Liver cancer is a challenging problem in the US and worldwide, but UCSF/Mount Zion researchers are hopeful a new treatment under study will provide a better option for persons with liver cancer.

The surgical treatment uses radiofrequency energy like that in conventional operating-room electrosurgical units and is delivered through special probes designed to heat tumor tissues. The instrument is developed by RITA Medical Systems, Inc., of Mountain View, Calif.

Heat is an effective way to kill cells, research has demonstrated. As tissue temperatures rise above 113-degrees Fahrenheit (60-65 degrees Celsius), protein is permanently damaged and cell membranes fuse, causing cellular death.

The UCSF/Mount Zion liver tumor study, headed by Allan Siperstein, MD, is investigating a novel method of delivering heat to the liver to treat liver tumors. The process involves delivering electrical energy to target tissues via a 15-gauge catheter that deploys four prongs to encompass and heat a sphere of tissue 3-4 cm in diameter. The cells die within 15 minutes. The surgery is performed laparacopically.

"The purpose of our initial study is to see whether we can ablate (eradicate) the tumor successfully and do it safely," Siperstein says.

The treatment has shown so far to be both safe and effective in providing local control of liver tumors in initial studies involving 16 patients. Now, researchers will examine whether the treatment can have an impact on long-term survival. While survival rates have yet to be studied, Siperstein and his team maintain that this procedure may improve the quality of life for patients.

Because the procedure is done laparoscopically, "Our patients have been able to go home the next day," Siperstein says. To date, there have been no complications of bleeding, significant pain or abscess formation.

Although the gold standard of surgical tumor excision is always the preferable method, 80 percent of liver tumors are not amenable to surgery at the time of diagnosis. Many other options, including chemotherapy and localized therapy have been tried, but few are optimal.

In recent years, surgeons have turned to cryosurgery, in which cells are frozen and thawed to reduce the tumor. While the technique is effective, the cryoprobes are big and result in a more invasive surgery.

More recently, pioneering surgeons in Italy began conducting studies applying heat via radiofrequency probes. Surgeons at UCSF/Mount Zion are among the first in the world to use the technique. Patients are currently being evaluated and enrolled in clinical trials.

The UCSF/Mount Zion surgical team conducting the study is comprised of Allan Siperstein, MD, Kristen Engle, MD, Stanley Rogers, MD, Barbara Klencke, MD, and Tamara Ryan, RN.

Patients with primary or metastatic malignancies of the liver are candidates for treatment. Physicians who have patients who might benefit from the treatment or patients who are interested may contact Tamara Ryan, RN, clinical research coordinator at (415) 885-7816.

By Dale Martin

1st appeared 08/21/97