Prostate cancer occurs when the cells in the prostate begin to grow uncontrollably. Sometimes, prostate cancer develops quickly and spreads to other organs, or metastasizes. Most often, prostate cancer spreads to the adrenal gland, bones, liver, and lungs.
In this article, we explain how prostate cancer spreads and how it affects the body. We also look at treatment options for metastatic prostate cancer, and the likely outlook for people with the condition.
Prostate cancer can spread to local or distant areas of the body.
Prostate cancer with local metastasis means that the cancer has spread to other organs within the pelvis, which usually means the nearby lymph nodes. However, this type includes any organ or structure in the pelvis.
Distant metastasis means that prostate cancer has spread beyond the pelvis. The bones, brain, liver, and lungs are common sites of cancer metastasis.
In many cases, prostate cancer grows very slowly. Some men do not even know that they have the disease. Sometimes, the disease metastasizes to other organs away from the prostate.
When prostate cancer metastasizes, it can become much harder for a doctor to treat.
Often, prostate cancer is symptomless. However, when symptoms do occur, they may include:
- frequent urination
- difficulty in controlling urination
- weak or interrupted urine flow
- pain or burning when urinating
- erectile dysfunction
- painful ejaculation
- producing less semen when ejaculating
- blood in the urine or semen
Many other conditions, including prostatitis and benign prostatic hypertrophy, can cause similar symptoms. However, anyone experiencing these symptoms should consult with their doctor as soon as possible to rule out prostate cancer.
Once a doctor makes a diagnosis of prostate cancer, complications from metastasis will depend on where the cancer spreads to, and how quickly it is growing.
For example, a person with prostate cancer that has spread to nearby lymph nodes may not experience any change in symptoms.
When prostate cancer metastasizes to the following areas, it can cause a range of complications.
There are many types of treatments available for advanced prostate cancer. A doctor or oncologist will develop a treatment plan that takes into account the individual's symptoms, prognosis, goals for treatment, age, and general health.
Hormone therapy for advanced prostate cancer shuts down the production of male sex hormones. This can help prevent the cancer from continuing to spread.
Chemotherapy uses medications that destroy cancer cells or prevents them from multiplying. People usually receive chemotherapy once the prostate cancer has stopped responding to hormone therapy.
Chemotherapy is usually a combination of two or more drugs that people receive intravenously, by injection, or by taking a pill.
People may use this in combination with hormone therapy if their prostate cancer has not yet become resistant.
A doctor may request the use of high powered radiation to shrink a tumor on the prostate or kill newly metastasized cancer cells in other areas. They administer external radiation therapy from outside the body using a machine.
External radiation therapy may also destroy healthy tissue around the site of the cancer.
After having radiation therapy, a doctor may suggest that a person also has hormone therapy to help prevent the cancer from spreading any further.
If prostate cancer spreads to the bone, doctors may request alpha emitter radiation therapy. This type of radiation therapy involves injecting a radioactive substance into the blood.
The radioactive substance collects in specific tissues, including areas of bone to which prostate cancer has spread.
Alpha emitter radiation therapy may damage less healthy tissue.
If prostate cancer has spread to the bones, it may cause considerable pain and high levels of calcium in the blood.
Bisphosphonates are a class of medication that doctors administer for some people with metastatic prostate cancer. They block a bone cell that causes the breakdown of bone.
Doctors use immunotherapy to trigger the immune system to attack cancer cells or "boost" the immune cells to respond to cancer cells.
The U.S. Food and Drug Administration (FDA) has approved sipuleucel-T (Provenge), a cell-based cancer vaccine to treat men with hormone resistant metastatic prostate cancer.
This type of treatment involves filtering immune cells out of the body and stimulating them at a lab to target prostate cancer. Doctors then reinfuse the cells back into the individual's body intravenously (IV). Cancer specialists often recommend this treatment before chemotherapy for men who experience minimal to no pain. However, it may also be effective in some men after they have received chemotherapy
Individuals receive a total of three treatments in a process that they undergo every 2 weeks. This treatment does not resolve symptoms or reduce tumor size. However, the Prostate Cancer Foundation advise that it can extend the lifespan of those with advanced prostate cancer.
The FDA have approved pembrolizumab (Keytruda), which is another type of immunotherapy for those with prostate cancer. Doctors only use it on people who have progressed on prior treatment but for whom there are no alternative treatment options.
Pembrolizumab is a type of "immune checkpoint inhibitor" that prevents specific chemical signals from masking cancer cells and activates immune cells that kill tumors.
Doctors give this IV treatment once every 3 weeks.
Watchful waiting and active surveillance
Because prostate cancer develops slowly, a doctor may not recommend any treatment at all. They may, however, perform regular tests and only medically intervene if results change or symptoms emerge.
Currently, clinical trials are looking at treating metastatic prostate cancer by removing the prostate gland and testicles.
People who are interested in clinical trials for cancer treatment should talk to a doctor about the benefits and possible risks, as well as how to participate.
Prostate cancer treatment can cause some severe side effects, including:
- urinary incontinence
- urinary retention
- erectile dysfunction
- hair loss
- loss of appetite
- nausea and vomiting
Luckily, there are many medications available to treat the side effects of cancer treatment. However, because these side effects can be quite severe, doctors often recommend watchful waiting before prescribing potent medications.
Prostate cancer often progresses slowly and causes few symptoms for most people. For this reason, a doctor may not feel that the risks of treatment outweigh the benefits.
However, if a person requires treatment for metastatic prostate cancer, they should not have to put up with uncomfortable adverse effects.
It is important for anyone undergoing cancer treatment to communicate with their healthcare team about any side effects they are experiencing.
The prognosis for advanced prostate cancer depends on where the cancer has spread, as well as how aggressively it is growing.
The American Cancer Society measures the outlook for many types of cancer using a 5-year survival rate. This compares the likelihood that a person will survive for 5 years beyond diagnosis to that of a person without cancer living for the same amount of time.
According to the American Cancer Society, survival rates are as follows:
- Local prostate cancer without spread has a 5-year survival rate at nearly 100%.
- Prostate cancer with local spread also has a 5-year survival rate at nearly 100%.
- Prostate cancer with distant metastasis has a 5-year survival rate of around 30%.
If a doctor diagnoses prostate cancer before it spreads, or if it has only spread to nearby structures, the survival rate is excellent. However, the survival rate does not take into account many other factors, such as a person's age and overall health.
A doctor with a working knowledge of a person's prostate cancer progression can produce a more accurate and individualized outlook.
This makes routine screening and early diagnosis essential to successfully treat prostate cancer.
Men over the age of 50 years should speak to a healthcare professional about the different screening options and which one is most appropriate for them.
How likely is it that my prostate cancer will spread?
This depends on the stage of the cancer at diagnosis as well as an individual’s health status, and response to treatment, among other factors.
Due to the slow-growing nature of prostate cancer, a doctor may decide to wait or start treatment depending on an individual’s risk factors.
Talk to your doctor about your risks for metastasis and your treatment options.Christina Chun, MPH Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.