Review of BRCA mutation detection rate in Queensland over the lasat five years
Aim: To assess the BRCA detection rate over a 5-year period in familial breast and ovarian cancer families using our criteria for offering BRCA gene testing.
Method: All clients referred had a detailed cancer family history recorded and were then categorised using the National Breast Cancer Centre (NBCC) guidelines. Assessment for BRCA gene testing requires a BRCAPRO estimate of > 15% probability of a BRCA mutation being identified. However occasionally when the BRCAPRO estimate was <15%, a clinical case review determined whether genetic testing would be undertaken. The Queensland Health Pathology Service and QCGS databases were accessed to identify all clients who had undergone new BRCA mutation gene analysis between 1st January 2001 and 31st December 2005. Each client’s file was reviewed to clarify their eligibility for BRCA gene testing. Denaturing High Performance Liquid Chromatography (DHPLC) was used to detect mutations in the entire coding regions and the splice junctions of the BRCA1 and BRCA2 genes. Direct DNA sequencing was used to identify sequence variations detected by DHPLC.
Results: A total of 245 clients were eligible for BRCA gene testing between 1st January 2001 and 31st December 2005. Of these, 49 BRCA1/BRCA2 mutations were identified. This gives a mutation detection rate of approximately 20% over the five year period. This is consistent with a previous internal audit demonstrated a 17.3% BRCA detection rate. The breakdown of the results from the current study will be discussed further.
Conclusion: BRCA mutation detection rate in Queensland is approximately 20% which is comparable to other major testing centres in Australia. Future studies will compare BRCAPRO with other mutation probability formulas to determine the most accurate tool for targeting clients for BRCA gene analysis.