Researchers have found that early screening measures for colorectal cancer has prevented up to half a million cases of cancer development over a 30-year period.

From 1976 to 2009, researchers from the Cancer Outcomes, Public Policy, and Effectiveness Research (COPPER) Center at Yale Cancer Center found that colorectal cancer was prevented from developing in thousands of cases thanks to early screenings.

During this 30-year time span, a steady increase was seen in the number of men and women undergoing screenings for the cancer, which included fecal occult blood testing, colonoscopies, and sigmoidoscopies. As a result, the incidence of colorectal cancer significantly decreased.

James Yu, M.D., lead study author and assistant professor of therapeutic radiology at Yale School of Medicine and the Yale COPPER team looked at the incidence of colorectal cancer from data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results database. The scientists discovered that late-stage cancer rates were reduced from 118 cases per 100,000 in those over age 50 down to 74 cases per 100,000.

These numbers represent real patients and families who have been spared the trauma of a cancer diagnosis and treatment. “Colorectal cancer screening is one of the major successes in cancer care,” said Yu in a statement.

The findings of this study are of particular interest, especially after the recent controversy regarding mammography screening for breast cancer, where false positives and over treatment have been associated with this screening.

The findings of the study are published in the journal Cancer.