Found only in men, the prostate is a small gland (usually compared to a walnut) that can cause big problems, the most severe of which is prostate cancer. When the prostate gland is functioning normally, it helps control urination and produces substances (minerals and sugar) that are found in semen. The prostate gland is also the muscle power behind ejaculation, and actually consists of about 30% muscular tissue, the rest being glandular tissue. The prostate gland begins development before birth, continues to grow through early adulthood, and then stops. It usually begins growing again at around the age of 60, and this is when problems can develop. Nearly all men have an enlarged prostate by the time they are 70 years of age. An enlarged prostate can be due to benign prostatic hyperplasia (BPH), prostatitis, or prostate cancer. BPH and prostatitis are both manageable conditions, but prostate cancer can be terminal.
Prostate cancer is a malignancy found in the prostate gland. If untreated, it can spread to adjacent organs, lymph nodes and bones.
The statistics regarding prostate cancer are sobering. Prostate cancer is the most common cancer in American men, second only to skin cancer. The American Cancer Society estimates that in the United States, roughly 192,280 new cases of the disease will be diagnosed and approximately 27,360 men will die of the disease by the close of 2009. Translated, this means that 1 man in 6 will be told he has prostate cancer during his lifetime. In addition, prostate cancer is behind only lung cancer in the number of cancer deaths in American men. Nearly 1 man in 35 will die from the disease. About 10% of cancer-related deaths are linked to prostate cancer.
There are two methods commonly used to monitor prostate health and diagnose prostate cancer: 1) the digital rectal examination or DRE and 2) the prostate-specific antigen (PSA) blood test. These two methods combined are extremely effective in diagnosing prostate cancer before it metastasizes.
The DRE takes less than a minute and is uncomfortable, but brief. During this examination the doctor inserts a gloved, lubricated finger into the rectum and palpates the prostate, feeling for any abnormalities.
The PSA test is a blood test that measures the levels of an antigen in the blood. High levels of the antigen indicate an enlargement or inflammation of the prostate. If PSA test results signal a problem, the physician will order further diagnostic procedures, such as a transrectal ultrasound or a biopsy.
The DRE and PSA tests should be included in a man’s yearly physical examination if he is 50 years of age or older. If there is a history of prostate cancer in a man’s family, these tests should be initiated at the age of 40.
The risk factors for prostate cancer are race/ethnicity, age, family history, genes, and diet. Other factors that are linked but have not been scientifically proven are obesity, vasectomy, inflammation of the prostate and infection. Studies on these possible factors have inconclusive.
The symptoms of prostate cancer include frequent, painful or difficult urination, blood or pus in the urine or semen, painful ejaculation, and pain in the pelvic area, lower back or upper thighs.
Treatment for prostate cancer is similar to other forms of cancer and involves surgery, radiation or drugs alone or in combination. The treatment given matches the severity of the cancer. Prostate cancer that is confined solely to the gland is often surgically removed in an operation called a “radical prostatectomy.” Some radiation can follow to be sure that the cancer cells have been eliminated from the surround area. Another option is called “watchful waiting.” This is primarily used if the patient is elderly and his cancer has been deemed to be slow-growing. In this case the patient is more likely to die from something other than the prostate cancer.
Prostate cancer is slow growing and responds well to treatment when diagnosed in its early stages. Over the past several years, the 5-year survival rate for the disease has increased from 67% to 99%. For these reasons, men should pay attention to their prostate and speak with their physician about prostate care and health.
Bone metastases and the pain they cause are common complications of advanced prostate cancer.
Treatment for bone metastases varies according to each patient’s overall health and cancer prognosis and usually involves some type of radiation therapy or administration of the bone-targeting agents called bisphosphonates. Before instituting a specific regimen, however, most physicians will want to discuss lifestyle habits and diet with the patient. Treatment for bone metastases and prostate cancer is sometimes exhausting and painful, but these aspects of therapy can be lessened if the patient maintains healthy eating and exercise habits. In particular, patients must be sure to maintain adequate levels of calcium and vitamin D, as these are crucial to the general health of the bones.
Radiation therapy and bisphosphonates are two ways to treat bone metastases and the accompanying pain. Radiation therapy is delivered via an x-ray machine (ie, External beam radiation therapy or EBRT) and by the injection of radiopharmaceuticals (ie, radioactive drugs). EBRT uses powerful x-rays to destroy the cancer cells found in bone. This type of treatment is developed and planned by a radiation oncologist, who determines exactly what areas of the bone need to be targeted. Precise and careful delivery of the x-rays will minimize damage to the surrounding bone and muscle tissue.
Strontium (ie, Metastron) and samarium (ie, Quadramet) are the two drugs used to treat bone metastases. In this type of radiation therapy, one of the drugs is injected into a vein, where it travels directly to the site of the bone metastasis and settles there, releasing radiation to kill the cancer cells. Studies have shown that strontium can be effective in relieving pain particularly when administered after doxorubicin (ie, Adriamycin), a drug commonly used in chemotherapy.
Radiopharmaceuticals and EBRT are called “directed palliative treatments” because they can target and alleviate pain in a specific area of the body.
Metastases are caused by an imbalance in bone cell activity. In a normal, healthy person, bone cells are constantly created and destroyed. Cells that form new bone cells are called osteoblasts and an increase in their activity eventually results in an overgrowth of bone tissue. Cells that destroy bone cells are called osteoclasts and an increase in their activity eventually results in brittle, porous bone tissue. In a man with prostate cancer who has bone metastases, these processes have basically run amuck and occur too quickly, causing skeletal instability and fractures. Bisphosphonates are drugs that are designed to normalize and re-coordinate the process of bone growth and destruction.
Some common bisphosphonates are alendronate (Fosamax), Zoledronic acid (Zometa), pamidronate (Aredia), and risedronate (Actonel). Zoledronic acid and pamidronate are administered via injection into a vein. Zoledronic acid has been shown to relieve pain as well as delay the onset of complications, and is usually administered once every 3 weeks as a 15-minute infusion. Some men have reported flu-like symptoms after the first few treatments of zoledronic acid, including generalized aches and pain, fatigue, nausea and vomiting; however, these side effects usually subside in a few days. In addition, this drug can cause kidney problems therefore physicians should draw blood prior to each treatment to insure proper kidney function. Pamidronate has demonstrated only limited benefit and is less frequently used.
Alendronate and risedronate are taken as a pill and often used to slow bone loss in men who are undergoing hormone therapy for prostate cancer.
Because bone metastases are so common in men with prostate cancer, researchers are continuing the search for new drugs and therapies to treat the pain and complications associated with these metastases.