Screening for cancer: are resources being used wisely?

Cancer screening is commonly offered in order to detect tumors at an early, treatable stage. These efforts are highly advocated and widely accepted by the general public. However, there is conflicting evidence about the benefits of screening for breast cancer in pre-menopausal women, prostate cancer in older men, and colorectal cancer for both sexes. This paper examines cancer screening in relation to a disease reservoir hypothesis. There is a reservoir of undetected disease that can be found with more aggressive screening. However, much of the disease that is detected may be classified as pseudodisease because it will have no effect of life expectancy or health-related quality of life. Pseudodisease is defined as detectable disease that will never be clinically significant. A second concern about screening is that randomized clinical trials often show benefits of cancer screening for disease-specific endpoints but no benefit for total mortality. Further, screening for some cancers may significantly increase healthcare costs without enhancing population health status. Improvements in biomarkers and in screening methodologies will significantly increase the number of cancers detected. Future research is necessary in order to determine which population-based screening programs are the best use of public health resources.