Medical Device Daily Contributing Writer

SEATTLE — Over the past decade, the medical community has increasingly focused on minimally-invasive procedures, as a plethora of new diagnostic and therapeutic technologies are enabling physicians to avoid invasive surgeries. There is perhaps no better venue to observe the minimally invasive phenomenon than at the annual meeting of the Society of Interventional Radiology (SIR; Fairfax, Virginia), just concluded.

Gary Onik, MD, an interventional radiologist from Celebration Health, Hospital Center for Surgical Advancement (Celebration, Florida), provided a vivid example of minimally invasive benefits in a talk titled “The Male Lumpectomy: Focal Therapy for Prostate Cancer Using Cryoablation,” during a session on Bone, Lung & Prostate Cancer Ablation.

According to the report “Cancer Facts and Figures — 2007,” from the American Cancer Society (Atlanta), prostate cancer is the most common malignancy afflicting men, accounting for 29%, or roughly 222,000, of an estimated 766,860 new cancer cases predicted for 2007.
About one-half of these patients are treated with radiation (brachytherapy seeds or external means), with about 30% undergoing a radical prostatectomy (RP) or surgical removal of the entire prostate gland. In the past few years, procedures using the less-invasive da Vinci robotic surgical device from Intuitive Surgical (Sunnyvale, California), have been gaining significant market share from traditional open surgery.

Cryoablation is an MIS procedure employing extreme cold to destroy prostate cancer. Although it accounts for less than 4% of the total prostate cancer procedures, it has been the fastest growing modality in the past few years. And Endocare (Irvine, California), the cryoablation market leader, enjoyed an increase of about 20% in procedures in 2006, Onik, recognized as one the early adopters in the field of interventional radiology (IR), drew a parallel between surgery for women with breast cancer and surgery for prostate cancer. He contended that breast surgeons have shown that a MIS lumpectomy, which spares breast tissue, can be as effective as a more aggressive procedure. He asserted: “A woman’s quality of life has been successfully upheld with minimally invasive breast cancer therapy.” He said that men received a parallel benefit in the MIS strategy for prostate cancer.

These patients could be safely treated with a “middle ground” between the two extreme methods of treating prostate cancer — the gold standard of radical prostatectomy and the more controversial and passive approach of “watchful waiting.” Armed with data from several clinical studies, Onik argued that about 80% of all prostate cancer is amenable to a less-invasive approach.

A key requirement of this approach — which Onik called focal therapy — is the need to accurately locate, stage and grade the cancer, but that the traditional imaging and biopsy methods that use transrectal ultrasound imaging are simply not sensitive enough. Focal therapy requires 3-D biopsy mapping in order to precisely locate the site of the cancer. Using cryoablation equipment and disposable probes manufactured by Endocare, Onik’s patients have enjoyed positive results.

He reported on 80 patients treated between mid-1995 and August 2006, with a mean follow-up of 3.6 years. As measured by their PSA scores, 96% of the patients are considered to be cancer-free. More impressively, 60% of this patient cohort was considered to be either a medium- or high-risk patient prior to the minimally-invasive procedure. Of these patients, 7% required re-treatment due to cancer in the untreated gland and this subgroup is also cancer-free. Other prostate cancer therapies, notably RP, often result in two troubling side effects: impotency and incontinence. Onik’s data, on the other hand, showed that 90% of the men maintained potency and all were continent.

Although his data came from a single operator at one center, Onik noted that these results are remarkably similar to a study of 28 patients treated with focal cryoablation by Duke Bahn, MD, a urologist at Prostate Institute—Community Memorial Hospital (Ventura, California).
Bahn’s data, reported in the September 2006 issue of Journal of Endourology, showed that after a mean follow-up of 70 months, 93% of his patients were disease-free.

His conclusion: “focal cryoablation can provide biochemical and local control of prostate cancer while preserving potency and continence. Further investigation is needed.”

Summing up, Onik noted that “cryo-lumpectomy” results to date are very encouraging and actually better than traditional treatments, with lower morbidity and justify larger controlled clinical trials.

And indeed, the two industry cryoablation leaders are moving in that direction.

Galil Medical (Okneam, Israel) initiated a single-center study, while Endocare hopes to commence a multi-center trial later this year. In late 2006, Galil completed a $52 million financing with a group of U.S. venture capitalists. The financing and related transactions enable it to expand its marketing and clinical programs in the U.S. and Europe. Another promising area in this field is the minimally invasive treatment of cancer, or interventional oncology, this emphasis captured in an article headline — “Interventional Oncology: The Next Wave” — in SIR’s daily newspaper.

Employing various image-guided diagnostic modalities and therapeutic tools, interventional radiologists are beginning to treat cancers, heretofore treated solely by oncologists, via an armamentarium of high-powered, very expensive and often-toxic chemo-therapeutic agents.
One of the most promising of these technologies is drug-eluting beads (DEBs), pre-formed, deformable microspheres delivered percutaneously with specialized micro-catheters. The beads occlude the blood flow to the target tissue and release a controlled and sustained local dose of one of several FDA-approved oncolytic drugs, e.g., doxorubicin, cisplatin or mitomycin. The procedure, dubbed trans-arterial chemo-embolization (TACE), was one of the hottest topics at the meeting.

In a paper titled “Combined RF Ablation and Doxorubicin Eluting Bead Chemo Embolization in Hepatocellular Carcinoma,” Riccardo Lencioni, MD, an interventional radiologist from the University of Pisa (Pisa, Italy), reported preliminary, but promising data in a small pilot study in Italy. TACE, combined with radiofrequency ablation (RFA), had a synergistic effect, and his study clearly showed that TACE significantly increased the effectiveness of RFA for the treatment of liver carcinomas.

Christoph Binkert, MD, associate professor of radiology at Brigham and Women‘s Hospital (Boston), discussed TACE and provided animal data that indicated a sustained release of the drug into the liver over several days. Binkert concluded that DEBS are “a new form of trans-arterial treatment of liver tumors with promising preliminary data.”

AngioDynamics (Queensbury, New York), sponsor of both talks, began marketing DEBs after acquiring RITA Medical (Fremont, California) in late January. RITA had obtained the North American marketing rights to DEBs last summer from Biocompatibles (Surrey, UK) and was enjoying robust growth after its market launch in the summer of 2006.