Once the diagnosis of cancer has been made with certainty, the next question we will wish to answer is could it have spread elsewhere such as to the lymph nodes, lung, liver or bone?
If the cancer is confined to the breast, then surgery has a high chance of curing the problem. If the cancer has already spread beyond the breast or lymph glands in the axilla (arm pit), then it is important to give treatment that will attack the cancer wherever it is. This usually means a combination of chemotherapy, radiotherapy and anti-oestrogen tablets rather than surgery.
The first step in staging is to check very carefully for involvement of the lymph glands in the under arm area. The surgeon will feel the area and check it using the ultrasound. If anything looks other than perfectly normal, then a needle aspiration will be required.
Since ductal carcinoma in situ (DCIS) is precancerous, it is very unlikely indeed to have spread and therefore no further test will be needed.
In the case of lobular cancer, which tends to be soft and more difficult to feel and more often present in more than one part of the breast, we will want to perform an MRI of the breast as part of the staging checks.
Otherwise the staging for both lobular and ductal cancer is the same. If the tumour is small, grade 1 or 2 and the lymph glands appear normal then it is our routine to perform a chest X-ray, liver ultrasound scan and bone scan. If the tumour is larger (over 2 cm), high grade or the lymph glands appear involved then we perform a CT scan of chest and abdomen (tummy) as well as a bone scan.
Please note that this is our routine and many other breast units place less emphasis on staging than we do.