Abstract P6-08-27: Disparities in cascade screening in BRCA1 or BRCA2 mutation carriers. Exploring rate and barriers in a Mexican population
Authors: Pacheco-Cuellar Guillermo , Campos-Gomez Karen , Valdes-Andrade Juan Jesus , Campos-Gomez Saul 
Published: March 2020

Abstract
Background. Hereditary predisposition explains 10-15% of Breast cancer (BC), individuals carrying germline BRCA1 andBRCA2 mutations have a 46-87% lifetime risk for BC. According to ACOG, Genetic Cascade Testing (GCT) refers to the performance of genetic counseling (GC) and testing in blood relatives of individuals who have been identified with specific genetic mutations. CGT could offer advantages to relatives in order to adjust surveillance and even offer risk reduction procedures. Even if CGT should be more affordable, its cost is still a burden for most Mexican health care institutions and patients (pts) as well. Herein, we intended to explore the CGT rate, and describe the barriers to CGT in Mexican pts with BC. Methods. Through this retrospective work, we collected clinical, demographic and familial information of BRCA1&2 mutation carriers diagnosed from nov2014-mars2019. Through GC or medical record review, we explored if some of the relatives older than 18 years had GT, and if CGT was complete for their 1st and 2nd degree relatives. Finally, pts available for an interview were asked to list CGT barriers. Also, we asked them whether a GC session was offered to their relatives. Descriptive and parametric tests were used. Results. We identified 27 pts carriers of a pathogenic variant in BRCA1 or BRCA2. 16 pts (59%) were carriers of BRCA1 mutations. Mean age was 44.52y (SD 10.3). (48.1%) 13 pts held bachelor or a higher degree. 6 pts (22.22%) reported some CGT. 2 pts (7.4%) described GT in offspring, and 1 pt (3.4%) in siblings. 2 pts described GT in 2nd or 3rd degree relatives. Nonetheless, only 1 pt (3.7%) had complete GT for 1st degree relatives. 5 pts were not available for interview, 2 deceased before we started collecting these data, and 2 pts were had their result too recently. Thus, we conducted 18 interviews. All patients had a positive attitude toward GT. The barriers described were: in 16 cases (88.8%) lack of coverage; in 12 (66.66%), the cost of GT; in 5 cases (27.7%), the relatives were beneficiaries of other health care institution, or declined the test because they were males and perceived a low risk. In 4 cases (22.22%), the relatives had not access to a genetics department, or indolence was referred too. In 3 cases (16.6%) family issues were reported. In 2 cases (11.11%), the relatives were comfortable having only clinical surveillance or their primary physician counseled it. A GC session in relatives was only performed in 9 families (33.3%). We found no association between CGT and age of diagnosis (p=0.372), education (p=0.301) or year of prescription of GT (p=0.477). Conclusion. Overall, we found a low cascade testing rate among our BRCA positive pts, and only one case was described as complete. Lack of coverage and cost of GT are described as the most important barriers. Only 1 pt disclosed the price of GT ($1000 for every single relative tested), which is not affordable for most of the population. Male gender was associated with lower testing rate, CG is necessary to improve understanding of risks according to gender and inheritance. Better communication between the different health care institutions could be helpful in order to identify relatives at risk. Unfortunately, we didn’t gather information about income, which could have an association with CGT. New modalities of GT are becoming more affordable and probably, more pts should be counseled about these options. Our sample is small, but it could be representative of a large issue along the whole country.
Citation Format: Guillermo Pacheco-Cuellar, Karen Campos-Gomez, Juan Jesus Valdes-Andrade, Saul Campos-Gomez. Disparities in cascade screening in BRCA1 or BRCA2 mutation carriers. Exploring rate and barriers in a Mexican population [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-08-27.