Diet,alcohol, and smoking and the occurrence of hyperplastic polyps of the colon and rectum (United States)

Hyperplastic polyps of the colon reveal a geographic distribution similar to that of colorectal cancer and adenomatous polyps. However, unlike adenomas—known precursors of colorectal cancer—little is known about the etiology or clinical significance of the hyperplastic polyp. In this prospective study, we set out to determine the main dietary and other lifestyle factors in the United States that might be associated with this lesion. Hyperplastic polyps of the distal colon and rectum were diagnosed in 219 of 12,922 men of the Health Professionals Follow-up Study having had an endoscopic procedure between 1986 and 1992, and 175 of 15,339 women of the Nurses' Health Study who had undergone an endoscopy for a variety of reasons between 1980 and 1990. After adjusting for age, family history of colon cancer, history of previous endoscopy, and total energy intake using multiple logistic regression, those consuming 30 g or more of alcohol per day were at increased risk relative to nondrinkers among men (relative risk [RR]=1.69; 95 percent confidence interval [CI]=1.01–2.80) and women (RR=1.79, CI=1.02–3.15). Current smoking also was found to be associated strongly positively with hyperplastic polyps in men (RR=2.45, CI=1.59–3.75) and women (RR=1.96, CI=1.16–2.86). High intake of folate was associated inversely with risk in both men (RR=0.74, CI=0.49–1.11, between high and low intakes of folate) and women (RR=0.45, CI=0.28–0.74, between high and low intakes of folate). Among macronutrients, a suggestive increase in risk existed with intake of animal fat, although this was attenuated in the full multivariate model (RR[men]=1.48, CI=0.94–2.41, and RR [women]=1.22, CI=0.77–1.94) between high and low quantities of animal fat intake. These prospective data provide evidence of associations between low folate intake, alcohol consumption, and current cigarette smoking, and risk of hyperplastic polyps of the distal colon and rectum. These same factors also have been found to be related to adenoma and cancer of the colon. The hyperplastic polyp is an indicator of populations at high risk for colorectal carcinoma, and it also may serve as a marker for factors that influence neoplastic evolution.Drs Giovannucci, Stampfer, Colditz, and Willett are with the Channing Laboratory, Department of Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA. Authors also are affiliated with: the Department of Nutrition, Harvard School of Public Health, Boston, MA (Drs Kearney, Rimm, Stampfer, Ascherio, and Willett); the Department of Epidemiology, Harvard School of Public Health (Drs Rimm, Stampfer, Colditz, Ascherio, and Willett); and the Department of Surgery, New England Deaconess Hospital, Boston, MA (Dr Bleday). Address correspondence to Dr Giovannucci, Channing Laboratory, 180 Longwood Avenue, Boston, MA 02115, USA. This project was supported by research grants number CA 55075 and HL 35464 from the National Institutes of Health and Special Institution Grant No. 18 from the American Cancer Society. Dr Colditz. was supported by a Faculty Research Award (FRA-398) from the American Cancer Society.     

Reproductive factors,exogenous female hormones,and colorectal cancer by subsite

The associations between reproductive factors, exogenous hormones, and colorectal cancer were examined among female subjects in a population-based case-control study in Sweden. The study was performed in Stockholm in 1986–88, and included 299 cases and 276 controls. There was little evidence that age at first birth, number of months of breast feeding, age at menarche, or age at menopause influenced the risk of colon or rectal cancer. However, the results indicate that postmenopausal hormone-replacement therapy might reduce the risk of colorectal cancer (age-adjusted relative risk [RR]=0.4, 95 percent confidence interval [CI]=0.2–0.9). Compared with nulliparous women, women with at least four births were at reduced risk for colon cancer (RR=0.5, CI=0.2–1.2) but not rectal cancer (RR=1.0, CI=0.4–2.6). However, no trend across increasing parity was observed. Adjustments for diet, body mass, and physical activity had little influence on the results.The authors are with the Department of Preventive Medicine, University of Southern California School of Medicine. Dr Gerhardsson de Verdier is also in the Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden. Address correspondence to Dr London, University of Southern California School of Medicine, Department of Preventive Medicine, PMB B306, 1420 San Pablo Street, Los Angeles, CA 90033, USA. The study was supported by two grants (2228-B86-013XA; 2228-B87-02XA) from the Swedish National Cancer Society.     

