Coming home after abdominal surgery for colon cancer, many people notice their feet and lower legs swelling even before chemotherapy has begun. Surgery and the recovery that follows leave several changes in how the body handles fluid and circulation.
The most common reason is simply staying in one position too long. Long hours lying or sitting slow the flow of blood in the leg veins and of lymph fluid, so fluid pools toward the feet. Intravenous fluids given during the operation, a drop in blood protein (albumin) during recovery, and a salty diet can all add to it. This kind of swelling is usually similar in both legs, is not painful, and eases when you raise your legs and move around.
There are, however, signs you must tell apart. People with cancer are more prone to blood clots, so if one leg suddenly swells and the calf is painful, firm to the touch, warm, or red, think of deep vein thrombosis. If sudden breathlessness or chest pain joins in, it may be a pulmonary embolism, which needs emergency care right away. When swelling comes with shortness of breath or a large drop in urine output, heart and kidney problems should also be checked.
Helpful everyday steps: when sitting or lying down, prop your feet a little higher than your heart, and do "ankle pumps" by flexing your feet up and down often. Short, frequent walks within comfort are good for circulation. Compression stockings can help venous or lymphatic swelling, but they may do harm if a clot has not been ruled out or if the leg's arterial blood supply is impaired, so check with your care team before wearing them and choose the right pressure and size.
If swelling lasts more than a month or keeps getting worse, it is better to tell your medical team than to keep waiting. They may check albumin, kidney and heart function, or use a leg ultrasound to look for a clot. This article is general information and does not replace medical care, so please discuss decisions about your own situation with your treating clinicians.