Although prostate cancer is a common cancer in men, there are different types of prostate cancer, and some of these are rare. Because they are rare, we don’t know so much about them. If you are diagnosed with one of the cancers mentioned here, speak to your doctor or nurse about what that means and what treatments are suitable for you.
Like all the organs in our body, the prostate is made up of different types of cells. The type of cancer that develops depends on the type of cell where it starts.
The most common kind of prostate cancer starts in some of the cells that line the prostate – called glandular epithelial cells. When we talk about typical prostate cancer here, we mean this common type of prostate cancer. You may hear it called adenocarcinoma, or sometimes acinar adenocarcinoma. You might see this written in your pathology report.
Some much rarer types of cancer can also develop from glandular epithelial cells in the prostate. And there are other types of prostate cancer which develop from different cells in the prostate. For example, small cell prostate cancer develops from cells called neuroendocrine cells, so it’s a neuroendocrine prostate cancer. These other types of prostate cancer are also rare.
Some men have more than one type of prostate cancer. For example, they have some typical prostate cancer as well as a rare cancer.
Some of these rare cancers may be more aggressive than typical prostate cancer. This means they may grow faster and are more likely to spread outside the prostate.
Some of the tests used to diagnose prostate cancer may not be as good at picking up rare prostate cancers. Because of this, some rare cancers may not be diagnosed until after they have spread outside of the prostate. For example, some – such as small cell prostate cancer – don’t cause your PSA level to rise, so they’re not always picked up by a PSA test.
These different types of prostate cancer look different under a microscope, so may be picked up after having a biopsy to check for prostate cancer, or a transurethral resection of the prostate (TURP) to treat an enlarged prostate. But rare cancers are not always given a Gleason score after a biopsy. This is because they can behave differently from typical prostate cancer and can’t be measured in the same way.
Because rare cancer can be aggressive and spread outside the prostate, you may have more tests, such as a CT scan or MRI scan, to check whether it has spread.
There are several kinds of rare cancers that can develop in the prostate.
Small cell prostate cancer develops from cells in the prostate called neuroendocrine cells. You may hear it called a neuroendocrine prostate cancer.
Neuroendocrine cells do not produce PSA, so a PSA test won’t help to diagnose small cell prostate cancer. And PSA tests won’t be used to monitor it, either.
Small cell prostate cancer may be aggressive. It may be treated with chemotherapy.
There’s also another type of neuroendocrine prostate cancer called large cell prostate cancer. Like small cell prostate cancer, it develops from neuroendocrine cells in the prostate. Large cell prostate cancer is very rare and we don’t know very much about it.
Like typical prostate cancer, some rare prostate cancers can develop from gland cells in the lining of the prostate. You may hear them called adenocarcinomas. Ductal prostate cancer, mucinous prostate cancer and signet ring cell prostate cancer are all glandular cancers.
You may also hear this called ductal adenocarcinoma.
Ductal prostate cancer may grow close to the urethra. It can cause peeing problems and blood in your urine. And it might be more aggressive than typical prostate cancer.
You may also hear this called mucinous adenocarcinoma.
Like typical prostate cancer, mucinous prostate cancer can cause the levels of PSA in the blood to rise.
There’s a lot we don’t know about mucinous prostate cancer. Some studies suggest it’s aggressive and doesn’t respond well to treatments for typical prostate cancer. But more recent research shows it might not be as aggressive as once thought.
You might also hear this called signet cell prostate cancer.
Most signet ring cell cancers in the prostate are secondary cancers – they have developed in another part of the body such as the bladder or stomach and then spread to the prostate. For example, a signet ring cell cancer that started in the stomach is stomach cancer, even if it has spread to the prostate. But if the cancer started in the prostate, it’s prostate cancer.
If your biopsy shows that you have signet ring cell cancer, you may need to have further tests to check whether it started in your prostate or somewhere else. If your cancer started in another part of the body, this could affect what kind of treatment you have. For example, if the cancer spread to the prostate from your stomach, you will be offered treatment for stomach cancer, not prostate cancer.
