From the Research
Out of 1000 fit tests, approximately 2-5% will result in a cancer diagnosis, which translates to around 20-50 cancers detected. This estimate is based on the assumption that the population being screened and the cutoff value used for the test are similar to those in previous studies 1, 2. The detection rate varies because FIT primarily detects blood in the stool, which can be caused by colorectal cancer but also by other conditions like hemorrhoids, polyps, or inflammatory bowel disease. Some of the evidence provided does not directly relate to the question of FIT tests and cancer detection, such as the study on lung cancer screening 1 or the overview of cancer 3. However, the study on cancer statistics 4 provides some context on the overall burden of cancer and the importance of early detection. It's worth noting that the sensitivity of FIT for detecting colorectal cancer ranges from 70-85%, meaning it will miss some cancers, but its high specificity (around 90-95%) means it has relatively few false positives 5. Regular screening with FIT has been shown to reduce colorectal cancer mortality by enabling earlier detection and treatment of cancers. Key points to consider when interpreting the results of FIT tests include:
- The population being screened and the cutoff value used for the test
- The sensitivity and specificity of the test
- The potential for false positives and false negatives
- The importance of regular screening and follow-up colonoscopies. Overall, while the exact number of cancers detected out of 1000 fit tests may vary, the evidence suggests that FIT is a useful tool for detecting colorectal cancer and reducing mortality from this disease 1, 2, 4.