To Treat or Not to Treat Prostate Cancer: That Is the Question
Imagine being told by your doctor, "You have cancer." Then imagine that their next words are "... but we probably don't need to do anything about it." Many people would immediately start looking for another doctor. But hold on just a moment.
Last month the National Institutes of Health (NIH) brought together experts from around the world for a summit to examine the state of our scientific knowledge on "active surveillance" as a management strategy for prostate cancer. For those of you who are unfamiliar with the term, active surveillance essentially means monitoring the cancer closely and delaying active treatment (surgery or radiation, for instance) until there are signs it is needed; the delay may be months, years, or forever. This summit pointed out that while there is still much we need to learn about this once-controversial approach, there is a wealth of data supporting the potential value of active surveillance for a large number of the 240,000 men in the United States who are diagnosed with prostate cancer each year.
Not treating cancer?
To most individuals, the idea of having cancer and choosing not to treat it smacks of fatalism, or just giving up. In order to understand why this is not the case, it is important to appreciate that all prostate cancers are not created equal.
There are many prostate cancers that can be singled out as likely to be slow growing and posing a low risk to the affected man; these can be identified by looking at a man's PSA level (prostate specific antigen; a protein made by the prostate gland and measured in the blood), Gleason score (a numerical representation of how a man's tumor looks under the microscope), and other factors (size of the tumor, how much of the prostate gland is invaded by cancer, etc.). The vast majority of men with these low-risk tumors will end up dying of something other than prostate cancer, and few of these men would ever experience any harm from their cancer if it went untreated (or if it was never found in the first place).
It's estimated that as many as half of the prostate cancers diagnosed each year in the US fit into this low-risk category. However, to most people the term "low-risk cancer" sounds like an oxymoron. This quandary prompted a number of summit speakers to question whether this type of tumor should even be called "cancer," or if the scientific community should come up with a new, less frightening term to describe these slow growing prostate lesions.
For most men who are told that they have prostate cancer the first question is, "How soon can we get rid of it?" In the US, 90% of these men move very rapidly to what is viewed as definitive therapy, usually prostatectomy (surgical removal of the prostate gland) or killing the cancer cells with radiation treatment. These treatments come with the risk of side effects and complications, most commonly damage to bladder or bowel function, and sexual difficulties. A recent report from the US Preventive Services Task Force estimates that 1 or more of these complications occur in up to 30 of every 100 men treated for prostate cancer; the same report indicates that 1 of every 200 men who undergo surgical removal of their prostate dies within 30 days of their surgery. These numbers point to why it's so important to explore alternative approaches to managing this disease.
Watchful waiting and active surveillance
Prostate cancer is primarily a disease of older men, and many men diagnosed with the disease already have multiple health problems (and in some cases a limited life expectancy). Given these circumstances it has long been the practice of doctors who treat prostate cancer to weigh these factors and to recommend to some men that, as opposed to beginning treatment shortly after diagnosis, they be observed by their doctors and begin treatment only if they develop symptoms that suggest that their cancer is getting worse. This approach is known as "watchful waiting."
Over time, evidence emerged that most men who were observed in this fashion did well for a number of years. This information, combined with the growing number of low-risk tumors being diagnosed as a result of having widespread PSA screening for prostate cancer, raised the question as to whether younger, healthy men might also benefit from a delayed treatment approach.
Managing the cancer in these men evolved from simple observation to more intensive follow up, including repeated PSA tests and regular biopsies of the prostate gland, treating the cancer only if it begins to grow or spread. This approach has become known as "active surveillance" (differentiating it from the more passive watchful waiting). Research studies were undertaken to find out about the impact of both of these approaches on the long-term outcomes of men with prostate cancer, and speakers at the NIH summit described findings from a number of such studies.
'A viable option' for low-risk patients
In one of these studies, the Prostate Cancer Intervention vs. Observation Trial (PIVOT), men diagnosed with low-risk prostate cancer were given the option of prostatectomy or observation; these men were then tracked over time. PIVOT used a traditional watchful waiting approach: men were simply observed and treatment was begun only if symptoms developed or if the man requested it. After approximately 10 years of follow up the risk of dying from prostate cancer was small (less than 10%), and was essentially the same whether a man chose surgery or observation. The risk of death from any cause, including both prostate cancer and other diseases (referred to as "all cause mortality") was also about the same between these groups.
A number of other studies have been carried out to look at outcomes of active surveillance, using observation combined with repeat PSA tests and prostate biopsies to look for whether the cancer was spreading or getting worse. These studies, some of which have been underway for 15 years or more, have found that only a small proportion of men diagnosed with low-risk disease will show signs of significant cancer progression.
Like PIVOT, most active surveillance studies have found low rates of death from prostate cancer among men with low-risk disease. They have also found similar rates of all cause mortality in men who choose active surveillance when compared to men who got immediate treatment. In addition, men who choose an observational approach (active surveillance or watchful waiting) avoid or delay the side effects associated with surgery or radiation. Based on the strength of the accumulated evidence the NIH expert panel concluded that "active surveillance has emerged as a viable option that should be offered to all low-risk patients."
So why do 9 out of 10 men with prostate cancer in the US end up being treated shortly after they're diagnosed? It turns out that many prostate cancer patients have never heard of active surveillance or watchful waiting, and are never told that observation is an option they could consider for their cancer. In other cases active surveillance is discussed as a potential management option but is presented in an unfavorable manner (i.e., "we can treat your cancer or we can just do nothing").
Even in circumstances where active surveillance is discussed in a fair, objective manner there are a number of other factors that may influence the likelihood of men choosing and sticking with this option. These include whether or not their physician supports their choice, support from family and friends, and the patients' personal perceptions of and experience with cancer (whether they themselves have had other types of cancer in the past, or observed friends or family go through cancer treatment).
So if you or someone close to you has been diagnosed with prostate cancer - slow down! After getting past the shock, start asking some questions. Find out all that you can about the tumor, and determine whether the cancer fits into the low-risk category. Be sure to explore all treatment options, including active surveillance. In some cases of prostate cancer "no treatment" may turn out to be the best treatment.
Brooks is director of prostate and colorectal cancers for the American Cancer Society.