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Prognosis and survival for breast cancer
If you have breast cancer, you may have questions about your prognosis. A prognosis is the doctor’s best estimate of how cancer will affect someone and how it will respond to treatment. Prognosis and survival depend on many factors. Only a doctor familiar with your medical history, the type, stage and characteristics of your cancer, the treatments chosen and the response to treatment can put all of this information together with survival statistics to arrive at a prognosis.
A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. A predictive factor influences how a cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together. They both play a part in deciding on a treatment plan and a prognosis.
Doctors use different prognostic and predictive factors for newly diagnosed and recurrent breast cancers.
Newly diagnosed breast cancer
The following are prognostic and predictive factors for breast cancer when it is first found and diagnosed.
The stage is the main prognostic factor for breast cancer. There is less risk that early stage breast cancer will come back (recur) so it has a more favourable prognosis. Breast cancer diagnosed at a later stage has a greater risk of recurrence, so it has a less favourable prognosis.
Doctors will consider if cancer has spread to lymph nodes and the size of the tumour when they predict a prognosis.
If cancer has spread to lymph nodes
Whether or not cancer has spread to lymph nodes is the most important prognostic factor for breast cancer. Breast cancer that has spread to lymph nodes has a higher risk of coming back and a less favourable prognosis than breast cancer that has not spread to the lymph nodes.
The number of lymph nodes that contain cancer (called positive lymph nodes) is also important. The more positive lymph nodes there are, the higher the risk that breast cancer will come back. Breast cancer that has spread to 4 or more lymph nodes has the highest risk for recurrence.
The size of the tumour
The size of the tumour is the 2nd most important prognostic factor for breast cancer. The tumour size will affect prognosis no matter how many lymph nodes have cancer in them.
Breast tumours that are 5 cm or larger are more likely to come back after treatment than smaller tumours. Breast tumours that are smaller than 1 cm and have not spread to the lymph nodes have a very favourable prognosis.
The grade of the breast cancer can affect prognosis. Low-grade tumours have a better prognosis because they grow slower and are less likely to spread than high-grade tumours.
Hormone receptor status
Hormone receptor–positive tumours usually have a good prognosis. They often are less aggressive, are lower grade and have a lower risk of spreading than hormone receptor–negative tumours. They usually respond well to hormonal therapy.
Find out more about hormone receptor status testing.
The HER2 gene controls a protein on the surface of cells that promotes their growth. HER2-positive breast cancer means that the cancer cells make too many copies of, or overexpress, the HER2 gene.
HER2-positive breast cancer is more aggressive and more likely to spread than HER2-negative breast cancer. They are also more likely to come back after treatment. This means that HER2-positive breast cancer has a less favourable prognosis than HER2-negative breast cancer.
Find out more about HER2 status testing.
Age at diagnosis
Women younger than 35 years of age tend to be diagnosed with more aggressive, higher grade tumours. Their breast cancer is often more advanced at the time of diagnosis. This means that younger women have a greater risk that their breast cancer will come back and a poorer overall prognosis than older, post-menopausal women.
Recurrent breast cancer
The following factors may affect prognosis for breast cancer that comes back after treatment.
Length of time before the cancer recurs
The longer the period of time before breast cancer comes back, the better the prognosis. Women whose breast cancer comes back more than 5 years after their diagnosis usually have a better outcome than those who have a recurrence less than 2 years after diagnosis.
Where the cancer recurs
Cancer that comes back in the breast (called a local recurrence) after a lumpectomy and radiation therapy has a more favourable prognosis than cancer that comes back in other organs (called distant recurrence, or distant metastasis).
If cancer comes back in the muscles on the chest, there is a greater chance that the cancer has also come back in another part of the body (called a distant recurrence). As a result, cancer that recurs in muscles on the chest has a less favorable prognosis.
Breast cancer that comes back in the liver, lungs or brain has a poorer prognosis than cancer that recurs in other parts of the breast, the muscle on the chest or lymph nodes under the arm (called the axillary lymph nodes).
Breast cancer that comes back in a bone has an intermediate prognosis. This means that it has a better prognosis than cancer that comes back in the liver, lungs or brain, but a poorer prognosis than cancer that comes back in the breast area or the chest muscles.
Taking action against all cancers
The latest Canadian Cancer Statistics report found that of all newly diagnosed cancers in 2017, half are expected to be lung, colorectal, breast and prostate cancers. Learn what you can do to reduce the burden of cancer.