Male Bladder Cancer Research Articles

Combined effect of glutathione S-transferase M1 and T1 genotypes on bladder cancer risk

To evaluate the association between genetic polymorphism of GSTM1, GSTT1 and development of bladder cancer, a hospital-based case-control study was conducted in South Korea. The study population consisted of 232 histologically confirmed male bladder cancer cases and 165 male controls enrolled from urology departments with no previous history of cancer or systemic diseases in Seoul during 1997–1999. The GSTM1 null genotype was significantly associated with bladder cancer (OR: 1.6, 95% CI: 1.0–2.4), whereas the association observed for GSTT1 null genotype did not reach statistical significance (OR: 1.3, 95% CI: 0.9–2.0). There was a statistically significant multiple interaction between GSTM1 and GSTT1 genotype for risk of bladder cancer ( P=0.04); the risk associated with the concurrent lack of both of the genes (OR: 2.2, 95% CI: 1.2–4.3) was greater than the product of risk in men with GSTM1 null/ GSTT1 present (OR: 1.3, 95% CI: 0.7–2.5) or GSTM1 present/ GSTT1 null (OR: 1.1, 95% CI: 0.6–2.2) genotype combinations.

SEXUALITY PRESERVING CYSTECTOMY AND NEOBLADDER: INITIAL RESULTS

Standard cystectomy for bladder cancer in males and females includes removal of organs that are vital to normal sexual function. We report the initial results of modified cystectomy in males and females meant to preserve all sexual function, called sexuality preserving cystectomy and neobladder. Sexuality preserving cystectomy and neobladder consists of pelvic lymph node dissection followed by cystectomy alone with preservation of the vasa deferentia, prostate and seminal vesicles in males, and all internal genitalia in females. An ileal neobladder is anastomosed to the margins of the prostate in males and urethra in females. Indications for this type of surgery are bladder cancer stages T1-T3 with absent tumor growth in the bladder neck in males and females, absent tumor in the prostatic urethra in males and absent invasive tumor in the trigone in females. Further requirements are patient motivation for the preservation of sexual function, no prostate cancer and no cervical/uterine abnormalities. Preoperative evaluation in males involves prostate specific antigen measurement and transrectal ultrasound with sextant prostate biopsies, while females undergo gynecological examination with a cervical smear and transvaginal ultrasound. Voiding and sexual function are assessed by a structured interview with preoperative urodynamics. Erectile function is evaluated by RigiScan (UroHealth Systems, Inc., Laguna Niguel, California) nocturnal penile erection measurement. A short course of 20 Gy. external radiation therapy to the bladder is given shortly before surgery. No patient has been lost to followup, which involves repeat RigiScan examination and regular endoscopy. All patients were entered in a prospective clinical trial approved by the medical ethics committee. From 1995 to 1998, 10 males and 3 females 38 to 71 years old (mean age 55) were enrolled in this protocol. Bladder cancer was stage T carcinoma in situ N0M0 in 1 case, Ta multiple grade 3 N0M0 in 1, T1 multiple grade 3 N0M0 in 4, T2 grade 3 N0M0 in 5, T2 grade 3 N1M0 in 1 and T3 grade 3 N1M0 in 1. Mean followup was 3.5 years (range 3 to 6). Two patients died of widespread metastasis without local recurrence. In 1 case prostate cancer developed 5 years after sexuality preserving cystectomy and neobladder, which was treated with external radiation therapy. Erection was normal in 7 men with antegrade ejaculation in 5 and vaginal lubrication was reported to be normal in all women. Daytime continence was achieved in 9 of the 10 males and 2 of the 3 females, while nighttime continence was achieved in 7 and 2, respectively. One woman and 3 men perform intermittent catheterization because of post-void residual urine after voiding. Postoperatively a vaginal fistula and ureteral stenosis developed in 1 case each. Sexuality preserving cystectomy and neobladder achieves maximal tissue conservation, resulting in preserved normal sexual function and satisfactory urinary tract reconstruction. Using strict criteria oncological results have not been jeopardized to date.

