# Cascade Genetic Testing for Hereditary Cancer Predisposition: Characterization of Patients in a Catchment Area of Southern Italy

## TL;DR

This study examines cascade genetic testing for hereditary cancer in southern Italy, showing improved early detection and prevention through family outreach.

## Contribution

The study provides real-world data on CGT trends and outcomes in a southern Italian population, emphasizing the importance of communication and prevention.

## Key findings

- 39% of relatives tested carried familial mutations and were referred to cancer prevention programs.
- 62% of carriers accessed genetic counseling within one year of the proband's diagnosis.
- Median age of those undergoing testing was reduced by about ten years.

## Abstract

Background: The national guidelines, informed by evidence from the National Institutes of Health (NIH), define the criteria for genetic testing of BRCA1/2 and other genes associated with Hereditary Breast and Ovarian Cancer (HBOC) and Lynch Syndrome (LS). When a germline pathogenic variant (PV) is identified in an index case, clinical recommendations advise informing at-risk relatives about the availability of predictive genetic testing, as early identification of carriers allows for timely implementation of preventive measures. Methods: This retrospective observational study examined data collected between 2017 and 2024 at the Medical Genetics Unit of the “Renato Dulbecco” University Hospital in Catanzaro, Italy. The analysis focused on trends in the identification of individuals carrying PVs in cancer predisposition genes (CPGs) and the subsequent uptake of cascade genetic testing (CGT) among their family members. Results: Over the study period, from 116 probands were performed 257 CGTs on 251 relatives. A notable reduction of approximately ten years in median age was observed, 39% were found to carry familial mutation and were referred to personalized cancer prevention programs. Among these, 62% accessed Oncological Genetic Counselling (CGO) within one year of the proband’s diagnosis, suggesting effective communication and outreach. Conclusions: The findings highlight the critical role of effective CGO and intrafamilial communication in hereditary cancer prevention. The identification of PVs, followed by timely CGTs and implementation of preventive strategies, significantly contributes to early cancer risk management. Periodic monitoring of CGT uptake and outcome trends, as demonstrated in this study, is essential to refine and optimize genetic services and public health strategies.