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There is no question that our ability
to detect prostate cancer is better than ever. But ask a man who
has had an unnecessary biopsy — or two, or three, which probably means
at least 36 needle sticks in his prostate, a dozen with each biopsy — and
he will tell you that there is still room for improvement. “Today,
the decision to biopsy is driven by abnormal findings on a digital
rectal exam, or a PSA test,” says scientist Alan K. Meeker,
Ph.D. Unfortunately, both of these can be abnormal even if a man
doesn’t have prostate cancer; in scientific terms, they are “lacking
in specificity.”
Worse, although it may feel extremely thorough to
the man who undergoes it, “the biopsy only samples a small
portion of the prostate,” Meeker adds, “and it can miss
cancer.” About one-third of men who turn out to have prostate
cancer have a falsely negative result on their first biopsy. “On
the other hand, many men who have a negative biopsy truly do not
have prostate cancer, despite suspicious physical exam or PSA results.” |
Ask a man who has had an unnecessary
biopsy — or three, which
probably means at least 36 needle
sticks in his prostate — and he’ll
tell you that there is still room for
improvement.
Thus
the biopsy dilemma: “Currently, we lack effective means for
distinguishing patients who are at high risk for harboring cancer
from those who are unlikely to have it.” Which brings us back
to the poor man at the beginning of this story, who has had one or
more repeat biopsies. With every procedure, he and his family experience
anxiety, wondering if there will be cancer this time — and
if so, what should he do — or if it will be another negative
result, with still another biopsy looming on the horizon in the near
future.
Meeker, with colleagues Christian Pavlovich and Kazutoshi
Fujita, is working on a simple urine test that may help. “Prostate
cancer cells can be shed into the urine,” he says, “and
detecting them would provide a convenient, noninvasive means of improving
diagnosis.” In fact, scientists attempted such a test decades
ago, but were unsuccessful. Today’s technology — with
the discovery of new molecular markers for prostate cancer, and new
staining techniques so they can be seen under the microscope — is
much better.
The scientists’ plan is to find the most promising
markers for cell staining, to “combine as many useful markers
as possible to provide a robust method for cancer cell identification,” and
to test them in the lab with human urine samples, Meeker explains.
Once he and colleagues have determined the best way to do the testing,
they will study urine samples collected in the clinic, from men with
suspected prostate cancer who are undergoing their first biopsy. Their
results will then be compared with the pathology results from this
and any subsequent biopsies. “If we are successful, this noninvasive
test will provide valuable additional information to help these men
and their doctors,” says Meeker. |
