Final answer:
A physician should order a biopsy to determine the presence and locations of cancer. Medical imaging techniques such as CT scans or MRI may also be used to provide more information about the extent of cancer spread.
Step-by-step explanation:
To determine the presence and locations of cancer, a physician should order a biopsy. A biopsy is a procedure in which a small piece of the suspected area is surgically removed and examined microscopically by a pathologist. This is the only definitive test for confirming a diagnosis of cancer. Additionally, medical imaging techniques such as CT scans or MRI may be used to provide more information about the extent of cancer spread.