Meeting spotlights future patient care improvements

By Larry Haimovitch

Medical Device Daily Contributing Writer

April 3, 2012

SAN FRANCISCO — The 37th annual meeting of the Society of Interventional Radiology (Fairfax, Virginia) took place here last week and showcased several technologies and procedures which show promise to improve patient care and become important contributors in the future.

One of the hot topics at last year's SIR meeting was treating chronic cerebrospinal venous insufficiency (CCSVI), which is a recently described condition affecting venous blood flow in patients with multiple sclerosis (MS).

The concept of interventional therapy to treat MS was first proposed in late-2009 by Paolo Zamboni, MD, a professor of vascular surgery, University of Ferrara (Italy). Zamboni found that many MS sufferers had three or more abnormalities in the venous architecture of their head and neck, specifically the internal jugular or azygos veins. This led to the concept of insufficient venous drainage being a culprit in some MS patients. Further, it was thought that once the major vessels were widened with an angioplasty procedure, there was an improvement in their MS symptoms.

The presentations at both last year and this year's SIR meeting emphasized that there are few treatment options for MS and that medical management has significant risks and side effects. However, whereas last year's meeting focused on the safety of this approach, with a cohort of 231 patients treated, the focus of this year's meeting shifted to efficacy.

Kenneth Mandato, MD, an interventional radiologist at the Albany Medical Center (Albany, New York) provided the short term results from a series of 213 patients, with 192 patients responding to a questionnaire assessing their quality of life (QOL). Analysis of the data showed that there was a 70% to 78% improvement in their QOL if the treatment was performed within ten years of the diagnosis of MS, whereas there was a smaller 60% to 66% for patients treated after ten years of initial diagnosis.

Mandato said that "endovascular treatment of CCSVI can produce significant, short-term improvements in the quality of life of patients with multiple sclerosis. In a question and answer period afterwards, he cautioned however that "there is a lot of work to do" on this topic before it can become a part of MS therapy.

Another group of patients, reported by Hector Ferral, MD, professor of radiology at Rush University Medical Center (Chicago), had less auspicious results with 56% of the patients reporting a positive response with sustained benefit for more than four weeks in at least one of their symptoms. However, 39% showed no improvement in any parameters and 5% of patients were lost to follow-up.

Ferral concluded his discussion, stating that "CCSVI deserves further study, in particular to identify patients who will benefit from this approach, as well as to determine how to improve their QOL."

Another prominent topic this year was the use of a relatively new ablation technology, irreversible electroporation (IRE), to treat cancer. IRE is a unique energy source, it does not use heat or cold to destroy tissues but rather 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. In contrast, RF and microwave ablation often cause too much collateral damage to surrounding structures and, as a consequence often cannot be safely used.

IRE was initially approved by the FDA for soft tissue ablation in November 2006. It features both capital equipment and needle-like disposable probes. It has been used to treat a variety of cancers but mainly in open surgical procedures.

Govindarajan Narayanan, MD, associate professor of clinical radiology at the University of Miami, Miller School of Medicine (Miami) reported on the percutaneous approach to treating pancreatic cancer at a press conference here. He noted the grim statistics for this dreaded condition – an estimated 44,000 people will be diagnosed with pancreatic cancer and about 37,390 people will die of the disease this year, according to the American Cancer Society (Atlanta). There is a bleak 6% survival rate at five years.

As for therapeutic alternatives, he noted that while surgical resection offers the best chance for a cure, only 10% to 20% of the patients will qualify.

This safety study addressed pancreatic cancer that had not spread but was inoperable due to encasement in major blood vessels. All patients had previously failed radiation and chemotherapy, the two mainstays of current therapy. A total of eight patients, with a median time between diagnosis and treatment at nine months, were treated between December 2010 and September 2011.

Out of the original eight inoperable individuals, two went on to have surgery. Both had successful resections and remain cancer-free after months following treatment.

The adverse effects were minimal and Narayanan said that "if we continue to get good results, this procedure could provide a huge benefit and . . . could potentially change the rules of how these cases are managed," he added.

However, he injected a note of caution, stating that "we think in another 15 to 24 months we will have a lot more evidence to support the use of irreversible electroporation for inoperable pancreatic cancer patients."

Two weeks ago, at the Society of Surgical Oncology (Arlington Heights, Illinois), 65th Annual Cancer Symposium held in Orlando, Florida, favorable open surgery data was reported by Robert Martin, MD, a surgical oncologist from the University of Louisville (Louisville, Kentucky).

This study addressed the treatment of locally advanced and unresectable pancreatic cancer and was concerned with the overall survival of these patients. The trial included 44 patients enrolled between December 2009 and October 2010 in a prospective, multi-center trial 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 vs. nine months and the overall survival was 20 vs. 13 months.

The authors concluded that "IRE ablation of locally advanced pancreatic tumors remains safe and . . . can achieve greater local palliation and improved overall survival when compared to standard chemoradiation-chemotherapy treatments."

IRE is being commercialized worldwide exclusively by AngioDynamics (Latham, New York) under the brandname NanoKnife. More than 1,000 patients have been treated with the device to date worldwide and AngioDynamics is currently pursuing an IDE for pancreatic cancer with the FDA. The product has a CE mark for Europe.

At another SIR press conference Francisco Carnevale, MD, chief of interventional radiology at the University of Sao Paulo Medical School (Sao Paulo, Brazil) presented an innovative interventional procedure that is designed to improve the QOL and provide symptom 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 do have myriad adverse effects, are generally restricted to prostate glands of 60 to 80 ccs and must be performed in a hospital operating room.

Prostatic artery embolization (PAE) uses a standard microcatheter and embolic beads which are deposited into the prostatic artery. The restriction of blood flow to the prostate after embolization causes it to shrink. Two key benefits are that It can be performed on an outpatient basis and on larger glands.

The early safety and efficacy of PAE appears solid. Indeed, in a study of 152 patients presented during a session here on embolization techniques and procedures, Joao Martins Pisco, MD, director of interventional radiology at St. Louis Hospital (Lisbon, Portugal) reported "clinical success" for 83% of the patients who had a one-year follow-up. Pisco noted that in patients with symptomatic BPH and failed drug therapy, "PAE appears safe and provides good short and medium term results."

James Spies, MD, an interventional radiologist at Georgetown University (Washington) who moderated a SIR press conference, indicated that his hospital is currently evaluating PAE in a hospital sponsored IRB trial. He further stated that he is aware of two companies that may be interested in beginning an IDE study in the U.S.

2012 Society of Interventional Radiology

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