What is prostate cancer?
Prostate cancer is cancer of prostate gland. The prostate gland is a walnut-sized gland present only in men, found in the pelvis below the bladder. The prostate gland wraps around the urethra (the tube through which urine exits the body) and lies in front of the rectum. The prostate gland secretes part of the liquid portion of the semen, or seminal fluid, which carries sperm made by the testes. The fluid is essential to reproduction.
Prostate cancer is comprised nearly always of adenocarcinoma cells -- cells that arise from glandular tissue. Cancer cells are named according to the organ in which they originate no matter where in the body we find such cells. Thus, if prostate cancer cells spread in the body to the bones, it is not then called bone cancer. It is prostate cancer metastatic to the bones. Metastasis is the process of cancer spread through the blood or lymphatic system to other organs/areas throughout the body. Prostate cancer more commonly metastasizes to lymph nodes in the pelvis and to the bones
What causes prostate cancer?
The exact causes of prostate cancer are not known. Several risk factors for developing prostate cancer have been identified, but which of these risk factors cause a prostate cell to become cancerous is not fully known. For a cancer to develop, changes must occur in the chemicals that make up the DNA, which makes up the genes in the cell. The genes control how the cell works, for example, how quickly the cell grows, divides into new cells, and dies, as well as correcting any mistakes that occur in the DNA of the cell to keep the cell working normally. Cancer occurs when certain genes that either control the growth or death of the cell are affected, which results in abnormal cell growth and/or death.
What are the risk factors for prostate cancer?
Certain risk factors may predispose a person to prostate cancer. These include the following:
- Age: Sixty percent of cases of prostate cancer arise in men over 65 years of age. The disease is rare in men under 40.
- Race or ethnicity: African-American men and Jamaican men of African ancestry are diagnosed with prostate cancer more often than are men of other races and ethnicities. Asian and Hispanic men are less likely to develop prostate cancer than are non-Hispanic white males.
- Family history: Prostate cancer can run in families. A man whose father or brother has or had prostate cancer is twice as likely to develop the disease. The younger the family member is when he is diagnosed with prostate cancer, the higher the risk is for male relatives to develop prostate cancer. The risk of developing prostate cancer also increases with the number of relatives affected.
- Nationality: Prostate cancer is more common in North America, Europe (especially northwestern countries in Europe), the Caribbean, and Australia. It is less common in Asia, Africa, and South and Central America. Multiple factors, such as diet and lifestyle, may account for this.
- Genetic factors: Mutations in a portion of the DNA called the BRCA2 gene can increase a man's risk of getting prostate cancer, as well as other cancers. This same mutation in female family members may increase their risk of developing breast or ovarian cancer.
- Other factors: Diets high in red meats and fatty foods and low in fruits and vegetables appear to be associated with a higher risk of developing prostate cancer. Obesity is also linked to a higher risk of the disease. Increased calcium intake and dairy foods may increase the risk of prostate cancer.
Smoking, a history of sexually transmitted diseases, a history of prostatitis (inflammation of the prostate), and a history of vasectomy have not been proven to play a role in causing prostate cancer. The role of fish oil in risk of prostate cancer remains under investigation
What are the signs and symptoms of prostate cancer?
A patient with early prostate cancer is usually asymptomatic. However, late stage disease and sometimes early stage disease may have the following signs and symptoms:
- Frequent urination, during the day and/or at night
- Difficulty in starting (hesitancy), maintaining, or stopping the urine stream
- A weak or interrupted urine stream
- Straining to urinate
- Inability to urinate (urinary retention)
- Loss of control of urination
- Difficulty urinating when standing, requiring sitting during urination
- Pain with urination or ejaculation
- Blood in the urine or in the semen
- Abnormal rectal examination
Many symptoms of early cancer of the prostate can also be attributed to benign (noncancerous) conditions of the prostate, including benign prostatic hypertrophy (BPH), or infection in the prostate gland or urinary system.
Signs and symptoms of advanced prostate cancer (late stage prostate cancer) that has already spread from the prostate gland to elsewhere in the body (called metastatic prostate cancer) include:
a new dull, then progressively severe, pain in the bones, especially the low back;
unexplained weight loss;
increasing shortness of breath while doing activities previously well tolerated;
swelling of the legs related to obstruction of the lymph tissue by prostate cancer.
It is always best to find and diagnose prostate cancer at an early stage and hopefully still confined to its site of origin. At that point, treatments can cure it. When prostate cancer is widespread or metastatic, it can be treated, but it cannot be cured.
What tests do health care professionals use to diagnose prostate cancer?
The diagnosis of prostate cancer ultimately is based on the pathologist's review of tissue removed at the time of the prostate biopsy. An abnormal PSA and/or abnormal digital rectal examination often are present and are the indications for the prostate biopsy.
