Reston, VA (October 13, 2025)--A
new fast and convenient approach to scintigraphy-based monitoring allows physicians
to efficiently and reliably assess prostate cancer progression or regression
during treatment. With this strong prognostic information, treatments for prostate
cancer patients can be personalized according to tumor evolution, significantly
impacting their overall survival. This research was published online in The
Journal of Nuclear Medicine.
177Lu-PSMA is a highly-targeted
radionuclide treatment for metastatic castration-resistant prostate cancer
(mCRPC). Conventional monitoring techniques during 177Lu-PSMA therapy
include analysis of the clinical condition and prostate-specific antigen (PSA)
measurements. PSMA PET/CT is also performed before and during treatment. 177Lu
SPECT imaging after each injection has shown potential for treatment
monitoring, however, it often has long imaging times.
"This drawback makes it challenging to systematically perform
SPECT after each 177Lu-PSMA injection including after the last
injection, which may provide the most substantial prognostic information," said
Laetitia Imbert, PhD, a physicist at Regional University Hospital Center in
Nancy, France. "However, this technical issue can now be largely overcome with
the advent of high-sensitivity 360 cadmium zinc telluride (CZT) SPECT systems,
which enable total-body SPECT recordings in under 20 minutes. Our study sought
to explore this new SPECT approach further in regard to
177Lu PSMA treatment monitoring."
The retrospective study included 72 mCRPC patients who received
up to six 177Lu-PSMA treatments. All patients underwent 68Ga-PSMA-11
PET before initial treatment, had their PSA measured before each injection, and
underwent 177Lu-PSMA CZT SPECT after each injection. Quantitative
image analysis and statistical image analysis were performed to predict overall
survival.
Most PSA, PET, and CZT SPECT variables were significant
univariate predictors of overall survival. However, only two 177Lu CZT
SPECT variables were multivariate predictors: detection of new bone lesions
during treatment and final total lesion activity (TLA). Means of survival times
were 19.7 months in the 19 patients who showed no new bone lesions and a low
level of TLA; 14.4 months in the 19 patients with only one of these two
criteria; and 6.9 months in the 19 patients with neither criterion.
"Fighting cancer is a battle against time, as the disease can evolve rapidly. This new scintigraphy camera will assist in changing
treatment plans for patients who do not respond well, at the earliest stage
possible, noted Caroline Boursier, MD, a physician at Regional University
Hospital Center in Nancy, France. Improvements could be achieved by adjusting
the injected activity of 177Lu-PSMA, substituting this radionuclide
therapeutic agent with an alternative, or combining it with other cancer
treatments such as chemotherapy, external radiotherapy, immunotherapy, or
anti-angiogenic drugs."
She added, "Logistically, monitoring patients with CZT SPECT is
easy to schedule because of the very fast imaging times and the fact that no
additional tracer injection is required. Scintigraphy imaging can therefore
begin as soon as the patient arrives at the nuclear medicine department, and in
our experience, they can leave in less than 30 minutes."