February 20, 2002
Prostate Cancer Imaging Agent Helps
to Detect Recurrence and Spread of Prostate Cancer Earlier, says Cytogen
Findings Published in Journal `Cancer' Show
That ProstaScint(R) Diagnostic Scan, Developed and Marketed by Cytogen
Corporation, Discovers Recurrent Prostate Cancer Before it is Likely to be
Found by Conventional Scanning Methods; Information Could Play Key Role in
study conducted by scientists at Duke University Medical Center and Johns
Hopkins Medical Institutions shows that the use of a prostate cancer
diagnostic imaging agent significantly improves a doctor's ability to detect
the location and extent of recurrent cancer in patients who previously had
their prostates removed. The study results were published in the February
15, 2002 issue of "Cancer."
The study followed 255 prostate cancer patients who were previously treated
with a radical prostatectomy, a procedure in which the entire prostate gland
and some surrounding tissue is surgically removed. Researchers found that
the use of the radiolabeled imaging agent ProstaScint(R) (Capromab Pendetide)
makes it possible to identify the existence and location of recurrent
prostate cancer earlier than using previously available imaging methods such
as a CT (computed tomography) scan. A radical prostatectomy is most often
used to treat localized disease (prostate cancer confined to the gland).
According to the American Cancer Society, nearly 40% of men with prostate
cancer have local recurrence of the disease after surgery, and approximately
11% are at high risk for metastatic spread of the disease.
After undergoing a radical prostatectomy, patients in the study received no
additional therapy and subsequently showed an increase in the level of PSA
(prostate-specific antigen) in their blood as the only indication that their
cancer had recurred. These patients, whose PSA levels ranged from 0.1-4.0 ng/mL,
were then given a ProstaScint scan to localize their disease. The
ProstaScint scan identified recurrent disease in 72% of patients with serum
PSA less than or equal to 4.0 ng/mL. Of patients who also underwent
additional imaging studies, bone and/or CT scans identified recurrence in
only 12% (16/139) and 16% (15/92) of patients, respectively.
"In most instances, conventional imaging modalities such as a CT scan detect
a recurrence of prostate cancer only when a volume of cancer effects changes
to normal anatomic structures, which also indicates a significant advance in
disease progression. This study suggests that a ProstaScint scan may detect
and localize recurrent prostate cancer earlier than previously thought
possible for patients with a low serum PSA after radical prostatectomy,"
said Ganesh V. Raj, M.D., Ph.D., the lead author on the study from the
Division of Urology, Duke University Medical Center.
ProstaScint(R), developed and marketed by Cytogen Corporation (NASDAQ: CYTO)
, is a radiolabeled monoclonal antibody that specifically targets PSMA
(prostate specific membrane antigen), a highly expressed marker found on
prostate cancer cells. During a ProstaScint imaging procedure, the
radiolabeled monoclonal antibody is administered intravenously into the
patient, travels through the bloodstream and binds to prostate cancer cells.
A gamma camera detects the radioactive isotope that has been attached to the
antibody, identifying the specific sites of cancer.
"A better understanding of the location and extent of disease may help to
determine the most appropriate course of therapy for recurrent prostate
cancer and could potentially help certain patients to avoid the risks and
side effects associated with unnecessary or overly-invasive treatments," Dr.
Approximately one in every six men will develop prostate cancer. It is the
second leading cause of cancer death among men in the United States,
exceeded only by lung cancer. The American Cancer Society estimates that
approximately 198,100 new cases of prostate cancer will be diagnosed this
year in the U.S., and that 31,500 men will die of this disease.