NEW YORK (GenomeWeb) – Rather than making treatment choices clearer, precision medicine may instead lead to greater uncertainty that needs to be communicated to patients, according to a commentary appearing this week in the New England Journal of Medicine.
In the column, David Hunter from the Harvard T. H. Chan School of Public Health argued that the information from genetic tests would give patients and their physicians more risk information that they need to weigh in conjunction with treatment options.
"The new tools for tailoring treatment will demand a greater tolerance of uncertainty and greater facility for calculating and interpreting probabilities than we have been used to as physicians and patients," he wrote, further calling for the development of new ways to help patients handle such probability and risk information as provided by genomic and other tests.
Hunter noted that cancer treatment is likely the frontline for precision medicine and gene expression tests like OncotypeDx, Agendia's MammaPrint, and PAM50 are already providing doctors and breast cancer patients with information about likely prognoses.
While companies developing these tests have gauged their prognostic utility, they are also examining the effect of adjuvant chemotherapy on groups stratified by predicted risk. But this can present patients and clinicians with trade-offs, he said.
For instance, a new study of the clinical utility of Agendia's MammaPrint, also in NEJM this week, found that women with early-stage breast cancer who had a high clinical risk, but low genomic risk of disease recurrence and who received chemotherapy had a 1.5 percentage points higher five-year survival without distant metastasis rate than women with the same risk, but who didn't receive chemotherapy.
While these and other findings suggested to those authors that women with high clinical risk, but low genomic risk of disease recurrence could forgo adjuvant chemotherapy, Hunter noted that these women are still "presented with a trade-off between the risk of recurrence and the toxic effects of treatment." And different women may interpret those risks differently, he added.
These risks and trade-offs have to be well communicated to patients. While researchers work on developing new analyses, Hunter argued that there need to be similar efforts toward creating methods to help patients make sense of large amounts of complex information and then act on that to choose among a number of options that each have their own set of trade-offs.
"Assessing and acting on these probabilities will require approaches to data presentation, risk quantification, and communication of uncertainty for which we are largely ill equipped and that we already struggle with," he said.