What Is Prostate Cancer
Overview
Cancer starts when cells in the body begin to grow out of control. Cells
in nearly any part of the body can become cancer cells and can then spread to
other areas of the body.
Prostate cancer begins when cells in the prostate gland start to grow
out of control. The prostate is a gland found only in males. It makes some of
the fluid that is part of semen.
The prostate is below the bladder (the hollow organ where urine is
stored) and in front of the rectum (the last part of the intestines). Just
behind the prostate are glands called seminal vesicles that
make most of the fluid for semen. The urethra, which is
the tube that carries urine and semen out of the body through the penis, goes
through the center of the prostate.
The size of the prostate can change as a man ages. In younger men,
it is about the size of a walnut, but it can be much larger in older men. Almost all prostate cancers are adenocarcinomas. These
cancers develop from the gland cells (the cells that make the prostate fluid
that is added to the semen). Other types of cancer that can start in the prostate include: These other types of prostate cancer are rare. If you are told you have
prostate cancer, it is almost sure to be an adenocarcinoma. Some prostate cancers grow and spread quickly, but most grow slowly. In
fact, autopsy studies show that many older men (and even some younger men) who
died of other causes also had prostate cancer that never affected them during
their lives. In many cases, neither they nor their doctors even knew they had
it. Some research suggests that prostate cancer starts out as a
pre-cancerous condition, although this is not yet known for sure. These
conditions are sometimes found when a man has a prostate biopsy (removal
of small pieces of the prostate to look for cancer). In PIN, there are changes in how the prostate gland cells look when seen
with a microscope, but the abnormal cells don’t look like they are growing
into other parts of the prostate (like cancer cells would). Based on how
abnormal the patterns of cells look, they are classified as: Low-grade PIN is not thought to be related to a man’s risk of prostate
cancer. On the other hand, high-grade PIN is thought to be a possible precursor
to prostate cancer. If you have a prostate biopsy and high-grade PIN is found,
there is a greater chance that you might develop prostate cancer over time. In PIA, the prostate cells look smaller than normal, and there are signs
of inflammation in the area. PIA is not cancer, but researchers believe that
PIA may sometimes lead to high-grade PIN, or perhaps directly to prostate
cancer. Other than skin cancer, prostate cancer is the most
common cancer in American men. The American Cancer Society’s estimates for
prostate cancer in the United States for 2022 are: About 1 man in 8 will be diagnosed with
prostate cancer during his lifetime. Prostate cancer is more likely to develop in older
men and in non-Hispanic Black men. About 6 cases in 10 are diagnosed in men who
are 65 or older, and it is rare in men under 40. The average age of men at
diagnosis is about 66. Prostate cancer is the second leading cause of
cancer death in American men, behind only lung cancer. About 1 man in 41 will
die of prostate cancer. Prostate cancer can be a serious disease, but most
men diagnosed with prostate cancer do not die from it. In fact, more than 3.1
million men in the United States who have been diagnosed with prostate cancer
at some point are still alive today. Research into the causes, prevention, detection, testing, and treatment
of prostate cancer is being done in many medical centers throughout the world. New research on gene changes linked to prostate cancer is
helping scientists better understand how prostate cancer develops. This could
make it possible to design medicines to target those changes. Tests for abnormal prostate cancer genes might also help identify men at
high risk who might benefit from screening or from chemoprevention clinical
trials, which use drugs to try to keep them from getting cancer. In men already diagnosed with prostate cancer, tests for certain gene
changes can give men and their doctors a better idea of how likely the cancer
is to grow and spread, which might influence treatment options. Researchers continue to look for foods (or substances in them) that can
help lower prostate cancer risk. Scientists have found some substances in
tomatoes (lycopenes) and soybeans (isoflavones) that might help prevent some
prostate cancers. Studies are now looking at the possible effects of these
compounds more closely. Scientists are also trying to develop related compounds that are even
more potent and might be used as dietary supplements. But so far, most research
suggests that a balanced diet including these foods as well as other fruits and
vegetables is probably of greater benefit than taking specific substances as
dietary supplements. One vitamin that may be important in prevention is vitamin D. Some
studies have found that men with high levels of vitamin D seem to have a lower
risk of developing the more lethal forms of prostate cancer. Overall though,
studies have not found that vitamin D protects against prostate cancer. Some research has suggested that men who regularly take certain
medicines (such as aspirin or cholesterol-lowering statins) for a long time
might have a lower risk of getting or dying from prostate cancer. Still, more
research is needed to confirm this, and to confirm that any benefit outweighs
potential risks. Scientists have also tested certain hormonal medicines called 5-alpha reductase inhibitors as a way of reducing
prostate cancer risk. Doctors agree that the prostate-specific antigen (PSA) blood
test is not a perfect test for finding prostate cancer early. It misses
some cancers, and it sometimes finds cancers that probably never need to be
treated. Researchers are working on strategies to address these issues. Another approach is to develop new tests based on other forms of PSA, or
