In a study reported in JAMA Network Open, Kahi et al found no differences in all-cause or cancer-specific mortality among veterans in the Veterans Affairs (VA) health-care system with colonoscopy-detected colorectal cancer vs those with postcolonoscopy-diagnosed colorectal cancer.
Study Details
The retrospective cohort study used Veterans Affairs-Medicare data to identify 29,877 veterans aged 50 to 85 years with newly diagnosed colorectal cancer between January 2003 and December 2013. Patients with colonoscopy less than 6 months before colorectal cancer diagnosis and no other colonoscopy within the previous 36 months were categorized as having detected colorectal cancer (DCRC). Patients who had a colonoscopy that did not detect colorectal cancer between 6 and 36 months before diagnosis were categorized as having postcolonoscopy colorectal cancer (PCCRC-3y). An additional group of patients consisted of those diagnosed with colorectal cancer who had no colonoscopy within the prior 36 months.
Key Findings
Among the 29,877 patients diagnosed with colorectal cancer, 1,785 (6%) were classified as having PCCRC-3y and 21,811 (73%) as having DCRC. A total of 6,281 patients had colorectal cancer diagnosed without colonoscopy within the prior 36 months.
All-cause mortality rates at 5 years were 42% for patients with DCRC vs 46% for patients with PCCRC-3y; the 5-year cancer-specific mortality rates were 25% vs 26%. On multivariate analysis, adjusted hazard ratios (HRs) for the PCCRC-3y vs DCRC groups were 1.04 (95% confidence interval [CI] = 0.98–1.11, P = .18) for all-cause mortality and 1.04 (95% CI = 0.95–1.13, P = .42) for cancer-specific mortality.
Among patients diagnosed with colorectal cancer who received no colonoscopy within the prior 36 months, 5-year rates were 63% for all-cause mortality and 45% for cancer-specific mortality. Compared with patients with DCRC, those with no colonoscopy had significantly higher all-cause mortality (HR = 1.76, 95% CI = 1.70–1.82, P < .001) and cancer-specific mortality (HR = 2.22, 95% CI = 2.12–2.32, P < .001).
Compared with patients with DCRC, patients with PCCRC-3y had significantly lower odds of having undergone a colonoscopy performed by a gastroenterologist (57% vs 73%, odds ratio = 0.48, 95% CI = 0.43–0.53, P < .001).
The investigators concluded, “This study found that PCCRC-3y constituted 6% of colorectal cancers in the VA system, which is similar to other settings. Compared with patients with colorectal cancer detected by colonoscopy, those with PCCRC-3y have comparable all-cause mortality and cancer-specific mortality.”
Charles J. Kahi, MD, MSc, of Indiana University, Indianapolis, is the corresponding author for the JAMA Network Open article.
Disclosure: The study was supported by Health Services Research and Development of the Veterans Health Administration and U.S. Department of Veterans Affairs. For full disclosures of the study authors, visit jamanetwork.com.