Digital rectal examination (DRE): As part of a physical examination, your doctor inserts a gloved and lubricated finger into your rectum and feels toward the front of your body. The prostate gland is a walnut or larger sized gland immediately in front of the rectum, and beneath your bladder. The back portion of prostate gland can be felt in this manner. Findings on this exam are compared to notes about the patient's prior digital rectal examinations.
Prostate specific antigen (PSA) blood test: The PSA blood test measures the level of a protein found in the blood that is produced by the prostate gland and helps keep semen in liquid form. The PSA test can indicate an increased likelihood of prostate cancer if the PSA is at an increased or elevated level or has changed significantly over time, but it does not provide a definitive diagnosis. Prostate cancer can be found in patients with a low PSA level, but this occurs less than 20% of the time.
If the PSA level is elevated (levels can depend upon your age, on the size of your prostate gland on examination, certain medications you may be taking, or recent sexual activity) or has increased significantly over time, further testing may be needed to rule out prostate cancer.
Prostate biopsy: A biopsy refers to a procedure that involves taking of a sample of tissue from an area in the body. Prostate cancer is only definitively diagnosed by finding cancer cells on a biopsy sample taken from the prostate gland.
A biopsy procedure is usually uncomplicated, with just some numbness, pain, or tenderness in the area for a short time afterward. Occasionally, a patient has some blood in the urine, stool, or the ejaculate after the procedure. Rarely, the patient may develop an infection after a biopsy procedure (urinary tract infection, prostate infection, testis infection) or be unable to urinate. If one develops a fever after the procedure, has continued blood in the urine or ejaculate, or has troubles urinating, further evaluation by
What are the stages of prostate cancer?
Cancer staging is first described using what is called a TNM system. The "T" refers to a description of the size or extent of the primary, or original, tumor. "N" describes the presence or absence of, and extent of spread of the cancer to lymph nodes that may be nearby or further from the original tumor. "M" describes the presence or absence of metastases -- usually distant areas elsewhere in the body other than regional (nearby) lymph nodes to which the cancer has spread.
What are the treatment options for prostate cancer?
Conventional medical treatment options for prostate cancer include the following:
Surgery (radical prostatectomy: open, laparoscopic, robotic, perineal)
Radiation therapy (external beam therapy and brachytherapy
Focal therapy, including cryotherapy
Immunotherapy/vaccine and other targeted therapies
Bone-directed therapy (bisphosphonates and denosumab)
Radiopharmaceuticals (radioactive substances used as drugs)
Research techniques including high-intensity focused ultrasound (HIFU) and others
Castrate-resistant prostate cancer (CRPC) and metastatic castration-resistant prostate cancer (MCRPC)
A patient is noted to have metastatic castrate resistant prostate cancer if the individual has progressive prostate cancer with metastases while on ADT. The individual should have a serum testosterone level obtained to make sure that it is at castrate level (< 50 ng/dL while on ADT). If the testosterone level is > 50 ng/dL, this would indicate that the source of the progression is inadequate androgen deprivation and alternative ADT should be considered. If the individual is determined to have a castrate level of testosterone on ADT with progression of disease (rising PSA) on ADT, the individual is considered to have metastatic castrate-resistant prostate cancer. If metastases are identified, then the individual has metastatic castration-resistant prostate cancer. Over the past several years, a number of therapies have been approved for the treatment of metastatic castrate-resistant prostate cancer, including a new androgen receptor blocker, chemotherapy, immunotherapy/vaccine therapy, as well as bone-directed therapies. Though each of these therapies have unique ways in which they work and different side effects, all have been demonstrated to prolong survival by approximately three to four months each. The sequencing of the various treatments (which should be used first) is not well defined at present.
High-intensity focused ultrasound (HIFU) is an approach to therapy that is presently approved for use in Europe, and is under study in the U.S. It uses high intensity sound waves focused on the prostate gland to heat and thereby kill cancer cells. It should only be used as part of a research study (a clinical trial). The safety, side effects, and comparative effectiveness to surgery and radiation therapy must be established.
Clinical trials are research studies being conducted to evaluate new treatments for prostate cancer. These include approaches such as HIFU, as well as modifications of surgical and radiation techniques, and new drugs and immune therapy approaches. The National Comprehensive Cancer Network, a group assembled from the major comprehensive cancer centers of the U.S., considers that the best care of a cancer patient is afforded by their participation in a clinical trial. Patients with prostate cancer should always ask if there is a clinical trial option for them at any point in their therapy. Clinical trial participation assures you that your treatment has been considered by numerous cancer experts and is at least as good as a standard treatment that you may receive off of a clinical trial. In addition, the results of your treatment will be carefully analyzed in anonymous fashion, and results can be used to help others.
Complementary and alternative care approaches
In addition to standard types of prostate cancer treatments, there are other approaches that patients may choose during their treatment for their disease.
