The introduction of biennial colorectal cancer screening increased the rate of diagnosis of high-risk precancerous adenomas by 89%, in a region of France. This research was reported at the European Society for Medical Oncology (ESMO) 2014 Congress in Madrid, Spain.
Vanessa Cottet, PhD, from INSERM Unité 866 in Dijon, France, and colleagues studied the region of Côte-d’Or, where a registry has been collecting data on adenomas since 1976. They wanted to evaluate the rate of diagnosis of adenomas before and after the initiation of a screening program using fecal occult blood testing that began in 2003.
The study included all residents age 50 to 74 years who had a first adenoma identified between January 1997 and December 2008. The researchers showed that 38.7% of these people had high-risk adenomas, which meant they were larger than 1 cm in diameter, involved the fingerlike projections, or villi, in the intestinal lining, or exhibited a high grade of dysplasia.
For such high-risk adenomas, age-standardized diagnosis rates were 136 per 100,000 people before the screening program and 257 per 100,000 after, which correlates to a percentage increase of 89%. The corresponding rates for nonadvanced adenomas were 235 and 392 diagnoses per 100,000, with a percentage increase of 68%.
These results reinforce the value of extending organized mass screening programs for colorectal cancer. “It is very important that public follows recommendations and participates in colorectal cancer screening campaigns,” Cottet said. “Participation rate is a major issue for the success of such programs.”
The authors also found that the rate of detection did not continue increasing between the 2005 and 2007 rounds of screening. However, they suggest that shifting the methodology used in the screening programs from the more common guaiac test to immunochemical testing will improve results in the future.
“Immunochemical fecal occult blood tests outperform guaiac tests for the detection of colorectal cancer and advanced adenoma,” Cottet said. “They have doubled the detection rate of invasive colorectal cancer, mostly at early stages, and led to a fourfold increase in the detection rate of noninvasive colorectal cancer and advanced adenomas.”
“Given the superior performance of immunochemical tests, it is reasonable to assume that an organized screening program using such tests would led to a greater reduction of colorectal cancer death and probably to a reduction in colorectal cancer incidence.”
“These data favor the widely used standard approach of routine use of FOBT followed by colonoscopy only when the FOBT test is positive, rather than colonoscopy first. However, if colonoscopy is restricted only to those patients who have positive FOBT, there is a high chance that adenoma or even cancer can be not identified. Therefore the optimal method remains the colonoscopy in all patients,” said Professor Hans-Joachim Schmoll, former head of the Division of Hematology and Oncology and director of the Center for Cell and Gene Therapy, Martin Luther University, Halle, Germany, and professor of medicine at Martin Luther University, Germany.