Why might jaundice be a sign that lung cancer has spread?

Jaundice is a clinical sign that lung cancer has reached an advanced stage and has spread (metastasized) beyond the lungs to other parts of the body.12

In the context of pathology, jaundice—the yellowing of the skin, sclera, and mucous membranes—occurs when bilirubin levels in the blood become significantly elevated. When lung cancer spreads, it can cause cholestatic (obstructive) jaundice if the malignancy creates an anatomical obstruction within the biliary tract, preventing the normal transport of bile. Alternatively, if the cancer metastasizes to the liver, it may cause severe damage to liver cells, leading to hepatocellular jaundice, where the liver loses its ability to properly transport bilirubin into the biliary system, causing the pigment to regurgitate into the bloodstream.34