Cancer genetic testing panels for inherited cancer susceptibility: the clinical experience of a large adult genetics practice

Next-generation sequencing genetic testing panels for cancer susceptibility (cancer panels) have recently become clinically available. At present, clinical utility is unknown and there are no set criteria or guidelines established for whom to offer such testing. Although it may be a cost-effective method to test multiple cancer susceptibility genes concurrently, the rate of finding variants of unknown significance (VUS) may be high and testing may yield mutations in genes with no established management recommendations. We describe our Center's experience over a 14-month period (April 2012-June 2013) for patient interest and uptake in cancer panel testing and whether there were predictors of pursuing testing or identifying mutations. Using a clinical ranking system, patients' family histories were ranked from 0 to 3 (low likelihood to high likelihood for underlying genetic susceptibility). The clinical ranking system was assessed to determine its predictability of finding mutations. Of the 689 patients who met inclusion criteria, the option of pursuing a cancer panel was discussed with 357 patients; 63 (17.6 %) patients pursued testing. Those who pursued testing were more likely to be older, male, affected with cancer, affected with multiple primary cancers, and had a higher clinical rank than non-pursuers. There were no significant predictors of finding a mutation on panel testing. Of the 61 patients who have received results, there was a 6.6 % mutation rate and 19.7 % VUS rate. The yield of cancer panels in clinical practice is low and the strength of family history alone may not predict likelihood of finding a mutation.