hi folks - in a nutshell, what this article says is that they are doing
tests that are  can detect was reasonable accuracy the cancer lesions
that may not show up on other tests.  the agent is absorbed into the
cancer cell tissue fairly quickly.  this test can tell if the cancer is
active or not
it also has shown that the prostate cancer cell with respond to a
medicine after one dose.  

they did not use a lot of people in these tests, so one will have to
remember that the results may be possibly skewed, but i felt it was
worth posting.   the article is below.

~ curtis

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two studies support the feasibility of using
(18F)-fluorodihydrotestosterone (FDHT)-positron emission tomography
(PET) to image prostate cancer, and they suggest a potential role for
the FDHT to predict response to hormonal therapy.

Steven Larson, MD from Memorial Sloan-Kettering Cancer Center in New
York CIty and lead author on the paper, said those results indicated the
presence of functioning androgen receptors.

in their paper, the researchers concluded that "FDHT is a promising
tracer for evaluation of the role of AR in the biology of the
progression of metastatic lesions of prostate cancer in castrate
patients."

in a phone interview with Medscape, Dr. Larson said, "now for the first
time, we have a way to look inside the prostate cancer cells to see if
there is this very important switch."  referring to the androgen
receptors, "it's a control for growth and proliferation of those cells.
When it's active it's not a good sign.  it means the cells is active."

FDHT is rapidly metabolized, "with 80% conversion within 10 to a
radiolabeled metabolite that circulated bound to plasma proteins.  tumor
uptake was also rapid, (with 80% uptake at 10 minutes) suggesting that
FDHT was the active radiopharmaceutical for targeting, and tumor
retention was prolonged."

a total of 59 lesions were identified using a combination of
conventional imaging procedures.  of the lesions, FDG-PET was positive
in 58 (98.9%) of 59 lesions.

FDHT-PET was positive in 46 (78%) of 58 lesions,.  testosterone therapy
in two patients led to markedly reduced FDHT uptake.

in a second study, by Farroh Dehdashti. MD, associate professor of
radiology in the Division of Nuclear Medicine at Washington University
School of Medicine,  15 patients with advanced prostate cancer were
scanned with FDHT-PET, bone scintigraphy, and computer tomography (CT).
ten of the 15 patients with aggressive disease had tumors that took up
FDHT.

FDHT-PET revealed numerous lesions in two patients.  one had widespread
osseous, which was confirmed by bone scintigraphy, and one had extensive
lymph node metastases, which was confirmed by CT.

in the eight remaining patients, 10 of 16 known osseous lesions were
shown on FDHT-PET, which were confirmed on bone scintigraphy, and also
detected all nine lymph node metastases that had been seen on CT.

in two additional patients, FDHT-PET found more extensive nodal
involvement (seven more lesions) and unsuspected lymph node metastatic
disease in one patient (six lesions).

according to the abstract. "all 10 of these patients underwent repeat
FDHT-PET after receiving flutamide for one day (250mg t.i.d.)  in all of
these patients, there was a decrease in tumor FDHT uptake after
flutamide.  

the results translates into a mean drop in intensity of about 60% after
one single dose of flutamide,  "so, does this early response to fluamide
predict the long-term therapy response to hormonal therapy?  well,
that's a study that needs to be done."  Dr Hagga said.     Meanwhile,
she noted, tumors that disappear on FDHT-PET might still be visible on
CT scan or FDG-PET.  "so this is a  very early indicator that
something's really going on in these cancers."

knowledge is power - growing old is mandatory - growing wise is optional