What is Prostate Cancer and How is it Diagnosed?
Prostate cancer occurs when cells within the prostate grow uncontrollably, creating small tumors. The term “cancer” refers to a condition in which the regulation of cell growth is lost and cells grow uncontrollably. Most cells in the body are constantly dividing, maturing, and then dying in a tightly controlled process. Unlike normal cells, the growth of cancer cells is no longer well regulated. Instead of dying as they should, cancer cells outlive normal cells and continue to form new, abnormal cells.
Abnormal cell growths are called tumors. The term “primary tumor” refers to the original tumor; secondary tumors are caused when the original cancer spreads to other locations in the body. Prostate cancer typically is comprised of multiple, very small, primary tumors within the prostate. At this stage, the disease is often curable (rates of 90% or better) with standard interventions, such as surgery or radiation, that aim to remove or kill all cancerous cells in the prostate. Unfortunately, at this stage the cancer produces few or no symptoms and can be difficult to detect.
If untreated and allowed to grow, the cells from these tumors can spread in a process called metastasis. In this process, prostate-cancer cells are transported through the lymphatic system and the bloodstream to other parts of the body, where they lodge and grow secondary tumors. Once the cancer has spread beyond the prostate, cure rates drop dramatically.
In most cases, prostate cancer is a relatively slow-growing cancer, which means that it typically takes a number of years for the disease to become large enough to be detectable, and even longer to spread beyond the prostate. However, a small percentage of patients experience more rapidly growing, aggressive forms of prostate cancer. Unfortunately, it is difficult to know for sure which prostate cancers will grow slowly and which will grow aggressively—complicating treatment decisions.
When prostate cancer spreads to another site, such as bone, the new tumor is still considered to be prostate cancer, not bone cancer.
How Common Is Prostate Cancer?
The Prostate Cancer Foundation (PCF) reports that prostate cancer is the most common non-skin cancer in America, affecting 1-in-7 men. A non-smoking man is more likely to develop prostate cancer than he is to develop colon, bladder, melanoma, lymphoma, and kidney cancers combined. In fact, a man is 35% more likely to be diagnosed with prostate cancer than a woman is to be diagnosed with breast cancer.
According to the American Cancer Society (ACS), in 2010, more than 217,000 men were diagnosed with prostate cancer, and more than 32,000 men died from the disease. About 1 man in 36 will die of prostate cancer. One new case occurs every 2.7 minutes, and a man dies from prostate cancer every 19 minutes.
Age of Prostate Cancer Diagnosis
The older you are, the more likely you are to be diagnosed with prostate cancer. Although only 1 in 10,000 under age 40 will be diagnosed, the rate increases to 1 in 38 for ages 40 to 59, and 1 in 15 for ages 60 to 69. In fact, more than 65% of all prostate cancers are diagnosed in men over the age of 65.
It is estimated that there are more than 2-million American men currently living with prostate cancer.
What are the Risk and Non-Risk Factors?
According to the PCF, African American men are 61% more likely to develop prostate cancer compared to Caucasian men and are nearly 2.5 times as likely to die from the disease. Men with a single first-degree relative—father, brother, or son—with a history of prostate cancer are twice as likely to develop the disease, while those with two or more relatives are nearly four times as likely to be diagnosed. The risk is even higher if the affected family members were diagnosed at a young age, with the highest risk seen in men whose family members were diagnosed before age 60.
Although genetics might play a role in deciding why one man might be at higher risk than another, social and environmental factors, particularly diet and lifestyle, likely have an effect as well.
When weighing risk factors for prostate cancer, it’s also important to recognize that there are non-risk factors, or factors that have not been linked to an increase in risk. The most common misperception about the risk of prostate cancer is that the presence of non-cancerous conditions of the prostate increases the risk of prostate cancer. Although these conditions can cause symptoms similar to those of prostate cancer and should be evaluated by a physician, there is no evidence that having BPH (benign prostatic hyperplasia) or prostatitis increases the risk for developing prostate cancer.
BPH is a non-cancerous enlargement of the prostate. Because the urethra, the tube that carries urine from the bladder out of the body, runs directly through the prostate, enlargement of the prostate in BPH squeezes the urethra, making it difficult, and often painful, for men to urinate.
