The Quebec College of Physicians is warning multiple sclerosis patients not to seek the "liberation" treatment at clinics outside Canada because the procedure remains scientifically unproven and may have unknown risks.

At the same time, the professional doctors organization assured MS patients that anyone who develops complications after taking part in such medical tourism would be cared for by doctors at home.

A growing wave of Canadians with the debilitating neurological disorder are travelling to clinics in the United States, Europe, India and elsewhere for the so-called liberation treatment, which is based on an Italian vascular specialist's hypothesis that MS is linked to blocked and twisted neck veins.

Dr. Paolo Zamboni believes these vein anomalies, which he calls chronic cerebrospinal venous insufficiency, or CCSVI, allow blood-borne iron deposits to damage brain cells. He argues that opening blockages in the veins with a tiny balloon can alleviate MS symptoms.

MS has long been considered an autoimmune disease. But since late last year, when Zamboni's procedure first made headlines, an untold number of MS patients have sought out private clinics abroad, paying thousands of dollars apiece for the treatment.

"I have received numerous messages from patients afflicted with multiple sclerosis ... and I understand their need to know where science stands with respect to this subject," college president and CEO Dr. Charles Bernard told a Montreal news conference Tuesday. "The college is saying to them today that we need to wait for the results of studies that are currently underway before generalizing Professor Zamboni's treatments.

"In particular, we are recommending to these individuals that they refrain from consulting any medical tourism clinics offering these treatments prematurely with little regard for their effectiveness and side-effects."

Liberation therapy is not available in Canada, and Health Minister Leona Aglukkaq announced three months ago that the federal government is awaiting results of several studies now underway before deciding whether pan-Canadian clinical trials should go ahead.

The Quebec College of Physicians is also taking the wait-and-see approach, said the group's secretary, Dr. Yves Robert.

"Our message is a message of caution," Robert said in an interview. "Before saying it is a magical treatment, we have to have more scientific evidence within a controlled framework."

Robert said balloon angioplasty -- a long-used technique for widening coronary arteries to prevent heart attack and stroke -- may have poorly documented risks when used in thinner-walled veins, which are more vulnerable to damage and hence to blood clots.

"So there are complications," he said. "And the link between the occlusion (blockage) of the veins and multiple sclerosis has not been conclusive."

In fact, several international studies have found that narrowed neck veins can occur in people without MS, said Dr. Marc Girard, president of the Quebec Association of Neurologists. And among people with the disease, such venous blockages are not always present when symptoms begin.

"According to preliminary data generated by current research, it would also seem that the venous obstructions appear late into the progression of the illness," Girard said. "As such, these findings show that the obstructions are not the cause of multiple sclerosis, as Professor Zamboni's hypothesis suggests."

In other words, no one knows whether blocked neck veins cause MS, are a result of MS or have no association with the disease at all.

"So in our view, for the medical community, it raises many more questions than it provides answers," said Robert.

Results from North American studies funded by the Canadian and American MS societies, and now underway, should answer some of those questions and help determine how research aimed at validating the procedure should go forward.

College director Dr. Guy Dumas, who has had MS for more than 20 years, said he understands too well the hope that Zamboni's proposed treatment has generated among patients.

"However, I urge them to exercise prudence," he said. "Patients should not be abandoning their current medications in favour of pursuing an unrecognized treatment. We must be sensible and patient. We must wait for the results of the research presently being carried out before taking any other action."