New Trial Tests Whether Chemotherapy Can Be Skipped in Genomic-Low, Anatomic-High Breast Cancer
The ECOG-ACRIN Cancer Research Group launched the RxFINE-Low trial to determine if patients with high anatomic risk but low genomic risk ER+/HER2- breast cancer can forgo adjuvant chemotherapy. Current practice gives chemotherapy to these patients despite their tumors' lower-risk biology, but no large randomized trial has tested omission. The study aims to clarify whether adding chemotherapy to endocrine therapy and CDK4/6 inhibitors provides any benefit.
The RxFINE-Low trial builds on earlier research establishing that chemotherapy can be safely omitted in certain lower-risk patients. The TAILORx and RxPONDER trials showed postmenopausal patients with early-stage disease and low Oncotype DX scores gained no benefit from chemotherapy even with cancer in up to three lymph nodes. Those studies, however, did not address larger tumors or more extensive nodal involvement.
This trial extends the question to a higher-risk anatomic group under newer treatment standards. Since NATALEE and monarchE demonstrated that adding CDK4/6 inhibitors like ribociclib to endocrine therapy reduces recurrence, most participants in those trials had already received chemotherapy, leaving the chemotherapy question unresolved. RxFINE-Low randomizes roughly 2,000 participants to chemotherapy plus endocrine therapy with ribociclib, or endocrine therapy with ribociclib alone, following them for up to ten years.
If the trial shows chemotherapy provides no additional benefit for this subgroup, thousands of patients annually could avoid the short- and long-term toxicities of chemotherapy, including neuropathy, fatigue, and cardiac effects. Treatment decisions could shift from purely anatomic staging toward genomic biology, potentially reducing healthcare costs and improving quality of life during and after treatment. Patients with large tumors or extensive lymph node involvement may gain confidence that endocrine therapy plus a CDK4/6 inhibitor alone is sufficient, though results remain years away.