Treating Prostate Cancer: The Big Picture

According to the American Cancer Society, about 186,320 Americans will be diagnosed with prostate cancer this year, and 28,660 will die from the disease. That makes prostate cancer the most common internal malignancy in American men, with a cancer death toll that trails only lung cancer (see “Malignancies in men in 2008” below). Researchers have made substantial progress in understanding the causes and basic biology of the disease, and clinicians have developed improved methods of diagnosis and therapy. Even so, basic questions remain unanswered; as a result, many important decisions about prostate cancer are not made by doctors but by patients.

The first decision a man faces is whether or not to have a blood prostate-specific antigen (PSA) test and a digital rectal exam (DRE) to screen for early prostate cancer. Although many men find the decision difficult, there is no wrong answer. Proponents of screening point out that PSA testing is the best way to diagnose prostate cancer in its earliest, most treatable stages. Skeptics counter that some men diagnosed by screening receive treatments that produce more ill effects than the disease itself. Odd as it sounds, both sides are right. That’s why Harvard Men’s Health Watch has not taken a position on PSA screening; instead, we’ve tried to explain the pros and cons so each man can decide what’s best for him. In fact, informed decision-making is the approach recommended by every major medical organization that has weighed in on the question, ranging from the American Cancer Society and the American Urological Association to the American College of Physicians and the American Academy of Family Physicians.

Once a man is diagnosed with prostate cancer, his decisions take on a new urgency. In the case of most malignancies, news of the diagnosis is accompanied by a crisp and confident treatment plan. Not so with prostate cancer; instead, the doctor who announces the diagnosis is likely to ask the patient what treatment he wants. That means the shock of a diagnosis is followed by the shock of learning that, in many cases, doctors disagree about which treatment is best.

It’s not that doctors haven’t tried to answer the question themselves. In 1995 and again in 2007 the American Urological Association published reports by the authoritative Prostate Cancer Clinical Guidelines Panel. In both cases, dozens of experts reviewed thousands of studies but were unable to establish standard-of-care recommendations. Instead, the experts recognized that there are many acceptable therapeutic options, and they suggested that doctors inform their patients about the advantages and disadvantages of each treatment, enabling every man to choose for himself. And a major 2008 review sponsored by the U.S. Agency for Healthcare Research and Quality agreed, concluding that “Assessment of the comparative effectiveness and harms of localized prostate cancer treatments is difficult because of lack of evidence.”

Let’s examine why prostate cancer is different from other malignancies, and what makes studies hard to perform and tricky to interpret.