But sometimes cancer starts in places where it won’t cause any signs or symptoms until it has grown quite large.
Cancers of the pancreas, for example, usually don’t cause symptoms until they grow large enough to press on nearby nerves or organs (this causes back or belly pain).
Symptoms can seem unimportant, especially if there’s a clear cause or the problem only lasts a short time.
In the same way, a person may reason that a symptom like a breast lump is probably a cyst that will go away by itself.
For example, some cancers of the pancreas can release substances that cause blood clots in veins of the legs.
Some lung cancers make hormone-like substances that raise blood calcium levels.
By the time a pancreatic cancer causes signs or symptoms like these, it’s usually in an advanced stage.