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19-05-2011 | Surgery | Article

Fittest benefit most from colorectal cancer screening


Free abstract

MedWire News: Older adults with the best life expectancies obtain the most benefit from current colon cancer screening methods, US study findings indicate.

For those with the worst life expectancies, the burdens of screening may outweigh the benefits, Christine Kistler (University of North Carolina, Chapel Hill) and colleagues report in the Archives of Internal Medicine.

"This study shows that we really need to target screening in older adults, so that those who will benefit do get screened and followed-up while those who won't benefit aren't exposed to unnecessary burdens," said Kistler.

The researchers explain that systematic reviews of colorectal cancer screening have called for more studies to assess the net benefit of real-world colorectal cancer screening practices.

To address this, Kistler and team followed-up 212 patients (aged 70-89 years), treated at one of four Veteran Affairs facilities, for 7 years after receiving a positive result in a fecal occult blood test (FOBT).

The researchers observed that 118 (56.0%) patients received a follow-up colonoscopy during the follow-up period. Of these, six (5.1%) had cancer, 34 (28.8%) had significant adenoma, and 70 (59.3%) had neither cancer nor significant adenoma.

In all, 20 (16.9%) of these 118 patients died within 5 years of causes other than colorectal cancer, and 12 (10.2%) suffered complications from either colonoscopy or cancer treatment.

Among the 94 patients who did not receive follow-up colonoscopy, 43 (45.7%) died of other causes within 5 years of their positive FOBT, while three (7.0%) died of colorectal cancer..

Of the 212 study participants, the researchers classified 33 (15.6%) as receiving a net benefit from their positive FOBT. These patients were diagnosed with cancer or significant adenomas on follow-up colonoscopy and lived at least 5 years.

Another 30 (14.2%) patients - with non-significant adenomas or no pathology report - were defined as receiving indeterminate benefit, while the remaining 149 (70.3%) patients were defined as receiving a net burden from colorectal cancer screening.

Of note, the proportion of patients receiving a net burden varied across three prognostic groups. It ranged from 87% among patients with the worst life expectancy (<5 years), to 70% among those with average life expectancy (5-10 years), and 65% among those with the best life expectancy (>10 years).

Kistler said there was "a spectrum of burden" among those in the net burden group. For some, the burden was that they never received a follow-up colonoscopy. Others received a colonoscopy but it found no evidence of cancer, and some died of causes other than colon cancer.

Our study supports guidelines that recommend using life expectancy to guide colorectal cancer screening decisions in older adults and argues against one-size-fits-all interventions that simply aim to increase overall screening and follow-up rates.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Laura Dean

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