Breast cancer classification according to immunohistochemistry markers: subtypes and association with clinicopathologic variables in a peruvian hospital database.

BACKGROUND: Molecular classification is an excellent prognostic and predictive method in breast cancer (BC). In this study. we evaluated differences in clinicopathologic features and overall survival (OS) in four BC molecular subtypes: luminal A, luminal B, basal cell-like, and HER2/neu. PATIENTS AND METHODS: Immunohistochemical evaluation of estrogen receptor (ER), progesterone receptor (PgR), and HER2 was performed using a Peruvian hospital database of 1198 BC patients who were diagnosed between 2000 and 2002. Overall survival was calculated. RESULTS: Out of 1198 patients with invasive BC, 49.3% were luminal A; 13.2%, luminal B; 21.3%, basal-like; and 16.2%, HER2. The mean of age at diagnosis was 51.5 years for luminal A; 49.6 for luminal B; 49.5 for basal-like; and 49.4 for HER2. The HER2 subtype showed 63.7% positive lymph nodes, 42.3% stage III and 9.7% stage IV cases. Basal subtypes showed the highest prevalence of a poorly differentiated phenotype (70.3%). Average follow-up was 60 months. Five-year OS was significantly different between all 4 groups (P < .0001); luminal A had the highest OS, followed by luminal B, basal-like; and HER2. Results are compared with other population studies. CONCLUSION: This study shows significant differences between the distribution of molecular subtypes and clinicopathologic features. Immunohistochemistry is useful in the clinical management of BC patients.

Prognostic effect of hormone receptor status in early HER2 positive breast cancer patients.

BACKGROUND: This study was conducted to determine the prognostic effect hormone receptor (HR) status in early HER2 positive (HER2+) breast cancer patients, since it has not yet been established whether HR status can be used in the prognosis of patients with (HER2+) breast cancer. PATIENTS AND METHODS: We obtained data from 299 patients with early HER2+ breast cancer who underwent surgery and received standard adjuvant chemotherapy, hormonal therapy and/or radiation between 2000 and 2002 at the Instituto Nacional De Enfermedades Neoplasicas, Perú. Clinical and pathological features were compared. Endpoints analyzed were disease free survival (DFS) and overall survival (OS). RESULTS: Overall, 155 patients were HR-positive (HR+) and 144 were negative (HR-). The two groups had similar characteristics except for histologic grade and extracapsular extension. With a median follow-up of 93 months, 5-year DFS was statistically different between the two groups: 65.0% for (HER2+/ HR-) and 74.6% for the (HER2+/ HR+) patients (p=.045). OS at 5 years was not statistically different between the two groups with 75.5% for (HER2+/ HR-) patients and 82.4% for the (HER2+/ HR+)(p=.140). CONCLUSIONS: Patients with (HER2+/ HR-) breast cancers treated with surgery and standard adjuvant chemotherapy exhibited a statistically worse DFS compared to those with (HER2+/ HR+) tumors. However, OS was similar in both groups.