Colorectal cancer test use from the 2005 National Health Interview Survey

BACKGROUND: Screening is effective in reducing colorectal cancer mortality. Recommended colorectal cancer screening options include a home fecal occult blood test (FOBT) or colorectal endoscopy (sigmoidoscopy or colonoscopy). Past surveys have indicated that colorectal cancer screening prevalence in the United States is low. The purpose of this analysis was to determine the prevalence of colorectal cancer test use in the United States by various factors and to examine reasons for not having a colorectal cancer test. METHODS: Data on respondents ages > or =50 years from the 2005 National Health Interview Survey (n = 13,269) were analyzed. The proportion of the U.S. population that had home FOBT within the past year or endoscopy within the past 10 years was examined by sociodemographic, health-care access, and other health-related factors. Reported reasons for not having FOBT or endoscopy were also analyzed. RESULTS: The age-standardized proportion of respondents who reported FOBT within the past year and/or endoscopy within the past 10 years was 50.0% [95% confidence interval (95% CI), 48.8-51.2]. Colorectal cancer testing rates were particularly low among people without health-care coverage (24.1%; 95% CI, 19.2-29.7) or without a usual source of health care (24.7%; 95% CI, 20.8-29.0). The most commonly reported reason for not having a colorectal cancer test was "never thought about it." CONCLUSIONS: In 2005, about half of Americans ages > or =50 years did not have appropriate colorectal cancer testing. Increased efforts to expand health-care coverage or to provide colorectal cancer tests to people without health-care coverage are needed to increase colorectal cancer screening.     

A case-control study of male colorectal cancer in Aichi Prefecture, Japan: with special reference to occupational activity level, drinking habits and family history

The relationships of occupational activity level, drinking habits and family history of cancer to the risk of male colorectal cancer by subsites were investigated in a case-control study involving 1,716 cases with colon cancer, 1,611 cases with rectal cancer and 16,600 controls with other sites of cancer identified from the Aichi Cancer Registry, Japan 1979-1987. An occupation with a low activity level was associated with an increased risk of colorectal cancer; the age-adjusted relative risk (RR) compared to the high activity level group was 1.92 (95% confidence interval (CI): 1.38-2.67) for proximal colon cancer, 1.52 (95% CI: 1.19-1.94) for distal colon cancer and 1.38 (95% CI: 1.17-1.62) for rectal cancer. Beer drinkers showed an increased risk of colorectal cancer; the age-adjusted RR was 1.49 (95% CI: 1.13-1.95) for proximal colon cancer, 1.65 (95% CI: 1.34-2.04) for distal colon cancer and 1.88 (95% CI: 1.62-2.18) for rectal cancer. The RR for family history of colorectal cancer was 3.40 (95% CI: 2.19-5.29) for proximal colon cancer, 2.54 (95% CI: 1.73-3.75) for distal colon cancer and 1.78 (95% CI: 1.28-2.49) for rectal cancer. Multivariate analysis controlled for age, residence, marital status and smoking in addition to occupational activity level, beer drinking and family history of colorectal cancer did not materially change the RRs. When these three variables were combined, the RR was 15.72 (95% CI: 5.40-45.78) for proximal colon cancer, 10.55 (95% CI: 4.24-26.27) for distal colon cancer and 6.69 (95% CI: 3.12-14.36) for rectal cancer.     

