FIT-Based Colorectal Cancer Screening Cuts CRC Deaths

By Megan Brooks

September 15, 2014

NEW YORK (Reuters Health) - Colorectal cancer screening programs based on the fecal immunochemical test (FIT) significantly reduce CRC-specific mortality much earlier and to a larger extent than reported for guaiac fecal occult blood test (gFOBT), according to an ecological study conducted in the Veneto Region of Italy.

Biennial FIT-based screening was introduced in different areas in the region between 2002 and 2009.

Dr. Manuel Zorzi of the Veneto Tumour Registry and colleagues compared CRC death rates between the areas where screening started in 2002-2004 (early screening areas) and areas that introduced screening in 2008-2009 (late screening areas).

Before the screening was introduced, CRC death rates and incidence rates in the two areas were similar, they note in a report online September 1 in Gut.

Compared with 1995-2000, 2006-2011 death rates were 22% lower in the early screening areas than in the late screening areas (rate ratio 0.78; 95% CI 0.68 to 0.89).

"Today, it is possible to tell to a person that if she/he undergoes a FIT and complies with the eventual subsequent diagnostic workup, he/she will reduce the risk of dying from colorectal cancer by more (and probably much more) than 20%," Dr. Zorzi told Reuters Health by email.

The impact of FIT programs on mortality was "greater and took place earlier" compared with available evidence on gFOBT-based screening programs, they note in their paper.

The reduction in CRC mortality with FIT was greater in women (RR 0.64; 95% CI 0.51 to 0.80) than in men (RR 0.87; 95% CI 0.73 to 1.04).

"We also showed a relevant impact in terms of a reduction of colorectal cancer resection rates. This is relevant both for the population's health and in terms of economic savings for the health system," Dr. Zorzi said.

"This ecological study provides the first evidence regarding the impact of FIT-based CRC screening programs on CRC mortality," they note.

They conclude, "A screening schedule based on a single FIT with a positivity cut-off for a hemoglobin concentration of 20 mg Hb/g feces (100 ng Hb/mL buffer) and an inter-screening interval of 2 years significantly reduces CRC mortality. The reduction of incidence rates associated with the removal of precancerous lesions may convey an even higher impact on mortality in the medium-long-term."

Dr. Zorzi said, "The real impact of FIT-based screening on mortality in the subjects who actually undergo FIT is surely higher also because our results are underestimated, given the nature of our ecological study. In fact, we compared the whole populations of areas with and without a screening programme, thereby including in the former all the subjects who did not comply with invitation to screening. This diluted our results. In order to overcome this limitation, we are carrying out a cohort study, where we compare the subjects who were actually screened with FIT with those who did not."

Do the findings have relevance to the U.S.?

Dr. Zorzi said, "The spread of total colonoscopy (TC) as the preferred screening tool in the U.S. could limit the relevance of our results. However, FIT may be an interesting alternative for all the subjects who, for different reasons, do not undergo a TC. Moreover, FIT could represent an effective strategy in the areas where the coverage with TC is limited due to shortage of endoscopists."


Gut 2014.


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