other tumor markers. Several newer tests seem to be more accurate than the PSA
test, including: These tests aren’t likely to replace the PSA test any time soon, but
they might be helpful in certain situations. For example, some of these tests
might be useful in men with a slightly elevated PSA, to help determine whether
they should have a prostate biopsy. Some of these tests might be more
helpful in determining if men who have already had a prostate biopsy that
didn’t find cancer should have another biopsy. Doctors and researchers are
trying to determine the best way to use each of these tests. Doctors doing prostate biopsies often rely on transrectal
ultrasound (TRUS), which creates black and white images of the prostate using
sound waves, to know where to take samples from. But standard ultrasound may
miss some areas containing cancer. There are several newer approaches to
diagnosing prostate cancer. Determining the stage (extent) of prostate cancer plays a key
role in determining a man’s treatment options. But imaging tests for prostate
cancer such as CT and MRI scans can’t detect all areas of
cancer, especially small areas of cancer in lymph nodes, so doctors are now
looking at newer types of imaging tests. Multiparametric MRI can be used to help determine the extent of the cancer and how
aggressive it might be, which might affect a man’s treatment options. For this
test, a standard MRI is done to look at the anatomy of the prostate, and then
at least one other type of MRI (such as diffusion weighted imaging [DWI],
dynamic contrast enhanced [DCE] MRI, or MR spectroscopy) is done to look at
other parameters of the prostate tissue. The results of the different scans are
then compared to help find abnormal areas. Enhanced MRI may help find lymph nodes that contain cancer cells. Patients
first have a standard MRI. They are then injected with tiny magnetic particles
and have another scan the next day. Differences between the 2 scans point to
possible cancer cells in the lymph nodes. Early results of this technique are
promising, but it needs more research before it becomes widely used. For standard positron-emission tomography (PET) scans, a type of
radioactive tracer known as FDG is injected into the body and then detected
with a special camera. Unfortunately, these scans aren’t very helpful in
staging prostate cancer. But newer types of PET scans may
be more helpful in detecting prostate cancer in different parts of the body.
These newer tests use tracers other than FDG, such as radioactive sodium
fluoride, fluciclovine, choline, or carbon acetate. Some newer tests (known as PSMA PET scans) use radioactive tracers that attach to
prostate-specific membrane antigen (PSMA), a substance that is often found in
large amounts on prostate cancer cells. Some of these newer tests are now being
used in certain centers, while others are still being studied. For more
information, see Tests to Diagnose and Stage Prostate Cancer. Newer treatments are being developed, and improvements are being made
among many standard prostate cancer treatment methods. Doctors are constantly improving the surgical techniques used
to treat prostate cancer. The goal is to remove all of the cancer while
lowering the risk of complications and side effects from the surgery. As described in Radiation Therapy for Prostate Cancer, advances in
technology are making it possible to aim radiation more precisely than in the
past. Current methods such as conformal radiation therapy (CRT), intensity
modulated radiation therapy (IMRT), and proton beam radiation help doctors
avoid giving radiation to normal tissues as much as possible. These methods are
expected to increase the effectiveness of radiation therapy while reducing the
side effects. Technology is making other forms of radiation therapy more effective as
well. New computer programs allow doctors to better plan the radiation doses
and approaches for both external radiation therapy and brachytherapy. Planning
for brachytherapy can now even be done during the procedure (intraoperatively). Researchers are looking at newer forms of treatment for early-stage
prostate cancer. These new treatments could be used either as the first type of
treatment or after unsuccessful radiation therapy. One treatment, known as high-intensity focused
ultrasound (HIFU), destroys cancer cells by heating them with
highly focused ultrasonic beams. This treatment has been used in some countries
for a while, and is now available in the United States. Its safety and
effectiveness are now being studied, although most doctors in the US don’t
consider it to be a proven first-line treatment for prostate cancer at this
time. Many studies have looked at the possible benefits of specific nutrients
(often as supplements) in helping to treat prostate cancer, although so far
none have shown a clear benefit. Some compounds being studied include extracts
from pomegranate, green tea, broccoli, turmeric, flaxseed, and soy. One study has found that men who choose not to have treatment for their
localized prostate cancer may be able to slow its growth with intensive
lifestyle changes. The men in the study ate a vegan diet (no meat, fish, eggs,
or dairy products) and exercised frequently. They also took part in support
groups and yoga. After one year the men saw, on average, a slight drop in their
PSA level. It isn’t known if this effect will last since the report only
followed the men for 1 year. The regimen may also be hard for some men to
follow. It's important for men thinking about taking any type of nutritional
supplement to talk to their health care team first. They can help you decide
which ones you can use safely while avoiding those that might be harmful. Several newer forms of hormone therapy have been developed in recent
years. Some of these may be helpful when standard forms of hormone therapy are
no longer working. Some examples include abiraterone (Zytiga), enzalutamide (Xtandi), and