Long-term efficacy of sigmoidoscopy in the reduction of colorectal cancer incidence

Screening sigmoidoscopy is associated with a reduction in both the incidence and mortality of colorectal cancer. Although current guidelines recommend sigmoidoscopy screening every 5 years, the duration of risk reduction is not known. We conducted a population-based case-control study to examine the association between sigmoidoscopy screening and colorectal cancer incidence. We collected information on screening history and risk factors from case patients with distal (n = 1026) and proximal (n = 642) colorectal cancer and from 1294 control subjects from October 1998 through February 2002. Screening sigmoidoscopy was associated with a statistically significant reduction in the incidence of distal colorectal cancer (odds ratio [OR] = 0.24, 95% confidence interval [CI] = 0.17 to 0.33). These reductions were sustained for up to 16 years with little attenuation. We also observed strong inverse associations between cancer incidence and sigmoidoscopy in analyses that included subjects with symptom-related tests. Current recommendations regarding the frequency of sigmoidoscopy screening may be unnecessarily aggressive.     

Parity and other reproductive factors and risk of adenomatous polyps of the distal colorectum (United States)

Evidence for an effect of reproductive factors on colorectal carcinogenesis is inconsistent and little is known about their role in development of precursor adenomatous polyps. We evaluated the relation between reproductive factors and distal colorectal adenomas (n = 982) during14 years of follow up of 26,983 participants in the Nurses' Health Study(United States). The women were free of diagnosed cancer or polyps in 1980,underwent endoscopy 1980-94, and had reported on their parity, oral contraceptive (OC) use, and ages at menarche, first term-pregnancy, and menopause. We calculated relative risks (RR) and 95 percent confidence intervals (CI) using multiple logistic regression. Women with higher parity had an increased risk of adenomas of the distal colorectum (P trend = 0.004;6+ cf 0 parity: RR = 1.3, CI = 0.9-1.8) or distal colon (P trend = 0.002, RR= 1.7, CI = 1.2-2.6). This association was significantly stronger among women with a family history of colorectal cancer ( P interaction = 0.03); comparing6+ term-pregnancies with nulliparity, among those with a family history, the RR for distal colon adenoma was 3.2 (CI = 1.4-7.2), while among those without a family history, the RR was 1.3 (CI = 0.8-2.2). We observed no association for distal colorectal adenoma and age at menarche, age at first term-pregnancy, ever use of OCs, or menopausal status. Further work is needed to clarify the relation of parity with colon adenoma risk. This revised version was published online in July 2006 with corrections to the Cover Date.     

Colorectal Screening is Associated with Reduced Colorectal Cancer Risk: A Case–Control Study within the Population-Based Ontario Familial Colorectal Cancer Registry

Objective: This is the first study to evaluate the association between colonic screening and colorectal cancer risk among Canadians.Methods: A case–control study was conducted. Cases were diagnosed with cancer of the colorectum, between 1997 and 2000, aged 20 to 74 years, identified through the population-based Ontario Cancer Registry and recruited by the Ontario Familial Colorectal Cancer Registry. Controls were a sex- and age-matched random sample of the population of Ontario. 971 cases and 1944 controls completed questionnaires (including colorectal screening history and many risk factors). Multivariate logistic regression analysis was used to obtain adjusted odds ratios (OR) estimates.Results: Having had a fecal occult blood screen was associated with reduced colorectal cancer risk (OR=0.76; 95% confidence interval (CI): 0.59, 0.97). Having had a screening sigmoidoscopy was associated with a halving of colorectal cancer risk (OR = 0.52; 95% CI: 0.34, 0.80). Having had a screening colonoscopy did not significantly reduce colorectal cancer risk (OR = 0.69; 95% CI: 0.44, 1.07); however, having had either screening endoscopy was associated with a significant reduction in colorectal cancer risk (OR = 0.62; 95% CI: 0.44, 0.87). Findings differed slightly by anatomic sub-site (proximal and distal colorectum).Conclusions: We report a reduction in colorectal cancer risk among persons who underwent colorectal cancer screening; in particular, sigmoidoscopy. Findings are of great importance for the prevention of colorectal cancer.^*Financial Support – This work was supported by the National Cancer Institute, National Institutes of Health under RFA # CA-95-011 (grant no. U01-CA74783).     

