A DVT (deep vein thrombosis) is a blood clot in a deep vein in the body, most commonly in the leg or pelvis.
DVTs often occur after a period of being inactive, such as bed rest, surgery or extended travel by car or plane. They are more common in people with chronic illnesses, such as lung cancer. Symptoms can include swelling, tenderness in the calf or discoloration of the leg. In some cases, there are no symptoms at all.
If a DVT breaks loose and travels in the bloodstream to the lungs, it can result in a life-threatening condition known as a pulmonary embolus.