A study published online on yesterday in the Journal of the National Cancer Institute shows, that lower levels of colorectal cancer (CRC) incidence and mortality are linked to a single flexible sigmoidoscopy screening between the ages of 55-64 years.

According to multiple randomized controlled trials, fecal occult blood testing (FOBT) in CRC screening can lower the mortality rate of patients diagnosed with CRC.

A lower incidence and mortality rate for cancer in the rectum and sigmoid colon (distal CRC) among patients who had undergone endoscopy indicate, that the removal of adenomas at screening can lead to long-term protection against the development of distal CRC. The findings were made through observational studies and a prior, randomized trial from the UK, called SCORE.

Researchers, led by Nereo Segnan, M.D., of the Epidemiology Unit at S. Giovanni University Hospital in Turin, Italy, mailed a questionnaire to a random population sample of men and women between the ages of 55-64 years, enquiring about their interest in FS screening to determine if single flexible sigmoidoscopy is a good preventative measure in CRC screening. Eligible interested participants were randomly assigned to two groups, the control group (N= 17148 – no further contact) or intervention group (N=17144 – invitation for flexible sigmoidoscopy).

The trial consisted of 9,911 participants of which 74 patients did not comply with the recommended total colonoscopy assessment.

From the total of 9,911 patients, 9,387 (94.71%) participants were discharged, 55 (0.55%) were referred for surgery and a follow-up surveillance colonoscopy was recommended to 395 individuals.

During a median follow-up period of 10.5 years for CRC incidence and 11.4 years for all-cause and CRC-specific mortality, 557 people (including those detected at initial screening) were diagnosed with a CRC and 148 died of the disease.

Researchers discovered, that in the intent-to-treat analysis, CRC incidence and mortality were lowered by 18% and 22%, respectively. Among screened patients, (per – protocol analysis) CRC incidence was reduced by 31%, and by 46% for advanced CRC cases. In addition, CRC mortality in screened subjects was statistically significantly reduced by 38% compared to the control group.

The reported findings are consistent with the observed reduction of CRC incidence and mortality among people screened in the recently published UK Flexible Sigmoidoscopy Screening Trial. Authors support the proposition, stating, “Flexible sigmoidoscopy screening offered just once represents a safe and effective method for CRC screening and ensures a long lasting reduction of CRC risk. A longer follow-up is needed to fully assess the impact on mortality and to estimate the duration of the protective effect.”

Timothy R. Church, Ph.D., of the University of Minnesota writes about what approach to CRC screenings may be best, in an accompanying editorial.

Taking the three main CRC tests (flexible sigmoidoscopy, FOBT, and colonoscopy) into consideration, Church mentions, that a cost-effective analysis is an important factor in determining the best available method, commenting, “these costs are driven by not only the up-front infrastructure costs for laboratories, equipment, endoscopy facilities, training, and manufacturing but also by the rates of false-positive results.”

He argues the best way to attack CRC is to endorse all three methods until more substantial evidence is collected, since none of the standard three approaches to CRC screening is more effective than the other. With regard to the possibility of obtaining conflicting results from the tests, Church comments, “Any concerns about the potential confusion that arises from multiple approaches may be balanced by the advantages of tailoring screening to the preferences of the patient.”

Written by Petra Rattue