Colon Cancer More Deadly For Blacks
Study suggests underlying biological cause for difference
MONDAY, May 24, 2004 (HealthDayNews) -- Black Americans who have had colon cancer surgery are 67 percent more likely to die within five years than whites are, a new study says.
This was despite the fact that their cancers were diagnosed at the same stage and treated the same. This suggests racial differences in survival rates may be due to genetic or underlying biological factors, researchers noted.
Results of the study appear in the May 24 online issue of Cancer.
"Several previous studies have attributed lower survival in African-Americans to late staging of their tumors and to the treatment options," said study co-author Upender Manne, an assistant professor in the department of pathology at the University of Alabama at Birmingham.
He said to compensate for these factors, the researchers only studied people who had undergone surgery to treat their colon cancer and compared people with the same stage of cancer.
"The key point is that even if you provide uniform treatment options, you still have some differences in long-term survival," Manne said.
Nearly 150,000 people are diagnosed with colon and rectal cancers every year, according to the American Cancer Society. More than 56,000 people die from the disease annually, the society reports.
For this study, the researchers compared 199 blacks and 292 non-Hispanic whites who had surgery for colon or rectal cancer at some point between 1981 and 1993. None had any other treatment for their cancer. The average age was 64.8 years, and 60 percent were male.
Overall, blacks had a 67 percent higher chance of dying in the first five years following surgery, and a 52 percent greater risk of dying in the 10-year period following surgery compared to whites.
The greatest differences were seen in people with stage II cancer, in which the tumor had not spread beyond the colon. Blacks with stage II colon cancer were 2.5 times more likely to die within five years, and had an 82 percent greater risk of death from their cancer over 10 years than whites did.
There were no statistically significant differences for people with rectal cancer.
Dr. Peter Kozuch, a hematologist and oncologist at St. Luke's Roosevelt Hospital in New York City, said the study was very intriguing, but added, "I think the real issue is that not all stage II cancers are the same." He said it's possible the tumors in the blacks were deeper and there may have been other risk factors.
He also pointed out that the blacks in the study had more tumors on their right side, which could have implications in terms of screening.
Both Kozuch and the study authors agreed more research needs to be done on these differences. In the meantime, they emphasized the need for regular screening exams.
Kozuch said the development of colon cancer is largely a failure of screening. "Ninety-five percent of colon cancer comes from polyps," said Kozuch, and polyps can be removed during colonoscopy, thereby preventing the cancer from ever developing.
The cancer society recommends that after age 50, people should have a yearly fecal occult blood test, and either a sigmoidoscopy every five years or a colonoscopy every 10 years.
Kozuch said colonoscopy is the gold standard in diagnosing colon cancer, and added that a prudent lifestyle, including plenty of exercise and eating right, could help prevent colon cancer.