The main signs of cancer include a persistent sore throat, changes in bladder or bowel habits, difficulty swallowing, indigestion and unusual discharge or bleeding, according to WebMD. Other signs include the formation of a lump or thickening in the testicles or breast, and changes in the shape, thickness, color or size of a mole, wart or sore in the mouth. Additionally, hoarseness and a nagging cough may indicate the presence of cancer.
Persistent nausea, vomiting, fatigue, headaches and low-grade fever may also signify certain types of cancer, notes WebMD. Chronic pain in the body, bone pain and chronic infections are also warning signs of cancer.
People afflicted with cancer in its early stages often remain asymptomatic, which makes diagnosis difficult, reports WebMD. However, as the disease progresses, tumors begin to grow large enough to be detected or cause other problems. For example, a growing tumor may press on nerves and cause pain or begin to interfere with the functioning of a particular body system or organ. Tumors penetrating blood vessels may cause bleeding.
Although many of the symptoms that indicate cancer are also indicative of other conditions, evaluation by a medical professional when experiencing symptoms often leads to early detection of cancer and a greater chance of survival.