Population stratification in epidemiologic studies of common genetic variants and cancer: quantification of bias.

Some critics argue that bias from population stratification (the mixture of individuals from heterogeneous genetic backgrounds) undermines the credibility of epidemiologic studies designed to estimate the association between a genotype and the risk of disease. We investigated the degree of bias likely from population stratification in U.S. studies of cancer among non-Hispanic Caucasians of European origin. An expression of the confounding risk ratio-the ratio of the effect of the genetic factor on risk of disease with and without adjustment for ethnicity-is used to measure the potential relative bias from population stratification. We first use empirical data on the frequency of the N-acetyltransferase (NAT2) slow acetylation genotype and incidence rates of male bladder cancer and female breast cancer in non-Hispanic U.S. Caucasians with ancestries from eight European countries to assess the bias in a hypothetical population-based U.S. study that does not take ethnicity into consideration. Then, we provide theoretical calculations of the bias over a large range of allele frequencies and disease rates. Ignoring ethnicity leads to a bias of 1% or less in our empirical studies of NAT2. Furthermore, evaluation of a wide range of allele frequencies and representative ranges of cancer rates that exist across European populations shows that the risk ratio is biased by less than 10% in U.S. studies except under extreme conditions. We note that the bias decreases as the number of ethnic strata increases. There will be only a small bias from population stratification in a well-designed case-control study of genetic factors that ignores ethnicity among non-Hispanic U.S. Caucasians of European origin. Further work is needed to estimate the effect of population stratification within other populations.

Cigarette smoking and bladder cancer in men: a pooled analysis of 11 case-control studies.

The primary risk factor for bladder cancer is cigarette smoking. Using a combined analysis of 11 case-control studies, we have accurately measured the relationship between cigarette smoking and bladder cancer in men. Available smoking information on 2,600 male bladder cancer cases and 5,524 male controls included duration of smoking habit, number of cigarettes smoked per day and time since cessation of smoking habit for ex-smokers. There was a linear increasing risk of bladder cancer with increasing duration of smoking, ranging from an odds ratio (OR) of 1.96 after 20 years of smoking (95% confidence interval [CI] 1.48-2.61) to 5.57 after 60 years (CI 4.18-7.44). A dose relationship was observed between number of cigarettes smoked per day and bladder cancer up to a threshold limit of 15-20 cigarettes per day, OR = 4.50 (CI 3.81-5. 33), after which no increased risk was observed. An immediate decrease in risk of bladder cancer was observed for those who gave up smoking. This decrease was over 30% after 1-4 years, OR = 0.65 (0. 53-0.79), and was over 60% after 25 years of cessation, OR = 0.37 (0. 30-0.45). However, even after 25 years, the decrease in risk did not reach the level of the never-smokers, OR = 0.20. (0.17-0.24). The proportion of bladder cancer cases attributable to ever-smoking was 0.66 (0.61-0.70) for all men and 0.73 (0.66-0.79) for men younger than 60. These estimates are higher than previously calculated.

Case-referent study on occupational risk factors for bladder cancer in southern Israel

To evaluate the possible association between occupational exposures (risk factors) and male bladder cancer in the Negev region (southern Israel) to enable preventive strategies to be applied. A total of 92 male bladder cancer patients, diagnosed at a regional medical center between 1989 and 1993, were studied by interview and compared with 92 males without oncological disease after matching by age and country of origin. A special questionnaire was developed to gather information on demography, life-time occupational history, smoking habits, coffee consumption, and health status. Statistical analysis of the case-referent data was done using the SPSS-5 package for performance of the chi-square test, conditional logistic regression, and multiple classification analysis. Significant associations were found between bladder cancer occurrence and (1) three different groups of occupational exposures [a - solvents (P = 0.002, OR not computed due to the lack of exposed persons among referents), b - dusts (P = 0. 02; OR = 4.67), and c - exposure to multiple chemicals (P < 0.001, OR = 6.25); (2) nephrolithiasis (P = 0.02, OR = 11.00); and (3) cigarette smoking (P = 0.01, OR = 1.87). Certain types of occupational exposure, different from that to aromatic amines and dyes, may be considered as contributing factors in the epidemiology of bladder cancer. Better identification of these chemicals and the work processes where they are used may help in abating such exposures, thus leading to a reduction in the risk for this relatively common cancer.

