New Study Shows RITA Medical Systems Radiofrequency (RF) Technology Increases Survival Rates for Patients With Colorectal Cancer That Spread to the Liver and Beyond

June 2, 2003 at 12:00 AM EDT
New Study Shows RITA Medical Systems Radiofrequency (RF) Technology Increases Survival Rates for Patients With Colorectal Cancer That Spread to the Liver and Beyond

MOUNTAIN VIEW, Calif., June 2 /PRNewswire-FirstCall/ -- RITA Medical Systems, Inc. (Nasdaq: RITA - News) today announced that the results of a study conducted at The Cleveland Clinic showed that its proprietary radiofrequency (RF) ablation technology can dramatically improve the overall survival rate for certain patients with colorectal cancer that has spread to the liver even if a limited amount of the disease has progressed outside the liver.

Data from the 135-patient prospective study, which was conducted to determine which patients respond best to the RF treatment, was presented by Allan Siperstein, M.D. of The Cleveland Clinic on June 1 at the 39th Annual Meeting of the American Society of Clinical Oncology (ASCO) at McCormick Place in Chicago. Other investigators included Robert Pelley, M.D., and Eren Berber, M.D., from The Cleveland Clinic.

The study showed the patients treated with RITA RF technology lived much longer -- often double or triple the survival rate -- than those treated with chemotherapy alone when they are treated quickly after the initial diagnosis, have low CEA (Carcinoembryonic Antigen -- a blood test that identifies cancer cells) readings and if the size of the dominant tumor is less than 3 cm in diameter. Furthermore, limited amounts of extra-heptatic (outside the liver) disease "does not appear to adversely affect survival," Dr. Siperstein said.

"This data underscores the fact that radiofrequency ablation is an important and positive adjunct to chemotherapy in patients with colorectal cancer that has spread to the liver," Dr. Siperstein said. "Beyond that, because patients whose disease had advanced outside the liver, into areas such as the lymph nodes or lungs, also responded positively to the treatment, it expands the indications for doing this ablation. We now believe many more patients are good candidates for the RITA treatment."

RITA's RF ablation system enables physicians to deliver monitored and controlled levels of RF energy into the tissue through an array of thin electrodes that heat and effectively destroy, or ablate, the targeted tissue. In many cases, this minimally invasive procedure can be performed with just local anesthesia.

The median (Kaplan-Meier) survival rate of all patients in the study was 28.9 months after RF ablation treatment. Those patients who received the treatment less than a year after their diagnosis had a median survival rate of 34 months and those patients whose dominant tumor was less than 3 cm had a median survival rate of 38 months. Based on historical data, survival rates for similar patients treated with chemotherapy alone is 11-14 months.

The study included patients treated from May 1997 to November 2002 who, like most liver cancer patients, were not appropriate candidates for surgery due either to the extent of the disease or other underlying medical conditions. A total of 80 percent of the patients in the study had experienced tumor progression despite chemotherapy.

Other results of the study included:

  • Patients with a dominant lesion less than 3 cm in diameter had a median survival of 38 months; lesions 3-5 cm had a median survival of 34 months; greater than 5 cm had a median survival of 21 months.
  • atients with a time from diagnosis of metastatic liver cancer to RF ablation of less than one year had a survival rate of 34 months compared to 21 months for those who had the treatment after one year.
  • Patients with a CEA less than 200 ng/ml had improved survival of 34 months; those with a CEA greater than 200 ng/ml had a rate of 16 months.

"This data not only adds to the now substantial body of evidence demonstrating the effectiveness of our RF ablation technology, it expands the market for our treatment," said Don Stewart, Chief Financial Officer of RITA Medical Systems. "We now have a better idea of which patients will respond best to the technology, which is important information for a physician making a recommendation to a patient, and to those patients suffering from an often deadly disease."

About RITA Medical Systems, Inc.

RITA Medical Systems develops, manufactures and markets innovative products for patients with solid cancerous or benign tumors. The proprietary RITA system uses radiofrequency energy to heat tissue to a high enough temperature to ablate it or cause cell death. While the Company's current focus is on liver cancer and metastatic bone cancer, the Company believes that its minimally invasive technology may in the future be applied to other types of tumors, including tumors of the lung, breast, uterus, prostate and kidney. The Company has received regulatory clearance in major markets worldwide, including the United States. In March 2000, RITA became the first radiofrequency ablation company to receive specific FDA clearance for unresectable liver lesions in addition to its previous general FDA clearance for the ablation of soft tissue. In October 2002, RITA again became the first company to receive specific FDA clearance, this time, for the palliation of pain associated with metastatic lesions involving bone. The Company has sold over 45,000 of its disposable devices throughout the world.

The statements in this news release related to the Company's expanded use of its technology in liver are forward-looking statements involving risks and uncertainties that could cause actual results to differ materially from those in such forward-looking statements. Information regarding these risks is included in the Company's filings with the Securities and Exchange Commission.

Source: RITA Medical Systems, Inc.