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