Occupational risk factors for bladder carcinoma. A case control study

Aim of this case-control study, performed on 412 male bladder cancer cases and 414 controls with benign prostatic hyperplasia in a former area of coal, iron and steel industries in Germany, was to identify occupations with an increased bladder cancer risk. In bladder cancer cases, smokers were overrepresented (58.3%) compared to controls (35.2%). The percentage of patients who had stopped smoking for at least 10 years did not differ in cases (10.2%) and controls (9.7%). Significantly elevated smoking-adjusted bladder cancer odds ratios (MH) were observed in painters and lacquers (MH 2.24, 95% CI 1.07-5.13), chemistry-related occupations (MH 2.44, 95% CI 1.05-5.67), coke plant workers (MH 2.89, 95% CI 1.16-7.16) and hard coal miners (MH 2.33, 95% CI 1.52-3.58). Significantly decreased smoking-adjusted bladder cancer odds ratios (MH) were observed in businessmen (MH 0.64, 95% CI 0.45-0.92) and office personnel (MH 0.58, 95% CI 0.41-0.81). In these two groups a relevant exposure to occupational bladder carcinogens is not likely.

Transitional Cell Carcinoma of the Urethra in Men and Women Associated With Bladder Cancer

Multifocal tumor occurrence in the entire urinary tract in time and space is a well-recognized characteristic of transitional cell carcinoma. Synchronous and asynchronous urethral transitional cell carcinoma, in relation to bladder cancer in male and female patients, is the subject of the present mini-review. It is imperative to rule out male and female patients having a high risk for urethral involvement or urethral recurrence. In male patients, prostatic urethral involvement and stromal invasion mainly due to in situ extension of carcinoma seems to be the most important risk factor. In female patients, bladder neck involvement by cancer seems most important. By excluding male and female bladder cancer patients having these characteristics for simultaneous urethrectomy, other patients are good candidates for reconstruction of the urinary tract after cystectomy by an orthotopic neobladder which will offer a good quality of life to bladder cancer patients.

Non-occupational risk factors for cancer of the lower urinary tract in Germany.

In a hospital-based case-control study conducted between 1989 and 1992 in Hessen (West Germany) 300 cases (239 male and 61 female) of histologically confirmed cancer of the lower urinary tract (LUT) were individually matched to controls from the same hospitals with respect to sex, age and area of residence. Smoking of cigarettes was associated with an elevated risk of 2.80 in males (95% confidence interval (CI): 1.65-4.76) and 5.33 (95% CI: 1.55-18.33) in females, as compared with nonsmokers. Variables like daily amount of smoked cigarettes, duration of smoking, age at beginning of cigarette smoking and time since smoking cessation showed a clear dose- and time-response relationship in males, but not in females. Elevated risks were observed for higher consumption of coffee, beer and wine, but - especially for the consumption of coffee were drastically reduced after adjustment for smoking. A weak association was found between the daily fluid intake and bladder cancer in males. Among females a significantly decreased odds ratio (OR) of 0.34 (95% CI: 0.11-0.99) was found for a daily fluid intake of more than two liters. Protective effects and risk reductions of approximately 50% were found for the regular intake of raw carrots, kale, salads and fruits. The findings of this investigation support an association between lifestyle factors and cancer of the lower urinary tract.

