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Prostate cancer is an incredibly common disease in the US and around the world. It’s the next most commonly diagnosed cancer in men after skin cancers. It’s also the second most common cause of cancer death after lung cancer. The American Cancer Society estimates that 174,650 men in the US will receive a prostate cancer diagnosis in 2019, and 31,620 men will die from the disease (ACS, 2019).
These stark figures aren’t the only reasons a prostate cancer diagnosis is so feared. Treatment can cause side effects like sexual dysfunction and urinary incontinence. Thanks to advancements in medicine, however, these symptoms are less common and easier to deal with than they used to be.
The earlier prostate cancer is detected, the more effectively it can be treated. According to a database maintained by the National Cancer Institute (NCI), nearly 100% of men diagnosed with localized or regional prostate cancer today will be alive in five years. But before we discuss prostate cancer and the implications of a diagnosis more fully, let’s get more familiar with the prostate itself.
- About 1 man in 9 will be diagnosed with prostate cancer during his lifetime, though only around 1 man in 41 will die from it.
- The three most important risk factors for prostate cancer are age, family history, and African American heritage.
- Screening for prostate cancer is a complex and controversial issue, partly because the side effects of treatment can sometimes be worse than those of the disease itself.
- If you are diagnosed with prostate cancer, you and your healthcare provider will need to take a few things into account when deciding on the best course of action or whether to take action at all.
The prostate is a small gland located below the bladder and above the muscles of the pelvic floor. In younger men, it’s about the size of a walnut and weighs around 30 grams or 1 ounce though typically, it gets larger as men age.
Directly behind the prostate is the rectum and it’s this proximity which makes it possible to insert a finger into the anus and feel the gland. The prostate is surrounded by a capsule of connective tissue and smooth muscle fibers, which is why a healthy prostate feels soft and elastic to the touch. This elasticity is what your healthcare provider is feeling for when he or she gives a digital rectal exam (DRE).
Because the prostate is situated between several other structures including the bladder, rectum, penis, and urethra, when it grows, it can cause a number of different symptoms. But as we’ll see in a moment, early-stage prostate cancer doesn’t usually cause symptoms. In fact, men with lower urinary tract symptoms are no more likely to have prostate cancer versus a non-cancerous enlargement of the prostate.
The prostate’s job is to produce and secrete prostatic fluid, one of the components of semen. This fluid both nourishes and transports sperm and typically accounts for 25-30% of semen volume. (65-70% of semen comes from the seminal vesicles while just 2-5% is sperm, which is produced in the testicles).
During ejaculation, smooth muscle cells inside of the prostate squeeze, pressing the fluid that has been stored in the prostate out into the urethra. Here, the prostatic fluid combines with sperm and with fluid from other glands to form semen, immediately before being ejaculated.
Risk factors of prostate cancer
It’s fair to say that all men are at risk for prostate cancer given that about 1 man in 9 will be diagnosed with the disease during his lifetime and around 1 man in 41 will die from it. Beyond being a man, the three most important risk factors for prostate cancer are age, family history, and African American heritage. Let’s look at each of these in turn.
Age is a risk factor for many diseases, prostate cancer among them. This is because we rack up genetic mutations as we age that increase the odds of developing cancer. Most prostate cancers are diagnosed in men who are 65 or older.
Aside from genetic mutations that happen during a person’s lifetime, there are also mutations that can be inherited that increase the risk of prostate cancer. This is where family history comes in. Two of these are mutations that occur in the BRCA1 and BRCA2 genes (Castro, 2012). Men with BRCA1 mutations have 3.5 times the risk of developing prostate cancer, and those with BRCA2 mutations have 8.6 times the risk. Also, men who are BRCA1 or BRCA2 positive tend to get more aggressive cancers than men who are negative and are more likely to die of the disease.
Another inherited mutation associated with an increased risk of prostate cancer is the HOXB13 gene (Ewing, 2012). This gene variant is more common in those with early-onset, familial prostate cancer. The role his gene plays a role in the development of prostate cancer is currently unknown, however.
African American men have higher risks of getting prostate cancer, dying from prostate cancer, and getting the disease at a younger age. The exact cause is unknown, though it may be because of genetic factors, environmental factors (diet and exercise habits), socioeconomic factors, limited access to healthcare, or some combination of these things.
While your age, family history, and ethnicity can’t be changed, other risk factors that may affect your chances of developing prostate cancer can. There’s evidence to suggest that making the following changes may lower your risk of developing prostate cancer.
- Exercising and maintaining a healthy weight
- Reducing your consumption of red meat, dairy, and saturated fat
- Eating more tomato products, which are rich in lycopene
- Eating more soy products
- Drinking coffee and green tea
- Ejaculating more frequently—one study showed that men who ejaculated more than 21 times per month had a lower risk of prostate cancer
- Taking drugs called 5-ɑ reductase inhibitors. These include finasteride and dutasteride.
- Quitting smoking.
