Receptor status in recurrent breast cancer-a retrospective study

Ally, Zain
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Background: Breast cancer recurrence is a major clinical event and represents a principal cause of breast cancer related death. A discordance rate between receptor status of primary and matched recurrence tumours has been reported in the literature but the extent of this in our population is unknown. Repeating Immuno-histochemistry (IHC) and fluorescent in-situ hybridization (FISH) studies have financial and workforce implications in a resource-constrained environment. However, the results of these receptor studies have prognostic implications. Therefore it is important to determine the extent of change in receptors in the recurrence. Aim: To compare the hormone receptor profile between breast cancer primary and matched loco-regional recurrence and to ascertain the extent of receptor discordance. Methods: All patients who presented to the respective breast care facilities for breast cancer recurrences between 2006 and 2014 were identified using the mammography department records. The specimens for each patient were scrutinized. Oestrogen receptor (ER) and progesterone receptor (PgR) status as well as the Human Epidermal growth factor type 2 receptor (HER2) receptor statuses were noted for each patient and a comparison was made between primary and matching recurrence, with loss and gain being noted. Results: In the analysis, significant discordance was found for matching hormone receptor status. Discordance in oestrogen receptor status occurred in 14.3% of cases: change occurred both from ER-positive to -negative and vice versa. For progesterone receptor status this occurred in 25.7% of cases. A discordance of 14.8% was noted for HER2 receptor status. These results are not dissimilar to what has been previously reported in the literature. Of note, adverse receptor discordance: positive to negative was noted in a total of 19 receptors (ER 4; PgR 11; HER2 4) Conclusion: These results confirm the phenomenon of receptor discordance between breast cancer primary and recurrence. The results support the necessity of confirming receptor status on all loco-regional recurrent disease. This reinforces the importance of obtaining a confirmatory biopsy in patients where recurrence is suspected and therefore allowing the appropriate targeted therapy to be selected.
MBBCh Department of Surgery University of the Witwatersrand 08 March 2017