Future cancer-screening more likely with prior false-positive tests

Last Updated: 2018-04-24

By Will Boggs MD

NEW YORK (Reuters Health) - Patients with false-positive results on cancer screening tests may be more likely to engage in future cancer screenings, according to a review of medical records.

Cancer screening yields false-positive results in 50% to 61% of women undergoing annual mammography, in 10% to 12% of men undergoing prostate-specific antigen (PSA) testing, and in about 23% of individuals undergoing regular fecal occult blood tests (FOBT). How such false-positive results influence an individual's willingness to continue screening for cancer remains unclear.

Dr. Glen B. Taksler from Cleveland Clinic, in Ohio, and colleagues used electronic medical record data from 2006 through 2015 to analyze the association between prior receipt of a false-positive test result and future participation in routine cancer screenings.

Overall, 29% of at-risk individuals had a prior breast-cancer false-positive result, 3% had a prior prostate-cancer false-positive result and 2% had a prior colorectal-cancer false-positive result.

For women with a prior false-positive breast-cancer test, the odds of being up-to-date with breast-cancer screening were 43% higher if they hadn't had a breast biopsy and 2.02-fold higher with a negative breast biopsy. These women also were 25% and 47%, respectively, more likely to be up-to-date with colorectal cancer screening, compared with other women (all P<0.001).

Similarly, men with a previous false-positive PSA test had 22% (without prostate imaging/biopsy) to 60% (with negative imaging/biopsy) higher odds of being up-to-date with colorectal cancer screening (both P<0.05), the researchers report in Cancer, online April 23.

In contrast, women with a false-positive colorectal FOBT were 27% less likely than other women to be up-to-date with breast cancer screening (P<0.001).

Increasing numbers of prior breast or prostate cancer false-positive results were linked to increasing odds of being up-to-date with screenings.

"Future research should seek to confirm the current study results, explore reasons for the possible long-lasting influence of false-positive findings, consider whether providers should be alerted to monitor cancer screening after a false-positive result (e.g., mammography after a false-positive FOBT), and address ways for health care providers to minimize negative impact on patients," the researchers conclude.

Dr. Joann G. Elmore and Dr. David C. Johnson from David Geffen School of Medicine, University of California, Los Angeles, wrote an editorial accompanying the report.

Dr. Elmore told Reuters Health by email, "Physicians need to remind all patients before they undergo cancer screening that they might be called back for additional testing. This is part of the screening process. My hope is that advance education and warning will help to reduce the anxiety and alarm that these experiences cause."

"The impact of false-positive cancer screenings needs to be recognized and studied, as we do not want to harm patients emotionally or financially from having undergone the cancer screening tests," she said.

Dr. Johnson added, "While documenting the risks and benefits or a surgery or procedure is standard practice, the harms of screening tests are often limited to identifying indolent cancer that will never pose a threat to the patient. This study provides compelling evidence that falsely positive cancer-screening tests weigh on patients' psyche and may influence future engagement in cancer screenings."

"Interestingly, this study suggests that the impact of a false-positive test may differ according to the type of cancer for which the false-positive screening test was found," he said. "The explanation for this phenomenon is poorly understood, but is necessary to elucidate in order to design effective interventions to minimize the harms associated with false-positive results."

Dr. Taksler did not respond to a request for comments.

SOURCE: https://bit.ly/2I0t2vf and https://bit.ly/2HGp0u2

Cancer 2018.