RITA Medical Systems Liver Cancer Survival Data and Lung Cancer Feasibility Data to Be Presented at ASCOMOUNTAIN VIEW, Calif., May 29 /PRNewswire-FirstCall/ -- RITA Medical Systems, Inc. (Nasdaq: RITA) announced today that data from studies on the use of its proprietary radiofrequency (RF) ablation technology in treating patients with lung cancer and colorectal cancer that has spread to the liver are expected to be included in three separate poster presentations on May 31 and June 1 at the 39th Annual Meeting of the American Society of Clinical Oncology (ASCO) at McCormick Place in Chicago.

Allan Siperstein, M.D. of the Cleveland Clinic will present data from a prospective study on predictors of survival after RF ablation of colorectal metastases to the liver. Professor Ricardo Lencioni of the University of Pisa will present data on RF ablation of primary lung cancer. Derek Glenn, M.D. of the University of New South Wales will present data on RF ablation of colorectal metastases to the lung.

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 only local anesthesia.

The Company estimates that the worldwide market opportunity for its products in treating unresectable liver cancer is $500 million and $400 million for treating unresectable lung cancer, in addition to $600 million for treating painful bone metastases.

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 plans to extend its technology to applications beyond the 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.

RITA and StarBurst are trademarks of RITA Medical Systems, Inc.

For further information, please contact: investors, Matt Clawson, matt@allencaron.com, or media, Len Hall, len@allencaron.com, both of Allen &

Caron Inc, +1-949-474-4300, for RITA Medical Systems, Inc.; or Don Stewart, Chief Financial Officer of RITA Medical Systems, Inc., +1-650-314-3400, dstewart@ritamed.com

SOURCE RITA Medical Systems, Inc.