A new commentary in the New England Journal of Medicine has cautioned clinicians to tone down the perceived benefits of earlier screening in colorectal cancer.
Two health policy researchers, both physicians, have cautioned clinicians to tone down the perceived benefits of earlier screening in colorectal cancer (CRC) as being responsible for the positive trends that have been witnessed with the disease.
In their commentary in the New England Journal of Medicine, H. Gilbert Welch, MD, MPH, and Douglas J. Robertson, MD, MPH, both from the Dartmouth Medical School, appreciate the impact that screening has had on CRC incidence and mortality. The authors reference multiple trials that established the positive impact of screening:
However, when the authors evaluated the overall disease trend over nearly 40 years, between 1975 and 2012, among adults older than 50 years, they observed a 40% reduction in incidence since 1975. Additionally, CRC-related death reduced by more than 50% during that period, they write.
What the authors question is the timing of the observed trends, considering the delayed adoption of CRC screening in the clinic—only 23% of those 50 years and older were screened in 1987 and only 50% in 2005. Accounting for the lag time in the effect on mortality, “it’s hard to imagine a substantial screening effect at the population level showing up much before this new millennium started,” according to the authors. They propose the following to explain the decrease in mortality:
At the recently held annual meeting of the National Comprehensive Cancer Network, Alan P. Venook, MD, professor of Clinical Medicine at the University of California, San Francisco, however explained that despite the advances in understanding CRC and the improved treatments, success—measured in terms of mortality—has been rather insignificant. “There have been significant improvements in diagnosis and imaging techniques over the past few years, which can aide decisions on who could gain from surgery. However, a sum of all treatments that have been developed over the last decade finds that 10 months [overall survival] seems the most that has been achieved, although progression-free survival keeps improving.”
Welch and Robertson warn that exaggerating the benefits of screening could result in unnecessary follow-up colonoscopies in the older population, which might even cause harm.
Welch HG, Robertson DJ. Colorectal cancer on the decline—why screening can’t explain it all. N Engl J Med. 2016;374:1605-1607. doi:10.1056/NEJMp1600448.