RATIONALE: Heating tumors to several degrees above body temperature may kill tumor cells.

PURPOSE: Phase II trial to study the effectiveness of heat therapy in treating patients who have unresectable primary or metastatic liver cancer.

OBJECTIVES: I. Determine the efficacy of radiofrequency ablation in patients with primary or metastatic liver cancer. II. Determine disease free survival, local recurrence rate in treated lesions as compared to known recurrence rates after hepatic cryoablation, and overall survival in this patient population receiving this regimen.

OUTLINE: Patients undergo laparoscopic or open laparotomy surgical procedure to identify unresectable tumors by ultrasound. Tumors are heated to a target temperature by electrodes for a maximum of 20 minutes. To achieve a 1 cm margin of ablated tissue around each lesion, multiple ablation courses may be performed, depending on the size of the lesions and the time required to complete the treatment. Patients may be retreated if tumor recurs or new disease appears. Patients are followed at 1 month, every 3 months for the first 2 years, every 6 months for next 3 years, and then annually thereafter.

PROJECTED ACCRUAL: A maximum of 59 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Diagnosis of unresectable malignant primary or metastatic liver tumors Tumors are deemed unresectable based on the following factors: 1-10 liver tumors Bilobar liver tumors Location of 1 or more lesions near a major intrahepatic vascular structure (hepatic vein, portal vein, vena cava) Severe cirrhosis to preclude a major liver resection No unresectable extrahepatic disease Prior failure of other therapeutic modalities allowed No more than moderate ascites No hepatic encephalopathy

PATIENT CHARACTERISTICS: Age: Any age Performance status: Zubrod 0-1 Life expectancy: At least 3 months Hematopoietic: Not specified Hepatic: No severe liver dysfunction (Child's Class C) Bilirubin no greater than 3.0 mg/dL Albumin no greater than 3.0 mg/dL PT no greater than 50% above normal Renal: No renal dysfunction Creatinine less than 2.0 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No altered mental status No active infection

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks since prior chemotherapy Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since prior radiotherapy Surgery: See Disease Characteristics