Saint Gallen 2025: A New Roadmap for Breast Cancer Treatment
Held every two years, the Saint Gallen International Breast Cancer Consensus Conference, which forms the basis for breast cancer treatment guidelines, opened the door to a new era in treatment strategies in 2025. Among the most striking topics this year were risk-adaptive treatment planning, a minimalist approach to surgical intervention, and biomarker-based decision algorithms.
New Criteria in Personalized Treatment
At the 2025 Saint Gallen meeting, the approach that “one-size-fits-all treatment is not suitable for everyone” has now become standard. Especially in ER-positive/HER2-negative tumors, decisions are now based not only on tumor size or lymph node involvement but also on molecular risk scores (e.g., Oncotype DX, MammaPrint, EndoPredict) and proliferation markers (Ki-67, PR level).
New Recommendations:
In ER+ patients with Ki-67 > 30%, the recommendation for chemotherapy was emphasized more strongly.
In node-positive (1-3 lymph nodes) patients with genomic low risk, it became clear that endocrine therapy alone could be used without chemotherapy.
Changing Paradigms in Systemic Therapy
New Approach in the HER2 Spectrum:
The role of ADCs (antibody-drug conjugates) such as trastuzumab deruxtecan (T-DXd) in “HER2-low” and “HER2-ultra low” tumors is now clear.
For patients in this subgroup, being HER2-negative no longer means “not eligible for HER2-targeted therapy.”
Innovations in ER+ / HER2- Patients:
Oral SERD agents (e.g., elacestrant) are now recommended as a strong alternative to tamoxifen in postmenopausal women.
Selective use of CDK4/6 inhibitors is recommended. Instead of routine administration to all patients, they are directed toward those at high risk of recurrence.
A New Era in Surgery: Less but Better
One of the most talked-about recommendations from Saint Gallen 2025 was the redefinition of the role of surgery. Key Headlines:
🔹 “Surgery-Free Follow-Up” Discussions:
In patients who achieved a complete response (pCR) after neoadjuvant therapy, studies on follow-up with only imaging + biopsy + radiotherapy without breast surgery were widely discussed.
However, most panelists emphasized that surgery-free follow-up is not yet suitable for clinical practice and should be limited to clinical trials.
🔹 Limits of Sentinel Lymph Node Surgery:
Axillary dissection is no longer recommended for patients with 1-2 positive sentinel lymph nodes.
In new guidelines, removal of the clipped node is considered sufficient (TAD – targeted axillary dissection).
🔹 Oncoplastic Surgery Becoming the New Standard:
Aesthetic outcomes are now considered essential not only for cosmetic reasons but also for psychosocial well-being.
The routine evaluation of oncoplastic techniques is now recommended during the surgical planning phase.
Technology and Artificial Intelligence Integration
Saint Gallen 2025 also heralded an era in which artificial intelligence will play an active role in breast cancer management.
Applications such as digital pathology for lymph node metastasis detection,
AI-supported recurrence risk prediction,
biomarker analysis algorithms that predict treatment response,
and digital planning of surgical margins are now available at many centers.
The Philosophy of “Less Treatment, Fewer Side Effects” is Gaining Strength
The clearest emphasis throughout the conference was on preventing unnecessary treatments.
Every chemotherapy or surgery is now evaluated not only based on the tumor's biology but also on its impact on the patient's quality of life.
It is recommended that the duration and intensity of treatment be adjusted according to the patient's genetic, biological, and social characteristics.
Result: Treatment Is Now Smarter and More Personalized
Saint Gallen 2025 clearly demonstrated that breast cancer treatment is no longer a “template” but is planned with a personalized strategy. Surgical interventions are becoming less invasive, while systemic treatments are becoming more precise and targeted.
Multidisciplinary teams will continue to be the cornerstone of the new era.
In breast cancer treatment, the goal is no longer just to “extend life,” but to improve the patient's overall well-being while maintaining their quality of life.