Signet ring cell cancer may be very aggressive.
You might hear this described as adenoid cystic prostate cancer. It can cause problems peeing, and it may be diagnosed after a transurethral resection of the prostate (TURP).
Basal cell prostate cancer is very rare and not much is known about it. We don’t know how aggressive it is. Some studies suggest it isn’t very aggressive. But other studies suggest it might be more aggressive.
Sarcomas are rare cancers that can develop anywhere in the body, including the prostate.
There are several types of prostate sarcomas. The most common in adults is called leiomyosarcoma. There is another type called rhabdomyosarcoma which may affect children and young men. This can be treated with chemotherapy and radiotherapy.
Not all prostate sarcomas are aggressive.
Some men with prostate sarcoma will have another type of prostate cancer as well, such as a glandular cancer . You may hear this called a sarcomatoid carcinoma or a carcinosarcoma. These cancers may be aggressive.
Different prostate cancers behave in different ways, and they might respond differently to treatments. Some rare cancers may be treated in a different way from typical prostate cancer.
Because these cancers are so rare, there isn’t enough evidence to say which treatments will work best for all of them. If you have any questions about your cancer speak to your doctor or nurse. They will be able to explain your test results and talk you through your possible treatment options.
Treatments for localised cancer
If your cancer is contained within the prostate (localised prostate cancer), you may be offered treatments that aim to get rid of the cancer such as surgery. But if your cancer is very aggressive, there may be fewer treatment options available.
Some rare prostate cancers may be more likely to come back after treatment than typical prostate cancer. If there’s a risk your cancer could spread outside the prostate after treatment, you might be given other treatments before, alongside or after your main treatment.
For example, if you have surgery, you might have radiotherapy and hormone therapy if there’s a risk that not all of the cancer was removed, or if there are any signs that it has come back. These treatments can help make the main treatment more effective. But they can also increase the risk of side effects.
If you have small cell prostate cancer you might have chemotherapy before another treatment.
Treatments for locally advanced and advanced cancer
All types of prostate cancer can spread outside the prostate – to the area around the prostate (locally advanced prostate cancer), and to other parts of the body, such as the bones (advanced prostate cancer). But some rare prostate cancers may be more likely to spread to places like the brain, lungs and liver.
Hormone therapy is often used to treat locally advanced and advanced prostate cancer, but not all rare prostate cancers respond well to it. This means you might have chemotherapy or a combination of chemotherapy and hormone therapy.
Your treatment depends on your situation – for example, the kind of cancer you have, your symptoms and any other treatments you’ve already had. Speak to your doctor or nurse about what treatments might be suitable for you.
When prostate cancer spreads to other parts of the body it can cause symptoms, such as pain. But there are ways to manage these.
You may be offered chemotherapy if hormone therapy stops working for you, or if hormone therapy isn’t suitable for your cancer.
In the UK, docetaxel (Taxotere®) is the standard chemotherapy treatment for men with advanced prostate cancer that is no longer responding to hormone therapy. But you might have a different chemotherapy if you have a rare cancer.
For example if you have small cell prostate cancer, you may have carboplatin or cisplatin chemotherapy. You will have these together with another chemotherapy, such as etoposide. You might have them with another treatment such as hormone therapy. This depends on your situation.
Like all treatments, chemotherapy has side effects. And different chemotherapy drugs may have different side effects. Macmillan Cancer Support has more information about the side effects of these chemotherapy drugs and ways of managing them.
Being diagnosed with any kind of prostate cancer can be frightening and overwhelming. If you are told you have a rare prostate cancer you may worry about what this means, and feel frustrated that there isn’t much information available about your diagnosis and treatment.
No matter what you’re feeling or thinking, there is support available if you want it.
The Rarer Cancers Foundation provides information and support to people affected by rare cancers, including rare types of a more common cancer. You can also join their online community.