New procedure assists in cancer detection

Craig Gustafson

A University biochemist and his former student have collaborated for the past 10 years before finding a new way to detect the spread of tumors and possibly destroy them without surgery.
Now the University and the Mayo Clinic in Rochester, Minn., have patented the process, which makes it easier for physicians to see how far cancer has spread.
In the new procedure, a radioactive atom is attached to vitamin B-12 and injected into the patient. A special camera is used to measure the cancer’s growth.
Professor Harry Hogenkamp, a University biochemist, and his former student Dr. Doug Collins, a diagnostic radiologist at the Mayo Clinic, developed the new technique.
Collins said the process is potentially better at detecting malignant tumors and finding the exact location of tumors in breast tissue.
“Examining a patient’s dense breasts is much like looking through frosted glass,” Collins said. He said it is difficult to find every single growth within the thick haze.
A case report issued by the Mayo Clinic provided an example of what can happen with this new process.
A 45-year-old woman had a two-centimeter tumor removed from her right breast in January 1996. However, the woman would not allow doctors to treat her with conventional medical therapy in follow-up sessions.
By October 1998, a seven-centimeter tumor was identified in her right breast and lymph nodes were also found under her arm.
The new process not only revealed the recurrent large tumor but also smaller, one-centimeter spots within her lungs. The smaller spots were not identified the first time she was examined.
The goal in fighting tumors is to find them before they grow larger than one centimeter.
But a lump in the breast normally cannot be felt until it reaches one to two centimeters, when it is often too advanced. The larger a tumor gets, the chance of successful treatment declines.
The vitamin B-12 process, however, clearly showed the extent of the cancer at a much earlier stage.
“The findings were very exciting,” Collins said.
Since its first use, the process has been successful in 30 other cases involving cancer of the breast, lungs, colon, brain, bone and thyroid.
Collins originated the idea in 1987 while still a student at the University’s Medical School.
He discussed the idea with his then-teacher, Hogenkamp.
“Harry has such a positive outlook,” Collins said. “If it were not for his encouragement and reputation, the B-12 project would have had difficulty getting off the ground.
“The fusion — his basic science skills and my diagnostic/therapeutic knowledge — has been great. It’s been one of the most enjoyable experiences in my life,” he added.
But at the beginning, the theory didn’t look as promising.
“There were a lot of wrong approaches until we hit a good one,” Hogenkamp said.
The new process uses less radioactive material and makes the tumor glow brighter than previous methods.
Vitamin B-12 was used because tumors act like drains, sucking up all of the body’s vitamin supply. So when B-12 is injected into the body, it acts like a missile seeking out the tumor.
The aggressiveness of the tumor’s growth determines the saturation of B-12. If the B-12 presence decreases, then the tumor is dying.
But the most difficult part of the process was modifying vitamin B-12.
Radioactivity lights up tumors, allowing doctors to see them without affecting other parts of the body.
But Collins and Hogenkamp needed a radioactive atom with a short half-life to ensure the radioactivity wouldn’t stay in the body for a long time.
A lecture Collins attended in 1994 gave him another idea for the vitamin B-12 process. The speaker suggested that boron atoms properly placed in a tumor could destroy it.
“I thought, ‘We could do that with B-12,'” Collins said.
Boron and vitamin B-12 also provided the partners with a destructive compound that could possibly destroy the tumor without surgery, something they hope to explore within the next few years.
Collins said that once boron is in the tumor, a process called neutron-capture therapy can be used to split the boron atom into one of the most destructive atoms around — helium.
Once helium is allowed free rein inside the tumor, it is only a matter of time before it is destroyed, Hogenkamp said.
The University has not decided what to do with the new process and its cancer-killing potential. Officials are looking into selling the idea to an outside company or creating their own spin-off company.

Craig Gustafson covers the Medical School and welcomes comments at [email protected] He can also be reached at (612) 627-4070 x3233.