
Genomic Testing and Precision Medicine in Cancer Care
Genetic and genomic testing in cancer, and in particular the use of multigene panels, has exploded over the past 4 years following the US Supreme Court's ruling that human genes are not patentable.[1] The ruling invalidated the patent on BRCA held by Myriad Genetics and thus blew open the field of clinical genomic testing to competition.
At least a dozen well-established companies now offer multigene panels, including one as low as $249 for a 30-gene panel.
How are oncologists using these panels in daily clinical practice? Are your colleagues regularly ordering genomic testing for their patients? When in the course of disease are they doing so? And how are genomic tests being paid for?
To answer these questions and many others, Medscape worked with H. Jack West, MD, medical director of the Thoracic Oncology Program at Swedish Cancer Institute in Seattle, to survey 132 medical oncologists and hematologist/oncologists on their use of genomic testing that sequences multiple genes or the entire tumor genome, beyond single-gene assays looking at BRCA or EGFR mutations, for example. Surveyed oncologists came from a broad range of practice settings, including solo and group practices, hospitals, and academic, research, military, and government institutions.
The results suggest that most oncologists consider genomic testing to be a potential major advance in oncology, but they also believe that it is significantly overpromoted to date.
(Note: Values in graphs have been rounded and may not match the sums noted in the captions.)
Genomic Testing and Precision Medicine in Cancer Care
Many oncologists feel that genomic testing holds promise as an advance for cancer treatment but that it currently underperforms in terms of clinical use.
Taken together, 71% of respondents said that genomic testing is either very important or extremely important to the field of oncology but more than half (55%) also said that these tests are overpromoted and that their value is either below or far below expectations.
Genomic Testing and Precision Medicine in Cancer Care
Genomic testing has a number of hurdles to overcome before physicians feel comfortable using it on a widespread basis. Oncologists said that the most important issue, not surprisingly, is that far too often test results do not lead to any changes in patient management; there simply isn't evidence that approved therapies will work for the vast majority of mutations found with genomic testing.
However, practical concerns related to tissue sampling, cost, and turnaround time were also significant. About 1 in every 6 oncologists reported that one of these issues was their most significant concern.
Genomic Testing and Precision Medicine in Cancer Care
As a marker of just how quickly technology has outpaced clinical benefit, Medscape asked oncologists what percentage of the patients they treat benefit from genomic testing. The result was clear: 9 out of 10 oncologists said that less than half of their patients would benefit from genomic testing. And 61% said that less than a quarter of their patients would benefit.
Genomic Testing and Precision Medicine in Cancer Care
Oncologists are not only concerned with the lack of clinically actionable results from genomic testing. More than two thirds of survey respondents also expressed concern with financial issues such as the cost-effectiveness of genomic testing and insurance coverage for both genomic tests and subsequent therapies in unapproved indications.
High numbers were also concerned with their colleagues' knowledge of genomic testing. Eight-six percent of respondents said that more physician education is needed before genomic testing can be widely advocated, and 49% said that genomic testing should currently be restricted to research settings.
Genomic Testing and Precision Medicine in Cancer Care
Despite the widespread concerns with genomic testing, a significant majority of oncologists have used genomic testing at some point. Among the 13% who have never ordered a genomic test for their patients, the primary reasons were that the tests provide too few actionable results, the belief that genomic testing is not standard of care yet, and the high cost of ordering a genomic test. It should be noted, however, that these directional results were among a small sample size (< 20) who had never used genomic testing.
Among those who have ordered genomic testing, use was recent. Ninety percent had ordered a genomic test within the past 5 months and nearly a quarter (23%) had ordered one within the past week.
Genomic Testing and Precision Medicine in Cancer Care
Oncologists overwhelmingly ordered genomic testing for clinical reasons, in spite of the fact that many also reported feeling that these tests provide too few clinically actionable results to be used on a widespread basis (see slides 3-5).
Sixteen percent of oncologists said they ordered genomic tests to guide a patient to a clinical trial, suggesting that many physicians order genomic tests at the point of disease progression on approved therapies or for patients in whom approved therapies are not an option for other reasons.
Genomic Testing and Precision Medicine in Cancer Care
Most oncologists reported that they were moderately confident (between 3 and 5 on a 7-point scale) in using genomic testing to guide treatment decisions and when counseling patients on the significance of their mutations.
