Screen-detected colon cancer patients experience fewer complications
medwireNews: Patients whose colon cancers are detected by routine screening have fewer postoperative complications than individuals whose cancers are diagnosed outside of a national programme, study findings indicate.
By contrast, the outcome of patients with rectal cancer showed no such relationship with screening status, the authors report in JAMA Surgery.
“One of the potential explanations might be that rectal cancer is becoming symptomatic at a relatively early stage compared with colon cancer, which reduces the differences between screen-detected and non–screen-detected cancers”, they hypothesize.
Michael de Neree tot Babberich (Academic Medical Center, Amsterdam, the Netherlands) and team gathered data from the Dutch ColoRectal Audit of patients who underwent colon cancer (n=36,242) or rectal cancer (n=17,416) resection between 2011 and 2016.
Colon cancer was detected during the national faecal immunochemical test screening programme in 22.8% of patients, while rectal cancer was identified by screening in 16.6% of cases.
The researchers found that patients whose cancer was detected by screening were, on average, younger than those diagnosed by another means (68 vs 70 years), were more likely to be male (60 vs 57%) and had fewer risk factors for surgery, as denoted by a lower American Society of Anesthesiologists score (III+, 13 vs 23%).
In multivariate analysis, taking into consideration age, gender and other risk factors, patients with stage I–III colon cancer who had screen-detected disease had a significantly lower likelihood of experiencing postoperative complications than those whose disease was not detected by screening.
This was true for a combination of pulmonary complications, infection and other nonsurgical events (11.8 vs 18.5%, odds ratio [OR]=0.81), for surgical complications (12.0 vs 17.0%, OR=0.80) and for the likelihood of a complicated postoperative course, when a patient required more than 14 days in hospital or reintervention, or died (9.2 vs 14.4%, OR=0.80).
These associations continued even after correcting for case mix, the researchers observe, “implying additional underlying factors favoring patients referred for surgery through the screening program.”
Among rectal cancer patients, the only significant impact screening appeared to have on outcome was found among stage IV patients, who had an increased risk of death with screen-detected disease.
“Stage IV screen-detected cancer may consist of a specific category of patients, with either aggressive tumor biology or relatively small asymptomatic primaries that eventually will develop metastases at an asymptomatic stage or patients who neglect initial symptoms and retrospectively should have been diagnosed earlier”, suggest de Neree tot Babberich et al.
Discussing their findings, the authors conclude: “Future studies on surgical outcomes of colorectal cancer treatment should be aware of the differences between patients detected through the screening program and non–screen-detected patients and consequently take this into account in their comparison models.”
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