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Background: Radioembolization (RE) with intra-arterial administration of 90 Y microspheres is a promising technique for the treatment of liver metastases from small intestinal neuroendocrine tumors (SI-NET) not amenable to surgery or local ablation. However, studies comparing RE to other loco-regional therapies are lacking. The aim of this randomized study was to compare the therapeutic response and safety after RE and bland hepatic arterial embolization (HAE), and to investigate early therapy-induced changes with diffusion-weighted MRI (DWI-MRI)., Methods: Eleven patients were included in a prospective randomized controlled pilot study, six assigned to RE and five to HAE. Response according to RECIST 1.1 using MRI or CT at 3 and 6 months post-treatment was recorded as well as changes in DWI-MRI parameters after 1 month. Data on biochemical tumor response, toxicity, and side effects were also collected., Results: Three months after treatment, all patients in the HAE group showed partial response according to RECIST while none in the RE group did (p = 0.0022). After 6 months, the response rates were 4/5 (80%) and 2/6 (33%) in the HAE and RE groups, respectively (NS). DWI-MRI metrics could not predict RECIST response, but lower pretreatment ADC (120-800) and larger ADC (0-800) increase at 1 month were related to larger decrease in tumor diameter when all tumors were counted., Conclusion: HAE resulted in significantly higher RECIST response after 3 months, but no difference compared to RE remained after 6 months. These preliminary findings indicate that HAE remains a safe option for the treatment of liver metastases from SI-NET, and further studies are needed to establish the role of RE and the predictive value of MR-DWI.

Purpose: Knowledge of natural tumour growth is valuable for understanding tumour biology, optimising screening programs, prognostication, optimal scheduling of chemotherapy, and assessing tumour spread. However, mathematical modelling in individuals is hampered by the limited data available. We aimed to develop a method to estimate parameters of the growth model and formation rate of metastases in individual patients., Materials and Methods: Data from one patient with liver metastases from a primary ileum carcinoid and one patient with lung metastases from a primary renal cell carcinoma were used to demonstrate this new method. Metastatic growth models were estimated by direct curve fitting, as well as with the new proposed method based on the relationship between tumour growth rate and tumour volume. The new model was derived from the Gompertzian growth model by eliminating the time factor (age of metastases), which made it possible to perform the calculations using data from all metastases in each patient. Finally, the formation time of each metastasis and, consecutively, the formation rate of metastases in each patient were estimated., Results: With limited measurements in clinical studies, fitting different growth curves was insufficient to estimate true tumour growth, even if patients were followed for several years. Growth of liver metastases was well described with a general growth model for all metastases. However, the lung metastases from renal cell carcinoma were better described by heterogeneous exponential growth with various growth rates., Conclusion: Analysis of the regression of tumour growth rate with the logarithm of tumour volume can be used to estimate parameters of the tumour growth model and metastasis formation rates, and therefore the number and size distribution of metastases in individuals.

Background: Hepatic artery embolization (HAE) is a palliative treatment for patients with liver metastases from neuroendocrine tumours. HAE reduces hormonal symptoms, but its impact on survival has been questioned., Methods: Biochemical responses and survival in consecutive patients with disseminated liver metastases from midgut carcinoid tumours were studied after HAE. Repeat HAE was performed in selected patients with radiological and biochemical signs of progression., Results: Of 107 patients who had HAE, the median survival from the first procedure was 56 (range 1-204) months. Prolonged survival showed a strong correlation with reduction of urinary 5-hydroxyindoleacetic acid (P = 0.003) and plasma chromogranin A (P = 0.001) levels. The biochemical response to repeat HAE was similar to that for the first procedure (P = 0.002). The complication rate was low (7.5 per cent), as was the mortality rate (1.9 per cent) within 1 month of HAE., Conclusion: HAE is safe, provides good control of hormonal symptoms, and prolongs survival in biochemically responsive patients. It is a valuable palliative option for patients with midgut carcinoid syndrome due to liver metastases and can be repeated in patients with a favourable response to the first procedure., (2009 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)

Several neuroendocrine tumours, such as carcinoids and pancreatic endocrine tumours, may manifest relatively slow tumour growth. The patients may suffer from severe hormonal symptoms, largely due to liver metastases which sometimes are amenable to cytoreductive surgery. If residual tumour after primary tumour resection is multilobar, liver transplantation may be one way to treat hormonal symptoms and possibly prolonging survival. Early long-term outcome of liver transplantation in patients with neuroendocrine tumours suggests prognosis to be more favourable for carcinoids than for endocrine pancreatic tumours. It is suggested that liver transplantation may be appropriate for patients with isolated hepatic tumour disease in the following situations: 1, tumour recurrence after liver surgery for cure; 2, non-resectable liver disease, especially in cases of severe hormonal symptoms; and 3, disease progression after hepatic arterial embolisation and medical therapy. These indications are discussed in the light of three case reports.

The survival of 64 consecutive patients with disseminated midgut carcinoid tumours was compared in a retrospective study with that of 25 consecutive patients with sporadic malignant endocrine pancreatic tumours treated according to similar surgical principles. The presence of hepatic metastases implied a worse prognosis in neuroendocrine tumours of pancreatic rather than midgut origin. This infers that these tumour types must be separated when treatments are evaluated.