It’s almost a mantra for us physicians: The earlier cancer is discovered, and treated, the better. A better chance at long-term survival, a better chance at cure, and no matter what the cost, physical and monetary, it’s worth it.
But is it? As we get better and better at detecting cancer early, we are faced with an interesting dilemma: Is it necessary to treat all cancers aggressively? Does it really make a difference in survival rates? Is it really the cancer that will kill you in the end?
This is the question that researchers from the University of Connecticut set out to answer. They were aided by hospital records, death certificates, and most importantly, the Connecticut tumor registry, which follows all Connecticut residents who are diagnosed with cancer. They evaluated 767 men who were diagnosed with localized prostate cancer between 1971 and 1984. The men were between the ages of 55 and 74 at the time of diagnosis. Their goal was to study the 20-year survival rate in men with localized prostate cancer who were either treated with hormonal (anti-testosterone) therapy or watchful waiting with no treatment at all.
Except for skin cancer, prostate cancer is the most common cancer diagnosed in men. It is the second leading cause of cancer deaths in men, second only to lung cancer (it’s those darned cigarettes again). One out of six men will get prostate cancer in his lifetime. African American men have the highest incidence of prostate cancer and the highest death rate from prostate cancer in the world. Asian men are the least likely to get the disease, with white men in the middle.
Like breast cancer in women, the risk of prostate cancer increases with age. So it becomes even more important to answer the question: If you’re 70 years old when your (localized) prostate cancer is diagnosed, is it the cancer that will kill you, or something else, like heart disease? An important question in this age of the Prostate Specific Antigen, or PSA, test. The use of the PSA test has increased the diagnosis of very early, localized prostate cancer. Since the PSA test became widely used, more than 90 percent of prostate cancers diagnosed are clinically localized disease.
The Connecticut researchers looked at cancer death rates and related them to the Gleason score of the tumor at the time of biopsy diagnosis. The Gleason score is used to determine how bad the cancer looks under the microscope. Tumors with a low Gleason score look a whole lot like the normal prostate cells – they are “well-differentiated” cancers. High Gleason score tumors are wacky and evil-looking. These “poorly differentiated” tumors have a much worse prognosis. Gleason scores range from 2 to 10.
The researchers were responding to an earlier study that found that death rates from prostate cancer increased considerably in the men who were still alive 15 years after their cancer diagnosis. The Connecticut researchers had more men in their study (over 700 vs. 223) and they found no increase in death rate from 15 to 20 years, regardless of Gleason score.
But by far the most interesting finding in their study was that of the 138 men with Gleason scores of 2 to 4, only 10, or 7 percent, died from the cancer. Twelve percent of the patients were still alive after 20 years, and the rest died of other causes (75 percent) or unknown causes (6 percent). The findings suggest that men with low-grade cancers have only a small risk of cancer progression after 20 years, and do not support radical surgery or X-Ray therapy for these men.
Randomized, controlled studies will need to look at the optimum mode of therapy for men diagnosed with low-grade, localized disease. Such studies are underway in Sweden, Great Britain, and here in the U.S. But this study suggests that these men might do well with minimal, maybe even no, intervention.
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