Staging is the process used to figure out how far invasive ductal carcinoma may have spread from its original location. The stage of the cancer is based on three pieces of information:
- the size of the tumor
- whether the cancer has spread to any lymph nodes, and if so, how many
- whether the cancer has spread to other parts of the body
Invasive ductal carcinoma is described on a scale from stage I (the earliest stage) through stage IV (the most advanced stage). (To read more about how breast cancer is staged, you can visit our Staging section.)
Based on a clinical exam and imaging studies, your doctor may have some sense as to whether the invasive ductal carcinoma cells have spread to the lymph nodes. However, your doctor will determine for sure whether any lymph nodes are involved at a later time by removing one or some of your lymph nodes for examination.
At this point, your doctor may look for clues as to whether invasive ductal carcinoma cells could have spread to other areas of the body. Your doctor may order certain blood tests, a test of your liver function, and a test for a substance in the blood called alkaline phosphatase, or ALP. ALP may be higher than usual in people who have cancer in the liver or the bones.
Based on these test results, a physical examination, and any symptoms you report, your doctor will decide whether or not additional tests are needed to check other areas of the body. In most cases, you can expect to have an x-ray of the chest to check the lungs. Beyond that, the need for additional testing is determined on a case-by-case basis. Tests that could be done include:
- Bone scan: This takes pictures of the bones after you are given a small injection of radioactive substance.
- CT (computerized tomography) scan, ultrasound, or MRI are used to create images of the abdomen and pelvis (the stomach area) or other areas of the body.
- PET/CT scan: PET (positron emission tomography)/CT scan is a newer technology used to obtain images of the body’s cells as they work. Now or later on, this test may be used if your doctor suspects that the breast cancer has spread to other parts of the body. First, you’ll be injected with a substance made up of sugar and a small amount of radioactive material. The scan then “highlights” any cancer cells throughout the body as they absorb the radioactive substance. Whether PET/CT is better than other tests at staging the cancer is yet to be determined.
These tests are useful only if your doctor has reason to believe that the breast cancer could have spread to other parts of the body. The most common sites of spread for IDC are the bones, liver, lung, and/or brain.