Analysis of outcome in patients with different primary localisation of neuroendocrine tumors after PRRT. 10 years single institution experience.

OBJECTIVE

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).

SUBJECTS AND

METHODS

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.

RESULTS

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).

CONCLUSION

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.