There is a wide array of methods to diagnose cancer. As researchers learn more about the mechanisms of cancer, new diagnostic tools are constantly being developed and existing methods refined. If your primary care physician suspects cancer, he or she may order some tests to confirm the diagnosis. These tests can either be conducted by your physician or by oncologists at cancer centers like MD Anderson. No matter who makes the diagnosis, a second opinion by a cancer expert is strongly recommended. Some types of cancer, particularly lymphomas, can be hard to classify, even for an expert. Accurate identification of cancer allows oncologists to choose the most effective treatment.