Depending on the type of symptoms a person presents, doctors use blood tests, imaging machines, laboratory biopsies and simple physical exams to detect the presence of cancer in the body. Because cancer forms as a tumor, X-rays, positron emission tomography scans and magnetic resonance imaging are common detection tools.
Sometimes, as is the case with skin cancer, a person's symptoms manifest on the exterior of the body and are somewhat easily identifiable to the human eye. WebMD explains that a doctor who observes a skin abnormality will likely pull a tissue sample from the affected area to test for cell abnormalities and malignancy. Other types of cancer, such as breast cancer, may require several testing methods to determine if a mass is cancerous. Exeter Hospital explains that women may find a lump in their breast or underarm tissue during a routine examination and then be referred by a physician to receive a mammogram. Often, if a mammogram shows a mass within a breast, further testing is completed to better understand the nature of a growth. A doctor may then order a breast ultrasound to provide a clearer image of the lump, or perform a tissue biopsy of the lump and send the sample to a lab to analyze the results. For more internalized cancers, such as lung cancer and pancreatic cancer, imaging tests are usually the first step taken to detect the presence and location of a mass, according to Mayo Clinic.