What are the goals of prostate cancer treatment?
Ideally, treatment for any cancer should cure the disease, be easily tolerated and cause minimal or no problems for the patient. This concept is particularly important in prostate cancer for several reasons. Some men have an aggressive form of cancer that can lead to death; some have a cancer that grows so slowly, it causes few (if any) problems during a patient's natural lifetime. Nevertheless, there is no absolute way to determine if prostate cancer will be aggressive or slow-growing. Therefore, for most men whose disease is confined to the prostate, treatment is preferable to waiting and watching. This is especially true because our life expectancies continue to increase, and even slow-growing cancers could, in time, become life-threatening.
In other words, the ideal treatment for prostate cancer should effectively arrest or cure the disease (particularly in men with aggressive cancer), but cause few (if any) problems, especially for men with slow-growing disease. Furthermore, since many men with prostate cancer are elderly or have medical problems that make it impossible to undergo radical treatment, a treatment that minimizes trauma and complications is essential.
What are the current treatment options of prostate cancer?
To ensure that prostate cancer does not develop further and is halted soon after diagnosis, early treatment is recommended to either remove or kill the tumor. The main treatment options for prostate cancer are chemotherapy, biological therapy, radical prostatectomy, external beam radiation therapy, hormone therapy and radioactive seed implants. Treatments are chosen based on the stage of the cancer.
Chemotherapy uses drugs to kill cancer cells. It may be taken by pill or be put into the body by a needle in the vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body and can kill cancer cells outside the prostate. To date, chemotherapy has not had significant value in treating prostate cancer, but clinical trials are in progress to find more effective drugs.
Biological therapy tries to cause your own body to fight the cancer. It uses materials made by either your own body or in a laboratory to boost, direct or restore your body's natural defenses against disease. Biological therapy is sometimes called biological response modifier (BRM) therapy or immunotherapy.
Radical prostatectomy is currently the most common treatment for early-stage prostate cancer in the US. It is a major surgical procedure in which the prostate gland is removed, usually through an incision in the lower abdomen. Radical prostatectomy requires hospitalization and is not tolerated well in older men who are not in overall excellent health. The side effects from surgery include impotence (inability to have an erection) in a high percentage of patients, and incontinence (a loss of urinary control) in a small percentage.
Robotic-assisted Radical Prostatectomy
External beam radiation therapy
Radiation to stop the growth of cancer cells is delivered using a machine (usually a linear accelerator) that shoots a beam of radiation from outside the body through normal body tissue to reach the cancer. The radiation is given in short sessions over a long period; usually once a day, five days a week over a seven- or eight-week period, to minimize damage to the normal tissue.
External beam radiation therapy has a good cure rate for early prostate cancer. Because it is not a surgical procedure, it is better tolerated, especially in older men. Hospitalization is not required and there are no life-threatening complications.
Although hospitalization is not necessary, the patient must make visits almost daily to the hospital for nearly two months. There is still a significant risk of impotence and external radiation damage to healthy tissue. While most side effects are minor and disappear shortly after therapy stops, they include fatigue, skin reactions in the treated areas, frequent and painful urination, upset stomach, diarrhea and rectal irritation or bleeding.
Most patients with advanced prostate cancer are placed on some form of hormone treatment as the primary therapy for their prostate cancer. These treatments uniformly involve a lowering of the male hormone levels.
Male hormones are usually referred to as "androgens." The most important -- and one of the most powerful -- androgens is testosterone. Almost all the male's testosterone is made in the testicles. Therefore, most of the hormone treatment for prostate cancer is aimed at reducing the testicles' production of testosterone. This treatment can be done through injected medications, such as Lupron (luprolide) or Zoladex (goserlin), or by surgical removal of the testicles. Another option is treatment with female hormones, which also suppress the testicles' production of testosterone. In addition, many patients receive drugs called anti-androgens, which also help by blocking the effects of any residual androgens on the prostate cancer. These drugs include flutamide (Eulexin) or bicalutamide (Casodex).
The response rate for hormone treatment is in the range of 70 to 80 percent. This response is usually associated with a dramatic falling of the prostate specific antigen (PSA) level as well as improvement to any of the symptoms that might be caused by the prostate cancer at that time.
Brachytherapy or radioactive seed implants
Radioactive seed implants (internal radiation therapy) are tiny pellets containing radioactive medication, such as Iodine-125 or palladium. Seeds are permanently implanted directly in the middle of the cancer, where they continuously give off low-level radiation for approximately one year. Using TRUS (transrectal ultrasound) guidance, these seeds can be positioned so that radiation is distributed throughout the prostate gland. Since only a small area is irradiated by each seed, relatively little radiation reaches the adjacent normal organs, such as the colon, which is directly under the prostate gland, or the bladder, which lies on top of the gland.
The implant procedure does not require a surgical incision. Instead, the seeds, which are smaller than grains of rice, are contained in thin needles that are passed into the prostate gland through the skin between the scrotum and rectum. As the needles penetrate through the prostate, they are seen on the screen of the ultrasound machine and can be accurately guided to their final position. While the needles are being inserted the ultrasound probe is in the rectum. When each needle is in its correct position in the prostate, the needle is slowly withdrawn and the individual seeds are injected into the prostate gland. The ultrasound probe and the needles are removed when the procedure has been completed. The numbers of needles and seeds required varies from patient to patient, depending on the size of the prostate gland.
Patients with early-stage and small prostate tumors are the best candidates. That means about 50 percent of the patients with prostate cancer will fit this criteria. The development of more sensitive tumor detection techniques means that prostate cancer patients are being diagnosed at earlier stages, permitting more patients to become potential candidates for seed implantation.
Seed implantation is normally done as an outpatient procedure, taking about one hour to perform. The patient usually leaves the hospital the same day as the implant procedure, or stays in the hospital for one night and then resumes normal activities within several days. Because they are placed at the site of the cancer, the seeds can deliver two to three times more concentrated radiation to the prostate gland than external radiation therapy, which must use a lower dose because it also affects healthy tissue.
HIFU (high intensity focused ultrasound) is a minimally invasive procedure which offers reduced side effects. HIFU elevates tissue temperature by focusing sound waves causing a localized temperature rise of 55-90°C in a matter of seconds, which destroys tissue via a process called coagulative necrosis.
HIFU offers reduced side effects, such as erectile dysfunction and incontinence, and the same efficacy rates as traditional, more invasive prostate treatment options. HIFU can be used to treat the entire prostate or just part of the prostate (also called “male lumpectomy”). HIFU received FDA clearance in 2015.