Cáncer de mama HER2-bajo: una nueva era en terapias dirigidas

Breast cancer is a heterogeneous disease that goes beyond traditional clinicopathological classifications. Identifying low and ultra-low levels of HER2 expression through immunohistochemistry, in tumors previously classified as HER2-negative, has led to a paradigm shift in patient management. This reclassification has expanded therapeutic options for a significant proportion of patients, with estimates indicating that over 60% of patients with hormone receptor-positive breast cancers fall into the HER2-low category.

Trastuzumab deruxtecan, an antibody-drug conjugate, has demonstrated significant survival benefits in patients with advanced HER2-low breast cancer, who, in most cases, were previously candidates solely for chemotherapy following hormonal treatment. However, this therapy is not exempt from toxicity, notably interstitial lung disease/pneumonitis, which can be severe and even fatal in some instances. Early detection of these toxicities and their interdisciplinary management are crucial to optimize clinical outcomes in these patients.

This article provides an overview of recent advancements in treating patients with HER2-low breast cancer, highlighting pivotal studies and emphasizing the importance of stringent monitoring for toxicities associated with new therapies.