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ASCO issues guideline for early detection, management of colorectal cancer
The panel included experts in medical oncology, surgery, cancer epidemiology, pathology, radiology, radiation oncology, and patient advocacy.
Colorectal cancer (CRC) ranks among the most common causes of cancer and cancer-related death in the US. The US Multi-Society Task Force (USMSTF) on Colorectal Cancer thus strongly endorsed using several available screening options.1 The published guidelines largely rely on age to define the target population (Table 1). For average-risk individuals, national and Veterans Health Administration (VHA) guidelines currently recommend CRC screening in individuals aged between 50 and 75 years with a life expectancy of > 5 years.1
Although case-control studies also point to a potential benefit in persons aged > 75 years,2,3 the USMSTF cited less convincing evidence and suggested an individualized approach that should consider relative cancer risk and comorbidity burden. Such an approach is supported by modeling studies, which suggest reduced benefit and increased risk of screening with increasing age. The reduced benefit also is significantly affected by comorbidity and relative cancer risk.4 The VHA has successfully implemented CRC screening, capturing the majority of eligible patients based on age criteria. A recent survey showed that more than three-quarters of veterans between age 50 and 75 years had undergone some screening test for CRC as part of routine preventive care. Colonoscopy clearly emerged as the dominant modality chosen for CRC screening and accounted for nearly 84% of these screening tests.5 Consistent with these data, a case-control study confirmed that the widespread implementation of colonoscopy as CRC screening method reduced cancer-related mortality in veterans for cases of left but not right-sided colon cancer.6
With calls to expand the age range of CRC screening beyond aged 75 years, we decided to assess survival rates of a cohort of veterans who underwent a screening or surveillance colonoscopy between 2008 and 2014.7 The goals were to characterize the portion of the cohort that had died, the time between a screening colonoscopy and death, the portion of deaths that were aged ≥ 80 years, and the causes of the deaths. In addition, we focused on a subgroup of the cohort, defined by death within 2 years after the index colonoscopy, to identify predictors of early death that were independent of age.
Methods
We queried the endoscopy reporting system (EndoWorks; Olympus America, Center Valley, PA) for all colonoscopies performed by 2 of 14 physicians at the George Wahlen VA Medical Center (GWVAMC) in Salt Lake City, Utah, who performed endoscopic procedures between January 1, 2008 and December 1, 2014. These physicians had focused their clinical practice exclusively on elective outpatient colonoscopies and accounted for 37.4% of the examinations at GWVAMC during the study period. All colonoscopy requests were triaged and assigned based on availability of open and appropriate procedure time slots without direct physician-specific referral, thus reducing the chance of skewing results. The reports were filtered through a text search to focus on examinations that listed screening or surveillance as indication. The central patient electronic health record was then reviewed to extract basic demographic data, survival status (as of August 1, 2018), and survival time in years after the index or subsequent colonoscopy. For deceased veterans, the age at the time of death, cause of death, and comorbidities were queried.
