Why are pathology results important?

Pathology results are vital to the successful management of breast cancer. Initial biopsy results establish a definite diagnosis and allow your surgeon to plan to treat your cancer in the most effective way. The complete examination of the cancer tissue once it has been removed tells us the type and grade but also whether it has has been completely removed, if it has gone to any lymph nodes, the receptor status and these and other features are used by your doctors (especially your medical oncologist) to estimate the risk that the cancer might have spread elsewhere and what options there are to treat it.

It is important to remember that it is the overall combination of features in the pathology result that is important, and not focus on just one feature that seems bad. This is where your treating specialists can help you in understanding and correctly interpreting your pathology results.

Margins

Margins refer to the edges of the tissue that your surgeon has removed. The pathologist carefully looks at these edges under the microscope to make sure there are no cancer cells extending up to these edges. When the edges are clear of the cancer these are called clear margins and no further surgery is needed to make sure the cancer has been removed. If there are cancer cells at any of the edges then that edge is called an involved margin and your surgeon will discuss with you the need to take out more tissue to make sure the cancer cells have all been removed.

Lymph Nodes

If there are no cancer cells seen in any lymph nodes that have been removed then we call this a "node negative" tumour (which is the best result when discussing lymph nodes).

If cancer cells are seen in any lymph nodes then the amount of involvement of the node by cancer cells is important. Sometimes the cancer cells can only be seen with special stains and are so few in number that it doesn't really matter that they have reached the lymph node. When the amount of tumour cells covers less than 0.2mm these cells are called isolated tumour cells (ITC)and we regard these lymph nodes as being the same as if they had no cancer in them.

Lymph nodes with cancer cells covering between 0.2 and 2.0mm are what we call micro-metastasis and if the cancer cells extend beyond 2.0mm than the node contains a macro-metastasis.

Receptors

The three standard receptors in the pathology report are for oestrogen, progesterone and HER-2.

Oestrogen and progesterone receptors respond to the female hormones they are named for. In general it's better to have hormone receptors on the cancer cells as this suggests that the cancer still relies on your hormones to help them grow, so blocking these hormones can be a very effective way of smothering the cancer cell's growth.

HER-2 is a protein that can be over-expressed in some breast cancers. When this occurs it can be associated with a more aggressive form of cancer, but fortunately treatment with targeted therapies specific for HER-2 are available to overcome this.

Sometimes it is the combination of receptors that is important. Tumours that are "triple-negative" are cancers that do not have oestrogen, progesterone or HER-2 receptors and are often associated with more aggressive cancers in younger patients, and with some of the known genetic risk factors such as BRCA gene mutations.

There are an increasing number of new markers that the pathologists may test for and report on your cancer. Your medical oncologist will usually be the best person to explain these results and what they might mean for the management of your specific cancer.