In the biggest advance against end-stage colorectal cancer in 40 years, researchers have found that combining a new drug with the standard ones can more effectively slow the cancer and prolong victims' lives slightly.
"We're starting to bring science to the point that it's breaking the logjam in progress," said Dr. Leonard Saltz of Memorial Sloan-Kettering Cancer Center in New York.
The drug irinotecan, also known as Camptosar, already is approved by the Food and Drug Administration for treating patients with advanced, Stage IV colorectal cancer after standard drugs fail.
Because such advanced colorectal cancer is practically a death sentence, researchers led by Saltz tested irinotecan together with the standard drugs, fluorouracil and leucovorin.
The three-drug combination increased average survival from 13 months to 15 months, and the share of patients whose tumors temporarily shrank went from 28 percent to 50 percent, compared with the standard treatment.
In addition, far fewer patients suffered from two serious side effects one of them a life-threatening decrease in infection-fighting white blood cells.
"It is a big step forward in giving patients a better chance for tumor shrinkage and longer survival," Saltz said.
Perhaps even more important, the promising three-drug approach is now being tested in Stage III patients, or those whose tumors have spread to nearby lymph nodes but not to other organs, as in Stage IV.
"We hope that this will lead to a greater number of people being cured," Saltz said.
The study appears in today's New England Journal of Medicine.
Colorectal cancer is America's No. 2 cancer killer after lung cancer, claiming 56,000 lives annually. While its exact cause remains unclear, it involves alterations in many genes over years and changes in the colon wall that let precancerous polyps develop. Doctors advise people 50 and older to get regular colonoscopies so polyps can be detected and removed.
Saltz is now heading a National Cancer Institute study at hospitals across North America to determine whether the three drugs, given after surgery to remove tumors in Stage III patients, can cure the more than the 65 percent now saved by surgery and the standard drugs.
Saltz said the study of about 1,200 Stage III patients should produce results within five years.