CanAssist Breast in routine clinical care: A real-world single-centre experience.

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Background: In Asian HR+/HER2- early-stage breast cancer (EBC) patients, data on prognostication using Western prognostic tests are limited and intriguing. To address this, CanAssist Breast (CAB), a proteomic-based prognostic test, was developed from Indian patients’ tumors and validated in multiple retrospective studies across India, the US, Europe, and in a completed, prospective-randomized TEAM trial in the Netherlands. CAB utilizes the expression of five biomarkers and three clinical parameters to categorize patients as ‘low-risk’ or ‘high-risk’ for distant recurrence within 5 years of diagnosis using an AI-based algorithm. CAB has been used as a prognostic tool to guide personalized adjuvant chemotherapy decisions since 2016. CAB is included in the treatment guidelines of the Asian Geriatric Oncology Society, the Indian Society of Medical and Paediatric Oncology, and the Association of Breast Surgeons of India. This study highlights our single-centre experience evaluating the impact of CAB on clinical decision-making. Methods: Data from 309 patients who underwent CAB testing at Rajiv Gandhi Cancer Institute and Research Centre (RGCIRC), Delhi, between 2017 and January 2026 were compiled. We analysed CAB-based risk stratification across different clinical subgroups and assessed treatment adherence based on CAB results. Results: CAB stratified 49% patients as ‘low risk’ and 51% as ‘high risk’ for distant recurrence. The patients’ median age was 58 years. Of the total cohort, 65% were >50 years old, and 35% were ≤50 years old. T2 tumors constituted 80% of the cohort, followed by T1 tumors (20%). Of the total cohort, 6% of patients presented with G1 tumors, while 53% had G2, and 41% had G3 tumors. 61% and 39% of patients were node-negative (N0) and node-positive (N+), with low- and high-risk proportions of 65:35 and 24:76, respectively. Treatment information was available for 267 (86%) patients; 100% of low-risk patients did not receive chemotherapy, whereas 91% of high-risk patients did. The overall treatment adherence was 96%. Notably, in patients conventionally considered clinically high-risk, the low- and high-risk treatment adherence (%) was as follows: ≤50 years, 100:98; N+, 100:90, respectively. Conclusions: CAB effectively stratifies patients into low- and high-risk categories for distant cancer recurrence, helping the low-risk patients in this cohort avoid chemotherapy even when presented with clinically high-risk features. This demonstrates the utility of CAB as a decision-making prognostic test in our study cohort, supporting that CAB serves as a cost-effective, ideal alternative to Western prognostic tests for HR+/HER2- EBC patients.