Inferior outcome of neuroendocrine tumor patients negative on somatostatin receptor imaging

Refardt, J., Zandee, W. T., Brabander, T., Feelders, R. A., Franssen, G. J. H., Hofland, L. J., Christ, E., de Herder, W. W. & Hofland, J., Nov-2020, In : Endocrine-Related cancer. 27, 11, p. 615-624 10 p.

Research output: Contribution to journalArticleAcademicpeer-review

  • Julie Refardt
  • Wouter T Zandee
  • Tessa Brabander
  • Richard A Feelders
  • Gaston J H Franssen
  • Leo J Hofland
  • Emanuel Christ
  • Wouter W de Herder
  • Johannes Hofland

Sufficient expression of somatostatin receptor (SSTR) in well-differentiated neuroendocrine tumors (NETs) is crucial for treatment with somatostatin analogs (SSAs) and peptide receptor radionuclide therapy (PRRT) using radiolabeled SSAs. Impaired prognosis has been described for SSTR-negative NET patients; however, studies comparing matched SSTR-positive and -negative subjects who have not received PRRT are missing. This retrospective analysis of two prospectively maintained NET databases aimed to compare matched metastatic grade 1 or 2 SSTR-positive and -negative NET patients. SSTR-negativity was defined as having insufficient tumor uptake on diagnostic SSTR imaging. Patients that underwent PRRT were excluded. Seventy-seven SSTR-negative and 248 SSTR-positive grade 1-2 NET patients were included. Median overall survival rates were significantly lower for SSTR-negative compared to SSTR-positive NET patients (53 months vs 131 months; P < 0.001). To adjust for possible confounding by age, gender, grade and site of origin, 69 SSTR-negative NET patients were propensity score matched to 69 SSTR-positive NET patients. Group characteristics were similar, with the exception of SSTR-negative patients receiving more often chemotherapy and targeted treatment. The inferior survival outcome of SSTR-negative compared to SSTR-positive NET patients persisted with a median overall survival of 38 months vs 131 months (P = 0.012). This relationship upheld when correcting for the main influencing factors of having a higher grade tumor or receiving surgery in a multivariate Cox regression analysis. In conclusion, we showed that propensity score-matched SSTR-negative NET patients continue to have a worse prognosis compared to SSTR-positive NET patients despite receiving more aggressive treatment. Differences in tumor biology likely underlie this survival deficit.

Original languageEnglish
Pages (from-to)615-624
Number of pages10
JournalEndocrine-Related cancer
Issue number11
Publication statusPublished - Nov-2020
Externally publishedYes

ID: 146262190