Age-specific sequence of colorectal cancer screening options in Germany: A model-based critical evaluation.

Background: The current organized screening program for colorectal cancer in Germany offers both sexes 5 annual fecal immunochemical tests (FITs) between ages 50 and 54 years, followed by a first screening colonoscopy at age 55 years if all of these FITs were negative. We sought to assess the implications of this approach for key parameters of diagnostic performance. Methods and findings: Using a multistate Markov model, we estimated the expected detection rates of advanced neoplasms (advanced adenomas and cancers) and number needed to scope (NNS) to detect 1 advanced neoplasm at a first screening colonoscopy conducted at age 55 after 5 preceding negative FITs and compared them with the corresponding estimates for a first screening colonoscopy at age 55 with no preceding FIT testing. In individuals with 5 consecutive negative FITs undergoing screening colonoscopy at age 55, expected colonoscopy detection rate (NNS) was 3.7% (27) and 0.10% (1,021) for any advanced neoplasm and cancer, respectively, in men, and 2.1% (47) and 0.05% (1,880) for any advanced neoplasm and cancer, respectively, in women. These NNS values for detecting 1 advanced neoplasm are approximately 3-fold higher, and the NNS values for detecting 1 cancer are approximately 8-fold higher, than those for a first screening colonoscopy at age 55 without prior FITs. This study is limited by model simplifying assumptions and uncertainties related to input parameters. Conclusions: Screening colonoscopy at age 55 after 5 consecutive negative FITs at ages 50–54, as currently offered in the German cancer early detection program, is expected to have very low positive predictive value. Our results may inform efforts to enhance the design of screening programs. Thomas Heisser and colleagues model outcomes from colorectal cancer screening in Germany. Author summary: Why was this study done?: The current screening approach for colorectal cancer (CRC) in Germany offers both men and women 5 annual fecal immunochemical tests (FITs, a test for blood in stool) at ages 50–54, followed by a first screening colonoscopy at age 55 in case all of these FITs were negative. The expected result of this sequential screening strategy is unknown. What did the researchers do and find?: In a simulated population of 100,000 men and 100,000 women, colonoscopy detection rates for cancer at age 55 were at or below 0.10% for both sexes after 5 consecutive negative FITs. Looked at another way, 1,000 colonoscopies would be needed in men and 1,900 colonoscopies would be needed in women to detect 1 CRC. These numbers are 8-fold higher than those for a first screening colonoscopy at age 55 without prior FITs. What do these findings mean?: Although annual FITs at ages 50–54 may contribute to earlier diagnosis of CRC, the current sequence of CRC screening, if fully adhered to, may not use screening capacities in the most efficient manner. Our results should inform and encourage efforts to design more rational sequences of screening offers. [ABSTRACT FROM AUTHOR]