A Case-Control Study of Male Colorectal Cancer in Aichi Prefecture, Japan: with Special Reference to Occupational Activity Level, Drinking Habits and Family History

The relationships of occupational activity level, drinking habits and family history of cancer to the risk of male colorectal cancer by subsites were investigated in a case-control study involving 1,716 cases with colon cancer, 1,611 cases with rectal cancer and 16,600 controls with other sites of cancer identified from the Aichi Cancer Registry, Japan 1979–1987. An occupation with a low activity level was associated with an increased risk of colorectal cancer; the age-adjusted relative risk (RR) compared to the high activity level group was 1.92 (95% confidence interval (CI): 1.38–2.67) for proximal colon cancer, 1.52 (95% CI: 1.19–1.94) for distal colon cancer and 1.38 (95% CI: 1.17–1.62) for rectal cancer. Beer drinkers showed an increased risk of colorectal cancer; the age-adjusted RR was 1.49 (95% CI: 1.13–1.95) for proximal colon cancer, 1.65 (95% CI: 1.34-2.04) for distal colon cancer and 1.88 (95% CI: 1.62–2.18) for rectal cancer. The RR for family history of colorectal cancer was 3.40 (95% CI: 2.19–5.29) for proximal colon cancer, 2.54 (95% CI: 1.73–3.75) for distal colon cancer and 1.78 (95% CI: 1.28–2.49) for rectal cancer. Multivariate analysis controlled for age, residence, marital status and smoking in addition to occupational activity level, beer drinking and family history of colorectal cancer did not materially change the RRs. When these three variables were combined, the RR was 15.72 (95% CI: 5.40–45.78) for proximal colon cancer, 10.55 (95% CI: 4.24–26.27) for distal colon cancer and 6.69 (95% CI: 3.12–14.36) for rectal cancer.     

Dietary patterns and subsequent colorectal cancer risk by subsite: a prospective cohort study

In order to investigate the associations between dietary patterns and the risk of colorectal cancer by subsite in Japan, the baseline data from a population-based cohort study of 20,300 men and 21,812 women were analyzed. We conducted factor analysis and identified 3 major dietary patterns, "healthy," "traditional" and "Western," and calculated the factor scores of each pattern for individuals. During 10 years of follow-up, 370 colorectal cancer cases were identified. We found a positive association between the traditional pattern and colon cancer risk in women [rate ratio for highest quartile (RR) = 2.06; 95% CI = 1.10-3.84; p for trend = 0.11], but not in men. This positive association was slightly stronger for proximal colon cancer (RR = 2.07; 95% CI = 0.84-5.12) than for distal colon cancer (RR = 1.84; 95% CI = 0.75-4.50). After multivariate adjustment, the Western dietary pattern was also positively associated with colon cancer risk in females (RR = 2.21; 95% CI = 1.10-4.45), with the strongest associations being observed for females with distal colon cancer (RR = 3.48; 95% CI = 1.25-9.65). We did not observe any significant association between the healthy dietary pattern and colon cancer risk. For rectal cancer, no significant associations were found for the 3 dietary patterns. In conclusion, we found that the traditional and the Western dietary patterns were positively associated with colon cancer risk in females.     

Correlates of screening sigmoidoscopy use among men in a large nonprofit health plan

