Modern medicine has developed screening as a tool to hopefully catch and treat various cancers at an early stage. This includes prostate cancer, breast cancer, and colon cancer. Does cancer screening save lives?
One need only spend a few minutes watching NFL football these days to see its “Crucial Catch” program to raise awareness of such screening.
However, screening is not a totally benign procedure: it carries with it risks as well. As detailed previously on this blog in the context of prostate cancer, there are risks of injury to the screening process itself, risks of false positives (detecting cancer when there is none), and the accompanying risk of harm from the cancer treatment itself (including radiation and chemotherapy).
Add to that the patient prep involved, and one begins to see that there are real world costs to screening. So the benefits should be, well, beneficial, if patients are going to go through the process.
Consider then, the New England Journal of Medicine article reflecting the results of the most recent study examining the effectiveness of colon cancer screening versus no screening. A handy summary and analysis can be found here: Understanding the Results of a Randomized Trial of Screening Colonoscopy.
The big picture: in a comparison between those people who were screened for colon cancer versus those who were not, only 18% of those screened were less likely to develop colon cancer. More striking, the overall death rate was about the same. That is – screening didn’t save any lives.
There are some possible explanations the authors give for this seemingly trivial benefit to screening. For one, fewer than half the people invited to participate in screening actually took advantage of it. Presumably, if more people are screened, more cancer will be detected. In a society such as ours (the study took place in Poland, Norway and Sweden), with a relatively high participation rate, it may show a greater incidence of detected (and subsequently treated) cancer.
And those who did participate seemed to be high risk people – these folks had high detection rates of cancer. It is possible, then, that the rates of cancer deaths would have been lower had more asymptomatic people agreed to participate (thereby catching more cancer at an earlier stage, as screening is intended to do).
Another possible explanation for these results includes that it takes time to realize whether the screening has indeed been effective at reducing cancer deaths. Consider that during screening, presymptomatic cancers are identified and removed. It will take time to understand how many cancer deaths are prevented from this practice.
Still, the results are sobering. From a medical malpractice perspective, this is reminiscent of the data on prostate cancer screening from years ago. If the claim is that the patient should have been screened for colon cancer and was not, and as a result undetected cancer was allowed to grow and cause harm, this study may call into question whether the standard of care requires such screening.
