Vatalanib and Octreotide in Treating Patients With Progressive Neuroendocrine Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed low-grade neuroendocrine tumors * The following tumor types are excluded: * Small cell lung cancer * Medullary thyroid cancer * Paraganglioma * Pheochromocytoma * Measurable disease * Radiographic evidence of disease progression after completion of any prior systemic therapy, chemoembolization, bland embolization, or observation within the past year, defined as either of the following: * Appearance of a new lesion * At least 20% increase in the longest diameter (LD) of any previously documented lesion or an increase in the sum of the LDs of multiple lesions in the aggregate of 20% PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,000/mm\^3 * Platelet count ≥ 75,000/mm\^3 * Hemoglobin ≥ 8.0 g/dL Hepatic * Bilirubin ≤ 2.0 times upper limit of normal (ULN) * AST ≤ 3 times ULN (5 times ULN if liver metastases are present) Renal * Creatinine ≤ 1.5 times ULN * Meets 1 of the following criteria: * Urine protein negative by dipstick * Urine protein:creatinine ratio \< 1.0 * Urine protein \< 1 g by 24-hour urine collection Gastrointestinal * Must be able to swallow tablets * No ulcerative disease * No uncontrolled nausea, vomiting, or diarrhea * No bowel obstruction * No other gastrointestinal tract disease resulting in an inability to take oral medication Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Must be able to receive a contrast-enhanced CT scan * No known history of allergic reaction to vatalanib or its derivatives or octreotide injections PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * At least 4 weeks since prior chemotherapy * No more than 1 prior systemic chemotherapy regimen * Chemoembolization is not considered systemic chemotherapy * No concurrent chemotherapy Endocrine therapy * Not specified Radiotherapy * At least 3 weeks since prior radiotherapy * No concurrent radiotherapy Surgery * At least 4 weeks since prior major surgery Other * At least 4 weeks since other prior systemic therapy * At least 4 weeks since prior local liver therapy * No prior anti-vascular endothelial growth factor agents * No concurrent grapefruit or grapefruit juice * No concurrent therapeutic warfarin or similar oral anticoagulants that are metabolized by the cytochrome P450 system * Concurrent heparin allowed