BACKGROUND: As the majority of patients diagnosed with colorectal cancer have no known risk factors, regular screening is strongly recommended. The authors examined factors associated with screening sigmoidoscopy use among participants in the California Men's Health Study (CMHS). METHODS: The authors conducted a cross-sectional study over a 5-year period nested within a prospective cohort study. The CMHS enrolled a large multiethnic cohort (n = 84,170) of men from 2 major California health plans. Because screening sigmoidoscopy was the preferred and most commonly used test for patients at average risk of colorectal cancer in the health plans, the authors excluded from the analysis men who completed a barium enema colonoscopy or a fecal occult blood test. RESULTS: Eligible subjects included 39,559 men at average risk for colorectal cancer. Prevalence of screening sigmoidoscopy use decreased with older age and increased with higher education and household income over the 5-year study period. Compared with whites, Asians (adjusted OR, 1.42; 95% CI, 1.30-1.56) and African Americans (adjusted OR, 1.18; 95% CI, 1.08-1.29) were more likely to undergo screening sigmoidoscopy. Screening increased with the number of outpatient visits and with having a primary care provider in internal medicine. Men who did not undergo prostate-specific antigen testing were also less likely to undergo sigmoidoscopy screening. Only 24.5% of current smokers had a screening sigmoidoscopy examination and were 25% less likely to undergo this procedure compared with nonsmokers (adjusted OR, 0.75; 95% CI, 0.69-0.82). CONCLUSIONS: In this insured population for whom financial barriers are minimized, screening sigmoidoscopy use was as low as reported in the general population. However, minority patients were not less likely to be screened.     

A prospective study of menopausal hormones and risk of colorectal cancer (United States)

The relation of colorectal cancer and its subsites with use ofmenopausal hormones was evaluated in the United States among 40,464postmenopausal women, 41 to 80 years of age, who initially volunteered for anationwide breast-cancer screening program and were followed for an averageof 7.7 years. Ever-use of menopausal hormones was not associated with risk oftotal colorectal cancers (relative risk [RR] = 0.99, 95 percent confidenceinterval [CI] = 0.79-1.2) or cancers of the colon (RR = 1.1, CI = 0.81-1.6)or rectum (RR = 1.1, CI = 0.59-1.9). Recent hormone users, however, had asmall nonsignificant reduction in risk of colorectal cancer (RR = 0.78, CI =0.55-1.1), which was most pronounced for distal colon (RR = 0.68, CI =0.29-1.6) and rectal tumors (RR = 0.64, CI = 0.24-1.7). No effect wasobserved for former hormone users, and risk generally did not vary by timesince last use, type of regimen, or duration of use. However, the reducedrisk for recent users was stronger for users of five or more years'duration. These data show some lowering of colorectal cancer risk amongrecent menopausal hormone users of long duration.     

Long-lasting reduction of risk of colorectal cancer following screening endoscopy

Several studies have suggested that incidence and mortality of colorectal cancer (CRC) may be strongly reduced for up to 10 years by endoscopic screening with removal of precancerous lesions, but so far there are no data on risk reduction beyond this period. We assessed long-term reduction of CRC risk following screening endoscopy in a statewide population-based case-control study in Saarland, Germany. Lifetime history of screening endoscopy was compared between 320 cases with CRC aged 45-80 and 263 controls with other forms of cancer recruited from the same population. Potential confounding factors were controlled for by multiple logistic regression. 11% of cases compared to 27% of controls had a history of endoscopy for screening purposes (adjusted odds ratio (OR) = 0.28, 95% confidence interval (CI): 0.16-0.48). This strong risk reduction was also seen (OR = 0.41, 95% CI: 0.19-0.89) in subjects who had their last screening endoscopy more than 10 years ago (median: 18.9 years). Long term (> 10 years since last screening) risk reduction appeared to be particularly strong for advanced (Dukes C or D) CRC (OR = 0.19, 95% CI: 0.06-0.64). We conclude that risk reduction by screening endoscopy is long lasting, in particular with respect to advanced CRC.     

