects of therapy, and goals of treatment. The choice between irinotecan- or oxaliplatin-based cytotoxic chemotherapy regimen is primarily based on differential toxicity profile because they have similar efficacy. Currently, three biologic agents—bevacizumab, cetuximab, and panitumumab—are approved for first-line treatment of metastatic colorectal cancer. For patients with mutant RAS and likely mutant BRAF V600E tumors, bevacizumab is the only biologic agent that can be used in conjunction with cytotoxic chemotherapy. The choice of anti–epidermal growth factor antibody or anti–vascular endothelial growth factor antibody in RAS wild-type tumors is based on the specific clinical scenario. Recently, some clinical and molecular biomarkers have emerged that may help in decision making. In this review, we discuss the role of biologics in the management of first-line treatment of metastatic colorectal cancer.

480 Background: COs associated with varying Tx patterns in mCRC pts are poorly understood because patterns diverge from the randomized trials (RCT). The RCTs of BV (Avastin) plus chemotherapy (CT) in mCRC pts continued BV until progressive disease (PD), even if CT was stopped/changed. Some RCTs of BV+CT in mCRC show ∼50% of pts stopping Tx early for reasons other than PD with possible lessening of benefit. It is unclear if this is due to use of a particular CT regimen or other practice pattern. While the beneficial effect of post-PD BV Tx has been shown in ARIES (HR 0.52 BBP vs No BBP) [A Cohn, ASCO 2010], the effect of stopping BV or CT before PD is unclear. ARIES, a community based observational study with a large cohort of 1st line BV-treated mCRC pts, will assess the COs associated with different 1st line Tx patterns (BV and CT) based on real world practice. Methods: ARIES enrolled mCRC pts receiving first- or second-line CT+BV. No Tx regimens or assessments are protocol specified. Data are collected prospectively at baseline (BL) and quarterly. Analyses included first-line pts with PD. Tx patterns of pts initially treated with FOLFOX/BV or FOLFIRI/BV are described and preliminary COs (PFS and OS) are estimated from K-M curves. Tx duration is calculated from enrollment date. Results: As of 2/5/10, 1,548 first-line mCRC pts enrolled (median follow up = 21 m); 1,133 pts had PD. Of 1,133 pts with PD, most had FOLFOX/BV (63%) or FOLFIRI/BV (16%) as first CT. BL characteristics were similar, but the FOLFOX/BV group had more stage 4 pts (74%). Main reasons for stopping BV include AE, max benefit achieved and CT holiday. Tx patterns and COs are in the table. Conclusions: ARIES first-line mCRC pts treated with FOLFOX/BV or FOLFIRI/BV had similar Tx patterns and COs despite the common opinion that they may differ in tolerability and possibly effectiveness. Additional analyses will assess the impact of stopping BV and/or CT before PD. [Table: see text] [Table: see text]

AbstractBackground.Preclinical and epidemiological data suggest that metformin might have antineoplastic properties against colon cancer (CC). However, the effect of metformin use on patient survival in stage III CC after curative resection is unknown. The survival outcomes were comparable regardless of the duration of metformin use.Patients and Methods.Before randomization to FOLFOX (folinic acid, 5-fluorouracil, oxaliplatin) with or without cetuximab, 1,958 patients with stage III CC enrolled in the N0147 study completed a questionnaire with information on diabetes mellitus (DM) and metformin use. Cox models were used to assess the association between metformin use and disease-free survival (DFS), overall survival (OS), and the time to recurrence (TTR), adjusting for clinical and/or pathological factors.Results.Of the 1,958 patients, 1,691 (86%) reported no history of DM, 115 reported DM with metformin use (6%), and 152 reported DM without metformin use (8%). The adjuvant treatment arms were pooled, because metformin use showed homogeneous effects on outcomes across the two arms. Among the patients with DM (n = 267), DFS (adjusted hazard ratio [aHR], 0.90; 95% confidence interval [CI], 0.59–1.35; p = .60), OS (aHR, 0.99; 95% CI, 0.65–1.49; p = .95), and TTR (aHR, 0.87; 95% CI, 0.56–1.35; p = .53) were not different for the metformin users compared with the nonusers after adjusting for tumor and patient factors. The survival outcomes were comparable regardless of the duration of metformin use (<1, 1–5, 6–10, ≥11 years) before randomization (ptrend = .64 for DFS, ptrend = .84 for OS, and ptrend = .87 for TTR). No interaction effects were observed between metformin use and KRAS, BRAF mutation status, tumor site, T/N stage, gender, or age.Conclusions.Patients with stage III CC undergoing adjuvant chemotherapy who used metformin before the diagnosis of CC experienced DFS, OS, and TTR similar to those for non-DM patients and DM patients without metformin use.

Even though significant improvements in the treatment of colorectal cancer (CRC) have been made in recent years, survival rates for metastatic colorectal cancer (mCRC) are poor. Effective treatment options for metastatic colorectal cancer remain limited, and new therapeutic strategies are desperately needed. Several tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) that target angiogenesis, a critical process for facilitating tumor cell growth, invasion, and metastasis, are either approved or in clinical development for the treatment of mCRC. Many of these agents have shown efficacy in mCRC, both as single agents and in combination with standard chemotherapy regimens. However, there is a need for predictive markers of response to identify those patients most likely to benefit from antiangiogenic therapy, and, to date, no markers of this type have been validated in patients. Additionally, because antiangiogenic agents typically cause cytostatic as opposed to cytotoxic antitumor effects, it is important to determine the best strategies for evaluating therapeutic response in mCRC to ensure maximum clinical benefit. In this review, we summarize the efficacy and tolerability of approved and investigational antiangiogenic agents for the treatment of mCRC. We also discuss potential markers of response to antiangiogenic agents and how these markers, along with appropriate endpoint selection, can improve clinical trial design.