Oral cancer exams among cigarette smokers in Maryland

BACKGROUND: Current and former smokers are at increased risk to develop oral cancer. This analysis was performed to determine whether current and former smokers are more likely to undergo an exam for oral cancer than non-smokers. METHODS: The Maryland Cancer Survey performed in 2002 was a population-based random digit dial, statewide survey on cancer screening and risk behaviors, targeting adults aged 40 years and older. The dataset contains self-reported information on oral cancer examinations, current smoking status, and health care access information for 4840 Maryland residents. RESULTS: 2062 (42.6%) of Marylanders aged 40 years and older reported ever having had an oral cancer examination. Dentists and dental hygienists performed 90.9% of the exams. Current and former smokers were no more likely than those who have never smoked to have ever had the examination (adjusted OR = 1.02, 95% CI = 0.85-1.23 and OR = 1.09, 95% CI = 0.94-1.25, respectively). Other predictors associated with having an oral cancer exam included having more than a high school of education, being female, non-black, being in good to excellent health, and having a recent physical exam. Having visited the dentist in the last year had the highest odds of having ever had an oral cancer exam. CONCLUSIONS: Current and former smokers are a high-risk group who need to be targeted for oral cancer exams by dental professionals and primary care physicians.     

Cumulative tar exposure. A new index for estimating lung cancer risk among cigarette smokers.

A new index for estimating lifetime exposure to tar from cigarette smoking was found to be the best measure of the relative risk for Kreyberg type I (KI) and Kreyberg type II (KII) lung cancer in a case-control study of 2296 cases (1274 KI and 1022 KII) and 4667 controls. There is a steep, near-linear dose-response of lung cancer risk of both histologic types to cumulative exposure to tar, although the odds ratios are three to five times higher for KI than for KII. The odds ratios for lung cancer in women are consistently higher than those in men with the same level of exposure to tar, particularly among long-term smokers who smoke heavily. Based on their estimates of odds ratios associated with tar exposure, the authors projected an approximate 15-20% decrease in KI lung cancer risk among long-term smokers who smoked heavily for every 10-mg decrease in tar in the cigarettes they smoked.     

Variations in lung cancer risk among smokers

BACKGROUND: Although there is no proven benefit associated with screening for lung cancer, screening programs are attracting many individuals who perceive themselves to be at high risk due to smoking. We sought to determine whether the risk of lung cancer varies predictably among smokers. METHODS: We used data on 18 172 subjects enrolled in the Carotene and Retinol Efficacy Trial (CARET)-a large, randomized trial of lung cancer prevention-to derive a lung cancer risk prediction model. Model inputs included the subject's age, sex, asbestos exposure history, and smoking history. We assessed the model's calibration by comparing predicted and observed rates of lung cancer across risk deciles and validated it by assessing the extent to which a model estimated on data from five CARET study sites could predict events in the sixth study site. We then applied the model to evaluate the risk of lung cancer among smokers enrolled in a study of lung cancer screening with computed tomography (CT). RESULTS: The model was internally valid and well calibrated. Ten-year lung cancer risk varied greatly among participants in the CT study, from 15% for a 68-year-old man who has smoked two packs per day for 50 years and continues to smoke, to 0.8% for a 51-year-old woman who smoked one pack per day for 28 years before quitting 9 years earlier. Even among the subset of CT study participants who would be eligible for a clinical trial of cancer prevention, risk varied greatly. CONCLUSIONS: The risk of lung cancer varies widely among smokers. Accurate risk prediction may help individuals who are contemplating voluntary screening to balance the potential benefits and risks. Risk prediction may also be useful for researchers designing clinical trials of lung cancer prevention.     

Determinants of lung cancer risk in cigarette smokers in New Mexico

Although cigarette smoking is the strongest known risk factor for lung cancer, the effects of specific smoking practices have not been completely characterized. The present study examines determinants of lung cancer risk in a population-based, case-control study conducted in New Mexico, 1980-82. The study included 521 cases and 769 controls matched for age, sex, and ethnicity. Either the index subjects or their next-of-kin were interviewed in person to obtain a detailed history of cigarette smoking and information concerning other risk factors. With the use of multiple logistic regression, a model was constructed of the effects of amount smoked, duration of smoking, cigarette type, and smoking cessation on lung cancer risk. Among current smokers, risk increased with each additional cigarette smoked per day (P less than .001). For duration of smoking, the risk per year smoked in individuals 65 years and older was only one-third that in persons under age 65 years. With regard to cigarette type, a somewhat higher risk was found associated with smoking nonfilter cigarettes, but there was no evidence of decreasing risk as the extent of filter smoking increased. Lifelong filter cigarette smokers and smokers of both filter and nonfilter cigarettes were at lower risk than lifelong smokers of nonfilter cigarettes only. In ex-smokers, the pattern of variation of relative risk with amount and duration was similar to that in the current smokers. Excluding those who had stopped for 1 year or less, the relative risk declined exponentially with duration of smoking cessation (P less than .01). These analyses confirm the strong benefits of smoking cessation and indicate possible reduction of risk from smoking filter cigarettes.     

