TORONTO (Canadian Press) -- A decade-long study of a form of laser treatment used to drastically reduce the size of benign enlarged prostates will help a Montreal doctor answer a question he often hears: "Is that good for life, sir?"

Dr. Mostafa Elhilali, a urologist at the Montreal University Health Centre, says he normally gets a laugh when he responds that he's not a car dealer and "we just give you a guarantee for 80,000 miles."

But now, he said the findings of his study, presented this week at the annual meeting of the American Urology Association in Washington, D.C., allow him to give a better answer.

"I can tell them that over 10 years, the likelihood that you're going to need another laser operation because the prostate grew back is 0.7 per cent. So 99.3 per cent will not come back over a 10-year period," he said from Montreal.

The technology is known as Holmium Laser Enucleation of the Prostate, or HoLEP, which has been used at the health centre since 1998 after a donation by philanthropist Michal Hornstein allowed for purchase of the device for about $200,000.

Elhilali said it was developed in New Zealand, and he trained to use it there. He said there are at least 50 machines in Canada now, but he has particular expertise in treating very large prostates, which can place pressure on the urethra and cause urination and bladder problems.

His study is a retrospective analysis of 952 patients with a median age of 70 treated with HoLEP at the centre between March 1998 and September 2010. The median size of prostate was 81 grams, which is above the average size for considering corrective surgery -- 40 to 60 grams.

The procedure is done with spinal anesthetic, rather than a general, and takes one to three hours, he said.

"We go through the penis, we go through a natural passage, and with the laser we separate -- that's why we call it enucleation -- we separate the prostate from its capsule," he explained.

"Imagine an orange. You remove the orange, but you leave the skin, so we go through this hole and with the laser we peel the orange from inside the skin of the orange, which in this case is the prostate capsule."

The tissue goes inside a morcellator to be cut up, then small pieces are sucked out, he said.

Patients can go home the same day, or the next day, compared to two to three days if they have another surgical technique known as TURP, or Transurethral Resection of the prostate, Elhilali said. Open surgery would take even more time for recuperation, five to seven days in hospital.

Among the benefits of HoLEP are no incisions and no bleeding, which means that patients on blood thinners can still have it done, he said. The study found a very low rate of complications.

"There is no deterioration with time, and the likelihood of reoperation is the lowest in any other technique."

In terms of durability, about 10 to 16 per cent of patients who have TURPs need to have the operation redone in a 10-year period, Elhilali said.

Men's prostates naturally increase as they grow older. Prior to treatment, some patients with an enlarged prostate will get up five to six times a night to urinate, Elhilali said. About 40 per cent of his patients arrive at the Montreal hospital with a catheter to empty their bladder because they're unable to urinate.

The Canadian Press, 2011