ABSTRACT
BACKGROUND: Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality. A well-defined precursor lesion (adenoma) and a long preclinical course make CRC a candidate for screening. This paper reviews the current evidence for the most important tests that are widely used or under development for population-based screening. MATERIAL AND METHODS: In this narrative review, we scrutinized all papers we have been aware of, and carried out searches in PubMed and Cochrane library for relevant literature. RESULTS: Two screening methods have been shown to reduce CRC mortality in randomised trials: repetitive faecal occult blood testing (FOBT) reduces CRC mortality by 16%; once-only flexible sigmoidoscopy (FS) by 28%. FS screening also reduces CRC incidence (by 18%), FOBT does not. Colonoscopy screening has a potentially larger effect on CRC incidence and mortality, but randomised trials are lacking. New screening methods are on the horizon but need to be tested in large clinical trials before implementation in population screening. CONCLUSIONS: FS screening reduces CRC incidence and CRC mortality by removal of adenomas; FOBT reduces CRC mortality by early detection of cancer. Several other tests are available, but none has been evaluated in randomised trials. Screening strategies differ considerably across countries.
Subject(s)
Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/prevention & control , Early Detection of Cancer , Mass Screening/methods , Adenoma/diagnosis , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Colonoscopy , Colorectal Neoplasms/mortality , Humans , Occult Blood , Patient Compliance , Sensitivity and Specificity , SigmoidoscopyABSTRACT
BACKGROUND AND STUDY AIM: While colonoscopy screening is widely used in several European countries and the United States, there are no randomized trials to quantify its benefits. The Nordic-European Initiative on Colorectal Cancer (NordICC) is a multinational, randomized controlled trial aiming at investigating the effect of colonoscopy screening on colorectal cancer (CRC) incidence and mortality. This paper describes the rationale and design of the NordICC trial. STUDY DESIGN: Men and women aged 55 to 64 years are drawn from the population registries in the participating countries and randomly assigned to either once-only colonoscopy screening with removal of all detected lesions, or no screening (standard of care in the trial regions). All individuals are followed for 15 years after inclusion using dedicated national registries. The primary end points of the trial are cumulative CRC-specific death and CRC incidence during 15 years of follow-up. POWER ANALYSIS: We hypothesize a 50 % CRC mortality-reducing efficacy of the colonoscopy intervention and predict 50 % compliance, yielding a 25 % mortality reduction among those invited to screening. For 90 % power and a two-sided alpha level of 0.05, using a 2:1 randomization, 45 600 individuals will be randomized to control, and 22 800 individuals to the colonoscopy group. Interim analyses of the effect of colonoscopy on CRC incidence and mortality will be performed at 10-year follow-up. CONCLUSIONS: The aim of the NordICC trial is to quantify the effectiveness of population-based colonoscopy screening. This will allow development of evidence-based guidelines for CRC screening in the general population.
Subject(s)
Colonoscopy/methods , Colorectal Neoplasms , Mass Screening/methods , Colonoscopy/psychology , Colonoscopy/statistics & numerical data , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/epidemiology , Colorectal Neoplasms/mortality , Colorectal Neoplasms/surgery , Early Detection of Cancer/methods , Early Detection of Cancer/statistics & numerical data , Europe/epidemiology , Female , Follow-Up Studies , Humans , Incidence , Male , Mass Screening/statistics & numerical data , Middle Aged , Patient Compliance , Patient Selection , Registries , Research Design , Survival Analysis , Treatment OutcomeABSTRACT
BACKGROUND AND STUDY AIMS: Screening colonoscopy for colorectal cancer (CRC) is recommended in several countries, but uptake rates are often low. Fear of pain and also time-consuming costly sedation are barriers for colonoscopy, and thus development of colonoscopy equipment that decreases patient discomfort is worthwhile. This randomized controlled trial investigated the performance of an ultrathin colonoscope in CRC screening. PATIENTS AND METHODS: Consecutive participants in a colonoscopy screening trial were randomized to examination with an ultrathin prototype colonoscope or a standard colonoscope. The main outcome measure was pain during the examination. Participants rated pain (no, slight, moderate, severe) using a validated questionnaire. RESULTS: From 187 enrolled participants (80 women [43 %]), 162 (87 %) responded to the questionnaire. The study groups were similar regarding baseline characteristics. Pain scores were significantly lower in the prototype instrument group compared with the standard group (78 % vs. 29 % of patients with no pain in prototype and standard groups, respectively; odds ratio [OR] 0.11; 95 % confidence interval [CI] 0.06 - 0.23; P < 0.001). Cecal intubation rate was 98 % in the prototype group and 92 % in the standard group (P = 0.085). Sedation was used in 2 % and 7 % in the prototype and standard groups respectively (P = 0.12). Adenoma detection rate was 13 % in the prototype group vs. 24 % in the standard group (P = 0.052). CONCLUSION: The new ultrathin Olympus colonoscope decreases patient pain during screening colonoscopy. This feature may improve uptake and patient satisfaction in screening colonoscopy. Further study is needed to evaluate the lower adenoma detection rate.
