Screening performance differs with distinct fecal test brands

(HealthDay)—Different brands of fecal immunochemical tests (FITs) with the same cutoff hemoglobin concentration perform differently in detection of colorectal cancer (CRC), according to a study published in the December issue of Gastroenterology.

Tsung-Hsien Chiang, M.D., from the National Taiwan University in Taipei, and colleagues examined whether two quantitative FITs with the same cutoff concentration of fecal hemoglobin perform equivalently. Data were collected from 956,005 Taiwanese subjects, aged 50 to 69 years, who participated in a nationwide CRC screening program. Results were compared from two FITs: the OC-Sensor (78 percent) and the HM-Jack (22 percent).

The researchers found that the OC-Sensor test and the HM-Jack test detected CRC in 0.21 and 0.17 percent of patients, respectively, with positive predictive values of 6.8 and 5.2 percent, respectively. Among patients receiving the OC-Sensor test and HM-Jack test, the rates of interval cancer were 30.7 and 40.6/100,000 person-years, respectively; the difference in test sensitivity was significant (80 versus 68 percent; P = 0.005) and was associated with the detectability of proximal CRC. There were significant differences between the tests in the positive predictive value for cancer detection (adjusted relative risk, 1.29) and rates of interval cancer (0.75), after adjustment for confounders. Each test was estimated to reduce CRC mortality by about 10 percent, with no significant difference noted in mortality between the two groups.

"Population-level data should be gathered to verify the credibility of quantitative laboratory findings," the authors write.

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