Steven J. Mongin

THE EFFECT OF FECAL OCCULT-BLOOD SCREENING ON THE INCIDENCE OF COLORECTAL CANCER

BACKGROUND Both annual testing for fecal occult blood and biennial testing significantly reduce mortality from colorectal cancer. However, the effect of screening on the incidence of colorectal cancer remains uncertain, despite the diagnosis and removal of precancerous lesions in many persons who undergo screening. METHODS We followed the participants in the Minnesota Colon Cancer Control Study for 18 years. A total of 46,551 people, most of whom were 50 to 80 years old, were enrolled between 1975 and 1978 and randomly assigned to annual screening, biennial screening, or usual care (the control group). Those assigned to the screening groups were asked to prepare and submit two samples from each of three consecutive stools for guaiac-based testing. Those with at least one positive slide in the set of six were offered a diagnostic examination that included colonoscopy. Screening was conducted between 1976 and 1982 and again between 1986 and 1992. Study participants have been followed with respect to newly diagnosed cases of colorectal cancer and deaths. Follow-up has been more than 90 percent complete. RESULTS During the 18-year follow-up period, we identified 1359 new cases of colorectal cancer: 417 in the annual-screening group, 435 in the biennial-screening group, and 507 in the control group. The cumulative incidence ratios for colorectal cancer in the screening groups as compared with the control group were 0.80 (95 percent confidence interval, 0.70 to 0.90) and 0.83 (95 percent confidence interval, 0.73 to 0.94) for the annual-screening and biennial-screening groups, respectively. For both screening groups, the number of positive slides was associated with the positive predictive value both for colorectal cancer and for adenomatous polyps at least 1 cm in diameter. CONCLUSIONS The use of either annual or biennial fecal occult-blood testing significantly reduces the incidence of colorectal cancer.

An epidemiological study of the magnitude and consequences of work related violence: the Minnesota Nurses' Study

Aims: To identify the magnitude of and potential risk factors for violence within a major occupational population. Methods: Comprehensive surveys were sent to 6300 Minnesota licensed registered (RNs) and practical (LPNs) nurses to collect data on physical and non-physical violence for the prior 12 months. Re-weighting enabled adjustment for potential biases associated with non-response, accounting for unknown eligibility. Results: From the 78% responding, combined with non-response rate information, respective adjusted rates per 100 persons per year (95% CI) for physical and non-physical violence were 13.2 (12.2 to 14.3) and 38.8 (37.4 to 40.4); assault rates were increased, respectively, for LPNs versus RNs (16.4 and 12.0) and males versus females (19.4 and 12.9). Perpetrators of physical and non-physical events were patients/clients (97% and 67%, respectively). Consequences appeared greater for non-physical than physical violence. Multivariate modelling identified increased rates for both physical and non-physical violence for working: in a nursing home/long term care facility; in intensive care, psychiatric/behavioural or emergency departments; and with geriatric patients. Conclusions: Results show that non-fatal physical assault and non-physical forms of violence, and relevant consequences, are frequent among both RNs and LPNs; such violence is mostly perpetrated by patients or clients; and certain environmental factors appear to affect the risk of violence. This serves as the basis for further analytical studies that can enable the development of appropriate prevention and control efforts.

Long-Term Mortality after Screening for Colorectal Cancer

BACKGROUND In randomized trials, fecal occult-blood testing reduces mortality from colorectal cancer. However, the duration of the benefit is unknown, as are the effects specific to age and sex. METHODS In the Minnesota Colon Cancer Control Study, 46,551 participants, 50 to 80 years of age, were randomly assigned to usual care (control) or to annual or biennial screening with fecal occult-blood testing. Screening was performed from 1976 through 1982 and from 1986 through 1992. We used the National Death Index to obtain updated information on the vital status of participants and to determine causes of death through 2008. RESULTS Through 30 years of follow-up, 33,020 participants (70.9%) died. A total of 732 deaths were attributed to colorectal cancer: 200 of the 11,072 deaths (1.8%) in the annual-screening group, 237 of the 11,004 deaths (2.2%) in the biennial-screening group, and 295 of the 10,944 deaths (2.7%) in the control group. Screening reduced colorectal-cancer mortality (relative risk with annual screening, 0.68; 95% confidence interval [CI], 0.56 to 0.82; relative risk with biennial screening, 0.78; 95% CI, 0.65 to 0.93) through 30 years of follow-up. No reduction was observed in all-cause mortality (relative risk with annual screening, 1.00; 95% CI, 0.99 to 1.01; relative risk with biennial screening, 0.99; 95% CI, 0.98 to 1.01). The reduction in colorectal-cancer mortality was larger for men than for women in the biennial-screening group (P=0.04 for interaction). CONCLUSIONS The effect of screening with fecal occult-blood testing on colorectal-cancer mortality persists after 30 years but does not influence all-cause mortality. The sustained reduction in colorectal-cancer mortality supports the effect of polypectomy. (Funded by the Veterans Affairs Merit Review Award Program and others.).

