Technology and innovation grab interest of radiologists

By Larry Haimovitch

Medical Device Daily Contributing Writer

April 17, 2013

NEW ORLEANS — The 38th annual meeting of the Society of Interventional Radiology (Fairfax, Virginia) has been taking place here in the past few days. The innovative and creative SIR physicians have for many years been developing and practicing a plethora of promising new technologies and procedures.

Kicking off a press conference here on Monday, moderator Robert Vogelzang, MD, of Northwestern University Feinberg School of Medicine (Chicago) said that "our mantra has always been about innovative technologies that are less invasive and costly than open procedures, offering faster recovery times for our patients."

One of the hottest topics at this year's meeting is prostatic artery embolization (PAE) a relatively new procedure that is designed to improve the quality of life (QOL) and provide symptomatic relief to men suffering from an enlarged prostate or benign prostatic hyperplasia (BPH). This condition, which afflicts aging men (typically over 60 years old) is commonly managed with medications like alpha blockers but it is estimated that up to half do not gain any major benefit. When medical management fails, surgical procedures like a transurethral resection of the prostate (TURP) or laser-based TURP-like procedures that effectively remove prostatic tissue are employed. However, they have myriad adverse effects, are generally restricted to prostate glands of 60 ccs to 80 ccs and must be performed in a hospital operating room.

PAE is an outpatient procedure that uses a standard micro-catheter to deliver an embolic agent (typically beads in the 100 to 400 micron range) into the prostatic artery. The restriction of blood flow to the prostate after embolization causes the enlarged prostate gland to shrink, thereby relieving the annoying symptoms of BPH.

At last year's SIR gathering in San Francisco, Francisco Carnevale, MD, chief of interventional radiology at the University of Sao Paulo Medical School (Sao Paulo, Brazil) reported very encouraging early safety and efficacy data. This year, there were several papers and a workshop presented from physicians performing PAE outside the U.S. This information provided further evidence that PAE may indeed be a very safe and effective alternative to the numerous other more invasive approaches to treating BPH. Although there is no accurate information on how much procedures have been performed worldwide, a good "guesstimate" would be somewhere between 500 and 1,000

At a press conference here, Sanjay Bagla, MD, from Inova Alexandria Hospital (Alexandria, Virginia) reported on the first U.S. experience with PAE. Since his hospital-sponsored IRB study began in January 2013, Bagla has treated 21 patients. He hopes to complete the 30-patient trial before the end of 2Q13. For patients who have had at least a one month follow-up, Bagla reported that 94% have enjoyed a "significant reduction" in their BPH symptoms. In addition to the efficacy, which also includes a major improvement in the QOL scores, he noted that the safety of the procedure is extremely good and that could prove to be a major advantage over competing BPH technologies.

In an interview with Medical Device Daily, Bagla said that he was "initially quite skeptical" about PAE. However, he has been "very pleasantly surprised" with the impressive early results. He cautioned that further clinical data needs to be developed. To that end, he pointed out that a company-sponsored IDE trial, comparing PAE to an already FDA-approved BPH technology, could commence later this year. He would not disclose the company nor the technology but did indicate it would be a randomized, prospective multi-center trial that ultimately could lead to a specific FDA approval for this approach.

Bagla also emphasized that PAE requires considerable skill because the prostatic artery is "microscopic" in size and therefore is not easy to locate. His hospital has a sophisticated imaging technology – cone based computed tomography – which makes visualization of this artery much easier. Without access to this imaging modality, he told MDD that the technique would be considerably more challenging.

Improved micro-catheter technology would also facilitate PAE procedures and in that regard, privately-funded Surefire Medical (Westminster, Colorado) has indicated that it may develop a micro-catheter specifically targeting the PAE market. Surefire, which was founded in 2009 to develop innovative infusion systems for the interventional radiology and interventional oncology markets, has grown rapidly since it entered the market with a unique micro-catheter which improves the delivery of embolic agents that are widely used in drug-eluting bead chemo-embolization procedures.

Another technology that continues to gain prominence in the interventional radiology community is irreversible electroporation (IRE), to treat cancer. IRE is a unique ablative energy source that uses high voltage low energy direct current electrical pulses to permanently open pores in the cell membranes of soft tissue. In turn, this causes the cancer cells to die. A key attribute of IRE is that while it effectively kills the cancerous tissues, it spares the adjacent blood vessels. This contrasts with the heat-based radiofrequency and microwave ablation approaches, which can cause too much collateral damage to surrounding structures.

Constantinos Sofoclaous, MD, from the venerable Memorial Sloan Kettering Cancer Center (New York) reported on the benefits of IRE in a wide variety of cancers that have metastazised, including brain, liver, lung and the pelvic region. His reported safety and efficacy data was excellent, with all 65 tumors that were treated showing that they were effectively destroyed.

He indicated that "IRE appears to be especially beneficial to people who do not have good treatment options and where the cancer is close to blood vessels, nerves and other sensitive structures."

IRE was initially approved by the FDA for soft tissue ablation in November 2006. It is being commercialized globally exclusively by AngioDynamics (Latham, New York) under the brand name NanoKnife. The product has a CE mark for Europe. The company has placed 74 units worldwide to date and approximately 2,000 procedures have been performed thus far.

The company is currently in discussions with the FDA to begin an IDE trial for pancreatic cancer, a dreaded condition. According to the report "Cancer Facts and Figures 2013," published by the American Cancer Society (Atlanta), approximately 45,000 people will be diagnosed with pancreatic cancer this year in the U.S.and about 38,000 people will die. The five-year survival rate is a grim 6%.

A significant improvement in longevity using IRE has previously been reported by other investigators. For example, at last year's Society of Surgical Oncology (Arlington Heights, Illinois), Annual Cancer Symposium, Robert Martin, MD, a surgical oncologist from the University of Louisville (Louisville, Kentucky) presented data on locally advanced and unresectable pancreatic cancer. The trial included 44 patients and their data was matched to 85 patients treated with standard radiation and chemotherapy.

The survival data for the IRE group was considerably better than the control group. To wit, the local progression free survival rate was 14 months vs. six months, distant progression free survival was 15 months vs. nine months and the overall survival was 20 months vs. 13 months.

2013 Society of Interventional Radiology

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