Analysis of outcome in patients with different primary localisation of neuroendocrine tumors after PRRT. 10 years single institution experience.
PRRT shows potential in delaying disease progression in advanced neuroendocrine neoplasms, but its impact on overall survival is limited.
Where it sits
this study against the rest of the octreotide corpusSummary and findings
This retrospective study analyzed outcomes in 32 patients with metastatic neuroendocrine neoplasms treated with peptide receptor radionuclide therapy. The treatment involved Lutetium-177-DOTA-TATE and/or Yttrium-90-DOTA-TOC, with a median of 4 cycles per patient. Disease progression was observed in 28% of patients, stable disease in 50%, and partial remission in 22%.
Abstract
The aim of this retrospective study is to analyze the outcome and survival of patients with well-differentiated metastatic neuroendocrine neoplasm (NEN) treated with peptide receptor radionuclide therapy (PRRT). The treatment was applied to 32 subjects, 18 men and 14 women, aged 39-79 years (median 65 years). The dominant grade of the tumor according to the Ki-67 index was G2 (75%) compared to G1 (25%). The average number of three-day protocol PRRT cycles was 4 (1.00-9.00). Lutetium-177- DOTA0,Tyr3,Thr8-octreotide (177Lu-DOTA-TATE) was used in 22 (69%), both 177Lu-DOTA-TATE and yttrium-90-DOTA0,Tyr3-octreotide (90Y-DOTA-TOC) in 8 (25%), and 90Y-DOTA-TOC in 2 (6%) patients. No adverse effects of PRRT were recorded excerpt one patient who has died soon after the first therapy due to ileus after surgery. Response to PRRT according to response evaluation criteria in solid tumors (RECIST) 1.1. criteria showed that 9 (28%) patients had disease progression, 16 (50%) had stable disease, and 7 (22%) had partial remission. Significantly shorter time until progression or death of 18 months was detected for patients with disease progression than for other groups with stable disease (34.5 months, P<0.02) and partial remission (35 months, P<0.05). However, the values obtained for overall survival were not significantly different between the studied groups being 33 months in subjects with disease progression, and 34.5 and 35 months in groups with stable disease and partial remission, respectively. In 6 subjects, an asymptomatic low hemoglobin level was detected that did not require intervention (Grade1). In 2 subjects, nephrotoxicity occurred with glomerular filtration rate (GFR) values below 30mL/min/1.73m2 (Grade3). It can be concluded that PRRT according to a three-day nephroprotection protocol is a reliable and safe method of treatment for advanced NEN. Longer time to disease progression and overall survival in most patients underline the great potential of this treatment method in patients with advanced NEN.
Background
This study addresses the outcomes of peptide receptor radionuclide therapy (PRRT) in patients with well-differentiated metastatic neuroendocrine neoplasms (NEN). PRRT is a targeted treatment option for NENs, which are often difficult to treat due to their varied presentation and progression. Understanding the effectiveness and safety of PRRT in this patient population is crucial for optimizing treatment strategies.
Methods
The study is a retrospective analysis conducted at a single institution over a 10-year period. It included 32 patients with well-differentiated metastatic NENs, predominantly with G2 tumors. Patients received a median of 4 cycles of PRRT using Lutetium-177-DOTA-TATE and/or Yttrium-90-DOTA-TOC. The primary outcomes measured were disease progression, stable disease, and partial remission according to RECIST 1.1 criteria.
Results
The primary endpoint showed that 28% of patients experienced disease progression, 50% had stable disease, and 22% achieved partial remission. The time to progression or death was significantly shorter for patients with disease progression (18 months) compared to those with stable disease (34.5 months, P<0.02) and partial remission (35 months, P<0.05). Overall survival did not differ significantly between groups, with median survival times of 33 months for progression and 34.5 to 35 months for stable disease and partial remission.
Interpretation
The study suggests that PRRT can stabilize or partially remit disease in a significant portion of patients with advanced NENs, although the overall survival benefit appears limited. The effect size for time to progression is statistically significant but may not translate into a substantial clinical advantage given the similar overall survival across groups. The retrospective design and small sample size limit the generalizability of the findings.
Key findings
- 32 patients, aged 39-79 years, median 65 years.
- 75% had G2 tumors, 25% had G1 tumors.
- 69% received 177Lu-DOTA-TATE, 25% received both 177Lu-DOTA-TATE and 90Y-DOTA-TOC.
- 28% had disease progression, 50% had stable disease, 22% had partial remission.
- Time to progression or death: 18 months for progression, 34.5 months for stable disease, 35 months for partial remission, P<0.02.
Limitations
- Retrospective design
- Small sample size (n=32)
- Single institution study
- No significant difference in overall survival
- Limited generalizability