SAN DIEGO -- A promising experimental treatment for colon cancer that has spread to the liver is being tested at the University of California San Diego Medical Center.

The therapy uses an altered herpes virus to attack and kill tumors.

Diana Kim is only the second patient to undergo a innovative new treatment for advanced colon cancer.

"I've had two surgeries and a round of chemotherapy to rid myself of this disease and none had worked," colon cancer patient Diana Kim said.

"She has stage four cancer. It's involving her liver. It started in her colon and metastasized to her liver and it subsequently spread to her lungs," UCSD hematologist-oncologist Dr. Tony Reid said.

But doctors believe Kim may have a fighting chance.

For the past four weeks, doctors at UCSD Medical Center have been injecting her liver with a modified herpes virus.

The therapy is designed to train her body to fight the cancer.

"It's basically like a vaccine -- a very weakened virus. But we have weakened it in a way that will allow it replicate within a tumor. Basically, we set up a viral infection within a tumor," Reid said.

Doctors inject the altered virus into an artery that supplies blood to the liver.

"The virus has a chance to kill the tumor directly by causing that infection, basically a blister-like reaction," Reid said.

This new approach could help shrink tumors so they can be surgically removed and it may even boost the power of other cancer treatments.

"We think we can enhance the effects of subsequent chemotherapies and there just isn't any other therapies around that can give us those kind of options," Reid said.

Kim's immune system seems to be fighting her cancer, but she won't know for certain until the months ahead.

"I know that I am taking a risk, but hopefully this will pay off me and a lot of people to follow," she said.

The experimental therapy is for only for colon cancer patients whose cancer has metastasized to the liver and they have failed all other therapies.

If you are over 18 years of age with diagnosed colon cancer that has spread to the liver, and have failed first-line chemotherapy, you may be eligible to participate in this study.

UCSD is the only site in California offering the treatment. For more information, call UCSD at (858) 657-7020.