The challenge of early detection in cancer.

Abstract

Tumor growth dynamics and the timing of metastasis impose limits on cancer screening The chances of survival for a patient with cancer are substantially improved if the disease is diagnosed and treated at an early clinical stage ( 1 ). This underpins the promise of early detection to improve prognosis. Longer survival time may reflect later death, but it may also reflect advancement of time of diagnosis or increased diagnosis of indolent tumors with no shift in time of death ( 2 ). Despite several decades of research, only a handful of early detection tests have been shown to reduce cancer-specific mortality. This benefit comes at a cost: the diagnosis and treatment of cancers that otherwise never would have been diagnosed in the lifetime of the patient. Further research is needed to improve cancer early detection methods, but fundamental issues surrounding tumor growth dynamics and the timing of metastasis make early detection challenging.