Impact of CanAssist-Breast in clinical treatment decisions in early stage HR+ breast cancer patients: Asian Scenario.

Abstract

109 Background: The utility of multigene prognostic tests in aiding treatment decisions for early stage hormone positive breast cancer patients is well recognized. CanAssist-Breast (CAB) is an immunohistochemistry (IHC) based prognostic test that uses a proprietary algorithm to combine IHC grading of 5 biomarkers and three clinical paramaters (tumor size, node status and Grade) to stratify patients into high or low risk of distant recurrence. CAB has thus far been validated on a retrospective cohort of > 1000 predominantly Asian patients. Distant Metastasis Free Survival (DMFS) of more than 95% was observed with significant separation (P < 0.001) between low-risk and high-risk groups. In this study we demonstrate the usefulness of CanAssist-Breast (CAB) in guiding physicians assess risk of cancer recurrence and to make informed treatment decisions for patients. Methods: A total of 353 Asian patients tested by > 100 physicians were included in this study. Clinical parameters were compiled from hospital data. Treatment decisions were confirmed for > 150 of these patients assess the level of adherence. Risk prediction using the modified Adjuvant! Online protocol was used to compare with performance of CAB. Luminal subtying was performed as per the St. Gallen’s criteria. Results: Majority of patients tested had node negative, T2 and Grade 2 disease. Age and luminal subtypes did not affect the performance of CAB. On comparison with Adjuvant! Online (AOL), CAB categorized twice the number of patients into low-risk. Impact of CAB testing on treatment decisions showed that 96% of low-risk patients were not given chemotherapy and 84% of high-risk patients were given chemotherapy. Overall, we observed that 92% patients were either given or not given chemotherapy based on whether they were stratified as high-risk or low-risk for distant recurrence respectively. Conclusions: CAB stratifies higher percentage of patients into low risk group as compared to AOL. We observed wide acceptance of CAB as a prognostic test for assisting treatment decsions in clinical settings. CAB helped avoid chemotherapy in 70% of patients tested thus providing a cost effective alternative to other prognostic tests currently available.