A new study suggests that tests for blood in the stool can detect colon cancer when used annually, U.S. News reports.

The researchers said these findings suggest that the stool test could be a screening alternative to colonoscopy.

Study co-author Dr. Douglas Corley, a research scientist with Kaiser Permanente in Oakland, Calif. said that experts examine stool samples for microscopic amounts of blood shed by colon tumors, known as fecal immunochemical tests.

For the study, the researchers analyzed annual fecal blood tests performed on nearly 325,000 Kaiser Permanente patients in California during a four-year period.

The first year of screening with fecal blood tests detected colon cancer in 84.5 percent of participants, the study reported.

"We found that the sensitivity for cancer was somewhat higher in the first year, and that's not surprising," Corley said. "The first year you screen someone, for breast cancer or for anything, you're going to find cancers that have been there for a while that may be larger or are easier to detect."

However, the effectiveness of the fecal blood test varied between 73 percent and 78 percent in years two through four.

The findings were published Jan. 25 in the Annals of Internal Medicine.

Dr. Richard Wender, chief cancer control officer at the American Cancer Society, said: "We really can find early cancers continuously as they're getting bigger. And over a 10-year period this test is in all likelihood going to prevent the same number of deaths as a colonoscopy performed once every 10 years."

These new results show that an annual blood fecal test could be just as effective as colonoscopy in screening for colon cancer, the researchers concluded.

On the other hand, the colonoscopy procedure only has to be done once every 10 years, and is close to 100 percent effective at detecting cancers and precancerous polyps.

Therefore, colon cancer screening programs should offer both fecal blood tests and colonoscopy, the experts said.

"You end up getting more people screened, because it allows people to select what works the best for them," Corley said.