Prospective evaluation of methylated SEPT9 in plasma for detection of asymptomatic colorectal cancer

Background As screening methods for colorectal cancer (CRC) are limited by uptake and adherence, further options are sought. A blood test might increase both, but none has yet been tested in a screening setting. Objective We prospectively assessed the accuracy of circulating methylated SEPT9 DNA (mSEPT9) for detecting CRC in a screening population. Design Asymptomatic individuals ≥50 years old scheduled for screening colonoscopy at 32 US and German clinics voluntarily gave blood plasma samples before colon preparation. Using a commercially available assay, three independent blinded laboratories assayed plasma DNA of all CRC cases and a stratified random sample of other subjects in duplicate real time PCRs. The primary outcomes measures were standardised for overall sensitivity and specificity estimates. Results 7941 men (45%) and women (55%), mean age 60 years, enrolled. Results from 53 CRC cases and from 1457 subjects without CRC yielded a standardised sensitivity of 48.2% (95% CI 32.4% to 63.6%; crude rate 50.9%); for CRC stages I–IV, values were 35.0%, 63.0%, 46.0% and 77.4%, respectively. Specificity was 91.5% (95% CI 89.7% to 93.1%; crude rate 91.4%). Sensitivity for advanced adenomas was low (11.2%). Conclusions Our study using the blood based mSEPT9 test showed that CRC signal in blood can be detected in asymptomatic average risk individuals undergoing screening. However, the utility of the test for population screening for CRC will require improved sensitivity for detection of early cancers and advanced adenomas. Clinical Trial Registration Number: NCT00855348

Risk factors for work-related assaults on nurses

Background: Work-related homicides have been the subject of considerable study, but little is known about nonfatal violence and relevant risk factors. Methods: We surveyed 6300 Minnesota nurses who were selected randomly from the 1998 licensing database and determined their employment and occupational violence experience. In a nested case–control study, we examined environmental exposures and physical assault. Cases of assault in the previous 12 months and controls randomly selected from assault-free months were surveyed about prior-month exposures. Results: After adjustment by multiple logistic regression, incidence of physical assault was 13.2 per 100 persons per year (95% confidence interval = 12.2–14.3). Among 310 cases and 946 control subjects, odds ratios for assault were increased: in nursing homes or long-term care facilities (2.6; 1.9–3.6), emergency departments (4.2; 1.3–12.8), and psychiatric departments (2.0; 1.1–3.7); in environments not “bright as daylight” (2.2; 1.6–2.8); and for each additional hour of shift duration (1.05; 0.99–1.11). Risks were decreased when carrying cellular telephones or personal alarms (0.3; 0.2–0.7). Conclusions: These results may guide in-depth investigation of ways protective and risk factors can control violence against nurses.

Validity of Four Self-reported Colorectal Cancer Screening Modalities in a General Population: Differences over Time and by Intervention Assignment

Little is known about the validity of self-reported colorectal cancer screening. To date, few published studies have validated all four screening modalities per recommended guidelines or included a general population-based sample, and none has assessed validity over time and by intervention condition. To estimate the validity of self-reported screening, a random sample of 200 adults, ages ≥50 years, was selected from those completing annual surveys on screening behavior as part of an intervention study. Approximately 60% of the validation sample authorized medical record review. Sensitivity, specificity, and positive and negative predictive values were calculated for baseline and year 1 follow-up reports for each test and for overall screening adherence. Sensitivity at baseline ranged from 86.9% (flexible sigmoidoscopy) to 100% (colonoscopy). Sensitivity at follow-up was slightly lower. Adjusting for validity measures, the sample overreported screening prevalence at baseline for each of the four modalities. At follow-up, overreporting was greatest for fecal occult blood test (13.0%). Overreporting across intervention conditions was highest for fecal occult blood test (10.8% for control; 24.8% for the most intense intervention) and overall screening adherence (10.9% for control; 14.3% for the most intense intervention). Sensitivity and specificity of self-reported colorectal cancer screening compared with medical records were high; however, adjusting self-reported screening rates based on relative error rates reduced screening prevalence estimates. Those exposed to more intense interventions to modify screening behavior seemed more likely to overestimate their screening rates compared with those who were not exposed. (Cancer Epidemiol Biomarkers Prev 2008;17(4):777–84)

