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Organ-Confined Prostate CancerBy Sunni Hosemann Introduction The natural history of prostate cancer tends to differ from that of many other cancers. The tumor usually grows slowly, and a decade or more can pass from when it is detected to when it causes problems. So, an early-stage prostate cancer in a man who is 85 years old may never affect his health. In fact, for men such as him, treating the cancer may take a greater toll than the cancer itself. Likewise, men in their 50s and in good health may wish to forestall treatment—and the potential side effects, discussed below—until the cancer poses a threat. Conversely, men of any age or health status may prefer to treat the cancer immediately rather than adopt a watch-and-wait approach. Thus, men diagnosed with organ-confined prostate cancer face complex decisions that hinge on many factors: an accurate assessment of the risk posed by the cancer, a consideration of life expectancy, evaluation of comorbid conditions and general health, and personal priorities. And the decisions can be confusing: Watch and wait, or opt for treatment? And if treatment is chosen, which one is best? Organ-confined prostate cancer in context Prostate cancers are currently classified according to:
Although stage, PSA level, and grade have some predictive value on their own, most specialists use the three variables in combination when assessing a cancer. The significance of each variable can be weighted and assigned in individual cases through the use of statistical models or nomograms to aid decision-making. According to the National Comprehensive Cancer Network, the most widely used nomogram for prostate cancer incorporates stage, PSA level, and grade and assigns cancers to one of the following four categories (in order of progression):
Treatment choices Observation Monitoring includes PSA testing, digital rectal examination, and repeated biopsy of the prostate. The frequency of such tests is usually based on life expectancy, with a more aggressive schedule recommended for younger, healthier men. The idea is that should disease progression occur, any needed intervention would still be timely, though this remains to be proven safe and effective. Changes may signal an increased risk of cancer progression and may indicate that treatment is needed. While firm criteria for disease progression have not been established, clinicians usually consider an increased grade on prostate biopsy, the appearance of a new nodule on digital rectal examination, a continued rise in PSA level over time, a PSA velocity greater than 0.75 (a doubling of PSA level in less than 3 years), or an increased volume of cancer on follow-up prostate biopsy to indicate progression and the need for treatment. Surgery However, radical prostatectomy is also associated with long-term erectile dysfunction and urinary incontinence. Approximately 30%–40% of men who undergo radical prostatectomy will experience erectile dysfunction, and 5%–10% will experience prolonged problems with urinary continence (although it is uncommon for any man to be left severely incontinent following surgery performed by experienced surgeons at a high-volume center). Whether nerves can be spared is an important factor. In approximately 75% of patients, one or both of the nerve bundles involved in erectile and urinary function can be spared. In others, sparing isn’t possible because of either tumor involvement or anatomic reasons. Erectile function is preserved in up to 80% of men in whom both nerve bundles are spared, depending on age and pre-existing erectile function, and 30% of those with one nerve bundle spared are able to maintain erectile function. Radiation Brachytherapy for prostate cancer uses “seeds” implanted in the prostate that emit radiation; the seeds gradually lose their radioactivity and become inert. The seeds are inserted via a needle using general or spinal anesthesia. The insertion is a one-time, outpatient procedure. Whether to use external beam therapy or brachytherapy is often a decision made between the physician and the patient, said Deborah A. Kuban, M.D., professor and chief of the Genitourinary Section in the Department of Radiation Oncology. Tumor characteristics, prostate size, and patient preferences are typically the factors considered. Side effects of radiation therapy during treatment can include bladder and bowel irritation. Long-term incontinence is uncommon. Typically, erectile function is initially preserved, but it can decrease over time. Other treatment options “The tools for delivering ablative heat and cold continue to improve, allowing us to deliver more accurate therapy,” Dr. Ward said. “However, for prostate cancer, current imaging doesn’t allow us to see which part of the prostate is affected by the cancer—which is the reason for multiple biopsy sites—and therefore patients must be selected carefully for ablative treatments.” Because of the long natural history of prostate cancer, studies must have at least 10 years of follow-up information to provide definitive answers about whether newer therapies should become standard. “That is partly why we have so many treatments and so few definitive answers. Right now, we are exploring these ablative energies to determine which can be safely applied with fewer side effects than surgery and radiation,” Dr. Ward said. The decision Observation or treatment? According to Dr. Ward, wives and significant others can be a big factor in surveillance protocols—they, too, must be comfortable with the plan. If treatment, which one? The importance of erectile function varies among men and does not necessarily correlate with age. There are men in their 70s and 80s, for example, who are in new marriages or relationships and who might place a higher value on erectile function than younger men in different life situations. “These are long conversations,” Dr. Ward said of the discussions needed to fully examine a patient’s priorities. “But if you want to do what’s right for the patient, you must spend the time.” Nerve-sparing surgery greatly reduces but does not eliminate the risk of erectile dysfunction, and thus surgeons can’t promise preserved erectile function to any man preoperatively. A “possibility” of preserved erectile function may not be good enough for a man for whom erectile function is a high priority. For others, just the possibility of preserved erectile function makes surgical removal of the tumor more attractive. Incontinence is also intimately related to a man’s lifestyle and what is important to him. Men who participate in sports are often particularly concerned about the risk of incontinence, as are men who are in new social situations or pursuing new relationships. Therefore, when considering treatment options, patients must take into account a particular treatment’s chances of eradicating the cancer as well as the associated long-term effects that can affect quality of life. This is why an objective multidisciplinary consultation involving a urologist and a radiation oncologist is invaluable—all issues can be discussed in detail and priorities can be weighed. Some considerations are practical ones. For some men, the time available for treatment is a critical factor and a reason to opt for a one-time treatment—surgery or brachytherapy—rather than a course of external beam radiation therapy that may require 30–40 clinic visits over a period of weeks. Others simply like the idea of removing the cancerous organ. Men who select radiation therapy give a variety of reasons for doing so. Some view radiation therapy as less invasive or feel that it has a gentler and more gradual impact on their health. Some select this therapy because they dislike the idea of surgery, anesthesia, or hospitalization. One might think that having a choice of equivalent treatments for a cancer would be a good thing. But according to Dr. Kuban, there is a downside. “We used to think patients wanted us to give them all the options so they could make their own choices,” she said. “But when we asked, they came across strongly saying, ‘We want more direction.’” Based on this feedback, M. D. Anderson opened its Multidisciplinary Prostate Cancer Clinic, where patients can meet with physicians from different specialties on the same day to discuss treatment options. Patient records and previous studies are evaluated by a team of physicians. The patient is examined by and meets with a urologist, a radiation oncologist, and if necessary, a medical oncologist. “This way the patient knows that if I recommend surgery, it’s because we think that’s the best choice for him, not because I’m a surgeon,” Dr. Ward said. Patients also have access to an advanced practice nurse specialist who can provide guidance, discussion, and follow-up information. The clinic is available to patients who have a prostate cancer diagnosis and want a second opinion or want to be treated at M. D. Anderson. In the future, imaging advances or refinements in tumor marker technology may predict how individual prostate tumors are likely to progress, which would make treatment decisions easier. “But for now, it’s a matter of weighing side effects against cancer control,” Dr. Ward said. Added Dr. Kuban, “It is important to individualize treatment recommendations.”
For more information on this topic or for questions about M. D. Anderson’s treatments, programs, or services, call askMDAnderson at (877) MDA-6789. Other articles in OncoLog, April 2009 issue:
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