Reliability of receptor assessment on core needle biopsy in breast cancer patients.

We compared the breast core needle biopsy and the resection specimen with respect to estrogen (ER), progesterone (PR) and human epidermal growth factor receptor 2 (HER2) status to identify predictors for discordant findings. We retrospectively collected data from 526 newly diagnosed breast cancer patients. ER, PR and HER2 status had been assessed in both the core needle biopsy and resection specimen. The assessment of ER by immunohistochemistry (IHC) in core needle biopsy was false negative in 26.5% and false positive in 6.8% of patients. For the PR status the false negative and false positive results of core needle biopsy were 29.6% and 10.3%, respectively. The results of the HER2 status, as determined by IHC and silver in situ hybridization (SISH), were false negative in 5.4% and false positive in 50.0%. We need to be aware of the problem of false negative and false positive test results in ER, PR and HER2 assessment in core needle biopsy and the potential impact on adjuvant systemic treatment. With current techniques, we recommend using the resection specimen to measure these receptors in patients without neoadjuvant treatment. A better alternative might be the use of tissue microarray, combining both core needle biopsy and resection specimen.

Cost-effectiveness of adjuvant systemic therapy in low-risk breast cancer patients with nodal isolated tumor cells or micrometastases.

BACKGROUND: The cost-effectiveness of adjuvant systemic therapy in patients with low-risk breast cancer and nodal isolated tumor cells or micrometastases is unknown. PATIENTS AND METHODS: A cost-effectiveness analysis of adjuvant systemic therapy was carried out using the costs per 1% event prevented after 5 years of follow-up as incremental cost-effectiveness ratio (ICER). Secondary objective was to establish when adjuvant systemic therapy becomes cost saving. Patients included in the MIRROR study with isolated tumor cells or micrometastases who had a complete 5-year follow-up and who either did or did not receive systemic therapy were eligible. Sensitivity analyses were carried out. RESULTS: In the no adjuvant therapy cohort (N = 366), 24.9% of patients had an event within 5 years versus 16.8% of patients in the adjuvant therapy cohort (N = 483) (P < 0.01). The ICER was €363 per 1% event prevented. Beyond 18 years after diagnosis, the extrapolated mean cumulative costs per patient in the no adjuvant therapy cohort exceeded those of the adjuvant therapy cohort. CONCLUSIONS: In this population of breast cancer patients with isolated tumor cells or micrometastases, €36 300 had to be invested to prevent one event in 5 years of follow-up. Adjuvant systemic therapy was cost saving beyond 18 years after diagnosis.