385P - Evaluation of discordance rates of HER2, ER and PR status between primary breast cancer and distant metastases or locoregional recurrences

Date 27 September 2014
Event ESMO 2014
Session Poster Display session
Topics Biomarkers
Breast Cancer, Metastatic
Presenter Soheir Ismail
Citation Annals of Oncology (2014) 25 (suppl_4): iv116-iv136. 10.1093/annonc/mdu329
Authors S. Ismail, H. Elwakiel, M. Elbassiouny, D. Abd Elghany, M. Alhefny
  • Clinical Oncology, Ain Shams University Hospitals, 11566 - Cairo/EG

Abstract

Aim

Primary objective was to determine the discordance rates in hormonal receptors (estrogen, progesterone receptors) and HER2 between primary breast cancer and matched locoregional or systemic recurrences in Egyptian patients, while secondary objective was to compare the disease free survival in patients with and without receptors discordance.

Methods

62 patients with recurrent breast cancer (47 locoregional and 15 distant metastases) were recruited from Ain Shams University Clinical Oncology Department, assessment of hormonal receptors (ER and PR) and HER2 status were done for both primary tumor specimens and corresponding specimens of recurrences using immunohistochemistry, with hormonal receptors positivity defined as equal or more than 1% of tumor cell nuclei staining positively, HER2 positive defined as IHC score (3+) and negative results is either score (0 or 1+), if HER2 status is equivocal (2+) biopsies will be retested for HER2 oncogene by (FISH), effect of adjuvant therapy on receptors discordance was also evaluated, disease free survival (DFS) was compared in patients with and without receptors discordance, the change in treatment decision was assessed by documentation of treatment decision before and after biopsy results.

Results

Discordance rate of ER was 22.6% with statistically significant difference between ER of primary tumors and ER of recurrences (McNemar's test p = 0.029), discordance rate of PR was 33.9%, also with significant difference (p = 0.027), HER2 discordance rate was 11.3% with non-significant difference (p = 0.45), with an overall discordance rate of 38.7%, effect of adjuvant therapy on receptors discordance demonstrated a statistically significant effect of adjuvant hormonal therapy in down regulation of the ER and PR from the tumor cells throughout disease progression (p = 0.008), there was non-significant difference between DFS of the discordant group and the concordant group (26.5 months vs. 30.5 months) p = 0.4, as a results of re-biopsy from recurrent disease treatment decision was changed in 17.7%.

Conclusions

We have shown a statistically significant discordance rates in hormonal receptors (ER and PR) between primary and recurrent breast cancer, and a change in treatment decision in a considerable number of patients, these findings prompt consideration of re-biopsy from recurrent tumors.

Disclosure

All authors have declared no conflicts of interest.