Breast cancer is the second most common cancer in the world. We all have breast tissue, so it can affect anybody, but it is most common in women. Thanks to research, there have been huge improvements in both diagnosis and treatment of breast cancer over the last few decades - more people are surviving the disease than ever before. But it is still the leading cause of cancer death in under 50s - because unfortunately, some breast cancers remain harder to treat than others.
You always hear people say that you don’t die of breast cancer – you live with it, but sadly that just isn’t true. It’s not just one cancer with good survival rates, there are much more aggressive types of breast cancer too – like the HER2+ breast cancer that Cathrin was diagnosed with.
There are dozens of different types of breast cancer.
It is important to understand what type of cancer a patient has to decide the best treatment for them, as different cancers respond to different treatments.
Types of breast cancer include those that test positive for hormone receptors, like ER-positive, PR-positive, and HER2-positive breast cancers, as well as breast cancers that test negative - like ER-negative, PR-negative, and HER2-negative breast cancers. There is also triple-negative breast cancer, where the cancer is found to not have any hormone receptors, as well as a number of less common types of breast cancer.
Our researchers are working hard to answer some of the most challenging questions we have about all types of breast cancer, so that we can start new cures and save more lives.
More information on the different types of breast cancer:
ER-positive/negative breast cancer
Oestrogen is a hormone produced in the ovaries. It helps control how cells grow and what they do in the body. Some cells in the breast carry receptors for oestrogen and are more dependent on the hormone to know when to grow. If breast cancer starts as one of these cells with oestrogen receptors (ER), it is classified as ER-positive (ER+), otherwise they are ER-negative. Around 8 in 10 cases of breast cancer are ER-positive, and these generally respond well to existing hormone therapies, like Tamoxifen, which prevent the cancer from growing.
PR-positive/negative breast cancer
Progesterone is also produced in the ovaries and helps control how cells grow and what they do. If breast cancer cells carry progesterone receptors (PR), the breast cancer is classified as PR-positive (PR+), otherwise they are PR-negative.
HER2-positive/negative breast cancer
Human epidermal growth hormone receptor 2 (HER2) is a normal part of the way cells communicate and signal cells to grow, however sometimes breast cancer cells can carry more HER2 than normal. If this is the case, the breast cancer is classified as HER2-positive (HER2+), otherwise it is HER2-negative. HER2+ breast cancers make up 15-20% of all cases.
Triple-negative breast cancer
If the breast cancer cells do not fall into any of the above categories, it is called triple-negative breast cancer meaning it is ER-negative, PR-negative, and HER2-negative. Most breast cancer treatments target one or more of these different receptors, so triple negative breast cancer can be more difficult to treat. It is also particularly aggressive and more likely to spread to other organs.
Less common types of breast cancer
- Inflammatory breast cancer, where the cancer cells block the small lymph vessels in the breast, causing the skin to become red and inflamed.
- Paget's disease of the breast, also known as Paget's disease of the nipple, which is a rare condition that may indicate that there is invasive breast cancer in the tissues behind the nipple.
- Angiosarcoma, which are breast sarcomas that start in the cells that make up the walls of the blood or lymphatic vessels.
- Phyllodes tumours, which are rare breast tumours that are usually benign (non-cancerous), but can sometimes be malignant (cancerous).
How can we better prevent and treat metastatic breast cancer?
The primary cause of breast cancer death is metastasis – when a cancer that starts in one place spreads to other parts of the body. Breast cancer often spreads to nearby lymph nodes, as well as the bones, lungs, liver and brain. Unfortunately, once the cancer has spread it becomes much more difficult to treat.
Diagnosing breast cancer early is crucial so that patients can start treatments before their cancer has spread. This can make a huge difference – in the UK, 96% of patients diagnosed with stage 1 breast cancer, before the cancer has spread, will survive for at least ten years after their diagnosis. This decreases to only 11.6% of people surviving their diagnosis for more than ten years if diagnosed at stage 4, when the cancer has spread.
How can we develop better targeted treatments for the different types of breast cancer?
For breast cancers that test positive for hormone receptors, like ER-positive, PR-positive and HER2-positive breast cancers, there are hormone-based medicines available. Around 8 in 10 cases of breast cancer are ER-positive, and these generally respond well to existing hormone therapies, like Tamoxifen, which prevent the cancer from growing.
But currently there are no targeted treatments available for triple-negative breast cancer (TNBC), where the cancer is found to not have any hormone receptors, making it much more difficult to treat.
How can we prevent breast cancers from becoming resistant to treatment?
Sometimes, breast cancer doesn’t respond to treatment. Cancer is always changing as cells divide, multiply and mutate, and unfortunately a therapy that seems to work at the beginning can sometimes stop working. This is described as treatment resistance and is a real challenge in tackling breast cancer.
I have a personal family history of breast cancer and cannot get used to the huge number of women affected by this disease. All my efforts are dedicated to a better understanding of this disease.
Discovery research like ours provides hope for the future of breast cancer.
As this article indicates, there are still a number of big questions that we need to answer in order to reach a day when no life is cut short by breast cancer. But discovery research like ours has already led to breakthroughs that could lead to innovative new treatments.
In 2006, we funded Dr Gertraud Orend's work into understanding why some breast cancer patients don't respond to immunotherapy treatment. Years later, we're excited to be funding her and her team in a new project investigating how her original findings could open up immunotherapy responses for those patients.
But it is not just the scientists who are making this happen. We cannot fund vital research like this without the support of Curestarters like you. Together we can save lives by discovering the next cure for cancer. Will you join us today?
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