The PRE.DI.CA. project for radiographic lung cancer screening in cigarette smokers

In heavy cigarette smokers and former smokers who have accumulated a high risk of lung carcinoma, a primary objective is early detection. Annual chest x-ray screening is a readily available, low cost method to detect asymptomatic lung carcinoma at an early stage (stage I) and, after radical resection, to improve the 5-year survival rate. A project of annual chest x-ray screening, named PRE.DI.CA. was started, for the early diagnosis of asymptomatic lung cancer in the high risk population of heavy cigarette smokers and former smokers, males and females, aged 45-75 years, in the province of Varese. Over a 7-year period, 4.598 heavy smokers enrolled in the PRE.DI.CA. lung project underwent 14.461 chest x-ray examinations. 45 asymptomatic lung cancers were detected and defined histologically. In the province of Varese it was possible to establish early diagnosis of lung carcinoma with annual chest x-ray screening of asymptomatic high risk smokers. 52% stage I diagnosis was achieved at the incidence screening.     

Differences between small-cell lung cancer and non-small-cell lung cancer among tobacco smokers

It is known that smoking increases the risk for all histological subtypes of lung cancer. To date, the factors that determine why some patients develop small-cell lung cancer (SCLC) while others develop non-small-cell lung cancer (NSCLC) remain unknown. We compared the characteristics of 774 smokers with SCLC and NSCLC diagnosed during the period January 1999 till December 2002. Multivariate logistic regression was used to estimate the odds ratio (OR) with 95% CI. Testing of linear trend across categories of pack-years was also conducted. Six hundred and sixty-five NSCLC were compared to 109 SCLC. Among SCLC, there were significantly more females (20.2% versus 12.8%), current-smokers (81.7% versus 71.9%) as well as smokers who had smoked more than 40 pack-years (75.6% versus 50.3%). Comparing SCLC with NSCLC among the men only, having smoked more than 40 pack-years was associated with a significantly elevated odds ratio (OR) of 3.71 of developing SCLC (95% CI, 1.05-13.1; p=0.041). There was a decreasing trend in OR with increasing smoking cessation period. When comparing SCLC with adenocarcinoma, the women had a higher OR of 2.37 of developing SCLC (95% CI, 1.05-5.31; p=0.037) compared to the men. Our findings suggest that cumulative smoking exposure in terms of pack-years smoked is an important determining factor for the preferred development of SCLC among smokers.     

Serum alpha-tocopherol and subsequent risk of lung cancer among male smokers.

BACKGROUND: Higher blood levels of alpha-tocopherol, the predominant form of vitamin E, have been associated in some studies with a reduced risk of lung cancer, but other studies have yielded conflicting results. To clarify this association, we examined the relationship between prospectively collected serum alpha-tocopherol and lung cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study cohort. METHODS: The ATBC Study was a randomized, clinical trial of 29 133 white male smokers from Finland who were 50-69 years old and who had received alpha-tocopherol (50 mg), beta-carotene (20 mg), both, or neither daily for 5-8 years. Data regarding medical histories, smoking, and dietary factors were obtained at study entry, as was a serum specimen for baseline alpha-tocopherol determination. alpha-Tocopherol measurements were available for 29 102 of the men, among whom 1144 incident cases of lung cancer were diagnosed during a median observation period of 7.7 years. The association between alpha-tocopherol and lung cancer was evaluated with the use of multivariate proportional hazards regression. RESULTS: A 19% reduction in lung cancer incidence was observed in the highest versus lowest quintile of serum alpha-tocopherol (relative risk = 0.81; 95% confidence interval = 0. 67-0.97). There was a stronger inverse association among younger men (<60 years), among men with less cumulative tobacco exposure (<40 years of smoking), and possibly among men receiving alpha-tocopherol supplementation. CONCLUSIONS: In the ATBC Study cohort, higher serum alpha-tocopherol status is associated with lower lung cancer risk; this relationship appears stronger among younger persons and among those with less cumulative smoke exposure. These findings suggest that high levels of alpha-tocopherol, if present during the early critical stages of tumorigenesis, may inhibit lung cancer development.     

