A Composite Assay for HER2-positive Early-stage Breast Cancer Management

A Composite Assay for HER2-positive Early-stage Breast Cancer Management

The goal of this observational study is to assess the prognostic value of a genomic classifier (S18) and its refined version (S*) in women with early-stage HER2-positive breast cancer. The study aims to determine whether these tools can predict event-free (EFS) and disease-free survival (DFS) in patients treated with neoadjuvant and/or adjuvant trastuzumab-based therapies.

The population includes women aged 18 or older with stage I-III HER2-positive breast cancer who received trastuzumab ± pertuzumab. Data and tumor tissue samples from this population have been collected prospectively from Istituto Nazionale dei Tumori IRCCS Fondazione Pascale, Naples (cohort A), and from Ospedale "Di Summa-Perrino", Brindisi (cohort B). The study integrates clinical-pathological and genomic data to refine and validate the prognostic capabilities of the S18 classifier.

Inclusion Criteria:

1. Age ≥ 18 years
2. Operable breast cancer (stage I-III)
3. Any status of hormone receptor in the primary tumor, according to institutional guidelines
4. HER2-positive primary tumor, according to ASCO guidelines, i.e., HER2-positive phenotype by immunohistochemistry (IHC) 3+ or 2+ with a positive result for ERBB2 gene amplification analysis using ISH techniques (CISH, SISH, FISH)
5. Neoadjuvant and/or adjuvant therapy based on trastuzumab ± pertuzumab
6. Written informed consent from patients

Exclusion Criteria:

1. Patient in follow-up for less than 3 years after surgery
2. A prior diagnosis of invasive cancer before the diagnosis of breast cancer