Editor’s Note: For patients with hormone receptor–positive (HR+) early breast cancer, when intensifying adjuvant endocrine therapy with a CDK4/6 inhibitor, should abemaciclib or ribociclib be preferred? At the 2025 Summer Breast Cancer Forum · Northern Salon, Professors Bin Song of Shanxi Bethune Hospital and Yuan Peng of Peking University People’s Hospital debated this question during the “Debate” session. Here, in Oncology Frontier’s “In-Depth” column, they share their perspectives supported by evidence. Key Arguments and Rationale
Professor Bin Song: Abemaciclib as the Preferred ChoiceOur discussion today focuses on high-risk HR+ early breast cancer. The monarchE study specifically targeted this population—patients with ≥4 positive lymph nodes, or those with 1–3 positive nodes plus additional clinical risk factors. Abemaciclib demonstrated strong efficacy in this setting, with five-year outcomes now available. Its adverse events are manageable and controllable, and it can be combined with either aromatase inhibitors (AIs) or tamoxifen, offering greater clinical flexibility.
Importantly, abemaciclib has already been included in the national reimbursement list, making treatment more affordable, and clinicians in China have gained substantial experience in its use. Taken together, these factors make abemaciclib the preferred option for adjuvant endocrine therapy intensification in high-risk HR+ early breast cancer.
Professor Yuan Peng: Ribociclib as the Preferred ChoiceAs I mentioned in discussions with Professor Song, abemaciclib and ribociclib should not be viewed as rivals. Both demonstrate clear efficacy in high-risk patients. However, ribociclib extends the benefit further—providing treatment opportunities, and even the possibility of cure, for intermediate-risk patients, as shown in the NATALEE trial. This is an advantage abemaciclib has not yet achieved.
From a surgical perspective, the trend in recent years has been toward “de-escalation” in axillary surgery. As a result, we may no longer determine the exact number of positive lymph nodes as precisely as when full axillary dissections were performed. In such cases, what we often know is simply that there are positive nodes, not the exact count. Ribociclib offers greater flexibility under these circumstances, making it a particularly valuable choice.
Professor Bin Song
Shanxi Bethune Hospital
Professor Yuan Peng
Peking University People’s Hospital
