Impact of immune assessment on patterns of care in stage II colon cancer.

Abstract

295 Background: Approximately 25% of patients with colon cancer are diagnosed at stage II. Recommendations for adjuvant chemotherapy and follow-up for these patients are risk-based, however the benefit of therapy is not supported by consistent, robust evidence and there are physical and financial harms associated with adjuvant treatments. Immunoscore is a novel paradigm for risk refinement through measurement of the immune response to the tumor. However, the impact of this tool on physician recommendations for clinical management has yet to be defined. Methods: Medical oncologists were presented with 10 patient profiles (real-life, de-identified stage II cases submitted for clinical Immunoscore testing) and queried for their recommendations (adjuvant chemotherapy and frequency of surveillance) via an online survey. Next, they took part in a live meeting where the Immunoscore data were introduced and completed the same patient survey, but this time with the Immunoscore classification (High or Low) assigned. A physician was counted as influenced by immune response assessment when there was at least one therapeutic modification (chemotherapy decision or surveillance de-intensification) after an Immunoscore test result was provided. We hypothesized that a rate of practice change of 30% (H1) would be considered an impactful result, while 10% would not be impactful (H0). According to A’Hern’s design with a one-sided alpha of 5% and 80% power, 25 physicians needed to be included to test the hypothesis. If 6 or more practice changes (≥ 24%) were observed, the study would be considered positive. Results: Twenty-five physicians were enrolled, representing a range of practice settings from academic medical centers, to high-volume hospital networks, to private community practices; all physicians had experience in treating stage II colon cancer. On average, physicians elected to change their chemotherapy and/or surveillance recommendations 56% of the time, therefore the objective of the study was reached. All but one physician (96%) changed their recommendations for at least one case, while 92% (23/25) changed their preference for chemotherapy in at least 1 case. The rate of change for chemotherapy prescription was 36% per patient case (range: 7-13 changes). Altered surveillance strategies were infrequently observed when chemotherapy recommendations changed. Conclusions: In this physician survey of real-world stage II colon cancer cases, Immunoscore classification significantly impacted decision-making. This impact can translate into a significant reduction in non-value care.