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New research shows link between infection-related diseases and risk of cancer

March 05, 2017

Presence of H. pylori is often asymptomatic, but Duane T. Smoot, M.D., chief of the gastrointestinal division at Howard University, Washington, D.C., suggested that there is more at stake than bacterial related illnesses.

"Not everyone gets sick from H. pylori infection and there is a legitimate concern about overusing antibiotics to treat it," said Smoot. "However, the majority of the time these polyps will become cancerous if not removed, so we need to screen for the bacteria and treat it as a possible cancer prevention strategy."

The link between H. pylori and cancer has been suggested before for other organ sites and ethnic groups, but the findings have been a subject of debate.

Smoot and colleagues observed 1,262 black participants who underwent bidirectional gastrointestinal endoscopy on the day they were enrolled. They assessed H. pylori status using immunohistochemistry on gastric specimens.

Results showed that colorectal polyps were 50 percent more prevalent in patients infected with H. pylori (43 percent) than in patients who did not have H. pylori (34 percent). Furthermore, there was a trend toward larger polyp size in infected patients. H. pylori status did not affect the histopathology or location of the polyps.

2791. Blood C-reactive protein levels and colon cancer risk

Circulating C-reactive protein (CRP), a marker of low-grade systemic inflammation, is associated with an increased risk of colon cancer.

"Elevated CRP levels may be considered as a risk marker, but not necessarily a cause, for the carcinogenic process of colon cancer," said Gong Yang, M.D., M.P.H., research associate professor at Vanderbilt University, Nashville, Tenn.

CRP is a protein found in the blood; levels rise in response to inflammation throughout the body. Yang and colleagues at the Vanderbilt-Ingram Cancer Center evaluated the link between CRP levels and colon cancer risk, and the potential effect of time on CRP measures.

Using the Shanghai Women's Health Study, the researchers conducted a case-control study of 338 cases of colorectal cancer and 451 individually matched controls with up to 10 years of follow-up.

CRP levels were positively associated with colon cancer risk in an analysis of 209 cases of colon cancer and 279 controls, according to Yang. Women in the highest quartile of CRP had a 2.5-fold increased risk of colon cancer compared to those in the lowest quartile. This risk was, however, much greater for women with higher levels of CRP measured in blood samples collected close in time to disease diagnosis.

"The positive association between circulating CRP and colon cancer observed in this and some previous studies may be partly explained by cancer-induced inflammation," Yang said.

SOURCE American Association for Cancer Research