Beliefs and attitudes about lung cancer screening among smokers

The National Lung Screening Trial (NLST) recently reported that annual computed tomography (CT) screening is associated with decreased lung cancer mortality in high-risk smokers. Beliefs about lung cancer and screening, particularly across race and ethnicity, and their influence on CT screening utilization are largely unexamined. Our study recruited asymptomatic, high-risk smokers, 55-74 years of age from primary care clinics in an academic urban hospital. Guided by the self-regulation theory, we evaluated cognitive and affective beliefs about lung cancer. Intention to screen for lung cancer with a CT scan was assessed by self-report. We used univariate and logistic regression analyses to compare beliefs about screening and intention to screen among minority (Blacks and Hispanics) and non-minority participants. Overall, we enrolled 108 participants, of which 40% were Black and 34% were Hispanic; the mean age was 62.3 years, and median pack-years of smoking was 26. We found that intention to screen was similar among minorities and non-minorities (p=0.19); however, Hispanics were less likely to report intention to screen if they had to pay for the test (p=0.02). Fatalistic beliefs, fear of radiation exposure, and anxiety related to CT scans were significantly associated with decreased intention to screen (p<0.05). Several differences were observed in minority versus non-minority participants' beliefs toward lung cancer and screening. In conclusion, we found that concerns about cost, which were particularly prominent among Hispanics, as well as fatalism and radiation exposure fears may constitute barriers to lung cancer screening. Lung cancer screening programs should address these factors to ensure broad participation, particularly among minorities.     

Interest in testing for genetic susceptibility to lung cancer among Black college students "at risk" of becoming cigarette smokers.

Receptivity to genetic testing for lung cancer susceptibility was assessed among African American college freshmen, who held attitudes favorable towards or had experimented with cigarette smoking. Students (n = 95) completed a telephone survey that assessed beliefs about genetics and lung cancer risk, interest in genetic testing, and expectations about the test outcome. Interest in being tested was moderately high (mean, 5; SD, 2.2; scale of 1-7) and highest among those who believed lung cancer was influenced by genetics (r = 0.22, P < 0.05) and those who expected to be at high risk (r = 0.27, P < 0.05). Overall, 34% thought if tested, the result would show high risk for lung cancer. In multivariate analyses, students' test result expectation was the only significant predictor of interest in testing. Those who believed the test would show them to be at higher risk were thrice more likely to be interested in testing than those who thought the test would show that they were at lower risk (odds ratio, 2.99; confidence interval, 1.03-8.64; P = 0.04). Future research is needed to understand how young adults will respond to genetic susceptibility feedback that confirms or contradicts their expectations about personal risks of smoking.     

Dietary B vitamin and methionine intakes and lung cancer risk among female never smokers in China

Purpose

B vitamins and methionine have been postulated to have potential effects on carcinogenesis; however, findings from previous epidemiologic studies on B vitamins, methionine, and lung cancer risk are inconsistent. We investigated associations of dietary intakes of B vitamins (i.e., riboflavin, niacin, vitamin B6, folate, and vitamin B12) and methionine with lung cancer risk among female never smokers.

Methods

The Shanghai Women’s Health Study, a population-based, prospective cohort study, included 74,941 women. During a median follow-up of 11.2?years, 428 incident lung cancer cases accrued among 71,267 women with no history of smoking or cancer at baseline. Baseline dietary intakes were derived from a validated, interviewer-administered food frequency questionnaire. Cancer incidence and vital status were ascertained through annual linkage to the Shanghai Cancer Registry and Shanghai Vital Statistics Registry databases and through biennial in-person follow-ups with participants. Adjusted hazard ratios (HR) and 95?% confidence intervals (CI) were calculated using Cox regression.

Results

Dietary riboflavin intake was inversely associated with lung cancer risk (HR?=?0.62; 95?% CI?=?0.43–0.89; p trend?=?0.03 for the highest quartile compared with the lowest). A higher than median intake of methionine was associated with lower risk of lung cancer (HR?=?0.78; 95?% CI?=?0.60–0.99); however, there was no dose–response relation. Intakes of other B vitamins were not associated with lung cancer risk.

Conclusions

Our study suggests that dietary riboflavin intake may be inversely associated with lung cancer risk among female never smokers, which warrants further investigation.     

