Volumetric Imaging Follow up of Patients With Liver Metastases of Small Intestinal Neuroendocrine Tumors (NETs).

More than 50% of intestinal NETs are metastatic at the time of diagnosis, the liver being the main affected organ in 50-90% of cases. Initial liver tumor burden and slope of the tumor growth rate are two major prognostic factors in patients with intestinal NETs, followed by tumor grade at pathology. They are used in routine practice by oncologists to adapt patient treatment. Unlike other tumors, most NETs metastases are slow-growing tumors. Previous studies have shown that approximately half of the patients diagnosed with liver metastases showed no progression over a period of 3 to 6 months. The aim of this non randomised retrospective cohort study is to investigate whether the volumetric monitoring of the total tumor burden compared to the RECIST 1.1 criteria (used in routine practice by radiologists) at baseline and early follow-up (3 to 6 months) is more suitable for NETs, making possible to predict the prognosis at the onset of the disease, and also allowing a better adaptation of the treatment. The secondary objectives are to evaluate if the initial volume of the liver tumor is a prognostic factor of time to progression, to correlate the initial liver tumor volume and the number of liver lesions to the blood concentration of Chromogranin A (CgA), the presence of extra-abdominal disease and to correlate the tumor growth rate (TGR) and KI 67 (%) at base-line.