Signs and symptoms of prostate cancer
Often, prostate cancers grow slowly and may not cause symptoms for years or ever. That’s why so many men can have prostate cancer and not know it. In general, early-stage tumors (stages I and II) do not cause symptoms, which is why most screen-detected cancers are found in asymptomatic men. Traditionally, prostate cancers were thought to cause symptoms when they press on local structures, like the urethra, causing lower urinary tract symptoms (LUTS) (Hamilton, 2004).
- Urinary hesitancy
- Urinary leakage
- Urinary urgency
- Weak urinary stream
- Pain or discomfort when urinating (dysuria)
- Urinary frequency, including at night (nocturia)
Most of the time however, LUTS result from benign conditions, most commonly benign prostatic hyperplasia (BPH), a non-cancerous growth of the prostate. Also, recent studies (Bhindi, 2017) examining the relationship between LUTS and prostate cancer suggest that LUTS do not increase the risk of having prostate cancer when compared to prostates of similar size.
Another way prostate cancers can cause symptoms is by metastasizing (spreading) to distant organs. The most common place that prostate cancer spreads is the bones, including the spine and ribs. In these cases, pain is the most common symptom, often present in any position and sometimes worse at night. Less common symptoms of prostate cancer include blood in the urine or semen, weight loss, and weakness or numbness of the legs due to the cancer pressing on the spinal cord.
Often, the symptoms that are most commonly associated with prostate cancer can be caused by several other health conditions that have nothing to do with the disease. For example, trouble urinating is often caused by BPH. Decreased erectile function can be a sign of several things, including diabetes, smoking, cardiovascular disease, or aging.
Put simply; symptoms alone are not enough to diagnose a man as having prostate cancer. That said, no matter what’s likely to be causing them, none of these symptoms should be considered “normal” and should be discussed with your healthcare provider.
Prostate cancer screening
Routine screening for prostate cancer typically includes two simple tests:
Prostate-specific anitgen (PSA) test. During a PSA test, a small amount of blood is drawn from the arm, and the level of PSA is measured. PSA is a protein made by cells in the prostate gland. When there is a problem with the prostate, including the development and growth of prostate cancer, more PSA is released.
Digital rectal exam (DRE). During this test, your healthcare provider inserts a gloved finger into the rectum to feel the prostate. This relatively simple in-office procedure is designed to evaluate the size, texture, and consistency of the prostate gland. When combined with a PSA blood test, it can help point your healthcare provider in the right direction, without the need for more invasive and costly diagnostic testing.
Both tests can be used to detect the presence of prostate cancer when no symptoms are present. Though they can help catch the disease at an early stage, routine screening for prostate cancer is a complex and controversial issue. Part of that controversy is due to the tests’ accuracy.
Many people who get a DRE test (Naji, 2018) negative still have the disease and many people who test positive do not have the disease. And while PSA screening is more accurate, it has not been found (Fenton, 2018) to decrease mortality, even though more people are diagnosed with prostate cancer if they are screened. Another concern with PSA screening is overdetection which can result in overdiagnosis that is likely to lead to overtreatment.
Overtreatment comes with the risks of causing treatment-related side effects in people who didn’t need treatment in the first place. These risks include infections, bleeding, and urinary problems due to biopsies, as well as erectile dysfunction (ED), urinary incontinence, and fecal incontinence from a range of treatments. Simply put, the effects of the treatment can be worse than those of the cancer. That’s why it’s generally recommended that screening be highly individualized, taking risk factors into account.
Medical organizations offer recommendations around prostate cancer screening with PSA that differ slightly in some respects.
The American Urological Association’s (AUA) recommendations:
|Men younger than 40||Prostate cancer screening not recommended|
|Men aged 40-54||Screening should be individualized, with risk factors for prostate cancer taken into consideration.|
|Men aged 55-69||Men should engage in shared decision-making with their doctors when deciding whether to screen for prostate cancer.|
|Men 70 and older||Prostate cancer screening not recommended. Some men age 70+ years who are in excellent health may benefit from prostate cancer screening.|
The United States Preventive Services Task Force (USPSTF) has recommendations that are very similar to the AUA, but they do not comment on men under the age of 55 or on men 70+ in excellent health.
The American Academy of Family Practice (AAFP) recommends against routine screening for prostate cancer because they believe the risks outweigh the benefits. The AAFP is unclear about whether healthcare providers should start a conversation with men about screening or should only screen if someone asks for it specifically.
You can learn more about prostate cancer screening here.
Grading and staging
If the results of the PSA test or DRE are abnormal, your doctor may perform more tests to confirm a prostate cancer diagnosis. These may include an ultrasound, magnetic resonance imaging (MRI) and a biopsy. After diagnosis is confirmed, the grade and stage of the cancer can be assessed.
The grade and stage of a tumor are two distinct things. The grade is an indication of how quickly it is likely to grow and spread while the stage refers to its size or extent and whether or not it has spread.
