For premenopausal patients with extensive nodal disease (e.g., N2), the clinical indication for chemotherapy is so strong that even a low-risk genomic score would not be enough to withhold treatment. This highlights the primacy of clinical staging over genomic data in certain high-risk scenarios.
When choosing between adjuvant CDK4/6 inhibitors for high-risk patients eligible for both, oncologists favor abemaciclib (monarchE). This preference is driven not just by overall survival data, but by the longer follow-up period *after* patients have completed therapy, ensuring the benefit is durable and the survival curves don't converge.
In high-risk, BRCA-positive patients eligible for both, clinicians favor giving a PARP inhibitor first. The rationale is based on established survival data, shorter one-year duration, and emerging biological evidence suggesting BRCA2-mutated tumors may be resistant to CDK4/6 inhibitors due to concurrent RB gene loss.
For high-grade, PR-negative ER+ breast cancers with very high Ki-67, oncologists may use intrinsic subtyping assays. If a 'basal-like' subtype is identified, they consider treating the patient with a triple-negative breast cancer regimen (like KEYNOTE-522) instead of standard ER+ therapy, a non-standard but biology-driven approach.
For high-risk early-stage breast cancer patients with a germline PALB2 mutation, clinicians would consider using an adjuvant PARP inhibitor off-label. This is justified by PALB2's biological similarity to BRCA2 and promising response data from the metastatic setting, providing an option for patients who meet Olympia trial criteria but have a different mutation.