If you’re completing that headline, “swollen legs are a sign of ca…” should not automatically be completed as “cancer.” Leg swelling has many possible causes, and cancer is only one possibility.
Common causes of swollen legs
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Fluid retention (edema) from prolonged sitting or standing, high salt intake, or certain medications.
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Venous insufficiency, where blood doesn’t return efficiently from the legs.
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Heart, kidney, or liver conditions, which can cause fluid to accumulate.
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Injury or inflammation affecting a leg.
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A blood clot (DVT), particularly when swelling develops suddenly and mainly affects one leg.
Some cancers can cause leg swelling directly or indirectly—for example, by affecting lymphatic drainage or by increasing the risk of blood clots—but swelling by itself is not a reliable sign of cancer.
When to get urgent help
Sudden swelling in one leg, especially with pain, warmth, redness, or tenderness, should be assessed promptly. If swelling occurs with sudden shortness of breath, chest pain, fainting, or coughing up blood, seek emergency medical care.
Persistent or unexplained swelling should also be evaluated by a healthcare professional rather than assumed to have one particular cause.
