Thalidomide in Treating Patients Who Have Undergone Surgery and Chemotherapy for Cancer That Has Spread Throughout the Abdomen Due to Colorectal Cancer or Appendix Cancer

DISEASE CHARACTERISTICS: * Pathologically confirmed peritoneal carcinomatosis or adenomucinosis secondary to colorectal or appendiceal cancer * Underwent cytoreductive surgery and intraperitoneal hyperthermic chemotherapy (IPHC) within the past 12 weeks * Patients with residual disease or no evidence of disease after IPHC are eligible * No extra-abdominal disease or parenchymal liver metastases PATIENT CHARACTERISTICS: * ECOG performance status 0-3 * Free of infection or postoperative complications * Hemoglobin \> 8.0 g/dL * Absolute neutrophil count \> 1,000/mm³ * Platelet count \> 100,000/mm³ * PTT or PT \< 1.5 times normal (except in patients who are receiving therapeutic anticoagulant therapy for non-related medical conditions, such as atrial fibrillation) * Bilirubin \< 1.5 mg/dL OR direct bilirubin ≤ 1.0 mg/dL (for patients with Gilbert's syndrome) * AST/ALT ≤ 2.5 times normal * Serum creatinine \< 2.0 mg/dL * No peripheral neuropathy \> grade 1, except localized neuropathy due to a mechanical cause or trauma * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use 2 effective methods of contraception for 4 months prior to, during, and for 4 months after treatment with thalidomide * No history of hepatic cirrhosis * No history of severe hypothyroidism * No history of medical problem such as severe congestive heart failure or active ischemic heart disease * No other malignancy within the past 5 years except nonmelanoma skin cancer * No known history of deep vein thrombosis or pulmonary embolus PRIOR CONCURRENT THERAPY: * More than 4 weeks since prior chemotherapy, biologic therapy, or radiotherapy (except for IPHC) * No other concurrent systemic therapy * No concurrent high level sedatives * No concurrent sedating "recreational" drugs or alcohol