Current Challenges in Imaging-Based Cancer Screening, From the Special Series on Screening.

The early detection of cancer confers many significant benefits for patients, primarily by enabling less invasive and more effective treatments and thus lowering disease mortality. Radiology is integral to early cancer detection, playing either a primary or complementary role in screening programs. Imaging-based screening is often performed in conjunction with other screening tests and may involve multiple modalities depending on patient demographics and cancer type. When a screening program for cancer early detection is being developed, both its potential benefits and harms need to be assessed. These harms, although specific to the modality and cancer, often include overdiagnosis, overtreatment, and false-positive examinations. As radiology technology improves and new tools become available, the risk-to-harm ratios of imaging-based screening will shift, and screening recommendations will need to adapt accordingly. Radiologists must be partners in the development and execution of screening guidelines to ensure the highest quality of care for patients. This review discusses the major challenges of cancer screening programs and guidelines, exploring sources of evidence as well as the harms of overdiagnosis and over-treatment. The article focuses on the most common cancer types that incorporate imaging-based screening, including lung cancer, breast cancer, colon cancer, prostate cancer, and hepatocellular carcinoma.