Though all tumors can be graded, prostate cancer has its own grading system called a Gleason score. A Gleason score is determined when the biopsy is looked at under the microscope. If cancer is present, the score indicates how aggressive it is or how likely it is to spread.
Scores range from 2 to 10. The lowest score a cancer can have is 6. In general, cancers with lower Gleason scores (6-7) are less aggressive, while cancers with higher Gleason scores (8-10) are more aggressive.
Staging, on the other hand, determines the extent of prostate cancer and provides an idea of how the cancer should be treated. The most common way for prostate cancer to be staged is with the American Joint Committee on Cancer’s TNM system. This system is broken down into three parts:
T = Tumor. This refers to the extent of the main tumor. It can be classified as:
- T1: The cancer cannot be felt or detected with imaging.
- T2: The cancer is larger and may be in one or both lobes of the prostate, but it does not extend beyond your prostate.
- T3: The cancer has spread beyond the prostate and may be in the seminal vesicles.
- T4: The cancer has spread to other organs, such as your bladder, rectum, or bones.
N = Lymph nodes. This refers to whether the cancer has spread to nearby lymph nodes.
M = Metastases. This refers to whether the cancer has spread to other parts of the body.
When describing the stage, healthcare providers often use the words localized, locally advanced, or metastatic.
Localized means that the cancer is only in the prostate. The cancer hasn’t grown into nearby tissues or to distant parts of the body. Localized prostate cancer includes stage I and stage II.
Locally advanced means the cancer has grown through the covering of the prostate (called the capsule) to nearby tissue. Locally advanced prostate cancer includes stage III and stage IV.
Metastatic means that the cancer has spread beyond the tissues surrounding the prostate to other parts of the body.
It’s easy to get overwhelmed with the number of treatment options available for prostate cancer. You and your healthcare provider will need to take a few things into account when deciding on the best course of action or whether to take action at all. These considerations include tumor stage, the side effects of treatment —including erectile dysfunction and urinary incontinence — the age and health of the individual, as well as his own goals and values.
- Watchful waiting.Watchful waiting is a strategy used when there is no intention to cure the prostate cancer because it has spread. Patients are followed over time and treated if they develop symptoms, but these treatments are not intended to cure the cancer.
- Active surveillance/active monitoring. Unlike watchful waiting, this strategy is often used in stage I or stage II disease (early stages). Patients are followed over time with physical exams, PSA tests, and often prostate ultrasounds and/or biopsies. Doctors begin treatment if there is evidence that the cancer is progressing.
- Surgery. A common treatment approach for men whose cancer has not spread. The main type of surgery for prostate cancer is a radical prostatectomy. In this operation, the surgeon removes the entire prostate gland plus some of the tissue around it.
- Radiation therapy. A cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing.
- Hormone therapy. A cancer treatment that reduces the level of male hormones (androgens), in the body, or to stop them from affecting prostate cancer cells. This is also calledandrogen deprivation therapy (ADT) or androgen suppression therapy.’Chemotherapy. A cancer treatment that uses anti-cancer drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy is sometimes used if prostate cancer has metastasized, and hormone therapy isn’t working.
- Biologic therapy. A treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. Sipuleucel-T (Provenge) is a type of biologic therapy. It is a cancer vaccine which boosts the body’s immune system to help prevent infections. This vaccine stimulates the immune system to help it attack prostate cancer cells. It is used to treat advanced prostate cancer that is no longer responding to hormone therapy but is causing few or no symptoms.
- Cryotherapy. A treatment that uses an instrument to freeze and kill prostate cancer cells. Cryotherapy is sometimes used to treat early-stage prostate cancer. Most healthcare providers do not use cryotherapy as the first treatment for prostate cancer. It is sometimes an option if the cancer has come back after radiation therapy.
Family history and African American heritage are both clear risk factors for prostate cancer though age is by far the most significant. According to the American Cancer Society, around six of every ten prostate cancer diagnoses are made in men over 65 years of age (ACS, 2019).
And according to a review (Jahn, 2015) of 19 studies published in 2015, is discovered at autopsy in over a third (36%) of white Americans and more than half (51%) of black Americans aged 70-79. Based on these findings, we might wonder whether, on a long enough timeline, every man will develop prostate cancer.
While its near-inevitably doesn’t make a prostate cancer diagnosis any less daunting, the sheer number of prostate cancer survivors living full, productive, and long lives tells us that prostate cancer is very often treatable and manageable. And when detected in its earlier stages, it’s often completely curable.
But we also know that routine screening comes with its own risks. Overdetection in a routine screening can lead to over overdiagnosis which, in turn, can lead to overtreatment. The side effects from certain treatments can often be more disruptive than the disease’s symptoms. Many men have lived long, productive lives, completely unaware that they’d had prostate cancer for years, even decades.
Knowing your risk for prostate cancer can help guide lifestyle choices and decisions about screening while honoring your unique set of circumstances will help you and your healthcare provider decide on the best course of action if you receive a diagnosis.