Less Anxiety With New Cancer Screening Innovation
Cancer is the second leading cause of death in the US, with approximately 600,000 cancer deaths projected this year. About 70 percent of these deaths are for cancers outside of the five cancers we typically screen for in the colon, breast, prostate, cervix, or lungs. These five and the ones we do not regularly screen for are often caught too late, after the cancer has progressed, is more difficult to treat, and therefore has worse health outcomes.
A recent innovation in earlier cancer detection includes a blood test that can detect a shared signal from over 50 cancer types by detecting tumor-derived cell-free DNA in circulation, complementing existing single cancer screens. This new test offers a previously unimaginable breakthrough in the war on cancer. For example, almost 90 percent of pancreatic cancers are detected when they have already spread, and treatment applied too late offers little help, with 5-year survival rates of 14% and 3% in patients diagnosed with regional and distant spread, respectively. But imagine a world where most of them are found earlier: evidence suggests that 78% of cancers currently detected at a late stage could be detected earlier with this new test.
However, some claim that these diagnostics will not be valuable because they increase the anxiety of having cancer. These arguments have been based on anecdotal introspections rather than systematic evidence based on research. When there are greatly varying experiences, anecdotes can always be used to justify any argument which raises the question what the objective evidence tells us.
The demand by patients for past cancer screening tests provides direct evidence of the value of the screens to those patients. One important driver of that value is what changes emerge from testing positive. If a positive test leads to a confirmed diagnosis and increased chance of successful treatment, the diagnostic is more valuable than if such a test resulted in a confirmed diagnosis with limited effective treatment options. Consider HIV testing and highly active antiretroviral therapy (HAART) that emerged in the 1990s. Before antiretroviral treatments were approved by the FDA, a positive HIV test was essentially a test into a death sentence. After the approval of HAART, a positive test facilitated earlier diagnosis and treatment, leading to increased survival. The value of testing into treatment rather than death means that improvements in treatments makes tests even more valuable.
Similar issues pertain to existing cancer diagnostics. Historically, a breast or colon cancer diagnosis was considered a death sentence, whereas today it’s often the start of life-saving treatments – because screening has translated into earlier detection. The new multi-cancer early detection (MCED) tests will continue this pattern. Because they allow for earlier detection, treatments are more likely to have increased effectiveness. Similar to single cancer screening, MCED tests will enable testing into treatment rather than testing into death – and for a much broader range of cancer types. Cleary this suggests a hypothesis that the new tests will be associated with a comparable or lower impact on anxiety relative to existing tests.
Recently presented data from PATHFINDER, a study evaluating a MCED test, revealed several important findings including confirmation of high test specificity, which confers test efficiency through minimization of false positive test results, and levels of general anxiety associated with MCED test results. First, general anxiety scores were low at baseline before the MCED test and did not change substantially a year out after the test irrespective of MCED test result. Second, as expected, anxiety scores rose for those testing positive but trended towards pre-test levels within a year, demonstrating a transient anxiety impact. Third, the proportion of study participants with false positive results (i.e., cancer signal detected but no cancer diagnosis) who experienced an initial rise in anxiety was comparable to the proportion of study participants with a negative MCED test (i.e., no cancer signal detected) by the end of study. Fourth, levels of distress associated directly attributable to a MCED test result disclosure were low. Finally, the study demonstrated a high level of participant satisfaction with the MCED test, regardless of test outcome. Overall, these results suggest that anxiety levels associated with MCED tests are mild and transitory.
This new evidence is important as it suggests there is nothing unusual about the new cancer tests in terms of affecting anxiety. More importantly, most patients understand and accept that screening may result in such mild anxiety stemming from positive results. But the patients, not third parties, should be the ultimate decision makers regarding the tradeoff between potential anxiety from an MCED test and the potential benefits of earlier cancer detection. For example, many people face anxiety about seeing a dentist but remain adherent to dental services. Indeed, it is hard to argue patients are worse off with the availability of novel MCED tests when they can always live in the world before the tests were invented by not using them.
Tomas J. Philipson is the Daniel Levin Professor of Public Policy Studies Emeritus at the University of Chicago and served in 2017-2020 as a member and acting chair of the President’s Council of Economic Advisers. He serves as a consultant to GRAIL, LLC, a subsidiary of Illumina, Inc.
