Search

Purpose To retrospectively evaluate the pattern of recurrence and outcome of node-negative breast cancer (BC) according to major subtypes. Patients and Methods In all, 1,951 patients with node-negative, early-stage BC randomly assigned in International Breast Cancer Study Group Trials VIII and IX with centrally reviewed pathology data were included. BC subtypes were defined as triple negative (TN; n = 310), human epidermal growth factor receptor 2 (HER2) positive (n = 369), and hormone receptor positive with high (luminal B–like [LB-like]; n = 763) or low (luminal A–like [LA-like]; n = 509) proliferative activity by Ki-67 labeling index. BC-free interval (BCFI) events were invasive BC recurrence in local, contralateral breast, nodal, bone, or visceral sites. Time to first site–specific recurrence was evaluated by using cumulative incidence and competing risks regression analysis. Results Median follow-up was 12.5 years. The 10-year BCFI was higher for patients with LA-like (86%) BC compared with LB-like (76%), HER2 (73%), and TN (71%; P < .001) BC. TN and HER2 cohorts had higher hazard of BCFI event in the first 4 years after diagnosis (pre-trastuzumab). LB-like cohorts had a continuously higher hazard of BCFI event over time compared with LA-like cohorts. Ten-year overall survival was higher for LA-like (89%) compared with LB-like (83%), HER2 (77%), and TN (75%; P < .001) BC. LB-like subtypes had higher rates of bone as first recurrence site than other subtypes (P = .005). Visceral recurrence as first site was lower for the LA-like subgroup, with similar incidence among the other subgroups when treated with chemotherapy (P = .003). Conclusion BC subtypes have different distant recurrence patterns over time. Defining different patterns of BC recurrence can improve BC care through surveillance guidelines and can guide the design of clinical studies.

Purpose To evaluate the benefit of adjuvant trastuzumab in patients diagnosed with human epidermal growth factor receptor 2 (HER2) –positive invasive lobular carcinoma (ILC) enrolled onto the Herceptin Adjuvant (HERA) trial. Patients and Methods Patients randomly assigned to receive one year of trastuzumab and one year of observation in the HERA trial were included (n = 3,401). Centrally reviewed estrogen receptor (ER), progesterone receptor (PgR), and HER2 copy numbers were used. First site-specific relapse pattern was evaluated for ILC and invasive ductal carcinoma (IDC). The magnitude of trastuzumab benefit was assessed using the Cox proportional hazards model for disease-free survival (DFS) and overall survival (OS). Results Median follow-up time was 4 years. A total of 187 ILC and 3,213 IDC patients were included. High Allred scores (6 to 8) were more common in patients with ILC than IDC for both ER (36.9% v 22.7%) and PgR (44.1% v 28.5%). A trend toward decreased HER2 copy number was observed in the ILC group. The ILC and IDC subgroups had similar patterns of first site of disease relapse. DFS hazard ratios (HRs) comparing 1 year of trastuzumab versus observation were 0.63 for ILC (95% CI, 0.34 to 1.15) and 0.77 for IDC (95% CI, 0.67 to 0.89; P for interaction = .49). The OS HRs comparing 1 year of trastuzumab versus observation were 0.60 for ILC (95% CI, 0.27 to 1.31) and 0.86 for IDC (95% CI, 0.71 to 1.06; P for interaction = .29). Conclusion In this retrospective analysis, there was no suggestion that patients in the ILC cohort experienced a different magnitude of benefit from adjuvant trastuzumab than those in the IDC cohort.

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers. It is a heterogeneous disease, not only on the molecular level, but also on the pathologic and clinical levels. TNBC is associated with a significantly higher probability of relapse and poorer overall survival in the first few years after diagnosis when compared with other breast cancer subtypes. This is observed despite its usual high sensitivity to chemotherapy. In the advanced setting, responses observed with chemotherapy lack durability. Early-stage clinical studies suggested impressive potential when a poly (ADP-ribose) polymerase (PARP) inhibitor is given for the treatment of advanced TNBC with BRCA gene dysfunction. The molecular complexity of TNBC has led to proposed subclassifications, which will be of great value for the development of targeted therapies. In this review, we discuss the biology of TNBC at the pathologic and the molecular levels. We also elaborate on the role of systemic therapies and the results of the first phase III clinical trial evaluating the addition of iniparib, a novel investigational anticancer agent that does not possess characteristics typical of the PARP inhibitor class, in combination with chemotherapy in advanced TNBC.