Abstract
Background: Pathological factors, based mainly on immunohistochemistry (IHC) and histological differentiation, are mostly used to differentiate breast cancer (BC) subtypes. Our present aim was to describe the characteristics and survival of a relapsing BC patient cohort based on clinico-pathologic subtypes determined for the primary tumors. Methods: We used a clinico- pathological definition of BC subtypes based on histological grade (HG), estrogen receptor (ER), progesterone receptor (PgR),and epidermal growth factor receptor type 2 (HER2) expression assessed by IHC. We determined variables associated with loco-regional recurrence (LRR), second primaries (SP), systemic recurrence (SR) and post-recurrence survival (PRS). Results: Out of 1,702 patients, 240 (14%) had an event defined as recurrence. Those with recurrent disease were significantly younger than those without,and were initially diagnosed at more advanced stages, with larger tumors, greater lymph nodal involvement and higher HG. With a median follow up of 61 months (1-250), 4.6% of patients without recurrence and 56.6% of patients with an event defined as recurrence had died. The median PRS for the LRR group was 77 months; 75 months for those who developed a SP and 22 months for patients with an SR (p <0.0001). In SR cases, the median PRS was shorter for ER- tumors than for ER+ tumors (15 vs. 26 months, respectively; p = 0.0019, HR 0.44; CI: 0.25-0.44). Conclusions: Subtype, defined through classic histopathologic parameters determined for primary tumors, was found to eb related to type of recurrence and also to prognosis after relapse.