Colorectal cancer deaths as determined by expert committee and from death certificate : A comparison. The Minnesota Study

For deaths during the first 13 years of follow-up of the Minnesota Colon Cancer Control Study, an expert committee using numerous medical documents, and a nosologist using only the death certificate independently determined whether colorectal cancer caused the death and, if not, whether the disease was present at death. Deaths due to colorectal cancer numbered 318 according to the nosologist and 323 according to the committee, a discrepancy of 1.5%, which is similar in magnitude to that in three previous studies. The nosologist and committee agreed that colorectal cancer caused the death in each of 290 individual cases; they disagreed widely on the number of deaths from other causes but with colorectal cancer. If it is important to know only the gross number of deaths from colorectal cancer, then the death certificate alone appears to be sufficiently accurate; if it is important to know the cause of death of individual subjects or the number dying from other causes but with colorectal cancer, then the expert committee method provides more accurate information.

Pancreatic cancer risk: associations with meat-derived carcinogen intake in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort.

Epidemiological studies report positive associations between high‐temperature cooked meat intake and pancreatic cancer. We assessed associations between dietary intake of heterocyclic amines (HCAs) and benzo(a)pyrene (BaP)—mutagens formed in meat cooked at high temperatures—and incident exocrine pancreatic cancer in a prospective cohort.

Thyroid cancer and employment as a radiologic technologist

The association between chronic occupational ionizing radiation exposure in the medical field and thyroid cancer is not well characterized. Thyroid cancer incidence was ascertained for 2 periods in a cohort of radiologic technologists certified for a minimum 2 years and enumerated in 1983: (i) cases identified prospectively in 73,080 radiologic technologists who were free of thyroid cancer at the baseline survey and completed a second questionnaire a decade later (N = 121), and (ii) cases occurring prior to cohort enumeration among 90,245 technologists who completed the baseline survey and were thyroid cancer free 2 years after certification (N = 148). Survival analyses estimated risks associated with employment as a radiologic technologist, including duration of employment, period of employment, types of procedures and work practices. The only occupational history characteristic associated with prospectively identified thyroid cancer was a history of holding patients for X‐ray procedures at least 50 times (HR = 1.47, 95% CI = 1.01–2.15). Total years worked as a radiologic technologist, years performing diagnostic, therapeutic, and nuclear medicine procedures, employment under age 20 and calendar period of first employment were not associated with thyroid cancer risk. Risk of thyroid cancers diagnosed before the baseline questionnaire was inversely associated with decade first employed as a technologist, and was elevated, albeit imprecisely, among those working more than 5 years prior to 1950 (HR = 3.04, 95% CI = 1.01–10.78). These data provide modest evidence of an association between employment as a radiologic technologist and thyroid cancer risk; however, the findings require confirmation with more accurate exposure models.

Agricultural injuries among operation household members: RRIS-II 1999.

The purpose of this study was to determine the magnitude and consequences of agricultural injuries, and to reveal potential risk factors among agricultural household members. The Regional Rural Injury Study (RRIS-II) collected injury and exposure data on agricultural households of 16,538 people in Minnesota, Wisconsin, North Dakota, South Dakota, and Nebraska for each six-month period of 1999. Adjusted injury rates, consequences, and potential risk factors were identified through analyses. Selection of variables for multivariate analyses was based on a causal model. Injuries reported here occurred while the individuals were involved in activities associated with their own farm or ranch, unless otherwise stated. Estimates of injury rates and the effects of various exposures were derived by Poisson and logistic regression. These models accounted for correlation within both subject and household, and were adjusted for non-response. The rate of agricultural injury to household members on their own operation was 74.5 injuries per 1,000 persons per year. Differences in rates due to age and gender diminished when rates were calculated according to hours worked. Although only 5% of injured persons required in-patient hospitalization, 28% required emergency department treatment, and 84% required some type of professional health care. Moreover, 47% of all injuries required time off from agricultural work, and 7% required time off from non-agricultural work. In multivariate analyses, decreased risks were associated with Minnesota, and increased risks were identified for those with prior injuries and for males.This study provides a basis for further research on agricultural injuries and their prevention.