Aromatic amine DNA adduct formation in chronically-exposed mice: considerations for human comparison

Lifetime chronic exposure of mice to the aromatic amines 4-aminobiphenyl (ABP) and 2-acetylaminofluorene (AAF) produces liver and urinary bladder tumors. In parallel experiments, DNA adduct levels in target tissues reach a steady-state (a balance between adduct formation and removal) after about four weeks of either AAF or ABP ingestion. For these and other carcinogens, steady-state DNA adduct levels most frequently increase linearly with dose, but the formation of tumors also depends upon a variety of factors, including the proliferative capacity of the target tissue, the sex of the animal, genotoxic properties of the specific adducts formed, and other unknown events. Chronic dosing experiments in animal models are of interest for human risk assessment because human exposure is typically intermittent, involving repeated exposures. However, it is to be expected that in a genetically-diverse human population, where the lifetime averages >70 years, the relationship between tumorigenesis and DNA adduct formation will be relatively more complex than that observed in mice. From our studies of chronic ABP exposure in male mice, we have obtained the daily dose of ABP and the steady-state level of N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP) adduct associated with a 50% mouse bladder tumor incidence. Our attempt at a human extrapolation for adducts and urinary bladder cancer in smoking males (20–40 cigarettes/day) is based on the ABP dose per cigarette, values for the dG-C8-ABP adduct in bladder biopsies of lifetime heavy smokers at age ∼70, and the smoking-related bladder tumor incidence (absolute lifetime risk) for Caucasian males in the United States aged 65–84 years. The extrapolation has produced two major predictions, one related to adduct formation and the other related to tumorigenesis. First, the observed level of smoking-related dG-C8-ABP in DNA of human bladder epithelium, expressed as a function of daily ABP intake, is about 3500-times higher than similar data for mice, which suggests that humans may perform the biotransformation of ABP more efficiently than mice. Second, at a similar bladder tumor incidence, mouse bladder contained adduct concentrations that were much higher than those observed in human bladder; for example, at a 2.6% tumor incidence, mouse bladder contained an average of 55.5 fmol dG-C8-ABP/μg DNA (1850 adducts/10 8 nucleotides), while bladders from Caucasian male smokers contained an average of 0.036 fmol dG-C8-ABP/μg DNA (1.2 adducts/10 8 nucleotides). This suggests that factors other than ABP–DNA adducts, such as adducts of other carcinogens, the influence of promoters, and synergistic effects of all of these factors contribute substantially to smoking-related bladder cancer in humans.

Testing for Occult Cancer in Patients with Idiopathic Deep Vein Thrombosis – A Decision Analysis

To determine the effectiveness and cost-effectiveness of testing for occult cancer in idiopathic deep vein thrombosis (IDVT). Threshold analysis was performed on the risk-adjusted cancer prevalence in a cost-effectiveness model of ideal testing for selecting cancers with potentially desirable utility (candidate cancers). Decision analysis was employed to compare different testing programs for candidate cancers with that of no testing. Life expectancy (LE) of early- and late-detected cancers and costs of testing were the dimensions of utility. Cost-effectiveness was expressed as marginal cost per year of life saved. The perspective of the third payer was adopted, and a discount rate of 3% was applied to both costs and benefits. Risk of cancer in IDVT, testing policies, test characteristics, and LE were gathered from literature. Costs were provided from our hospital rate book and accounting service. Ideal testing would support a gain of LE of 40 days or more for prostate, colon and bladder cancer in males and for colon, breast and endometrium cancer in females aged from 60 to 69 years. Testing females with colonoscopy and mammography in any sequence provides 70 days of life gained. Testing males with colonoscopy provides 27 days of life gained. Lower and older ages reduce testing effectiveness. The qualitative results are stable over plausible ranges of test characteristics, while variations in the value of benefit for early cancer diagnosis may modify the strategy. Incremental cost-effectiveness ranges from $1,789 to $ 6,979 per year of life gained. According to the effectiveness criterion adopted, the only worthwhile investigation strategy includes colon and breast cancer in females. Testing for colon cancer in males is desirable at a lower criterion of effectiveness. All the strategies are cost effective.

