Immunotherapy for triple negative breast cancer: the end of the beginning or the beginning of the end? (original) (raw)

2022, Cancer and Metastasis Reviews

Triple-negative breast cancer (TNBC), which comprises 10-20% of all breast malignancies, remains a subtype with the most dismal prognosis. TNBC cells, due to lack of estrogen (ER), progesterone (PR), and human epidermal growth factor receptor-2 (HER-2) receptor expression, are insensitive to all known endocrine and anti-HER-2-targeted therapies. As a result, chemotherapy remains the standard of care for this subgroup of patients, in whom a high recurrence rate and poor overall survival are observed. The biology of TNBC is distinctive, not only in comparison to other breast cancers, but its natural course differs among individuals. This heterogeneity makes it even harder to define new therapeutic targets or predictive factors. Therefore, an urgent need to develop effective therapies exists, as only 20% of TNBC patients treated in a neoadjuvant and adjuvant setting achieve a pathological complete response (pCR), which is a strong surrogate marker for longer overall survival (OS). The remaining 80% are exposed to highly toxic treatment that causes a significant decrease in quality of life, while at the same time providing little clinical benefit. The efficacy of palliative chemotherapy is even more disappointing. Following the spread of the disease, most commonly to visceral organs or to the brain, the mean survival time is only 10.2 months [1]. Initially, the success of immunotherapy in treating malignancies exhibiting a pessimistic prognosis, such as malignant melanoma or lung cancer, raised hope for TNBC patients.