Concordance of histology type between synchronous and metachronous contralateral breast carcinoma: Is there susceptibility for breast cancer of particular histology?

Abstract

e21030 Background: Contra-lateral breast cancer (CBC) is considered to be the most frequent new malignancy after primary breast cancer (PBC) However, there are few reports whether the histology and other major molecular characteristics differs between PBC and CBC. The aim of this paper is toevaluate and compare PBC/CBC histology according to the time to CBC development. Also, age at CBC and major molecular characteristics (tumor grade, estrogen/progesterone receptors, HER2) have been analyzed. Methods: A cohort of 113 patients with CBC, without distant metastases, has been prospectively registered during 28 months. Patients are divided in 2 groups according to the time of CBC diagnose: 1. Synchronous, if the CBC (S-CBC) was diagnosed either simultaneously or within 6 months after PBC; 2. Metachronous (M-CBC) if CBC was diagnosed > 6 months after PBC. Results: Results are presented in Table 1. Median age was calculated at the time of CBC diagnose. Patient with S-CBC are median 7 years older than patients with M- CBC that is statistically significant difference (p-0.007) S-CBC is more likely to be of the same histological type (76%) than M-CBC (56%) (p 0.006) In the whole analyzed group, and each subgroup separately, lobular carcinoma is registered in higher percentage (41%) than expected (~20%) For all other analyzed BC characteristics, statistical difference was not confirmed, however ~ 25% of specimens were not available for testing. Conclusions: Although it is still unclear what could be the clinical significance of these findings, genetic susceptibility to particular histology type of BC might be reasonably speculated. [Table: see text]