Dr Batra-Sharma on Conducting a Clinicopathologic Investigation Into Metaplastic Breast Cancer

Hemali Batra-Sharma, MD, fellow, Hematology/Oncology, University of California San Diego (UCSD) Medical Center, UCSD Health, discusses a single-institution, retrospective clinicopathologic analysis of patients with metaplastic breast cancer, findings from which were presented at the 2023 ASCO Annual Meeting.

Investigators evaluated 30 patients from UCSD with metaplastic breast cancer, finding that this patient population had similar features to populations recorded in other epidemiologic cohort studies, Batra-Sharma begins. The median age of patients at diagnosis was 47.5 years, and 86.7% of patients were diagnosed with early-stage disease. Despite 88.5% of patients receiving systemic neoadjuvant therapy followed by surgery, adjuvant radiation, and adjuvant systemic therapy, 61.5% of patients had localized or distant relapse, Batra-Sharma explains. Notably, the lungs were the most common site of disease recurrence.

Investigators examined potential trends in neoadjuvant systemic therapies received by patients in the study and found no superior neoadjuvant systemic regimen, Batra-Sharma expands. This lack of a superior neoadjuvant regimen is important because pathologic complete response rates with neoadjuvant systemic therapy are lower in patients with metaplastic breast cancer compared with patients with other breast cancer subypes, Batra-Sharma explains, adding that this discrepancy varies by study. The study investigators also found no clearly superior immunotherapy plus chemotherapy combination regimen in this population, she adds.

Additionally, when the investigators examined patients with advanced and metastatic disease, they found no clearly superior treatment regimen, Batra-Sharma continues. In the phase 3 KEYNOTE-355 trial (NCT02819518), patients with PD-L1–positive triple-negative breast cancer (TNBC) achieved an improvement in progression-free and overall survival with the addition of pembrolizumab (Keytruda) to chemotherapy. Although the KEYNOTE-355 data provide a standard of care for the management of patients with PD-L1–positive TNBC, no optimal approach exists for addressing metaplastic breast cancer in the advanced setting, Batra-Sharma concludes.