Timely diagnosis is often crucial for effective treatment.
Surprisingly, for many cancers, early detection does not increase survival rates. Doctors believe that for some tumors, early detection while the tumor is small doesn't lead to better outcomes, but simply delivers the bad news earlier. Early detection sometimes fails because tests cannot reveal the problem early enough. For example, chest X-rays and sputum cultures are inadequate for detecting lung cancer at an early stage. For this reason, research is now focusing on developing tests to detect substances released into the blood when a cancer first appears.