ESMO 2024: 10-Year Trial Update on TILs and Overall Survival in Early-Stage Breast Cancer

By: Amanda E. Ruffino, BA
Posted: Monday, September 16, 2024

Maria Vittoria Dieci, MD, of the University of Padua, Italy, and colleagues presented their findings from a 10-year follow-up of the ShortHER trial at the European Society for Medical Oncology (ESMO) Congress 2024 (Abstract 239MO). The results highlight tumor-infiltrating lymphocytes (TILs) as a significant prognostic biomarker for both distant disease–free and overall survival in patients with HER2-positive, early-stage breast cancer treated with the monoclonal antibody trastuzumab and chemotherapy. Higher TIL levels were linked to better outcomes. In fact, they added, patients with TILs ≥ 20% may safely receive shorter trastuzumab treatments without an apparent increased risk of death, supporting de-escalation strategies for this group.

The ShortHER study enrolled 1,254 patients with HER2-positive, early-stage breast cancer, randomly assigning participants to either 9 weeks or 1 year of adjuvant trastuzumab plus chemotherapy. Centralized scoring of TILs was available for 866 cases.

After a median follow-up of 9 years, multivariable analysis revealed that for each 1% increase in TILs, there was a significant improvement in both distant disease–free (hazard ratio [HR] = 0.972, P = .001) and overall (HR = 0.977, P = .016) survival. These findings build on earlier results, according to the investigators, and seem to demonstrate a consistent positive impact of TILs on long-term outcomes.

A key observation was the interaction between treatment duration and TIL levels, especially at the 20% cutoff. Patients with low TILs (< 20%) showed better outcomes with longer trastuzumab treatment (10-year distant disease–free survival rate, 88.7% vs 81.0%, P = .006). In contrast, patients with high TILs (≥ 20%) performed better with the shorter trastuzumab regimen (10-year distant disease–free survival rate, 92.2% vs 87.1%). For overall survival, a similar trend was observed but did not reach statistical significance.

Disclosure: For full disclosures of the study authors, visit cslide.ctimeetingtech.com.

ESMO Congress 2024

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