According to a new study from the Dana Farber Cancer Institute, family history increases your chance of developing colon cancer, but researchers also found that family history can also decrease your chance of dying from the disease.
Jennifer A. Chan, M.D., M.P.H., of the Dana-Farber Cancer Institute, Boston, and colleagues examined patients with stage 3 colon cancer from 1999-2007 (eight years). The patients had undergone a complete surgical resection of the tumor and also received chemotherapy.
18 percent of the patients had a parent or sibling diagnosed with colon cancer. Researchers found a family history of colon cancer significantly decreased their chance of recurrence and death.
“The main finding was that patients who had a family member with colon or rectal cancer had improved outcomes,” said Dr. Chan “Patients with a family history of colon or rectal cancer had an approximately 25 percent decrease in the chances of having a cancer recurrence or death.”
Examining just the risk for cancer recurrence, patients with a family history of colorectal cancer had a 26 percent reduced risk compared with patients without a family history. Cancer recurrence occurred in 27 percent of patients with a family history of colorectal cancer and 35 percent of patients without a family history. The reduced risk of death for patients with a family history of colorectal cancer was 25 percent.
The apparent benefit associated with family history was stronger with an increasing number of affected family members. Compared with participants without a family history of colorectal cancer, participants with two or more affected relatives had a 51 percent lower risk for cancer recurrence or death.
“Beyond rare, well-characterized hereditary colorectal cancer syndromes, our data support the hypothesis that a relatively common though less penetrant genetic predisposition may not only influence colorectal cancer risk but also patient survival. This finding may reflect a distinct underlying molecular and pathogenic mechanism in cancers that develop in the setting of a common (i.e., sporadic) family history,” the researchers write. “Further studies are needed to more fully elucidate potential mechanisms by which a common family history may influence the outcome for patients with colorectal cancer.”
The study appears in the June 4 issue of JAMA.