Colorectal Cancer Benefits With Flexible Sigmoidoscopy Screening in SCORE Trial Are Generalizable to Broader Population
The Italian SCORE trial is among several recent large European randomized trials showing the benefit of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality. In a study reported in the Journal of the National Cancer Institute, Senore et al found that characteristics of individuals who responded to the SCORE recruitment questionnaire who were interested in screening had a similar risk of colorectal cancer as the remainder of the target population, suggesting that self-selection did not result in obvious bias in the trial and that outcomes in SCORE can be generalized to the broader population.
Among all individuals sent a screening questionnaire, 115,565 (83.3%) did not respond, 9,462 (6.8%) responded but were uninterested in screening, and 13,638 (9.8%) responded and were interested in screening. Both interested and uninterested responders were better educated than nonresponders. Among responders, men and individuals aged < 60 years were more likely to volunteer.
Similar Colorectal Cancer Incidence, Reduced Mortality
At 11-year follow-up, the risk of colorectal cancer did not differ among interested responders, uninterested responders, and nonresponders (multivariate hazard ratios [HRs] = 0.96, 95% confidence interval [CI] = 0.84–1.09, for interested responders and 1.00, 95% CI = 0.85–1.16, for uninterested responders vs nonresponders). Compared with nonresponders, colorectal cancer mortality was significantly reduced among interested responders (multivariate HR = 0.70, 95% CI = 0.54–0.91) and nonsignificantly reduced among uninterested responders (multivariate HR = 0.84, 95% CI = 0.62–1.12), and all-cause mortality was reduced both among interested responders (HR = 0.61, 95% CI = 0.57–0.65) and uninterested responders (HR = 0.81, 95% CI = 0.76–0.86).
The investigators concluded: “[R]esponders expressing their interest in having screening represented a better-educated, health-conscious subgroup of the target population of the SCORE trial, showing similar [colorectal cancer] incidence and a substantially reduced overall, as well as [colorectal cancer], mortality. We can therefore assume that the implementation of a population-based screening program with [flexible sigmoidoscopy] would result in a similar reduction in [colorectal cancer] incidence, as observed in the trial. Efforts aimed at increasing [colorectal cancer] awareness in the general population could enhance screening participation also among nonresponders, resulting in a larger impact on [colorectal cancer] mortality.”
Carlo Senore, MD, MSc, of AOU Citta della Salute e della Scienza, Centro di Prevenzione Oncologica, Turin, is the corresponding author of the Journal of the National Cancer Institute article.
The SCORE trial was supported by the Associazione Italiana per la Ricerca sul Cancro and the Italian National Research Council. The study authors reported no potential conflicts of interest.
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