The difference between locally advanced and metastatic breast cancer

René Botha outlines the different types of breast cancer, highlighting locally advanced and metastatic breast cancer.

Even though we may think of breast cancer as a single disease, it’s important to understand that there are different types of tumours and stages of disease.

The tumour type is determined by the type of tissue in the breast where the cancer originated, e.g. ductal carcinomas start in the milk ducts (tubes that carry milk to the nipple) and lobular carcinomas start in the lobules (where milk is produced). Occasionally the cancer originates in other tissue types but this is uncommon.

We also classify breast cancers according to their genes and proteins. The hormone receptor status refers to whether or not the cancer cells have specific proteins that act as ‘receptors’ for the hormones, oestrogen and progesterone. Cells that have these proteins are called ER-positive or PR-positive. This means that these hormones may fuel the cancer’s growth.

Cancer cells that don’t have these proteins are hormone receptor negative. The receptor status influences treatment. Inhibiting these hormones in receptor-positive cancers may reduce the risk of spread.

The level of a growth-promoting protein, called HER2, is used to classify the cancer as either HER2-positive or HER2-negative. Cancers which express high levels of the HER2 protein, or HER2-positive cancers, may grow faster than other types of breast cancer, but they can be treated with drugs that target the HER2 protein. These drugs wouldn’t have the same effect in HER2-negative cancers.

Staging

The staging refers to whether the cancer is localised to the area where it originated, whether it has spread into nearby lymph glands or even further to other parts of the body. Sometimes breast cancers are only discovered when they are fairly large, locally advanced or metastatic. It’s important to understand the difference between locally advanced and metastatic breast cancer.

Locally advanced breast cancer

The cancer may have one or more of the following features: may be bigger than 5cm; cells may have spread into the tissue around the breast (ribs, muscles or skin); cancer has spread into multiple regional lymph nodes (above and below collar bone, under the arm or along the breast bone); or it’s an inflammatory breast cancer.¹

Even though the chances of curing locally advanced breast cancer are less than for early breast cancers, with the right treatments, cure is still possible for many patients. The treatment would usually include a combination of systemic therapy, such as chemotherapy, targeted therapy and/or endocrine therapy, surgery and radiation.

Metastatic breast cancer

May also be referred to as advanced or Stage 4 breast cancer. This means that the cancer has spread beyond the breast and regional lymph nodes to other areas of the body. This happens when cancer cells break away from the primary tumour in the breast and move through the blood or lymphatic system to other areas and begin to grow there. The most common sites for spread are the liver, brain, bones and lungs. The metastatic tumour in other parts of the body still consist of the same cells as the original breast cancer.²

Even though the chances of curing a metastatic cancer are low, and the cancer might never completely go away, many patients live productive lives with metastatic breast cancer, some even for years.

There are a wide variety of treatments that may control the cancer for years, slowing it’s progression. This allows patients to live longer with less symptoms and improved quality of life. The treatment usually comprises systemic therapy, which may include chemotherapy, targeted and endocrine therapy. Other treatments that may be used in conjunction with these: bone-modifying agents and sometimes even surgery and radiation.

There may be times that the cancer is controlled and patients can have a treatment break. The main aim of treatment is to improve quality of life while controlling the cancer for as long as possible.²

MEET THE EXPERT – René Botha

René Botha is a radiotherapist with a special interest in treatment planning. She works in private practice and is based at the Wits University Donald Gordon Medical Centre.