A patient with a VEGF and endostatin producing gastrointestinal autonomic nerve tumour

Gastrointestinal autonomic nerve tumors: a clinical review

PURPOSE

Gastrointestinal autonomic nerve tumors (GANTs) are believed to be rare accounting for 1 % of all malignant gastrointestinal tumors. Many gastrointestinal surgeons and gastroenterologists are unaware of this entity. This review aims to highlight the salient clinical features and prognosis of GANTs.

METHODS

Using the common search engines and manual cross-referencing, a search of the English literature was conducted for "gastrointestinal autonomic nerve tumor."

RESULTS

All of the published literature on GANTs is either case reports or small case series. From 49 retrieved articles, a total of 107 GANT cases were collected with a mean age of 54 years and equal male to female preponderance. The most commonly affected site was small bowel followed by stomach. Esophageal and colorectal GANTs were less frequent. Clinical presentation was variable ranging from non-specific symptoms, abdominal pain, weight loss, iron-deficiency anemia, to obstruction and gastrointestinal bleeding. Acute presentation due to free rupture or perforation with subsequent peritonitis was extremely rare. Endoscopic and radiological investigations were valuable in tumor localization and determination of distant spread. Thirteen patients were lost to or had no follow-up, leaving 94 patients for long-term outcome analysis. All patients were treated by radical surgical resection of the involved organ as this offered the only hope of cure. Local recurrence, metastases, or both developed in 40 % of cases despite radical surgical resection. Resection for local recurrences and hepatic metastases was feasible in some selected cases. Response to adjuvant chemoradiation was poor and imatinib mesilate was effective in cases of metastatic or inoperable CD117-positive GANTs.

CONCLUSION

Radical surgical resection of GANTs is the mainstay of treatment. The aggressive behavior after radical resection coined with the poor response to adjuvant chemotherapy call for the urgent need to develop new adjuvant therapies.

Recombinant human endostatin administered as a 28-day continuous intravenous infusion, followed by daily subcutaneous injections: a phase I and pharmacokinetic study in patients with advanced cancer

BACKGROUND

Endostatin is an endogenous collagen XVIII-fragment with anti-angiogenic properties and remarkable antitumor activity in mice. Preclinical data suggest that continuous low dose administration of endostatin is much more potent than intermittent dosing. The feasibility of this approach is tested in a phase I study.

PATIENTS AND METHODS

We determined the safety and pharmacokinetic profile of 4-week continuous intravenous infusion of recombinant human (rh)-endostatin, followed after an interval of 1 week by twice daily subcutaneous injections in patients with advanced cancer. Thirty-two patients received rh-endostatin in six dosing cohorts, ranging from 3.75 mg/m(2)/day to 120 mg/m(2)/day. Serum endostatin pharmacokinetics, toxicity and antitumor response were determined.

RESULTS

A total of 160 cycles were delivered without significant toxicities. Pharmacokinetic analysis showed a linear increase of steady-state serum endostatin concentrations with dose (i.v. r(2)=0.96; s.c. r(2)=0.99) reaching 300--1,000 ng/ml for the two highest doses, with considerable interpatient variation. The main pharmacokinetic values for both routes of administration were similar. The apparent steady-state concentration and AUC reached at 60--120 mg/m(2)/day were within the range expected to induce anti-angiogenic and antitumor effects based on preclinical tumor models. Although no objective responses were observed, two patients had long-lasting stable disease (defined as a tumor increase<100%).

CONCLUSION

rh-endostatin was safely administered both by continuous infusion and by twice daily subcutaneous injections up to 120 mg/m(2)/day. Predictable pK was seen in this dose range and the target endostatin levels were reached from 60 mg/m(2)/day and above.