Clinical Predictors of Inherited Breast Cancer at a Comprehensive Cancer Centre in Oman: Is it time for universal germline genetic testing?

Objectives: This study aimed to explore the clinical, histopathological and demographic characteristics of female Omani breast cancer (BC) patients to identify possible predictors of a positive test result. Additionally, it aimed to evaluate the applicability of the National Comprehensive Cancer Network (NCCN) guidelines for germline genetic testing in risk assessment.

Methods: This study was conducted at the Sultan Qaboos Comprehensive Cancer Centre, Oman, between September 2021 and September 2022. The variables examined included age, disease stage, presence of metastasis at diagnosis, hormone receptor status, human epidermal growth factor receptor 2 status, histopathological type, Ki-67 levels, family history of cancer (presence/absence) and the applicability of NCCN guidelines. Data were retrieved and summarised using electronic patient files and family pedigrees collected by geneticists and genetic counsellors. Logistic regression analysis was used to identify predictors of a positive test result.

Results: Except for age, there were no statistically significant differences in the baseline characteristics between patients with positive and negative genetic testing results. Furthermore, age was found to be a poor screening tool for differentiating between positive and negative patients, as indicated by an area under the receiver operating characteristic curve of 0.67.

Conclusions: A strict application of the NCCN testing criteria in Omani BC patients may lead to underdiagnosis of hereditary BC. Universal testing of all BC patients could be appropriate for Omani individuals with BC, provided that careful consideration is given to cost-effectiveness and the testing methods employed.