Oncologists Differ On Cancer Gene Testing, Study Says

Some doctors are embracing genetic testing, while others are not convinced it's the right path for patients.

Gene testing seems to be everywhere. From spit-in-a-tube kits available online to in-office doctor tests, you can now see what sort of genetic disposition you have to a plethora of diseases, almost like looking into a crystal ball. Except this crystal ball is based on real science.

The most well-known of the gene tests is probably the breast cancer gene test, which was made famous by Angelina Jolie. But the test was also famous because it was an expensive monopoly, a test that cost almost $3,500 and was only offered by one company. The U.S. Supreme Court ended that monopoly last summer, and now the test is offered at Quest Diagnostics for $2,500. But gene testing is not limited to breast cancer. In fact, according to a new report by Dana-Farber Cancer Institute (DFCI), many cancer researchers believe that cutting-edge advances in genomics like this will pave the way for personalized or “precision” cancer medicine in the very near future.

But, a new study by researchers at DFCI suggests that not all doctors are ready to embrace tests that look for hundreds of DNA changes in patients’ tumor samples. Yet other doctors are planning to offer this type of cancer gene testing to most of their patients. The results seem to be mixed, and the findings are published in the Journal of Clinical Oncology.

According to the report:

The wide variation in attitudes was in part determined by physicians’ genomic confidence. Physicians who had a lot of confidence in their ability to use and explain genomic findings were more likely to want to prescribe the test and consider using test results when making treatment recommendations. Physicians with lower levels of genomic confidence were more reluctant to offer such testing. These findings are particularly interesting because the survey was carried out at the Dana-Farber/Brigham and Women’s Cancer Center (DF/BWCC), which has a comprehensive research program that allows all consenting patients to have tumor testing that could find mutations and other DNA changes that drive their cancer. In some cases those genomic tumor profiles can provide targets for specific drugs known to be effective against particular mutations.

The researchers were “perplexed,” according to the study, by another key finding: approximately 42 percent of responding oncologists approved of telling patients about test results even when the patient’s outlook and treatment remained uncertain. This issue “comes with the growing use of predictive multiplex testing, which can hunt for tens or hundreds of mutant genes simultaneously and which often detects rare DNA variants that may or may not be relevant to an individual’s cancers,” the study says.

Dr. Stacy W. Gray, a researcher at Dana-Farber, and the first author of the report, says that the oncologists surveyed in the study were mixed on whether or not they should return results to their patients. “The fact that we found so much variation in physicians’ confidence about their ability to use genetic data at a tertiary care National Cancer Institute-designated Comprehensive Cancer Center makes us pause and wonder about how confident physicians in the community are about dealing with this,” she says. “It begs the question at a national level, how are we going to make sure that this technology for cancer care is adequately delivered?”

The survey, which was conducted in 2011 and early 2012, served as a baseline assessment of a physicians attitude prior to the rollout of the tumor profiling project called Profile at Dana-Farber. According to the study:

The Profile technology platform includes complete DNA sequencing of more than 300 genomic regions to detect known and unknown cancer-related mutations. The technology can also examine those regions for gains and losses of DNA sequences and rearrangements of DNA on chromosomes. The results are entered into a database for research purposes, but, if patients agree, the clinically important findings can also be returned to their doctor for use in the clinic.

Medical oncologists, surgeons, radiation oncologists, and other doctors (a total of 160 adult cancer physicians) participated in the survey. According to report on the study, the physicians were asked about their current use of somatic testing (testing patients’ tumors for known mutations one at a time), their attitudes about multiplex testing, and their confidence in their ability to understand and use genomic data.

The study results:

Respondents said they ordered tumor genomic testing on an average of 24 percent of patients. Twenty-two percent of the doctors reported low confidence in their knowledge about genomics. Fourteen percent lacked knowledge in explaining these concepts to patients, and 26 percent doubted their ability to make treatment recommendations based on genomic data. Perhaps for these reasons, 18 percent of the physicians said they planned to use multiplex tumor testing only infrequently.

As with any new technology, it seems that doctors not exactly sure what to do with it. Gray and her colleagues conclude in the study that there’s “little consensus” on how physicians plan to use this new tool for personalized cancer care, and so, they are suggesting the need for evidence-based guidelines to help doctors determine when testing is needed and/or appropriate.

“One of the strengths of this study is that its information comes from an institution where ‘precision cancer medicine’ is available to everyone,” says Dr. Barrett Rollins, a co-author on the paper and Dana-Farber’s chief scientific officer. “It highlights the fact that there’s a lot of work to be done before this can be considered a standard approach in oncology.”

Below, a video of Dr. Gray talking about the new study.