Moss, Jonathan R.

e14564 Background: Recent long-term clinical trial follow-up suggests that adding Ox to a fluoropyrimidine (FP) may provide less benefit in adjuvant CC than originally believed (Tournigand JCO 2012). In addition, emerging data on tissue biomarkers such as microsatellite mismatch repair (MMR) and the 12-gene Recurrence Score (RS) suggest these assays may be helpful in better defining treatment benefit, and a new report provides evidence that RS may specifically predict the value of Ox (O'Connell ASCO 2012). In view of these developments we sought to document current use of adjuvant chemotherapy and physician perceptions about these decisions. Methods: U.S.-based oncologists were recruited to complete a survey and contribute treatment data for their last three patients (pts) with stage II disease and last pt with a stage III tumor. Results: 25 gastrointestinal cancer clinical investigators and 77 practicing oncologists participated, providing data from a total of 408 cases (92% treated since 2011). Findings from the two groups are similar and are presented in aggregate. A median of 9 and 15 pts annually were evaluated with Stage II and III tumors, respectively. Clinicians stated that they require a median of a 5% absolute reduction in relapse rate to use a FP alone and an additional 5% reduction to add Ox. Ox/FP was administered to 95 of 102 pts with stage III tumors (93%) and 85 of 306 pts with stage II disease (28%), particularly to those under age 70 or with T4 tumors (Table). MMR was evaluated in 127 pts (42%) with stage II and 20 pts (20%) with stage III disease. RS was obtained for 46 pts (15%) with stage II tumors, but only 2 pts (2%) with stage III. Conclusions: Adjuvant Ox is employed widely in spite of the fact that it may provide less benefit than many oncologists report requiring to initiate its use. However, several recent research developments may be laying the groundwork for a change in this treatment practice. [Table: see text]