Recent advancements in breast cancer treatment are showing promising results in reducing the need for aggressive chemotherapy. The SERENA-6 trial, presented at the 2025 ASCO Annual Meeting, demonstrated that adding camizestrant to continued CDK4/6 inhibition significantly improved progression-free survival (PFS) in patients with ESR1-mutant, ER-positive, HER2-negative advanced breast cancer. Patients receiving camizestrant and CDK4/6 inhibition had a median PFS of 16.0 months compared to 9.2 months for those who continued with an aromatase inhibitor and CDK4/6 inhibitor. This represents a substantial improvement, nearly doubling the PFS for this specific patient group. Furthermore, the time to deterioration in global health status/quality of life also improved significantly with camizestrant, from 6.4 months to 23.0 months, indicating a better quality of life for patients.
Another significant development comes from the OPTIMA trial, which focused on early-stage, hormone-sensitive breast cancer that has spread to nearby lymph nodes. This international clinical trial, led by UCL, involved over 4,400 patients and found that many can safely avoid chemotherapy. By using the Prosigna gene test, which measures the activity of 50 genes related to breast cancer growth, researchers could identify patients who would benefit equally from hormone therapy alone. Specifically, 68% of the trial participants had a low Prosigna score, and for these individuals, five years after treatment, 93.6% of those treated with hormone therapy alone were alive and recurrence-free, compared to 94.8% of those who also received chemotherapy. This suggests chemotherapy offered little additional benefit for this group.
The OPTIMA trial's findings indicate that for patients aged 40 and older with hormone-sensitive breast cancer and a low Prosigna score, chemotherapy can be safely avoided, potentially sparing thousands of patients from its debilitating side effects. Researchers estimate that over 5,000 NHS patients per year could avoid chemotherapy due to these findings. The Prosigna test, manufactured by Veracyte, can be run by NHS laboratories, making it a readily accessible tool for guiding treatment decisions. This shift towards more personalized medicine is expected to transform oncology guidelines and improve the overall treatment experience for a large population of breast cancer patients, moving away from a "one-size-fits-all" approach.
Separately, Irish researchers at UCD and the Royal College of Surgeons have explored the use of AI to identify breast cancer patients who may, or may not, benefit from chemotherapy. Their study, focusing on early-stage ER+HER2- breast cancer (accounting for about 70% of all diagnoses annually), found that analyzing cytotoxic T-cells in the tissue surrounding a tumor provided a more accurate assessment of patient risk. Patients with high cytotoxic T-cell density were found to be less susceptible to chemotherapy, suggesting some may not need it. While this AI-based approach requires further study before implementation, it represents another avenue for reducing unnecessary chemotherapy and improving patient quality of life. The Royal College of Surgeons in Ireland (RSCI) and University College Dublin have filed a patent for this method, aiming to integrate this technology into clinical practice in Ireland in the future.
