Tumor size refers to the physical dimensions of a tumor, which can be measured in centimeters or millimeters. It is an important factor in diagnosing and staging various types of cancer. Larger tumors may indicate a more advanced disease, while smaller tumors might suggest an earlier stage. Medical professionals often use imaging techniques, such as CT scans or MRI, to determine tumor size. This information helps guide treatment decisions and predict patient outcomes. In some cases, tumor size can also influence the choice of surgical procedures or the need for additional therapies like radiation or chemotherapy.