Use of a simple immunochemical fecal occult blood test (FOBT), in combination with the traditional guaiac FOBT, can more accurately detect colorectal cancer and may reduce the need for a more invasive colonoscopy.
That finding appears in a study published Thursday in The Lancet Oncology journal.
While guaiac FOBT, which detects blood in the feces, is inexpensive and relatively easy to do, it’s not very accurate and has low clinical sensitivity and specificity, because cancer is not the only cause of blood in feces, the British researchers noted.
People who test positive on guaiac FOBT have a follow-up colonoscopy, which is a more expensive procedure and carries some risks, the study authors added.
They proposed that people who have weak or moderate positive guaiac FOBT results have a follow-up immunochemical FOBT to identify those who would be less likely to have cancer and not require a colonoscopy.
The researchers used the immunochemical FOBT to test samples from more than 700 people who had a positive guaiac FOBT. Of these people, 22 percent tested negative in both samples (N/N), 16 percent tested positive in one of two samples (N/P), and 62 percent tested positive in both samples (P/P).
Only one patient in each of the N/N and N/P groups had colorectal cancer, compared with 38 (8 percent) in the P/P group, the researchers said.
The research was led by Dr. Callum G. Fraser, of the department of biochemical medicine at Ninewells Hospital and Medical School in Dundee, England.