Practice-Changing Insights from the SUPREMO Trial at the San Antonio Symposium

Practice-Changing Insights from the SUPREMO Trial at the San Antonio Symposium

The SUPREMO trial (Selective Use of Postoperative Radiotherapy After Mastectomy) presented its long-term results at the recent San Antonio Breast Cancer Symposium, marking a significant moment in the management of intermediate-risk breast cancer. As the only practice-changing presentation at the symposium, this trial provides robust evidence for the de-escalation of chest wall irradiation (CWI) in specific patient populations following mastectomy.

About the Trial:

SUPREMO is a phase III international, multicenter trial designed to assess whether CWI improves overall survival (OS) or reduces recurrence in intermediate-risk breast cancer patients. This group includes patients with tumors exhibiting certain characteristics that make the need for postoperative radiotherapy uncertain【1】【2】.

Key Findings (Median Follow-Up: 9.6 Years):

• Overall Survival (OS):

No statistically significant difference was observed in 10-year OS between patients receiving CWI (81.4%) and those who did not (82.0%). This confirms that CWI does not confer a survival advantage in this population【1】【2】【3】.

• Local Recurrence:

While CWI reduced the relative risk of chest wall recurrence by more than 50%, the absolute reduction in recurrence was less than 2%, deemed clinically insignificant for most patients【2】【3】.

• Subgroup Analysis:

Both node-negative patients (N0) and those with T1-T2 tumors with 1-3 positive lymph nodes (N1) demonstrated no OS advantage with CWI. This suggests that many intermediate-risk patients, previously considered candidates for postoperative radiotherapy, may safely omit this treatment【1】【3】.

Clinical Implications:

The SUPREMO trial supports a tailored, de-escalated approach to radiation therapy in intermediate-risk breast cancer patients. By identifying subgroups unlikely to benefit from CWI, clinicians can reduce treatment-related morbidity while maintaining excellent oncologic outcomes. Patients meeting the following eligibility criteria may particularly benefit from this evidence【1】【2】:

1. pT1-2, N1 Disease: Tumors ≤50 mm with 1-3 positive axillary lymph nodes.

2. pT3, N0 Disease: Tumors >50 mm with no nodal involvement.

3. High-Risk Features in Node-Negative Disease: Tumors >20 mm but ≤50 mm with grade 3 histology and/or lymphovascular invasion (LVI).

Context and Broader Impact:

These findings align with an ongoing shift toward de-escalation strategies in oncology, prioritizing individualized treatment plans that balance efficacy and quality of life. The trial provides additional support for reducing overtreatment, especially in light of advancements in systemic therapies, which may further mitigate recurrence risk in intermediate-risk breast cancer【3】【4】.

Future Directions:

While SUPREMO guides practice for intermediate-risk patients, further research is needed to refine the role of radiotherapy in other subgroups, including those with high-risk features or specific molecular subtypes. Additionally, long-term follow-up beyond 10 years will provide further clarity on late recurrences and survival outcomes【4】.

References:

1. Kunkler, I. H., et al. Postmastectomy Radiotherapy for Intermediate-Risk Breast Cancer: Results from the SUPREMO Trial. Lancet Oncology, 2023.

2. San Antonio Breast Cancer Symposium 2023. SUPREMO Trial Results. [Conference Abstracts and Presentations].

3. Kunkler, I. H., et al. Radiotherapy De-Escalation in Breast Cancer: Lessons from SUPREMO. Journal of Clinical Oncology, 2023.

4. Smith, B. D., et al. Tailored Radiotherapy Approaches in Breast Cancer. Nature Reviews Clinical Oncology, 2023.