Abstract 1116P
Background
Well-differentiated neuroendocrine tumors (NETs) can arise in almost any organ system but are most commonly reported in the gastrointestinal tract or in the lung. Less than 100 cases of NETs arising in the kidney are described in the literature, mostly in form of case reports or small series with very limited information on follow-up, metastasis and systemic treatment.
Methods
The combined prospective and retrospective NET database of our center was retrospectively reviewed for NETs of the kidney presenting between 04/2011 and 03/2021. Poorly differentiated neuroendocrine carcinomas were excluded from the analysis.
Results
Among 1206 patients in the database, 6 patients (3 females) with renal NETs could be identified (median age 51 years, range 42-61). All cases were NET G2 with median Ki67 of 10 %. 4 patients presented with synchronous metastases, the remaining 2 developed metachronous metastases. Most common metastatic sites were lymph nodes and bone. Resection of primary was performed in 3 patients, for metastasis in 3 patients. First-line somatostatin analogue (SSA) treatment was administered to 3 patients, with stable disease (SD) as best response for 7.2 months ongoing, SD with progression after 41.6 months and progressive disease after 3.1 months. Peptide receptor radionuclide therapy was administered to 4 patients (including 2 as first-line treatment because of high symptomatic tumor burden). All patients showed a partial remission for 2.8 months ongoing, 16.1 months ongoing, 16.5 months ongoing and 72.7 months respectively. 1 patient receiving everolimus showed SD with progression after 8.1 months. No patient received chemotherapy. Molecular profiling via whole genome sequencing was performed in one patient. It showed a low tumor mutation burden, however signs of homologous repair deficiency, as well as a loss of PTEN and a deletion of VHL. During a median follow-up of 23.3 months (range 9.7-159.5), all patients were alive.
Conclusions
NETs of the kidney can be considered a very rare disease. While both SSAs and everolimus showed some activity in single patients, especially PRRT can be considered a highly effective treatment. Even in case of advanced metastatic disease, prognosis seems quite favorable.
Clinical trial identification
The trial was approved by the institutional research ethics committee (approvals S-207/2005 and S-428/2014).
Editorial acknowledgement
Legal entity responsible for the study
National Center for Tumor Diseases (NCT) Heidelberg.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.