Predictors of serum selenium in cigarette smokers and the lack of association with lung and prostate cancer risk.

Epidemiological studies have suggested that low levels of selenium are associated with a higher incidence of both lung and prostate cancer. We analyzed the selenium serum concentration in 356 Carotene and Retinol Efficacy Trial (CARET) participants who later developed lung cancer and 356 matched controls and in 235 prostate cancer cases and 456 matched controls. Serum samples were obtained a mean of 4.7 years before diagnosis for both tumor types. Controls were matched to cases by year of randomization, age, smoking status, treatment arm, exposure population (asbestos workers or cigarette smokers), and year of blood draw. In the control population (n = 820), significant predictors of low serum selenium concentration were current smoking status and East Coast locations of the study center. Overall, there was no significant difference in mean serum selenium in lung cancer cases versus controls (11.91 microg/dl versus 11.77 microg/dl) or prostate cancer cases versus controls (11.48 microg/dl versus 11.43 microg/dl). No statistically significant trend in odds ratio was seen across quartiles of serum selenium for lung cancer (P = 0.49) or prostate cancer (P = 0.69). In a subpopulation of 174 prostate cancer patients who had clinical and pathological staging material reviewed, there was no association between serum selenium and Gleason score or clinical or pathological stage. In the CARET population of current and former smokers consuming an ad libitum diet, the serum concentration of selenium was not a risk factor for either lung cancer or prostate cancer.     

Risk of gastric cancer among smokers infected with Helicobacter pylori

Infection with the gastric bacterium Helicobacter pylori (in particular infection with CagA-positive strains) and smoking have been identified as risk factors for the development of gastric cancer. Both risk factors are typically acquired early in life and prevail over decades if not for life. We assessed the individual and joint impact of both risk factors on gastric cancer risk in a population-based case-control study from Germany including 71 patients with histologically verified gastric cancer and 363 patients with colorectal cancer who served as controls. Information on smoking and potential confounding factors was collected by standardized interviews. H. pylori infection was measured serologically by immunoglobulin G antibody titers against H. pylori. In addition, antibodies against the CagA antigen were determined by Western blot. Twenty-seven percent of cases compared with 15% of controls were smokers, and 43% of cases compared with 23% of controls were infected with CagA-positive H. pylori strains. After control for potential confounders, the relative risk of gastric cancer was 2.6 (95% CI 1.2-5.7) for nonsmoking subjects with CagA-positive H. pylori infections and 7.2 (95% CI 2.2-23.6) for smoking subjects with CagA-positive H. pylori infections compared with subjects without these risk factors. The corresponding relative risks for noncardia gastric cancer were 6.1 ( 95% CI 2.3-16.5) and 16.6 (95% CI 4.3-64.2). We conclude that smoking subjects with CagA-positive H. pylori infections have a strongly increased risk of gastric cancer and may be an important group for targeting efforts of prevention and early detection.     

Doses of nicotine and lung carcinogens delivered to cigarette smokers

BACKGROUND: Cigarette smoke yields of tar and nicotine obtained under the Federal Trade Commission (FTC)-specified machine-smoking protocol (35-mL puff volume drawn for 2 seconds once per minute) may not accurately reflect the delivery of toxins and carcinogens to the smoker. We conducted this study to obtain more realistic estimates of exposure to components of cigarette smoke that affect lung cancer risk. METHODS: We used a pressure transducer system to evaluate puffing characteristics for 133 smokers of cigarettes rated by the FTC at 1.2 mg of nicotine or less (56 smokers of low-yield cigarettes [相似文献   

Risk of gastroesophageal cancer among smokers and users of Scandinavian moist snuff

Although Scandinavian moist snuff ("snus"), no doubt, is a safer alternative to smoking, there is limited evidence against an association with gastroesophageal cancers. In a retrospective cohort study, we investigated esophageal and stomach cancer incidence among 336,381 male Swedish construction workers who provided information on tobacco smoking and snus habits within a health surveillance program between 1971 and 1993. Essentially complete follow-up through 2004 was accomplished through linkage to several nationwide registers. Multivariable Cox proportional hazards regression models estimated relative risks (RR) and 95% confidence intervals (CIs). Compared to never-users of any tobacco, smokers had increased risks for adenocarcinoma (RR = 2.3, 95% CI 1.4-3.7) and squamous cell carcinoma (RR = 5.2, 95% CI 3.1-8.6) of the esophagus, as well as cardia (RR = 2.1, 95% CI 1.5-3.0) and noncardia stomach (RR = 1.3, 95% CI 1.2-1.6) cancers. We also observed excess risks for esophageal squamous cell carcinoma (RR = 3.5, 95% CI 1.6-7.6) and noncardia stomach cancer (RR = 1.4, 95% CI 1.1-1.9) among snus users who had never smoked. Although confounding by unmeasured exposures, and some differential misclassification of smoking, might have inflated the associations, our study provides suggestive evidence for an independent carcinogenic effect of snus.     