Female urethra-sparing cystectomy and orthotopic bladder replacement.

Orthotopic bladder replacement after cystoprostatectomy has long become the method of choice in the treatment of infiltrating bladder cancer in males. Very good quality of life in patients thus treated stimulated the work on a similar approach applicable to females. Twelve females were treated by urethra-sparing cystectomy. The surgical technique preserves not just the urethra itself but also the pelvic floor and relevant innervation. Diurnal continence was achieved in 11 patients, 1 of whom had a so-called hypercontinence with a residual volume of 300 ml. The remaining patient suffered from stress incontinence. The described urethra-sparing radical cystectomy in female patients with a urothelial tumor, with normal pelvic floor and with a low risk of secondary affection of the urethra, permits reconstructing a continent orthotopic neobladder from a detubularized intestinal segment.

Decreasing bladder cancer mortality in The Netherlands.

To evaluate the prediction that the observed increasing trend in male bladder cancer mortality in the Netherlands between 1955 and 1988 would change to a decreasing trend. Using demographic and mortality data from the Netherlands Central Bureau of Statistics, male and female bladder cancer mortality per 10(5) person-years from 1955 to 1994 were calculated. Changes in the age structure of the Dutch population were adjusted using direct standardization to the European "standard' population. The effects of age, calendar period and birth cohort on the temporal trend in mortality were evaluated using log-linear modelling. Male mortality from bladder cancer increased from 6.2 per 10(5) in 1955 to 12.6 per 10(5) in 1990, but decreased thereafter. Female mortality from bladder cancer has remained stable throughout the study period, at 2.8 and 2.7 per 10(5) in 1955 and 1994, respectively. The changing trend among men is consistent with an increasing risk for successive birth cohorts until the 1910 cohort and a decreasing risk for cohorts born after 1930. This cohort effect is probably caused by changes in the smoking behaviour of the male Dutch population. There were no differences in risk for successive birth cohorts of females. Male mortality from bladder cancer in the Netherlands will probably decrease for at least another decade. A future increase in female mortality from bladder cancer, as recorded for lung cancer, is unlikely.

Myeloperoxidase activity and whole blood chemiluminescence in bladder cancer-influence of smoking

Polymorphonuclear leukocytes (PMNs) from 63 male bladder cancer patients do not differ from 65 cases of the control group in myeloperoxidase activity (MPO) nor in whole blood chemiluminescence response (CL). MPO activity increased in control smokers compared with the control nonsmokers (p < 0.05) and correlated significantly with cigarette consumption. CL response was also higher in control smokers (p < 0.05) than in control nonsmokers, and correlates significantly with the MPO activity. Both MPO and CL showed significant association with the increased number of peripheral blood PMNs. Although substantial evidence implicates oxygen free radicals, not only in chemical carcinogenesis, but also in the antitumor system (especially the myeloperoxidase system), we were unable to establish either an increase or a decrease in the axidant generating capacities in bladder cancer patients, although a trend towards a higher MPO and CL activity was observed in nonsmokers of this group. In conclusion, we found an enhanced oxidant-generating status of the smokers' PMNs, but its biological significance in carcinogenesis of the bladder remains to be established.