apalutamide (Erleada), which are described in Hormone Therapy for Prostate
Cancer. Others are now being studied as well. 5-alpha reductase inhibitors, such as finasteride (Proscar) and
dutasteride (Avodart), are drugs that block the conversion of testosterone to
the more active dihydrotestosterone (DHT). These drugs are being studied to
treat prostate cancer, either to help with active surveillance, or if the PSA
level rises after prostatectomy. Studies in recent years have shown that many chemotherapy drugs can
affect prostate cancer. Some, such as docetaxel (Taxotere) and cabazitaxel
(Jevtana) have been shown to help men live longer. Results of large studies have shown that giving men with metastatic
prostate cancer chemotherapy (docetaxel) earlier in the course of the disease
might help them live longer. Other new chemo drugs and combinations of drugs are being studied as well. The goal of immunotherapy is to boost the body’s immune system to help
fight off or destroy cancer cells. Unlike vaccines against infections like measles or mumps, prostate
cancer vaccines are designed to help treat, not prevent, prostate cancer. One
possible advantage of these types of treatments is that they seem to have very
limited side effects. Several other types of vaccines to treat prostate cancer are being
tested in clinical trials. An important part of the immune system is its ability to keep itself
from attacking other normal cells in the body. To do this, it uses
“checkpoints” – proteins on immune cells that need to be turned on (or off) to
start an immune response. Cancer cells sometimes use these checkpoints to avoid
being attacked by the immune system. But newer drugs that target these
checkpoints hold a lot of promise as cancer treatments. For example, newer drugs such as pembrolizumab (Keytruda) and nivolumab
(Opdivo) target the immune checkpoint protein PD-1, while atezolizumab
(Tecentriq) targets the related PD-L1 protein. These types of drugs have been
shown to be useful in treating many types of cancer, including some prostate
cancers with DNA mismatch repair (MMR) gene changes (although these
are rare in prostate cancer). Studies are now being done to see how well these
drugs might work against other prostate cancers. One promising approach for the future might be to combine a checkpoint
inhibitor with another drug. For example, combining it with a prostate cancer
vaccine might strengthen the immune response and help the vaccine work better.
Other types of drugs might help the immune system better recognize the cancer
cells, which might help the checkpoint inhibitor itself work better. In this treatment, immune cells called T cells are removed from the
patient’s blood and altered in the lab so they have receptors called chimeric
antigen receptors (CARs) on their surface. These receptors can be made to
attach to proteins on the surface of prostate cells. The altered T cells are
then multiplied in the lab and put back into the patient’s blood. The hope is
that they can then find the prostate cancer cells in the body and launch a
precise immune attack against them. This technique has shown some encouraging results against prostate
cancer in early clinical trials, but more research is needed to see how useful
it can be. CAR T-cell therapy for prostate cancer is a complex treatment with
potentially serious side effects, and it is only available in clinical trials
at this time. Newer drugs are being developed that target specific parts of cancer
cells or their surrounding environments. Each type of targeted therapy works
differently, but all alter the way a cancer cell grows, divides, repairs
itself, or interacts with other cells. Some men with prostate cancer have mutations in DNA repair genes (such
as BRCA2) that make it hard for cancer
cells to fix damaged DNA. Drugs called poly-adenosine diphosphate ribose
polymerase (PARP) inhibitors work by blocking a different DNA repair pathway.
Cancer cells are more likely to be affected by these drugs than normal cells. PARP inhibitors such as olaparib, rucaparib, and niraparib have shown
promising results in early studies of men with one of these gene mutations, and
these drugs are now being studied in larger clinical trials. These are manmade versions of immune proteins that can be designed to
attach to very specific targets on cancer cells (such as the PSMA protein on
prostate cancer cells). For prostate cancer, most of the monoclonal antibodies
being studied are linked to chemo drugs or to small radioactive molecules. The
hope is that once injected into the body, the antibody will act like a homing
device, bringing the drug or radioactive molecule directly to the cancer cells,
which might help them work better. Several monoclonal antibodies are now being
studied in clinical trials. Doctors are studying the use of radiofrequency ablation
(RFA) to help control pain in men whose prostate cancer
has spread to one or more areas in the bones. During RFA, the doctor uses a CT
scan or ultrasound to guide a small metal probe into the area of the tumor. A
high-frequency current is passed through the probe to heat and destroy the
tumor. RFA has been used for many years to treat tumors in other organs such as
the liver, but its use in treating bone pain is still fairly new. Still, early
results are promising. 
Types of prostate cancer
Possible pre-cancerous conditions of the prostate
Prostatic intraepithelial neoplasia (PIN)
Proliferative inflammatory atrophy (PIA)
How common is prostate cancer?
Risk of prostate cancer
Deaths from prostate cancer
What’s New in Prostate Cancer
Research?
Genetics
Prevention
Early detection
Diagnosis
Staging
Treatment
Surgery
Radiation therapy
Newer treatments for early-stage cancers
Nutrition and lifestyle changes
Hormone therapy
Chemotherapy
Immunotherapy
Vaccines
Immune
checkpoint inhibitors
Chimeric
antigen receptor (CAR) T-cell therapy
Targeted therapy drugs
PARP inhibitors
Monoclonal
antibodies
Treating prostate cancer that has spread to the bones