Association of serum phospholipid fatty acids with breast cancer risk among postmenopausal cigarette smokers

Objective  To examine the association between breast cancer risk and the fatty acid composition of phospholipids in prediagnostic serum samples. Methods  We analyzed the fatty acid composition in 130 incident postmenopausal breast cancer cases and 257 matched controls nested within the β-Carotene and Retinol Efficacy Trial Cohort. The fatty acid composition was measured by gas chromatography. Multivariate-adjusted odds ratios and corresponding 95% confidence intervals for the risk of breast cancer were estimated using logistic regression. Stratified analysis was conducted by smoking status. Results  There were no associations with breast cancer risk for total saturated, monounsaturated, n-3, n-6, or trans fatty acids among all women. For individual fatty acids, we observed an inverse association with the trans linoleic acid, 18:2n6tt (p _trend = 0.0002). Among current smokers, long-chain saturated fatty acids (22:0 and 24:0) and total 16:1 trans fatty acids were positively associated with the risk of breast cancer, whereas these fatty acids showed no association among former smokers. Conclusion  Overall, we observed no significant association between serum phospholipid fatty acids and breast cancer risk, except for the trans linoleic acid isomer 18:2n6tt, which was unexpected. Our finding of a positive association of long-chain saturated fatty acids (22:0 and 24:0) and total 16:1 trans fatty acids with the risk of breast cancer only in current smokers may suggest an effect modification by smoking status. Our findings need to be replicated in future epidemiologic studies.     

Validation of a model of lung cancer risk prediction among smokers

The Bach model was developed to predict the absolute 10-year risk of developing lung cancer among smokers by use of participants in the Carotene and Retinol Efficacy Trial of lung cancer prevention. We assessed the validity of the Bach model among 6239 smokers from the placebo arm of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. The expected numbers of lung cancer cases and deaths without lung cancer were calculated from the Bach model and compared with the observed numbers of corresponding events over 10 years. We found that the risk model slightly underestimated the observed lung cancer risk (number of lung cancers expected/number observed = 0.89, 95% confidence interval [CI] = 0.80 to 0.99) over 10 years. The competing risk portion of the model substantially underestimated risk of non-lung cancer mortality (number of non-lung cancer deaths expected/number observed = 0.61, 95% CI = 0.57 to 0.64) over 10 years. The age-specific concordance indices for 10-year predictions were 0.77 (95% CI = 0.70 to 0.84), 0.59 (95% CI = 0.53 to 0.65), 0.62 (95% CI = 0.57 to 0.67), and 0.57 (95% CI = 0.49 to 0.67) for the age groups 50-54, 55-59, 60-64, and 65-69 years, respectively. Periodic radiographic screening in the ATBC Study may explain why slightly more cancers were observed than expected from the Bach model.     

Urinary levels of cigarette smoke constituent metabolites are prospectively associated with lung cancer development in smokers

Polycyclic aromatic hydrocarbons (PAH) are believed to be among the principal causative agents for lung cancer in smokers, but no epidemiologic studies have evaluated the relationship of PAH uptake and metabolism to lung cancer. In this study, we quantified prediagnostic urinary levels of r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), a validated biomarker of PAH uptake and metabolism, as well as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and cotinine and its glucuronides (total cotinine), validated biomarkers of uptake of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and nicotine, respectively, in relation to lung cancer risk among current smokers in a nested case-control study within a cohort of 18,244 Chinese men in Shanghai, China. Urinary levels of PheT, total NNAL, and total cotinine were significantly higher in cases than controls (N = 476 matched pairs). ORs (95% confidence intervals) for lung cancer in the second, third, fourth, and fifth quintiles of PheT were 1.70 (1.00-2.88), 1.07 (0.62-1.84), 1.48 (0.86-2.53), and 2.34 (1.33-4.11), respectively, relative to the lowest quartile (P(trend) = 0.023) after adjustment for self-reported smoking intensity and duration and urinary total NNAL and total cotinine. This study also confirmed that urinary total NNAL and total cotinine are independently related to lung cancer risk.