Overall, however, oncologists felt slightly more confident using the tests for clinical management than they did for explaining test results, such as unexpected genetic findings or the significance of moderate-penetrance genes in terms of actual cancer risk.
It is noteworthy that 86% of respondents said that more physician education is needed before genomic testing can be widely advocated (slide 5).
Genomic Testing and Precision Medicine in Cancer Care
As noted earlier, 16% of oncologists said that their primary motive for ordering genomic testing was to guide patients to a clinical trial.
But in reality, oncologists who order genomic tests said this happened relatively rarely. Three out of four said that ordering a genomic test led to clinical trial enrollment for fewer than 25% of their patients.
Genomic Testing and Precision Medicine in Cancer Care
It has not yet been clearly established when genomic testing should be ordered for cancer patients. For example, in the research setting, genomic tests are frequently used to guide advanced cancer patients toward precision medicine targeted therapies, as in ASCO's TAPUR Trial.[2] Similarly, research institutions are using broader genomic panels to assess patients' overall number of mutations or tumor mutational burden, which may be a potential marker for response to immunotherapy.
Medscape's survey results suggest that oncologists are using genomic testing in a similar fashion—when patients are no longer responding to standard-of-care options or when standard-of-care options are not available, particularly among metastatic patients, and in the research setting.
A small minority of oncologists (16%) reported that they have ordered or would order genomic testing in the setting of earlier-stage, potentially curable disease to guide adjuvant or neoadjuvant treatment decisions.
Despite the wide range of time points reported for ordering genomic testing, a significant majority of oncologists (69%) said they felt confident as to when genomic testing should be ordered.
Genomic Testing and Precision Medicine in Cancer Care
Unlike companion diagnostic, single-gene tests for approved cancer drugs, there is not clear guidance on when physicians should order a multigene genomic test, nor on the size of the panel to be ordered. Multigene panels run the gamut from as few as two genes to hundreds of genes, with many companies offering multiple panels of varying size for the same disease setting.
Many companies also offer "guidelines-based" panels that include only the most well-established genes; others provide site-specific panels focusing on tumor location. Still others offer comprehensive panels that include dozens or hundreds of genes with less well-established cancer therapy recommendations.
Fewer than half of respondents (44%) most commonly used National Comprehensive Cancer Network (NCCN) guidelines when ordering genomic tests; nearly a third (32%) referred directly to published studies when deciding to order a multigene test.
While 30% of respondents reported that their institution provided some guidance on ordering genomic tests, a very small number (8%) said that institutional or practice pathways were their primary source when ordering genomic testing.
Genomic Testing and Precision Medicine in Cancer Care
When it comes to who should pay, genomic testing is very much a gray area. Oncologists report that they're reluctant to advocate for widespread use of genomic testing, in part because of the uncertain clinical utility of the results (slides 3-5); yet the vast majority (78%) said that insurers should pay for these tests on the basis of the existing body of evidence.
Patients may be less convinced of the value of genomic testing, at least if they would be expected to cover its cost. A high proportion of patients (73%) would not be willing to pay expensive out-of-pocket costs for genomic testing, according to surveyed oncologists.
Regardless of payment source, when given the choice, more than half of patients (59%) proceed with genomic testing, according to oncologists.
Genomic Testing and Precision Medicine in Cancer Care
Private health insurance is by far the most common way that genomic testing is paid for among cancer patients, although research funding and patient self-pay also constitute substantial proportions.
Taken together, the data suggest that oncologists have a mix of payment sources for the genomic tests they order, with some tests falling into insurance-approved settings and others requiring research funding or patient out-of-pocket costs.
Genomic Testing and Precision Medicine in Cancer Care
All signs point to greater use of genomic testing in the coming decade. Precision medicine trials, in which patients are given anticancer therapies based on mutational status as opposed to disease site, are more and more common. The cost of genomic testing is dropping rapidly; the evidence base for markers like tumor mutational burden in the use of immunotherapies is increasing.
Oncologists' opinions reflect these trends. Many see genomic testing as already useful, but even among those unconvinced at present, a vast majority believe that genomic testing will become clinically useful within the next 10 years.
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