Patterns of breast cancer relapse in accordance to biological subtype.

Abstract

To evaluate the pattern of recurrence of breast cancer according to its biological subtype in a large cohort of patients treated with therapy representative of current practice. Patients treated between 2000 and 2016 with known biological subtype were eligible. Data were prospectively collected. Primary endpoint was the subtype-dependent pattern and time of recurrence. Loco-regional and distant site and time of recurrence were assessed. Median follow-up time was 80.8months. For 12,053 (82.5%) of 14,595 patients with primary non-metastatic invasive breast cancer a subtype classification was possible. The luminal A subtype had the highest 10-year survival followed by luminal B and luminal/HER2. The worst survival demonstrated HER2 enriched and TNBC. HER2 and TNBC had the highest rate of recurrence in the first 5years, whereas the rate of recurrence for luminal A and luminal B tumors was initially low, but remained continuously even after 10years of follow-up. Luminal A tumors demonstrated the lowest rate of distant metastases predominantly in bone. So did luminal B tumors. HER2 enriched subtype was characterized with increased rate of loco-regional recurrence and distant metastases in bone, liver and brain. Luminal/HER2 had pattern of relapse similar to HER2 enriched tumors, with exception of loco-regional relapse and brain metastases. TNBC had higher rate of lung, bone and brain metastases as well as loco-regional relapse. Breast cancer subtypes are associated with different time and pattern of recurrence and it should be considered during treatment decision.