Breast cancer patients tend to overestimate the “truth-value” of gene expression profile (GEP) tests by placing too much confidence in the tests’ validity due to their own emotional needs at the time, according to a study published in Current Oncology. The authors say the study’s findings point to the need to improve patient understanding of these tests and their limitations, given the impact of test results on clinical decisions. Several GEP tests have been validated as prognostic for distant disease recurrence and predictive of the benefit of adjuvant chemotherapy for patients with estrogen receptor–positive disease. These test results affect treatment decisions both recommended by oncologists as well as patient preferences. The study relied on focus group (n = 4) and individual telephone interviews (n = 24) with early-stage breast cancer patients who used GEP testing conducted using semistructured discussion guidelines. The researchers found that most patients (68 percent) did not undergo chemotherapy, largely because of the GEP test results. Patients’ understanding of GEP testing was variable, and misapprehensions were common, including about how laboratories conduct analysis. Participants understood that the test would indicate whether chemotherapy would be beneficial in their care but generally did not understand that their results were […]
Breast cancer patients tend to overestimate the “truth-value” of gene expression profile (GEP) tests by placing too much confidence in the tests’ validity due to their own emotional needs at the time, according to a study published in Current Oncology. The authors say the study’s findings point to the need to improve patient understanding of these tests and their limitations, given the impact of test results on clinical decisions.
Several GEP tests have been validated as prognostic for distant disease recurrence and predictive of the benefit of adjuvant chemotherapy for patients with estrogen receptor–positive disease. These test results affect treatment decisions both recommended by oncologists as well as patient preferences. The study relied on focus group (n = 4) and individual telephone interviews (n = 24) with early-stage breast cancer patients who used GEP testing conducted using semistructured discussion guidelines.
The researchers found that most patients (68 percent) did not undergo chemotherapy, largely because of the GEP test results. Patients’ understanding of GEP testing was variable, and misapprehensions were common, including about how laboratories conduct analysis. Participants understood that the test would indicate whether chemotherapy would be beneficial in their care but generally did not understand that their results were founded on population-based statistics and were not uniquely personal to them. Additionally, responses indicated faulty interpretation and confused accounts of numbers, charts, and graphs showing recurrence risks.
Responses indicated that patients valued the test because it provided them with “certainty amidst confusion, with options and a sense of empowerment, and with personalized, authoritative information.” The authors say patients commonly believed that the test was better and fundamentally different from other clinical tests. This kind of “magical thinking” was derived from an inflated sense of the test’s validity, with many patients acknowledging they had “willingly suspended critique.”
The authors say that the patients’ need for reassurance about their treatment choices contributed to the overwhelming trust in the test. Respondents indicated that GEP test results were the primary deciding factor in treatment decisions, even patients who were initially reluctant to undergo chemotherapy.
“A type of ‘magical thinking’ underpinned their perceptions of the test, which was founded on a belief that GEP testing had unique scientific power and, therefore, truth-value,” write the authors, led by Yvonne Bombard Ph.D., from University of Toronto in Canada. “Very few question[ed] or even discuss[ed] the test’s potential limitations with their oncologist. When prompted to think about why they hadn’t considered the possible limitations of the test, several participants identified emotional reasons for not doing so.”
