A new study has found that less than 7% of patients newly diagnosed with cancer are tested for germline genetic mutations, and the rate is even lower among racial and ethnic minorities. Germline genetic testing can affect a patient’s cancer care, as it can indicate whether targeted therapies would be beneficial and can have implications for close relatives who may carry the same genes. The data for the study came from the Surveillance, Epidemiology, and End Results (SEER) registry and analyzed information on over 1.3 million individuals across two US states. The result indicated that the rate is well below guideline recommendations, which could be addressed through creative solutions such as telemedicine during the COVID-19 pandemic, embedding genetic counselors in oncology clinics, and using chatbots to respond to patient questions. Suggestions to widen access to genetic testing include the use of point-of-care testing and tele-counseling. Furthermore, clinicians should recommend testing to their patients and provide them with the information necessary to make informed decisions about whether to undergo testing. Variants of uncertain significance (VUS) were more likely to be found among non-White patients than among White patients, which increases patient and physician anxiety and may have unclear optimal management recommendations for these patients.
The study found that germline genetic testing is increasingly essential for cancer care, as it is central to risk-adapted screening and secondary prevention, the use of targeted therapies, including PARP and checkpoint inhibitors, and cascade testing to identify at-risk relatives. The team behind the study suggested that innovative care delivery is needed to tackle the low percentage of germline genetic testing and streamline pretest counseling, make posttest counseling more widely available, and employ long-term follow-up to track patient outcomes. Germline genetic testing has evolved rapidly, with panels including more and more genes, the cost of these tests falling, and guidelines becoming more expansive. The number of genes for which testing was conducted increased from a median of two in 2013 to 34 in 2019. Rates of VUS increased more than that for pathologic variants and substantially more so in non-White patients. Overall, germline genetic testing was performed in 93,052 (6.8%) of patients over the study period. Women were more likely to have undergone germline mutation testing than men.
The study revealed that testing is not offered to all patients, there may be poor access to genetic counseling resources, or patients may be offered testing but decline it, which may cause racial and ethnic disparities in the testing rate, indicating that racial and ethnic differences in testing exist after controlling for age, cancer type, and year. Testing rates were higher among White patients (8.0%) compared with Asian, Black, and Hispanic patients (~6.0%), and lower among men regardless of the type of cancer they suffer from.
In conclusion, the study’s results represent a missed opportunity for decreasing the population-level burden of cancer, and clinicians should recommend testing to their patients and provide them with the information necessary to make informed decisions about whether to undergo testing. Wider access to genetic testing resources for patients with cancer, particularly for racial and ethnic minorities, could prevent cancer diagnoses and related deaths in family members. It is essential to raise awareness and increase access to genetic testing resources for patients with breast cancer, particularly for racial and ethnic minorities, as this may show that they are candidates for treatment with PARP inhibitors, which may have a direct impact on cancer-related mortality. Finally, the study suggests that with greater emphasis on overcoming both health system and patient-level barriers to gender cancer susceptibility testing, treatment outcomes will improve.
