RESUMEN
AIM: To assess multi-gene assay (MGA) effects on chemotherapy use, toxicities, recurrences, and costs in estrogen receptor-positive early breast cancer. METHODS: Meta-analysis performed using data from public databases. Results: Studies included 12,202 women. Relative to no testing, chemotherapy use was higher with 12-gene and 70-gene and lower with PAM50 (commercial) and 21-gene MGAs. Overall, 1643 distant recurrences occurred with no testing, declining by 231 (21-gene), 121 (70-gene), 54 (12-gene) and 94 (PAM50); only the 21-gene assay resulted in no risk of increasing the number of distant recurrences. Relative to 'no testing', total cost of care declined only with 21-gene MGA. CONCLUSION: MGAs differ in chemotherapy use and related outcomes for women with estrogen receptor-positive early breast cancer.