Clinically Localized Prostate Cancer
Statistics: Prostate cancer is the most common cancer in U.S. men with approximately 218,850 new cases expected in 2007. Prostate cancer is expected to kill 27,050 American men in 2007, third behind lung cancer and colorectal cancers. The death rate from prostate cancer has declined by about 30% in the past 15 years as a result of early detection and improved treatment. While nearly 40% of U.S. men will develop some form of prostate cancer, many will not be diagnosed with or die from this cancer.
Natural history: Prostate cancer grows locally within the prostate and eventually invades into nearby tissues (bladder, seminal vesicals, muscles and fat). When it spreads, it typically goes to lymph nodes and bone, and later to other organs. When it spreads well beyond the prostate, survival is reduced and cure improbable.
Prostate cancer is graded based upon its microscopic appearance. Well differentiated tumors somewhat resemble normal prostate and behave less aggressively than poorly differentiated tumors, which barely resemble normal prostate glandular tissue. The Gleason Score is from 2 (well differentiated) to 10 (poorly differentiated). A tumor’s Gleason Score can be used to predict how that particular cancer will behave. The prostate specific antigen blood test (PSA) can be normal or elevated, but markedly elevated PSA values are less favorable than lower PSA levels. When the Gleason score, PSA, recent rate of PSA increase (termed PSA Velocity), clinical stage (finding on digital rectal examination (DRE) and prostate ultrasound) are combined, an impression can be made regarding expected outcome of treatment options. Low grade, low stage cancers take longer to impact on an individual’s life than high grade or high stage tumors. Marked individual variance in tumor behavior commonly occurs, thus long-term predictions or prognoses are often inaccurate. ‘Clinically localized prostate cancer’ refers to a cancer that appears to be confined to the prostate and, therefore, potentially curable. To avoid prostate cancer morbidity and mortality, both early detection and effective treatment must be accomplished.
Treatment considerations: Since men are often older (60’s, 70’s, 80’s) when prostate cancer is diagnosed, and some tumors are relatively slow growing, the relative morbidity of prostate cancer must be weighted against expected survival from other life-limiting illnesses. For example, a man with significant heart disease that is expected to live less than 5-6 years may not want to aggressively pursue curative therapy for a low stage, low grade prostate cancer that will not cause significant problems for 5-7 years or more. The same tumor in a man with less threatening medical problems who is likely to live longer might consider curative treatment to prevent cancer-related complications or even death from prostate cancer. Factors that make treatment decisions difficult include: uncertain life expectancy, unpredictable tumor behavior, variable incidence of treatment related complications, inaccurate clinical staging and therefore, unpredictable treatment effectiveness. Once the cancer spreads away from the prostate, cure is not considered possible.
Active Surveillance: In patients with low grade, low stage cancers and a limited life expectancy; periodic monitoring of the PSA, DRE, overall symptoms and periodic restaging ultrasound and biopsy can track the behavior of the cancer. Watchful waiting without curative treatment risks complications of disease progression, but avoids treatment related risks in the short-term. For men without prostate related symptoms and a cancer that does not appear to pose a threat in the anticipated future, watchful waiting may be a suitable management approach. The problems with watchful waiting are related to our relative inability to accurately assess the time that a specific cancer will take to cause problems, and, once the cancer shows signs of aggressive behavior, the chance for cure is often lost. There is less short-term risk and more long-term risk if life expectancy or cancer aggressiveness is underestimated.
Hormone manipulation: Elimination of testosterone (made in the testicles) by either removal of the testicles or suppression with hormone shots usually causes prostate cancer to go into remission for several years. This form of therapy has not been found to be curative but sometimes offers cancer control for longer than the typical 2-3 years. Side effects of testosterone removal (by either method) may include hot flashes, loss of libido, loss of potency, mild anemia, reduced energy, reduced muscle tone, earlier osteoporosis, cognitive (thought) changes and occasionally subtle mood changes. Most men note significant alterations in their bodies while on hormone therapy. Hormone therapy is generally used when the initial management approach (radiation, watchful waiting or surgery) fails.
Radiation therapy: Radiation therapy attempts to destroy cancer cells without seriously harming normal, adjacent tissues. Radiation can be delivered to prostate tissues by either external beam treatments (daily treatments for 8 weeks) or by surgically implanting permanent or temporary radiation ‘seeds’ into the prostate gland (1 - 2 hour outpatient surgical procedure). These treatments have similar side effects and fairly similar success rates. A patient with a small gland without urinary symptoms, a small volume of cancer, a PSA less than 10 and a Gleason score of 6 or less may be a candidate for one type of radiation. Less favorable cancer characteristics may require a combined approach including more than one type of radiation with or without temporary hormone therapy. Men with larger glands or prior prostate surgery are more likely to have significant urinary side effects including incontinence. Other methods of radiation such as neutron beam and proton beam therapy are still considered investigational and are available at a few research centers.
Cryotherapy: Cryotherapy is the controlled freezing of the prostate. Cryotherapy more effectively ablates (destroys) the cells (benign and cancerous) in the prostate. Recent technological advances in prostate cryotherapy have lead to renewed interest in this treatment option. Today, cryotherapy is more effective at ablating the prostate than radiation. Additionally, cryotherapy can be done without harming the bladder and rectum. If an initial treatment with cryotherapy is found to be incomplete, it can safely be repeated – an option not possible after radiation fails. Cryotherapy is performed as an outpatient under anesthesia in the operating room. A catheter is left in the bladder for one week after therapy and post-treatment PSA levels should be undetectable in successful cases. While men generally have improved voiding after cryotherapy and incontinence rates are 2 – 6%, impotence is almost universal. Modern cryotherapy has less long term risk than radiation, but is less effective than surgery.
HIFU (High Intensity Focused Ultrasound): HIFU is the newest minimally invasive treatment for localized prostate cancer. It is an outpatient procedure done in the operating room under anesthesia. HIFU focuses a tissue heating energy in the prostate causing ablation of the tissue. While HIFU is available in very few research centers in the United States, it is available in Canada and Mexico. Some prostate cancer specialists (including Dr. Harris) have direct access to this technology through arrangements. While incontinence is uncommon and potency often preserved, it is less effective compared to surgery done by the best surgeons.
Radical prostatectomy: The surgical removal of the prostate and seminal vesicals is the gold standard for treatment of localized prostate cancer. Radical prostatectomy can be accomplished through an abdominal incision (radical retropubic prostatectomy - RRP), through a perineal incision between the scrotal sac and the anus (radical perineal prostatectomy - RPP) or by a laparoscopic approach with six finger-sized holes puncturing the abdominal wall into the pelvic area. Most laparoscopic prostatectomies are done with the assistance of a robotic instrument between the surgeon and the patient as robotic instruments have a greater range of motion inside the patient than conventional laparoscopic instruments (robotic assisted laparoscopic prostatatectomy or RALP).
Summary: The most important step a man with newly diagnosed prostate cancer can do is to adequately study the personal results of any physician he consults with to treat his cancer. After initial therapy, salvage options are relatively limited if suboptimal results are obtained. The table below provides a brief comparison of the above treatments that are intended to cure prostate cancer. The results are based upon the best physician’s experiences in each technique.