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.