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