A substantial fraction of early-stage triple-negative breast cancer (eTNBC) is characterized by high levels of stromal tumor-infiltrating lymphocytes (sTIL) and has a good prognosis even without systemic treatment, highlighting the importance of an endogenous anticancer immune response. Still, a considerable proportion of patients with eTNBC need some “therapeutical push” to kick-start this immune response. Exploiting this immune response with immune-checkpoint inhibition (ICI), in combination with chemotherapy, has made its way into standard of care in eTNBC. Major challenges in the near future include finding those patients with eTNBC who can be treated with ICI alone or with a reduced chemotherapy backbone. Exploring the optimal duration of ICI and finding biomarkers to predict response will be key to enable personalized implementation of ICI in patients with eTNBC. For patients who currently do not respond effectively to ICI plus chemotherapy, challenges lie in finding new immunomodulatory therapies and developing response-guided neoadjuvant approaches.

doi: 10.1158/1078-0432.CCR-22-0701 - 2023