The Prognostic Value of Fdg-pet Scan in Neuro-endocrine Tumours. a Retrospective Analysis of 46 Patients Treated in One Centre
(2010) 12th World Congress on Gastrointestinal Cancer — Location: Barcelona (Spain) (30.June.2010)
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- Abstract
- [Background:] Neuro-endocrine tumours (NET) are rare and generally indolent tumours. For diagnostic purpose, the sensitivity of FDG-PET scan is known to be low in this setting. Though, when positive, its prognostic value is not well defined in NET. Aim: To assess the value of FDG-PET on the prognosis of patients diagnosed with neuro-endocrine tumours, treated and followed-up in one centre (Cliniques universitaires Saint-Luc, Brussels, Belgium). [Methods:] A retrospective analysis of all NET patients that benefited of a FDG-PET scan and Octreoscan during their diagnostic work-up was made. Data regarding origin of the tumour, pathology characteristics (Ki67 proliferation index) were analyzed according to FDG-PET positive or negative status. From 1999 until 12/2009, 46 patients (30 males), 55±15 years, had one FDG-PET scan; 43/46 had also an Octreoscan. They consisted of 26 pancreatic tumours, 9 midgut tumours, 2 duodenum, 2 main biliary tract, one lung, one stomach, one liver and 3 unknown primary NET. We looked at overall survival (OS) and time-to-therapeutic failure (TTF), which we defined as radiologic progression leading to a change in therapy. Survival and TTF curves were estimated according to the Kaplan-Meier method and compared with the Log-Rank test. A p value <0.05 was considered significant. Results: FDG-PET was positive in 26/46 (59%) and Octreoscan in 33/43 (77%). Rates of positive PET scans were comparable formidgut (57%) and pancreatic tumours (64%). After a median follow-up of 31,5 months (3-108 months), median OS of patients with negative FDG-PET was not reached whereas survival of patients with positive FDG-PET scans was 72 months; the difference was not statistically different (p=0.13). However, we could show an important and statistically significant difference in TTF: 19 months vs 88 months for patients with positive and negative FDG-PET respectively (p=0.014). Patients with positive FDG-PET had tumours with significantly higher proliferation rates, assessed by Ki67 values found at histology, compared to negative FDG-PET patients: 28±6% vs 7±1% (mean±SE, p=0.007). Patients with positive Octreoscan had a mean Ki67 of 26±10% vs 17±5% for Octreoscan negative patients (NS). No association was found between presence/absence of functional symptoms, metastatic status at diagnosis or origin of the primary tumour and FDG-PET scan status. [Conclusion:] In this retrospective series, we found a significant correlation between FDG-PET scan positivity and shorter TTF of NET patients. This was independent from metastatic status or primary tumour origin. Patients with positive FDG-PET scans had significantly more aggressive tumours as assessed by Ki67. These results suggest that FDG-PET could eventually be used to guide therapy when histology and Ki67 value cannot be obtained, and orientate clinicians to a more close follow-up after curative treatment. These results warrant confirmation in a prospective setting to further strengthen the value of FDG-PET in NET.
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Sacré, F., Lhommel, R., Lonneux, M., Gigot, J.-F., Sempoux, C., Borbath, I., Jouret-Mourin, A., & Fiasse, R. (2010). The Prognostic Value of Fdg-pet Scan in Neuro-endocrine Tumours. a Retrospective Analysis of 46 Patients Treated in One Centre. Annals of Oncology, 21(S6), 100-101. https://hdl.handle.net/2078.5/232041 (Original work published 2010)