Early diagnosis in cancer: a blessing or a curse?

12 March 2018 (Last Updated March 12th, 2018 16:33)

Many research groups and private companies are attempting to develop a test that can accurately and effectively determine whether or not a person has cancer.

Early diagnosis in cancer: a blessing or a curse?
Overdiagnosis is an important consideration in cancer screening. Credit: Daniel Sone/National Cancer Institute (NCI)

Many research groups and private companies are attempting to develop a test that can accurately and effectively determine whether or not a person has cancer. These are often blood-based tests, such as liquid biopsies, which aim to provide early diagnosis in asymptomatic patients. One health start-up in this area, Grail, has garnered worldwide attention due to investments from Bill Gates, Amazon and Google.

There are many advantages to detecting cancer early; the most frequently cited is that early detection allows for better treatment and increased long-term patient survival. However, the introduction of new cancer screening programs has sometimes been shown to come with certain pitfalls.

A major concern for any new test is the likelihood that it will give rise to false positives or false negatives. False positives, where someone is misdiagnosed with cancer, place a high psychological burden on the patient and often lead to costly follow-up procedures. False negatives can potentially delay cancer diagnosis, resulting in a more advanced and difficult-to-treat disease.

The dangers of overdiagnosis

Another issue that needs to be carefully considered in cancer screening is overdiagnosis. Not all cancers will cause symptoms or death in a patient’s lifetime. Increased detection of these harmless tumours could result in unnecessary treatment that can have devastating physical, psychological, and financial consequences for an individual. Overdiagnosis also has economic implications for governments and healthcare institutions, which must accommodate extra consultations and flow-on treatments after a diagnosis is made.

For some cancers, such as lung and ovarian cancer, patients tend to present with advanced stage disease, leading to poor prognosis. In these and other similar instances, it is tempting to speculate that new technologies enabling early detection could dramatically reduce disease mortality. However, it is important to recognise that this may not be true for every cancer type. Studies have shown that methods that increase the detection of breast, prostate, and thyroid cancer do not improve patient survival in average-risk individuals.

There is little doubt that early cancer diagnostic tests would represent an in-demand product in today’s health-conscious society. Throughout the last decade, there has been a rise in the popularity of genetic testing. People are keen to unlock the secrets hidden in their DNA, and the internet now markets direct-to-consumer kits that test for mutations associated with various diseases.

Recently, the FDA approved 23andMe for its inclusion of three BRCA1 and BRCA2 gene variants, allowing the company to sell at-home cancer risk screening. However, the long-term implication of these tests on patients, healthcare providers, insurance companies, and government reimbursement schemes remains to be determined.

Related Reports

GlobalData (2017). Prostate Cancer Diagnostic Tests – Medical Devices Pipeline Assessment, October 2017, GDME0460EPD

GlobalData (2017). Breast Cancer Diagnostic Tests – Medical Devices Pipeline Assessment, October 2017, GDME0461EPD