A comparative case-control study of colorectal cancer and adenoma

We conducted a comparative case-control study of colorectal cancer and adenoma involving 221 cases with colorectal cancer, 525 cases with colorectal adenoma and 578 neighborhood controls. Daily vegetables intake was associated with lower risks of distal colon adenoma (relative risks (RR) = 0.59, 95% confidence interval (CI): 0.39-0.89) and rectal cancer (RR = 0.46, 95% CI: 0.25-0.84). Daily beans intake was associated with lower risk of colon adenoma (RR = 0.58, 95% CI: 0.37-0.91 for the proximal colon and RR = 0.63, 95% CI: 0.45-0.88 for the distal colon) and daily intake of seaweeds was associated with lower risk of rectal cancer (RR = 0.42, 95% CI: 0.22-0.82). Daily intake of fish and shellfish also showed an inverse association with the risk of colon adenoma (RR = 0.67, 95% CI: 0.45-0.99 for the proximal colon and RR = 0.70, 0.52-0.94 for the distal colon). Generally, intakes of animal or vegetable fat-rich foods, especially meats, were associated with decreases in risks of both adenoma and cancer, though the association of cancer was not statistically significant. Other than dietary factors, daily alcohol drinking was associated with an increased risk of adenoma in the proximal colon (RR = 1.95, 95% CI: 1.15-3.29) and ex-drinkers showed higher risks for colon adenoma and colorectal cancer. Sports or occupational activities and coffee drinking were inversely associated and family history of colorectal cancer was positively associated with the risk of both colorectal adenoma and cancer.     

Mismatch repair polymorphisms and the risk of colorectal cancer

Rare germline variants in mismatch repair genes have been linked to hereditary nonpolyposis colorectal cancer; however, it is unknown whether common polymorphisms in these genes alter the risk of colorectal cancer. To examine the association between common variants in mismatch repair genes and colorectal cancer, we conducted a case-cohort study within the CLUE II cohort. Four single nucleotide polymorphisms in 3 mismatch repair genes (MSH3 R940Q, MSH3 T1036A, MSH6 G39E and MLH1 I219V) were genotyped in 237 colorectal cancer cases and a subcohort of 2,189 participants. Incidence rate ratios (RRs) and 95% confidence intervals (95% CIs) for each polymorphism were estimated. The MSH3 1036A variant was found to be associated with an increased risk of colorectal cancer (RR=1.28, 95% CI: 0.94-1.74 and RR=1.65, 95% CI: 1.01-2.70 for the AT and TT genotypes, respectively, with p(trend)=0.02), particularly proximal colon cancer. Although the MSH3 940Q variant was only weakly associated with colorectal cancer overall (p(trend)=0.07), it was associated with a significant increased risk of proximal colon cancer (RR=1.69, 95% CI: 1.10-2.61 and RR=2.68, 95% CI: 0.96-7.47 for the RQ and QQ genotypes, respectively with p(trend)=0.005). Processed meat intake appeared to modify the association between the MSH3 polymorphisms and colorectal cancer (p(interaction) < 0.10 for both). No association was observed with the MSH6 and MLH1 polymorphisms overall. This study suggests that common polymorphisms in the mismatch repair gene, MSH3, may increase the risk of colorectal cancer, especially proximal colon cancer.     

Whole grain consumption and risk of colorectal cancer: a population-based cohort of 60,000 women

We examined prospectively the association between whole grain consumption and colorectal cancer risk in the population-based Swedish Mammography Cohort. A total of 61,433 women completed a food-frequency questionnaire at baseline (1987-1990) and, through linkage with the Swedish Cancer Registry, 805 incident cases of colorectal cancer were identified during a mean follow-up of 14.8 years. High consumption of whole grains was associated with a lower risk of colon cancer, but not of rectal cancer. The multivariate rate ratio (RR) of colon cancer for the top category of whole grain consumption (> or = 4.5 servings day(-1)) compared with the bottom category (<1.5 servings day(-1)) was 0.67 (95% confidence interval (CI), 0.47-0.96; P-value for trend=0.06). The corresponding RR after excluding cases occurring within the first 2 years of follow-up was 0.65 (95% CI, 0.45-0.94; P-value for trend=0.04). Our findings suggest that high consumption of whole grains may decrease the risk of colon cancer in women.     

