SONOGRAPHICALLY GUIDED MICROWAVE COAGULATION TREATMENT OF LIVER-CANCER - AN EXPERIMENTAL AND CLINICAL-STUDY

OBJECTIVE. Percutaneous microwave coagulation was performed with a mod ified system in animal experiments and in a clinical study to evaluate this technique as a treatment option for liver cancer. SUBJECTS AND M ETHODS. As an in vitro study, a microwave electrode was inserted 56 cm into separated egg white, homogenate of pig liver, and pig liver, wit h different power outputs and different lengths of inner conductors. I n the animal experiment, the sonographically guided coagulation was pe rformed percutaneously nine times and at laparotomy 43 times on 17 adu lt dogs. The thermal needles were placed parallel to and 5 mm, 8-12 mm , and 15 mm from the electrode. Clinically, 41 patients with hepatocel lular carcinoma and 10 patients with hepatic metastases were treated w ith a 60-W microwave emission for 240-300 sec. RESULTS. Microwave coag ulation using the modified system at 60 W for 300 sec produced a necro sis volume of 3.7 x 2.6 x 2.6 cm. The coagulated volume was elliptic w hen the exposed inner conductor of the electrode was 27 mm. The temper ature at the periphery was 62.0 + 5.8 degrees C. During a mean follow- up period of 23 months, in 41 patients with hepatocellular carcinoma, 79% (46/58) of lesions became smaller, and the intratumoral blood flow disappeared in 89% (47/53). All tumors showed decreased density on un enhanced CT, and 84% (32/38) of tumors showed no enhancement on contra st-enhanced CT. In 21 patients with an elevated a-fetoprotein level, t he level decreased in all 21 and was normalized in 17. A second biopsy on 19 patients showed complete destruction of tumor in 18. In 10 pati ents with hepatic metastases, the mean follow-up period was 13 months. Shrinkage of lesions occurred in 84% (21/25), and the blood flow insi de the tumor disappeared in 75% (12/16) of lesions. Seventy-three perc ent (8/11) of the nodules showed no enhancement. A second biopsy on si x patients showed complete necrosis in five. CONCLUSION. Sonographical ly guided microwave coagulation performed with this modified system wa s an effective and safe treatment for liver cancer.