MOUNTAIN VIEW, Calif., Dec. 4 /PRNewswire-FirstCall/ -- RITA Medical Systems, Inc. (Nasdaq: RITA) announced today that the results of a multi-center study on the use of its proprietary radiofrequency (RF) ablation technology confirm that the minimally invasive procedure provides cancer patients with effective, rapid and durable relief from the pain that often occurs when cancer spreads to the bone. Data from the study, which was conducted at nine centers in the United States, Italy, Germany and France, were presented at the Radiology Society of North America (RSNA) 88th Scientific Assembly and Annual Meeting, being held in Chicago December 1-6, by Matthew Callstrom, M.D., Ph.D. Dr. Callstrom is a radiologist at Mayo Clinic. Earlier results from this study had been presented at the 38th Annual Meeting of the American Society of Clinical Oncology (ASCO) held in Orlando, Florida in May 2002.

The study involved 62 patients with cancer that had spread or metastasized to the bone and who had either failed or were not eligible for conventional pain-relieving treatments, including radiation and opioid analgesics. These patients were treated using RITA Medical Systems' RF ablation system. This system enables physicians to deliver monitored and controlled levels of RF energy into the tissue through an array of thin electrodes that heat and destroy, or ablate, the targeted tissue. In many cases, this minimally invasive procedure can be done with just an overnight stay.

In the study, 95 percent of the patients had a clinically significant reduction in their pain. Patients were asked to report their pain on a standard 10-point pain rating scale before and after the procedure with 10 being pain 'as bad as you can imagine.' Half the patients achieved significant relief in just four weeks, with an average pain reduction of 69 percent at 24 weeks. Follow-up on these patients indicates they continue to enjoy significant pain relief up to six months after their RF treatment.

The study was conducted at nine centers including Mayo Clinic, Johns Hopkins Hospital, M.D. Anderson Cancer Center, Northwestern Memorial Hospital, St. Luke's Medical Center, Cancer Institute, Turin, Italy, Orthopedic Trauma, Florence, Italy, Institute for Microtherapy, Bochum, Germany and Gustave- Roissy, Paris, France.

William Charboneau, M.D., a radiologist at Mayo Clinic in Rochester, Minnesota and the senior investigator of the recent study, said the study shows that the RF system provides an effective, rapid and durable method for treating pain from localized metastases involving bone. "This study provides evidence that the RF procedure is safe, the relief of pain is dramatic and should provide an alternative for the palliation of painful bone metastases when standard treatments fail," said Charboneau.

The most common site of the spread of cancer is the bone, and as many as 50 percent of patients with this condition suffer debilitating pain that is not adequately relieved by any conventional means. This study follows the company's recent FDA clearance, which enables it to specifically market its products as a means of relieving pain caused by metastatic bone tumors and opens a new market opportunity for RITA's RF system that is estimated by the company at $600 million annually worldwide.

Barry Cheskin, RITA's President and Chief Executive Officer, said that with the results of this study and the recent FDA clearance, the company is officially launching its products for use in bone. "This is a new market for RITA which is as large or larger than our existing market for liver cancer. This is a very exciting time for the company as we are able to validate our platform technology in this very important new application and provide another avenue for continued growth in the future."

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 40,000 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, future growth and the company's projections of the market potential related to liver and non-liver applications 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 and other risks is included in the Company's filings with the Securities and Exchange Commission.

RITA is a trademark 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.

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SOURCE RITA Medical Systems, Inc.