Racial/ethnic differences in colorectal cancer risk: the multiethnic cohort study

Incidence rates in the United States show clear racial/ethnic disparities for colorectal cancer. We examined the extent to which ethnic differences in risk factors could explain the age-adjusted variation in the risk of colorectal cancer, overall and by stage at diagnosis, among 165,711 African Americans, Japanese Americans, Latinos, Native Hawaiians and whites participating in the Multiethnic Cohort Study. Over a median follow-up period of 10.7 years, 2,564 incident cases of colorectal cancer were identified through surveillance, epidemiology and end result tumor registry linkages in Hawaii and California. Multivariable-adjusted Cox proportional hazard models were used to estimate relative risks (RR) and 95% confidence intervals (CI) for each ethnic group compared to whites. After accounting for known/suspected risk factors, Japanese Americans (men, RR = 1.27, 95% CI = 1.09-1.48; women, RR = 1.49, 95% CI = 1.24-1.78) and African American women (RR = 1.48, 95% CI = 1.23-1.79) remained at increased risk of colorectal cancer relative to whites; African American and Japanese American women were also at increased risk of advanced disease compared to whites. In site-specific analyses, after multivariable adjustment, African Americans (both sexes) and Japanese American women remained at increased risk for colon cancer, and Japanese Americans (both sexes) and Native Hawaiian men for rectal cancer compared to whites. The results of our study suggest that differences in the distribution of known/suspected risk factors account for only a modest proportion of the ethnic variation in colorectal cancer risk and that other factors, possibly including genetic susceptibility, are important contributors to the observed disparities in incidence.     

Lung Cancer Screening With Low Dose Computed Tomography in Patients With and Without Prior History of Cancer in the National Lung Screening Trial

IntroductionPatients with a prior history of cancer (PHC) are at increased risk of second primary malignancy, of which lung cancer is the most common. We compared the performance metrics of positive screening rates and cancer detection rates (CDRs) among those with versus without PHC.MethodsWe conducted a secondary analysis of 26,366 National Lung Screening Trial participants screened with low dose computed tomography between August 2002 and September 2007. We evaluated absolute rates and age-adjusted relative risks (RRs) of positive screening rates on the basis of retrospective Lung CT Screening Reporting & Data System (Lung-RADS) application, invasive diagnostic procedure rate, complication rate, and CDR in those with versus without PHC using a binary logistic regression model using Firth’s penalized likelihood. We also compared cancer type, stage, and treatment in those with versus without PHC.ResultsA total of 4.1% (n = 1071) of patients had PHC. Age-adjusted rates of positive findings were similar in those with versus without PHC (Baseline: PHC = 13.7% versus no PHC = 13.3%, RR [95% confidence interval (CI)]: 1.04 [0.88–1.24]; Subsequent: PHC = 5.6% versus no PHC = 5.5%, RR [95% CI]: 1.02 [0.84–1.23]). Age-adjusted CDRs were higher in those with versus without PHC on baseline (PHC=1.9% versus no PHC = 0.8%, RR [95% CI]: 2.51 [1.67–3.81]) but not on subsequent screenings (PHC = 0.6% versus no PHC = 0.4%, RR [95% CI]: 1.37 [0.99–1.93]). There were no differences in cancer stage, type, or treatment by PHC status.ConclusionsPatients with PHC may benefit from lung cancer screening, and with their providers, should be made aware of the possibility of higher cancer detection, invasive procedures, and complication rates on baseline lung cancer screening, but not on subsequent low dose computed tomography screening examinations.     