The growth of the prostate in men with BPH is unrelated to prostate cancer, and a number of research studies have shown that the presence of BPH does not make a man any more or less likely to develop prostate cancer.
Prostatitis is an infection in the prostate and is the most common cause of urinary-tract infection in men. Most treatment strategies are designed to relieve the symptoms of prostatitis, which include fever, chills, burning during urination, or difficulty urinating. Research has shown that the presence of prostatitis does not make a man any more or less likely to develop prostate cancer.
What are the Signs and Symptoms of Prostate Cancer?
According to ACS, early prostate cancer usually has no symptoms. With more advanced disease, individuals may experience weak or interrupted urine flow; inability to urinate or difficulty starting or stopping the urine flow; the need to urinate frequently, especially at night; blood in the urine; or pain or burning with urination. Advanced prostate cancer commonly spreads to the bones, which can cause pain in the hips, spine, ribs, or other areas. Many of these symptoms are more likely to be caused by conditions other than prostate cancer, however.
How is Prostate Cancer Diagnosed and Staged?
Historically, screening for prostate cancer has been performed in a physician’s office using two tests: the PSA (prostate-specific antigen) blood test and the digital rectal exam (DRE). Although the DRE and PSA tests cannot diagnose prostate cancer, they can signal the need for a biopsy to examine the prostate cells and determine whether they are cancerous. In some men, changes in urinary or sexual function lead to a full evaluation by the doctor; and, if prostate cancer is suspected, a biopsy will be performed.
In asymptomatic cases showing elevated PSA, physicians now have the option to conduct a supplemental non-PSA blood test to aid in the assessment of risk for the presence of prostate cancer. This technology, called APIFINY, is based on the measurement of specific biological markers known to be associated with an immune system response to prostate cancer. The use of APIFINY results may supplement other information about prostate-cancer risks and may therefore aid in earlier diagnosis of prostate cancer and potentially increase survival rates.
APIFINY should be used in combination with other accepted methods of patient management. In men with elevated PSA, APIFINY is designed to aid in the assessment of risk for the presence of prostate cancer and in the selection of patients for initial or repeat biopsy.
A biopsy is a procedure in which a sample of body tissue is removed and then looked at under a microscope. A core needle biopsy is the main method used to diagnose prostate cancer. It is usually done by a urologist, a surgeon who treats cancers of the genital and urinary tract, which includes the prostate gland. Using transrectal ultrasound, the doctor quickly inserts a needle through the wall of the rectum into the prostate gland. When the needle is pulled out, it removes a small cylinder (core) of tissue, usually about 1/2-inch long and 1/16-inch across. This is repeated from 8 to 18 times; but most urologists will take about 12 samples. These are sent to the lab to see if cancer is present. The biopsy procedure may cause some discomfort or pain; but the procedure is short, and can usually be performed without an overnight hospital stay.
Typically, 20-30% of biopsy results are positive upon which the urologist and patient consider all factors and determine the best treatment program.
However, 70-80% of biopsy results are typically negative, and the urologist and patient can then decide to order an APIFINY blood test to gain additional risk-assessment information.
What are the Prostate Cancer Treatment Options?
Treatment options vary depending on age, stage, grade of the cancer, and other medical conditions and should be discussed with the individual’s physician. The grade assigned to the tumor, typically called the Gleason score, indicates the aggressiveness of the cancer and ranges from 2 (nonaggressive) to 10 (very aggressive).
Surgery, external beam radiation, or radioactive-seed implants (brachytherapy) may be used to treat early-stage disease; hormonal therapy may be added in some cases. Careful observation (“active surveillance”) rather than immediate treatment may be appropriate for some men with less aggressive tumors, especially men who are older or who have other health problems.
Hormonal therapy, chemotherapy, radiation, or a combination of these treatments is used to treat more advanced disease.
What is the Survival Rate of Prostate Cancer Patients?
According to the American Cancer Society, more than 90% of all prostate cancers are discovered in the local and regional stages; the 5-year relative survival rate for patients whose tumors are diagnosed at these stages approaches 100%. According to the most recent data, relative 10-year survival is 93% and 15-year survival is 79%.
References: http://www.cancer.org/cancer/prostatecancer/ Accessed September 4, 2015; http://www.pcf.org/ Accessed September 4, 2015