SNMMI 2018: Effect of Targeted Radionuclide Therapy on Metastasis in Prostate Cancer
Posted: Friday, July 13, 2018
The effect of the targeted radionuclide therapy Lu-177-PSMA-617 (Lu-PSMA)on metastasized castration‑resistant prostate cancer and patients’ bone and lymph node metastases is “a complex therapeutic response” that depends on the individual’s pattern of metastasis, concluded Philip A. Taeger, MD, of the University Hospital Cologne, Germany, and colleagues. They presented their study findings at the 2018 Society of Nuclear Medicine and Molecular Imaging (SNMMI) Annual Meeting in Philadelphia (Abstract 523).
The researchers attempted to evaluate the effect of up to three cycles of Lu-PSMA specifically on bone (osseous) metastases versus lymphatic metastases. They used positron-emission tomography scans before, during, and after therapy (mean of 2.7 cycles) but found the results of their 20-patient study to be less than clear-cut.
“Lu-PSMA therapy shows therapeutic effect on the viability of osseous metastases (in terms of maximum PSMA expression) in most cases, however without completely preventing expansion of metastatic disease,” wrote Dr. Taeger and his team. “Regarding [lymphatic metastases], PSMA therapy appears to result in more distinct regression in size and maximum [standardized uptake value]. However, 25% of patients showed new lymphatic metastases despite response of existing lesions.”
In addition, the value of prostate-specific antigen monitoring as a “suitable response parameter” was questionable, according to the authors. “Therapy effects on [standardized uptake value], affected bone volume, and lymph node diameters were mostly independent of [prostate-specific antigen] response.”
The men’s average age was 71.1 years, with a mean disease duration of 6.7 years.