Men with prostate cancer at higher colon cancer risk

Men who have prostate cancer have a higher risk of developing colon cancer than men who do not have prostate cancer, US researchers said on Tuesday.

Researchers at the University at Buffalo (UB) in New York state found in a study of more than 2,000 men that patients diagnosed with prostate cancer had significantly more abnormal colon polyps, known as adenomas, and advanced adenomas than men without prostate cancer.

Most colon cancers begin as adenomas, the researchers said as they presented the findings of their study at the annual meeting of the American College of Gastroenterology in San Antonio, Texas.

"Our study is the first to show that men with prostate cancer are at increased risk of developing colon cancer," said report author Ognian Pomakov, an assistant professor at UB's department of medicine.

Prostate cancer is the second leading cause of cancer death in American men, only behind lung cancer. Colorectal cancer is the third most common cancer diagnosed in men and women in the United States.

The researchers reviewed the patient records, colonoscopy reports and pathology reports, as well as data on the prevalence of adenomas, advanced adenomas, cancerous adenomas and their location within the colon, in 2,011 men who had colonoscopies at the Veterans Affairs Medical Center in Buffalo.

When the researchers compared the colonoscopy results from 188 men diagnosed with prostate cancer with the rest of the patients, they found that the prostate cancer patients had significantly higher prevalence of abnormal polyps and advanced adenomas compared to the rest of the study sample.

Forty-eight per cent of prostate cancer patients had adenomas, compared to 30.8 per cent of the men without prostate cancer. More than 15 per cent of
prostate cancer patients had advanced adenomas compared to 10 per cent of the men without prostate cancer.

Pomakov stressed the importance of men who have been diagnosed with prostate cancer having routine screening for colon cancer and called for larger studies to be done to determine if screening for colorectal cancer should begin earlier for prostate cancer patients than the currently recommended age of 50.