Much of Sultan Kosen's eight feet, two-inch stature rose up in an 17-year period starting at age 10, when the benign tumor in his brain's pituitary gland highjacked the organ, causing it to secrete massive amounts of growth hormone, making Mr. Kosen's body grow fast and grow without ceasing. He will need to wait several months to find out if his Gamma Knife® surgery last Thursday at the University of Virginia (UVA, Charlottesville, Va.) has inactivated the tumor and he has reached his final height, but his physicians are optimistic.

Mr. Kosen—confirmed by Guinness World Records as the Tallest Living Man—had reached the limits of what open surgery, standard radiation therapy or medication could do for him to treat the tumor responsible for his acromegaly.

"What was left was a small amount of tumor in a difficult-to-reach area," says Jason Sheehan, M.D., Ph.D., co-director of UVA's Gamma Knife Center. "We delivered his Gamma Knife radiosurgery in about an hour-and-a-half on August 18. Mr. Kosen experienced a little discomfort as we tried to fit the stereotactic frame around his head, but were able to assemble the frame around his large cranium. Overall, the treatment went very smoothly and his prognosis is pretty favorable. We predict either his growth hormone secretion will hit a normal level within six to 24 months or it will be sufficiently improved that his acromegaly can be much more easily controlled with medication."

Gamma Knife radiosurgery, a gentler alternative to traditional brain surgery, delivers up to thousands of low-intensity radiation beams to one or more targets and with pinpoint accuracy. In Mr. Kosen's case and many patients with recurrent or residual pituitary adenomas, "there is no better treatment than Gamma Knife surgery for lesions in the pituitary region," Dr. Sheehan notes.

Filming of a TLC (The Learning Channel) documentary on Kosen, The World's Tallest Man: Still Growing (aired August 8, 2010), ultimately brought Dr. Sheehan and Mr. Kosen together.

"Following several tests at UVA, I was presented with Gamma Knife surgery as an option to treat the tumor," Mr. Kosen says. "After returning to Turkey, Dr. Sheehan kindly offered to perform this treatment."

Acromegaly a growing problem in more ways than one

Mr. Kosen's experience with acromegaly has been similar to those of many other sufferers, an ongoing litany of problems, from the practical and mundane to the life threatening. Standard clothing and cars are simply too small for him, among a multitude of other things. More seriously, Mr. Kosen's condition affects his internal organs—requiring monthly injections to control their growth—and joints which have to cope with the stresses of supporting a massive body.

"As I continue to grow, it will have an adverse effect on my internal organs, particularly my heart," he says. "Since I was diagnosed with acromegaly at age 10, I have had five surgeries, three of which were to remove the pituitary tumor. However, the doctors couldn't completely remove the tumor due to the risk of causing blindness, stroke and even death."

"Two years ago, I had radiotherapy, which reduced the tumor's size considerably," Mr. Kosen continues. "My last surgery was on my knee, which dislocated as a result of my height. I was in the hospital for six months and this is why I have to use sticks when I walk. I'm hoping to find a sponsor for physiotherapy to help me build up muscle tone to the point I don't need the sticks anymore."

The 27-year-old's knee problems ultimately precluded him from a regular job, but he has been able to earn a living through TV show appearances and other media opportunities.

Despite the challenges of living with acromegaly, Mr. Kosen is optimistic about his prospects and derives a certain amount of pride from his world record setting dimensions.

"I won the title of the world's tallest man in September 2009 from the previous holder Xiu Xung from China, who is 7'9"," he notes. "It appears that I am still growing and have grown a couple of centimeters over the last year. I was nervous and excited about my Gamma Knife treatment—I had never heard of Gamma Knife before because I am from a very small village in Turkey. I just want to live a regular life, so anything that can help me I'm willing to try. My hopes and optimism have kept me going through some very difficult periods in my life, and it is with the same optimism that I take on my next challenges."