Although less than 1% of patients in each of the 5 distinct regional trajectory groups for genomic testing adoption were tested at baseline, in group 1 (lowest adoption), testing increased to 4.0% from June 2017 to July 2018. In group 5 (highest adoption), testing use increased to 33.8% of all patients tested during the same period.
The study included 3 dominant, commercially available tests for use in prostate cancer, Prolaris, OncotypeDX and Decipher, as well as ProMark, a new risk assessment tool, Leapman said. Presently, any differences between the 4 available tests in prostate cancer seem negligible as each test has clinical value, according to Lindsay Harris, MD, program director for breast cancer in the Cancer Diagnosis Program in the Division of Cancer Treatment and Diagnosis at the National Cancer Institute.
The next step will be to correlate the study’s findings with clinical outcomes. “Even though these tests are prognostic,” Leapman said, “it’s really a question of whether in human hands they lead to better medical decisions.”
This is not an easy question to answer, not only because genomic testing carries similarly high costs as magnetic resonance imaging, he said, but also because “they can be ordered by anybody” and subsequently sent to a laboratory. “These are not required tests; they’re highly discretionary,” Leapman added.
“This is an observational study, looking at trends of uptake in testing and the reasons for it,” with educational levels perhaps more important than any other influencing factor, Harris observed. “Either patients don’t understand these tests or they’re unconvinced they might be helpful to them.”
Nevertheless, as testing has become more available, so too has evidence of patient benefit, said Harris, who cited breast cancer as a field for which gene expression testing has emerged as a new standard component of treatment. “As you can see [from] this data, testing has increased in frequency of use since the technology’s development around 2013 or 2014,” Harris said.
Disclosures: Some of the study authors disclosed financial relationships with the pharmaceutical industry and/or the medical device industry. For a full list of disclosures, please refer to the original study.
Leapman MS, Wang R, Ma, S, Gross CP, Ma X. Regional adoption of commercial gene expression testing. JAMA Oncol. Published online November 25, 2020. doi:10.1001/jamaoncol.2020.6086