When a man is diagnosed
with prostate cancer, his first question is almost always: "How
bad is it? When a man is diagnosed with Gleason 7 disease, the
answer is a little tricky. This is because not all Gleason 7 cancers
are alike. In fact, the differences can be great.
The Gleason system (see
this story) is based on a score — the sum of the two
most common patterns that the pathologist sees under the microscope.
The equation, "2 + 2 = 4," for example, would signal a very mild,
slow-growing form of cancer, and one that is rarely diagnosed today.
On the other hand, "5 + 5 = 10" would represent much more aggressive
disease. The first number in the equation represents the predominant
type of cancer. In the case of Gleason 7, this can go two ways:
"3 + 4 = 7," or "4 + 3 = 7."
with a Gleason score of 4 + 3 are more aggressive and predictive
of advanced disease at the time of surgery, compared to Gleason
3 + 4 tumors," explains Mark L. Gonzalgo, M.D., Ph.D., assistant
professor of urology and oncology. In a recent study, published
in the journal Urology, Gonzalgo and urologists Alan W. Partin,
M.D., Ph.D., and Patrick C. Walsh, M.D., investigated the relationship
between a manís biopsy Gleason score, the Gleason score in the entire
prostate (the specimen removed during radical prostatectomy) and
the recurrence of PSA among men who were diagnosed with Gleason
7 cancer in a needle biopsy.
"The good news is that the vast majority
— 75 percent — of these men turned out to have the less aggressive
type of Gleason 7 cancer," Gonzalgo says. "Their Gleason score determined
after surgery remained the same, or turned out to be less aggressive."
For men diagnosed with the more aggressive form (Gleason 4 + 3),
the news was also reassuring: Almost half were found to have less
aggressive disease (3 + 4, or less) in their prostates at the time
all Gleason 7 cancers are
alike. Fortunately, most men
have the less aggressive type.
"What this means," Gonzalgo continues,
"is that nearly half of all men diagnosed with the more aggressive
type of prostate cancer on needle biopsy are actually found to have
less aggressive disease. These men are also more likely to have
more favorable outcomes after surgery. In the majority of cases,
prompt diagnosis and treatment will lead to a cure." In futher laboratory
research, Gonzalgo and colleagues are also studying molecular markers
that may help identify men who have a higher risk of having more
aggressive prostate cancer.