Some of these treatments are called complementary treatments and may help with control of symptoms or problems the patient may be experiencing. Examples of these include acupuncture for pain control, yoga and meditation for relaxation, as well as guided imagery, aromatherapy, and other techniques. Tell your doctors about all treatment approaches you are engaged in. These approaches usually will be of no harm to you, and may be very beneficial. Knowing what you are doing may help your doctor to better understand and coordinate your treatments and medications. Herbal therapies have been demonstrated in the lab to affect prostate cancer cells, but in many cases, have not been proven to be clinically effective. PC-SPES is an herbal therapy that has been used in the past for prostate cancer. It was associated with an increased risk of blood clots. Thus, prior to taking this or other herbal therapies, discuss these therapies with your doctor.
Be very careful about alternative treatments. The vast majority of medical professionals keep up-to-date on the latest advances, or are willing to research them for patients when asked. No truly effective treatments are being withheld from patients, though alternative care providers often say they are in an attempt to sell patients on their types of treatment. Such alternative therapies can do harm to patients, and can interfere with conventional treatment. Alternative care providers can be reasonably said to be preying on the desperation of cancer patients.
If nutritional supplements are suggested in addition to conventional therapy by an alternative care professional, tell all your doctors what you are taking. Some nutritional substances can interfere with the effectiveness of some conventional cancer treatments. Some "natural" substances can be toxic and can result in side effects or problems your regular doctor may not recognize unless they know what you are taking.
Prostate cancer patients, like all cancer patients, are frightened. Discuss your anxiety and concerns with your primary care doctor, urologist, and radiation and medical oncologists. They have many ways to help.
What is the prognosis for prostate cancer?
Staging evaluation is essential for the planning of treatment for prostate cancer. A basic staging evaluation includes the patient examination, blood tests, and the prostate biopsy including ultrasound images of the prostate. Further testing and calculations may be performed to best estimate a patient's prognosis and help the doctor and patient decide upon treatment options. Prognosis refers to the likelihood that the cancer can be cured by treatment, and what the patient's life expectancy is likely to be as a consequence of having had a prostate cancer diagnosis.
If a cancer is cured, your life expectancy is what it would have been had you never been diagnosed with prostate cancer. If the cancer cannot be cured due to it recurring in distant locations as metastases, or recurs either locally (where it started) or in an area no longer able to be treated in a curative manner, then estimates can be made of what is likely to be your survival based again on group statistics for people who have been in the same situation.
The prognosis for prostate cancer varies widely, and depends on many factors, including the age and health of the patient, the stage of the tumor when it was diagnosed, the aggressiveness of the tumor, and the cancer's responsiveness to treatment, among other factors.
Is it possible to prevent prostate cancer?
For a disease as common as prostate cancer, a condition which one man in six will be diagnosed with in their lifetime, the ideal approach is to prevent men from getting prostate cancer.
Two clinical trials referred to as the Prostate Cancer Prevention Trial (PCPT) and the subsequent Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial were conducted over the past two decades. These studies demonstrated that both finasteride and dutasteride (Propecia and Avodart), when used in men between 50 and 75 years of age, reduced the incidence of prostate cancer by 28% and 23% respectively as compared to similar men taking a placebo.
The reduction in the overall incidence of prostate cancer was significant. The use of these drugs and their FDA-approval for prevention has been slow to come in part because of the lingering concern over the high-grade prostate cancer risk. Men in these trials got less prostate cancer if treated with these drugs, but the prostate cancers that they did get were more often high-grade (had higher Gleason scores) and thus appeared to be at risk for behaving more aggressively. Men with a family history of prostate cancer or other high risk factors, and in fact any man, should discuss the use of these drugs for this purpose.
Trials have been conducted on several vitamins and nutritional supplements and naturally-occurring compounds in an attempt to prevent prostate cancer.
Vitamin E and selenium were not effective in the prevention of prostate cancer in the SELECT trial. Vitamin E supplementation may have increased the incidence of prostate cancer.
Lycopene was also ineffective as a preventive agent.
Pomegranate juice had no meaningful impact on prostate cancer prevention.
Green tea had some early results suggestive of a possible protective effect, and a larger trial is under way.
Vitamin D and its derivatives have been studied in prostate cancer. There is no evidence that vitamin D protects against prostate cancer. The vitamin D derivative, calcitriol, has some therapeutic utility against this disease, and is still under study.
Prostate cancer is the most common cancer in men (after skin cancer), and the second leading cause of death from cancer in men. The biology of prostate cancer is better understood today than it was in the past. The natural history of the disease and its staging have been well defined.
There are numerous potentially curative approaches to prostate cancer treatment when the disease is localized. Treatment options also exist for prostate cancer that has spread. Ongoing research continues to search for treatments for metastatic prostate cancer.
Coping with prostate cancer
The diagnosis of cancer can cause great anxiety to the individual and his family and friends. At times, one may have troubles coping with the diagnosis, the disease, and its treatment. Searching online for information may prove overwhelming also and may not be the best resource. Ask your physician or local hospital about local resources. Often, there are local prostate cancer support groups which may help you cope with your feelings and provide local resources for more knowledge.