https://www.medpagetoday.com/upload/2008/3/6/CRC.pdf

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(96)03386-7.pdf

Randomised controlled trial of faecal-occult-blood screening for colorectal cancer

BACKGROUND In the National Polyp Study (NPS), colorectal cancer was prevented by colonoscopic removal of adenomatous polyps. We evaluated the long-term effect of colonoscopic polypectomy in a study on mortality from colorectal cancer. METHODS We included in this analysis all patients prospectively referred for initial colonoscopy (between 1980 and 1990) at NPS clinical centers who had polyps (adenomas and nonadenomas). The National Death Index was used to identify deaths and to determine the cause of death; follow-up time was as long as 23 years. Mortality from colorectal cancer among patients with adenomas removed was compared with the expected incidence-based mortality from colorectal cancer in the general population, as estimated from the Surveillance Epidemiology and End Results (SEER) Program, and with the observed mortality from colorectal cancer among patients with nonadenomatous polyps (internal control group). RESULTS Among 2602 patients who had adenomas removed during participation in the study, after a median of 15.8 years, 1246 patients had died from any cause and 12 had died from colorectal cancer. Given an estimated 25.4 expected deaths from colorectal cancer in the general population, the standardized incidence-based mortality ratio was 0.47 (95% confidence interval [CI], 0.26 to 0.80) with colonoscopic polypectomy, suggesting a 53% reduction in mortality. Mortality from colorectal cancer was similar among patients with adenomas and those with nonadenomatous polyps during the first 10 years after polypectomy (relative risk, 1.2; 95% CI, 0.1 to 10.6). CONCLUSIONS These findings support the hypothesis that colonoscopic removal of adenomatous polyps prevents death from colorectal cancer. (Funded by the National Cancer Institute and others.)

/pdf/colonoscopic-polypectomy-and-long-term-prevention-of-26sw5itn6w.pdf

Colonoscopic Polypectomy and Long-Term Prevention of Colorectal-Cancer Deaths

https://louisville.edu/medicine/departments/medicine/divisions/gimedicine/physician-resources/lectures/gi-neoplasms/surveillance-colonoscopy

Colorectal cancer screening and surveillance: clinical guidelines and rationale-update based on new evidence

https://www.gastrojournal.org/article/S0016-5085(97)00049-8/pdf

Colorectal cancer screening: Clinical guidelines and rationale

Validity of clinical examination and mammography as screening tests for breast cancer

OBJECTIVE--The aim was to assess the extent to which selection bias affects a case-control study of breast cancer screening in which attenders and non-attenders for screening are compared. DESIGN--There were two retrospective case-control studies, one estimating the risk of death from breast cancer in women in the screening district relative to those in the comparison district (study A), the second estimating the relative risk for women who had ever been screened compared with women who had never been screened in the screening district alone (study B). For cases and controls in study B, the women's screening history was summarised for the time period from date of entry to diagnosis of the case, or the equivalent time from date of entry for the matched controls. For cases detected by screening, the screen at which cancer was detected was included in the screening history. SUBJECTS--Cases were deaths from breast cancer in women with disease diagnosed after entry to the trial, up to 31 December 1986 or a maximum of seven years from date of entry, in one of the screening districts (Guildford) and one of the comparison districts (Stoke) participating in the UK Trial of Early Detection of Breast Cancer: study A: 198 deaths in Guildford and Stoke; study B: 51 deaths in Guildford only. There were five age matched controls for each case, with length of follow up at least as great as the time from entry to death of the case. MAIN RESULTS--The estimate of the risk of death from breast cancer in the screening district relative to the comparison district from study A was 0.76, thus implying a reduction of 24% in the screening district, similar to that obtained from a cohort analysis of data from the two districts. In contrast, the relative risk in study B for ever v never screened women was 0.51, which, taking the 72% compliance into account, would result in a relative risk of 0.65 for the screening district if there were no selection bias. The risk of breast cancer mortality in the never screened relative to the comparison district was 1.13, despite the fact that incidence rates in the two populations were similar. This suggested that cancers in the never screened group had a particularly poor prognosis, contributing to selection bias. CONCLUSIONS--The possible existence of selection bias should lead to caution in interpretation of the results of case-control studies of the effect of breast cancer screening on mortality.

A case-control evaluation of the effect of breast cancer screening in the United Kingdom trial of early detection of breast cancer.

Screening for colorectal cancer by testing for faecal occult blood (FOBT) is effective for early diagnosis, but the success of a screening programme also depends on compliance. The aims of this study were to assess the effect of health education on compliance and to assess any addition to general practitioner workload that resulted. Altogether 3860 patients were recruited and randomly allocated to test or control group. The test group was further divided into subgroups, some of which received health education. Compliance with FOBT was 54.7% (210/384) in the subgroup receiving only the doctor's letter, which fell to 48.1% (743/1544) in the group receiving health education. General practitioner consultation rates were similar in test and control groups.

A comparison of methods for increasing compliance within a general practitioner based screening project for colorectal cancer and the effect on practitioner workload.

Jocelyn Chamberlain

Papers

Randomised controlled trial of faecal-occult-blood screening for colorectal cancer

Validity of clinical examination and mammography as screening tests for breast cancer

A case-control evaluation of the effect of breast cancer screening in the United Kingdom trial of early detection of breast cancer.

A comparison of methods for increasing compliance within a general practitioner based screening project for colorectal cancer and the effect on practitioner workload.

Human benefits and costs of a national screening programme for neural-tube defects