June 3, 2008 -- Advanced colon cancer patients with a family history of the disease are more likely to be cured with treatment than patients with no family link, new research suggests.
Compared to patients with no family history, those with relatives who've had colorectal cancer were less likely to die or have colorectal cancer recur. And the more relatives they had with a history of colorectal cancer, the better their odds.
The findings suggest that as yet unidentified genetic influences are associated with both an increased risk for developing colorectal cancer and an improved prognosis for surviving the disease, Jennifer A. Chan, MD, PhD, who led the study, tells WebMD.
The study appears in tomorrow's Journal of the American Medical Association.
"This is reassuring for patients with a family history, but it could also be important for treatment," says Chan, who is an instructor of medicine at Harvard Medical School. "If we are able to identify the factors associated with family risk and improved prognosis, this could help guide treatment decisions in the future."
Greater Risk, Better Survival
As many as one in five colorectal cancer patients have a close family link to the disease, and having a first-degree relative such as a parent, sibling, or child with the cancer is associated with a twofold increase in risk.
While it is clear that family history is an important risk factor for developing colorectal cancer, its influence on recurrence and survival are not well understood.
In their effort to change this, Chan and colleagues from Harvard Medical School and the Dana-Farber Cancer Institute followed 1,087 patients with stage III colon cancer who were treated with surgery followed by chemotherapy.
A total of 195 patients (18%) reported a history of colorectal cancer in one or more first-degree relatives.
During an average of 5 1/2 years of follow up, 29% patients with a family history of the disease and 38% of patients with no family history either died of their disease or experienced disease recurrence.
Patients with a family history were 26% less likely to have their disease recur than patients with no afflicted close family members.
Screening Wasn't a Factor
Aggressive colorectal cancer screening is recommended for people with a family history of the disease.
The American Cancer Society recommends earlier and more frequent screening for anyone with a first-degree relative who has had the disease, especially if that relative was diagnosed before age 60.
Early screening saves lives, but it did not appear to be a factor in the improved survival among patients in this study, because all the patients had the same stage of advanced disease.
The patients also had similar treatments, suggesting that genetic influences were the key to better survival.
In an editorial accompanying the study, Boris Pasche, MD, PhD, director of the Cancer Genetics Program at the Northwestern Feinberg School of Medicine, writes that family history "may well become a new prognostic factor for colorectal cancer."
Pasche tells WebMD that the study should spur additional research to identify the genes associated with increased risk and better prognosis.
This, in turn, could lead to treatments that target a patient's specific risk, he says.
"There is a lot of interest right now in this type of targeted approach to cancer treatment," he says. "Studies like this one hint at, but do not yet prove, that this is the direction we will take in the future."