Impact of molecular tumor board on late-stage gastrointestinal malignancies at a tertiary center.

Abstract

483 Background: Inova Schar Cancer Institute formed a molecular tumor board in early 2016 to identify treatment options for patients with gastrointestinal malignances based on molecular testing and to track outcomes. Methods: From March 2016 to June 2017, 78 patients with advanced gastrointestinal malignancies were presented at our molecular tumor board. The most common mutations, the percentage of patients who received targeted therapies, responded to targeted therapies, died or went on hospice prior to receiving a recommended therapy, and had an available Association of Molecular Pathology Tier 1 or Tier 2 recommendation available were reviewed retrospectively. We also compared the overall survival of patients who received a new treatment after MTB compared to those who did not. N-of-One, Inc. provided curation of molecular testing and participated in the MTB. Results: 78 patients with gastrointestinal cancers were presented between March 2016 and June 2017. Thirteen (19%) patients received targeted therapy and 31% had partial response, 15% had Stable Disease, and 54% had progression of disease. 12 patients (15%) died or went on hospice before recommendations could start and 11 patients (14%) are waiting to start recommended therapy. 38 (49%) patients did not have a mutation that prompted a MTB recommendation. Median OS of the 33 patients who started a new therapy (including chemotherapy or unrelated clinical trials) after MTB was 15.3 months vs. 11.5 months in 40 patients who continued current therapy (P = 0.016 Wilcoxon). The three most common mutations detected were TP53, KRAS, and APC. The majority of cases had more than one variant. 18% of cases had a variant classified as Tier 1; 74% of cases had a variant with the highest AMP classification of Tier 2. Conclusions: The majority of patients with Gastrointestinal malignancies presented to the Inova MTB had a finding that supported a molecularly-guided therapy, with a small but meaningful number of partial responses. Barriers to the use of molecular guided therapy included molecular testing and presentation at a late disease stage, and alternative chemotherapeutic options.