New York, Researchers, including one of Indian-origin, have found that early screening based on family history may have dramatic effects on colorectal cancer detection.

In an analysis that included information on adults diagnosed with colorectal cancer between 40 and 49 years of age, almost all patients could have been diagnosed earlier if they had been screened according to current family history-based screening guidelines.

"Our findings suggest that using family history-based criteria to identify individuals for earlier screening is justified and has promise for helping to identify individuals at risk for young-onset colorectal cancer," said study researcher Samir Gupta from the University of California San Diego in the US.

The study, published in the journal Cancer, said that in many countries, colorectal cancer rates are rising in adults under age 50.

To identify those at risk, current guidelines recommend early screening for colorectal cancer among individuals with a family history of the disease.

For example, for individuals with a first-degree relative with colorectal cancer, several medical societies recommend initiating screening at 40 years of age or 10 years prior to the age at diagnosis of the youngest relative diagnosed with colorectal cancer.

To estimate the potential impact of family history-based guidelines for screening, the research team examined information on individuals 40 to 49 years of age - 2,473 with colorectal cancer and 772 without - in the Colon Cancer Family Registry from 1998 to 2007.

The Colon Cancer Family Registry contains information and specimens contributed by more than 15,000 families around the world and across the spectrum of risk for colorectal cancer.

The investigators found that 25 per cent of individuals with colorectal cancer and 10 per cent of those without cancer met the criteria for family history-based early screening.

Almost all (98.4 per cent) patients with colorectal cancer who met these criteria should have been screened at a younger age than when their cancer was diagnosed.

Therefore, they could have had their cancer diagnosed earlier, or possibly even prevented if earlier screening had been implemented based on family history-based guidelines, the researchers said.