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Watchful Waiting as a Treatment Option for Prostate Cancer
When it comes to treating prostate cancer, there are no certainties, only statistics. And the statistics from three recent studies indicate that men newly diagnosed with prostate cancer should at least consider whether immediate treatment is necessary.
This is especially true for older men and men diagnosed with the lowest risk tumors.
Three recent studies have prompted a reassessment of the ways in which prostate cancer is diagnosed and treated as well as who should be treated. One study found that over one million men diagnosed with prostate cancer in the last twenty years had cancers which ultimately caused few or no symptoms. The second study found that, since 1992, elderly men who elected conservative treatment of their prostate cancer had a much higher survival rate than in earlier eras and were six to seven times more likely to die from causes other than their cancer. Finally, a third study found that men who elected to defer treatment for their prostate cancer were faring nearly as well eight years later as those who elected immediate treatment.
Taken together, these results suggest that watchful waiting is a reasonable treatment option for many men. Yet only about 10% of all men choose this route.
"Watchful waiting" is continuing to monitor the cancer for signs of progression without treating it by radiation, surgery, hormones or other method. Although there is a risk that the cancer will progress and become clinically active disease which might have been cured when the cancer was initially found, on the other hand, the patient has avoided the undesirable effects of these treatments and may outlive any risk from the cancer itself. And if the cancer starts changing, so can the treatment.
Risks and Classifications of Prostate Cancer
The danger from prostate cancer is that it will spread from the prostate to other parts of the body. Yet unlike most other cancers, prostate cancer usually spreads slowly and spreads even more slowly the older a man is. Around 85% of all prostate cancers are localized: confined to the prostate gland when diagnosed. Many of these are small tumors which will remain in the prostate gland for the entire life of the patient.
Prostate cancers are classed as low−risk or high−risk based on three factors: the size of the tumor, whether it is confined to the prostate gland and its microscopic appearance (the lowest risk tumors are not that different in appearance from normal prostate tissue; these are called well−differentiated tumors). The lowest risk tumors are small, well−differentiated tumors which are confined to the prostate gland.
The problem in selecting a treatment comes from the fact that a small number of these low−risk tumors will spread to other parts of the body fairly quickly and doctors are unable to tell which ones will do this. Whether the odds of this happening are one in fifty or one in a million, nobody wants to be the one. And treatment is usually selected as if the patient will be that one.
For men with low−risk tumors, the anxiety, expense and side effects of treatment options such as surgery or radiation can be more disruptive than the cancer itself. Side effects of these treatments may include impotence and incontinence. Bouncing a grandchild on your knee is not a good idea when you have radioactive seeds implanted in your prostate.
The PSA Screening Test
In the first study, published in the October 7 issue of the Journal of the National Cancer Institute, H. Gilbert Welch and Peter C. Albertsen found that since the introduction of PSA screening, 1.3 million men were diagnosed with and over one million treated for prostate cancers that would have gone undetected without PSA screening. The fact that these cancers would never have been diagnosed indicates that most of them caused no symptoms in their patients. This suggests that these cancers did not require treatment. The diagnosis of a disease in patients where that disease will never cause symptoms is called over−diagnosis.
The death rate due to prostate cancer has also fallen since the introduction of PSA screening. How much of this is due to the screening? The authors estimate that if the entire decrease in the death rate was due to PSA screening—which is highly unlikely—over 20 men were diagnosed with prostate cancer for every life saved. Since around 80% of those diagnosed sought treatment, roughly 15 of every 20 men whose prostate cancer was found because they were screened for PSA sought treatment needlessly.
The Risks for Men Over 65
For one group, men diagnosed with moderately differentiated tumors at age 66−74, the ten−year death rate from prostate cancer was 6%, compared to 15−24% in the pre−PSA era. The risk of these men dying of causes other than prostate cancer in those ten years was over 50%. Advanced age, not cancer, was the chief culprit here.
Liu−Yao suggests that this should cause physicians and their patients to reconsider conservative treatment, particularly in light of earlier studies suggesting little if any benefit from more aggressive treatment. Liu−Yao stresses that the information in her study applies only to those over 65 at the time of diagnosis; the results should not be applied to younger men.
In the third study, published in the August 31 issue of the Journal of Clinical Oncology, a team that included Martin G. Sanda sought to examine the consequences of choosing deferred treatment after a diagnosis of prostate cancer. The men in this study were an average age of 60 at the time of their cancer diagnosis. Using data on 51,529 men from the Health Professionals Follow−up Study (HPFS), the team found no statistical difference in the death rates due to cancer of those who elected treatment within one year and those who did not. Only 1% of those who elected immediate treatment and 2% of those who didn't eventually died of their cancer. While this difference is twofold, it involves such a small total number of men that it's statistically no difference at all. It's similar to the difference between finding a penny inside of your couch and finding two pennies. The difference is only a single penny.
HPFS began in 1986 and is ongoing. It collects detailed medical information on a variety of topics and is not specifically about prostate cancer. Information is updated by questionnaire every two years. At some point during the study, 3,331 men were diagnosed with prostate cancer. Only 342 of these men—just over 10%—opted to defer treatment for a year or more.
Most of the men who elected to defer treatment had been diagnosed with low−risk tumors or were elderly; none were under 50. At the study's end, half of them still had not undergone any treatment. And they were doing fine. On average, this was 7.7 years after their cancer had been diagnosed.
Sanda notes that this is a compelling reason for men with low−risk tumors to consider watchful waiting as a treatment option.
These three studies all suggest that more men should consider treating their prostate cancer with watchful waiting. There's still much disagreement among doctors about who is and isn't an appropriate candidate. Each case of prostate cancer has to be assessed individually.
To anyone who has recently received a diagnosis of prostate cancer, deciding on an appropriate course of treatment is not easy. There's too much information and too much uncertainty. Fortunately, with prostate cancer, an immediate decision on treatment is rarely necessary. There's usually time to think the matter out. One place to get an overview of the many issues involved is at the National Cancer Institute's website. There's a prostate cancer summary available, as well as detailed information on many prostate cancer related topics.
October 15, 2009
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