Temporal evolution of metastatic disease: part I—an in-depth review of the evolution of metastatic disease across diverse spectrum of non-neural solid tumors on serial oncologic imaging studies and relevant practical applications

With improved survival rates of patients with metastatic disease due to continuously evolving multimodality treatment options, radiologists are increasingly interpreting imaging studies from patients with protracted metastatic disease. It is thus crucial for radiologists to have an in-depth understanding of the temporal evolution of metastatic spread and the accompanying findings on imaging studies, to provide accurate interpretation that supports optimal management. A general overview of the evolution of cancer spread on serial imaging studies and common pathways of tumor spread across multiple tumor types and tumor locations is not readily available in radiology literature. The key common pathways of tumor spread across diverse spectrum of tumors relevant to radiologists are summarized in a logical schematic approach which focusses on aiding radiologists to understand the pathways of spread resulting in current sites of metastatic disease involvement and then to potentially predict future sites of metastatic involvement. This article also summarizes the practical applications of this knowledge to the routine oncologic imaging interpretation.