Colon cancer screening, lifestyle, and risk of colon cancer

Objectives: Sigmoidoscopy screening and fecal occult blood (FOB) tests have been demonstrated as effective ways to reduce mortality from colorectal cancer. However, most studies of colorectal cancer screening and cancer mortality have not taken into consideration lifestyle factors that could account for the observed associations. The purpose of this study was to determine the association between screening and incidence of colon cancer, taking into consideration important lifestyle factors. Methods: We estimated the association between screening and colon cancer after taking into consideration health and lifestyle factors using data obtained as part of population-based case–control study of incident colon cancers. Results: Sigmoidoscopy screening, especially as part of a checkup, was protective against incident colon cancer in both men (OR 0.56, 95% CI 0.44–0.77) and women (OR 0.53, 95% CI 0.33–0.77) after adjusting for other risk factors for colon cancer. For men, associations were stronger for distal tumors (OR 0.48, 95% CI 0.31–0.71) than for proximal tumors (OR 0.67, 95% CI 0.45–1.11). We did not observe significant associations between FOB test and colon cancer. Differences in characteristics between those who were screened and not screened were also observed. Men were more likely to report having a sigmoidoscopy as part of a checkup than were women, as were people with higher levels of education. People who reported having a sigmoidoscopy as part of a checkup also reported eating diets lower in fat and higher in fiber, folate, and vegetables. Men were more likely to report higher levels of physical activity, and women were more likely to report taking hormone replacement therapy (HRT) if they also reported a sigmoidoscopy. Both men and women who reported a sigmoidoscopy for screening purposes were more likely to have a family history of colorectal cancer. Conclusions: These data provide additional support for the benefits of having a screening sigmoidoscopy. The associations between screening sigmoidoscopy and colon cancer do not appear to be the result of lifestyle factors.     

Colorectal cancer screening using fecal occult blood test and subsequent risk of colorectal cancer: a prospective cohort study in Japan

BACKGROUND: To investigate prospectively the association between colorectal cancer screening and subsequent risk of colorectal cancer death in a large-scale population-based cohort study (the JPHC study) with a 13-year follow-up period in Japan. METHODS: We analyzed data from a population-based cohort of 42,150 (20,326 men and 21,824 women) subjects. Subjects who had undergone fecal occult blood test (FOBT) screening during the preceding 12 months were defined as the screened group. A total of 132 colorectal cancer deaths and 597 cases of newly diagnosed colorectal cancer were identified during the follow-up period. RESULTS: We observed a nearly 70% decrease in colorectal cancer mortality in screened versus unscreened subjects (RR=0.28, 95% CI=0.13-0.61). Screening participation was associated with a 30% reduced risk of death from all causes other than colorectal cancer (RR=0.70, 95% CI=0.61-0.79). However, the extent of mortality reduction was greater for colorectal cancer than other causes. A significant decrease in the incidence of advanced colorectal cancer was seen in screened subjects (RR=0.41, 95% CI=0.27-0.63), although the overall incidence rate did not differ significantly between the screened and unscreened groups. CONCLUSION: Although self-selection bias could not be fully controlled, these findings suggest that colorectal cancer screening may be associated with a reduction in mortality from colorectal cancer in the Japanese population.     

Green tea and black tea consumption in relation to colorectal cancer risk: the Singapore Chinese Health Study

The relationships between green tea and black tea consumption and colorectal cancer risk were examined within the Singapore Chinese Health Study, a prospective cohort study of diet and cancer involving >60,000 men and women. Intake of green tea and black tea was assessed through in-person interviews. Incident cancer cases and deaths among cohort members were identified through record linkage of the cohort database with respective databases from the nationwide Singapore Cancer Registry and the Singapore Registry of Births and Deaths. The proportional hazard regression method was used to examine the associations between intake of green and black tea separately and colorectal cancer risk with adjustment for potential confounders. After an average of 8.9 years of follow-up, 845 colorectal cancer cases were identified. Subjects who drank green tea exhibited a statistically non-significant increase in risk [relative risk (RR) = 1.12, 95% confidence interval (CI) = 0.97-1.29] relative to non-drinkers of green tea. This risk increase was mainly confined to men (RR = 1.31, 95% CI = 1.08-1.58); the comparable RR in women was 0.89 (95% CI = 0.71-1.12). In men, the green tea-colorectal cancer association was noted mainly in those with advanced disease (Duke C or D) (RR = 1.53, 95% CI = 1.19-1.97), and the association was dose dependent (P for trend = 0.0002). This latter association was especially strong within the colon subsite (RR = 1.75, 95% CI = 1.24-2.46; P for trend < 0.0001). Irrespective of gender, intake of black tea was not associated with risk of colorectal cancer (RR = 0.92, 95% CI = 0.79-1.07) in this Asian population.