M. Roman-Zamudio (Monterrey, Mexico)
Escuela de Medicina y Ciencias de la SaludAuthor Of 1 Presentation
- A. Aranda-Gutierrez (San Pedro Garza Garcia, Mexico)
- A. Ferrigno (San Pedro Garza Garcia, Mexico)
- B. Vaca-Cartagena (San Pedro Garza Garcia, Mexico)
- F. Gonzalez-Mondellini (Monterrey, Mexico)
- A. Becerril-Gaitán (San Pedro Garza Garcia, Mexico)
- M. Roman-Zamudio (Monterrey, Mexico)
- M. Acosta-Sandoval (Monterrey, Mexico)
- M. Torres-Leal (Monterrey, Mexico)
- C. Treviño-Alanis (Monterrey, Mexico)
- H. Diaz-Perez (San Pedro Garza Garcia, Mexico)
- S. Cardona (San Pedro Garza Garcia, Mexico)
- C. Villarreal-Garza (San Pedro Garza Garcia, Mexico)
179P - Discordance rates of clinicopathological features in bilateral breast cancer
Abstract
Background
Bilateral breast cancer (BBC) constitutes 2-11% of all BC diagnoses. The management of this uncommon entity can be complex, particularly when inter-tumoral differences are present in molecular subtype or disease stage. However, scarce information exists regarding the discordance rates of clinicopathological features in BBC.
Methods
Medical records of women with primary BC diagnosed between 2013-2020 in a center in Monterrey, Mexico were reviewed. Overall survival (OS) rates of synchronous BBC (SBBC) and metachronous BBC (MBBC) patients were estimated using the Kaplan–Meier method after excluding patients with in situ or stage IV disease.
Results
A total of 1765 patients were diagnosed with BC, of which 53 (3.0%) were SBBC (≤3 months between diagnoses) and 15 (0.8%) were MBBC (median time elapsed between diagnoses: 36 months). In patients with BBC, the median age at diagnosis was 51 years (range 24-77). The most common molecular subtype in BBC was HR+/HER2- (60.3% in SBBC and 40.0% in MBBC). Concordance and discordance rates are presented in the table. OS rates at 3 years were 92.9% (95%CI 59.1-99.0%) in MBBC and 84.7% (95%CI 61.0-94.6%) in SBBC (p>0.05 by log-rank test). Discordance rates of clinicopathological features in BBC
SBBC MBBC Clinical stage - Concordant 49.1% 53.3% - Discordant 50.9% 33.3% - Unknown 0 13.3% Histological type - Concordant 84.9% 80.0% - Discordant 13.2% 13.3% - Unknown 1.9% 6.7% Histological grade - Concordant 41.5% 20.0% - Discordant 24.5% 33.3% - Unknown 34.0% 46.7% HR status - Concordant 73.6% 46.7% - Discordant 11.3% 13.3% - Unknown 15.1% 40.0% HER2 status - Concordant 75.5% 60.0% - Discordant 9.4% 0 - Unknown 15.1% 40.0% Molecular subtype - Concordant 66.0% 46.7% - Discordant 18.9% 13.3% - Unknown 15.1% 40.0%
Conclusions
A substantial rate of molecular subtype discordance (>10%) was documented in both SBBC and MBBC, with important proportions of unknown concordance/discordance. These findings highlight the need of characterizing the clinicopathological features of both tumors in order to optimize the treatment strategy. Future studies are needed to elucidate if the survival tendency in SBBC is due to the presence of two simultaneous tumors or other clinicopathological features such as discordance in molecular subtype or disease stage.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.