Peptide radionuclide therapy (PRRT) demonstrated long-term effectiveness in patients with malignant neuroendocrine tumors, reported authors of a study published in the Journal of Nuclear Medicine.
Many studies have proven the effectiveness of PRRT and its overall response rate is positive, ranging from 70-80% for the two most commonly used radiopharmaceuticals— yttrium-90 (90Y)-DOTATOC and lutetium-177 (177Lu)-DOTATATE. However, long-term patient outcomes are still lacking, according to lead author Michael Gabriel, MD, of the department of nuclear medicine at the Medical University of Innsbruck in Austria, and colleagues.
Gabriel et al. tested 177Lu-PRRT and 90Y-PRRT in 44 consecutive patients (27 men and 17 women) with advanced neuroendocrine tumors and enhanced somatostatin receptor expression. The mean age at diagnosis was 60 years old and median follow-up was 80 months.
When testing 177Lu-PRRT—used for smaller tumors—the mean number of cycles administered was 5.3 ± 2.5. For 90Y-PRRT—favored in larger tumors—the mean cycles administered was 5.5 ± 2.6.
Results showed that median overall survival was 79 months, with 32% of patients still alive more than 12 years after beginning PRRT. The authors noted that patients who respond to PRRT generally have a median time to disease progression of three to four years. Poor prognoses were noted in patients who progressed to disease early after therapy. Women and patients with two tumor sites or less received the most benefits from PRRT.
“This study clearly demonstrates the long-term efficacy of PRRT over more than a decade in patients with metastatic tumor disease of neuroendocrine origin,” said Gabriel and Irene J. Virgolini, MD, also with the Medical University of Innsbruck, in a news release. “PRRT can be repeatedly used with limited side effects. From this perspective, a relatively stable tumor situation can be achieved over many years in a large number of patients. None of the patients who were still alive at the end of the observation period were dialysis-dependent, and most of the patients showed a still very high KPI (key performance indicator), which underlines the positive effect of PRRT in terms of the quality of life.”