Prognostic Significance of Selected Lifestyle Factors in Urinary Bladder Cancer

To examine the prognostic significance of lifestyle factors in urinary bladder cancer, we conducted a follow‐up study of 258 incident bladder cancer patients, who were originally recruited in a case‐control study in metropolitan Nagoya. Information on individual survivals was obtained from the computer data‐file of the tumor registry of the Nagoya Bladder Cancer Research Group. Univariate analyses revealed significant associations of 5‐year survivorship with educational attainment, marital status, drinking habits and consumption of green tea in males, and age at first consultation, histological type and grade of tumor, stage and distant metastasis in both sexes. After adjustment for age, stage, histology (histological type and grade) and distant metastasis by means of a proportional hazards model, drinking of alcoholic beverages was significantly associated with the prognosis of bladder cancer in males. Its adjusted hazard ratio was 0.46 (95% confidence interval: 0.26–0.79), favoring patients who had taken alcoholic beverages. In detailed analysis, ex‐drinkers and all levels of current drinkers demonstrated hazard ratios smaller than unity, although no clear dose‐response relationship was detected. No prognostic significance was found for such lifestyle factors as smoking habit, uses of artificial sweeteners and hairdye, and consumption of coffee, black tea, matcha (powdered green tea) and cola.

Bladder cancer, parity, and age at first birth.

The excess of bladder cancer in males (M:F ratio of 4:1 in the United States) is not explained fully by gender differences in smoking habits or occupational exposures. Laboratory studies suggest that some androgenic hormones stimulate (or do not inhibit) oncogenesis in bladder tissue, and that estrogenic hormones have the opposite effect. These observations suggest that bladder cancer risk in females may be modified by sex hormones which undergo profound changes during and following pregnancy. Mail-questionnaire data from 317 incident female cases, and 833 population-based controls in Iowa were used to measure the effect of parity and maternal age at first birth on bladder cancer risk. Parous women were at decreased risk relative to nulliparous women (odds ratio [OR] = 0.67, 95 percent confidence interval [CI] = 0.44-1.00), after adjustment for age, tobacco use, and previous bladder infection. The overall risk reduction was restricted to women who had never smoked (OR = 0.51, CI = 0.30-0.88), with no apparent effect of parity among ever-smokers (OR = 0.93, CI = 0.49-1.77). Risk appeared to decrease with increasing age at first birth, but did not vary with increasing parity after the first birth. Our findings are consistent with the hypothesis that oncogenesis in transitional cell tissue of the human bladder is influenced by sex hormones, and that hormonal changes related to pregnancy thereby can decrease risk.

Work‐related Bladder Cancer Risks in Male Japanese Workers: Estimation of Attributable Fraction and Geographical Correlation Analysis

One hundred and forty‐nine relative risks (RRs) on occupations and bladder cancer were extracted from 27 case‐control studies and geometric means were calculated for 27 occupations as summary RRs. Those in high risk occupations, among whom the summary RRs significantly exceeded unity, were found to be petroleum workers (RR=3.51), dye workers (RR = 3.38), machinists (RR=2.76), drivers (RR = 2,22), rubber workers (RR=2.19), printers (RR = 2.12), clothing/tailors (RR = 2,10), wood workers/carpenters (RR=1.70), miners (RR = 1.68), textile workers (RR = 1.63), mechanics (RR=1,54), engineers (RR = 1,54), leather workers (RR=1.49), painters (RR=1.48) and chemical workers (RR = 1.44). The estimated numbers of male bladder cancers in 1980 in the high risk and other occupations were 820 and 2065 cases, respectively. The estimated number of work‐related bladder cancer was 548 cases, the attributable fraction being 19% in active employees and 12% in the entire population. The geographical distribution of male bladder cancer deaths in Japan was positively correlated with the distributions of workers in the transport/communications industry and in tertiary industries including services, wholesale, retail, finance and insurance, whereas it was negatively correlated with the distribution of workers in the agricultural industry. These findings suggest that workers in certain industries may be at high risk of bladder cancer, but lifestyle modification associated with urbanization and industrialization could be an alternative explanation.

A CASE-CONTROL STUDY OF BLADDER CANCER USING CITY DIRECTORIES AS A SOURCE OF OCCUPATIONAL DATA

Commercial city directories, currently produced in 1,250 United States cities, potentially provide yearly information on occupation and employer for all city residents over age 18 years. To investigate the usefulness of these occupational data, the authors have conducted a case-control study of male bladder cancer mortality in Hamilton County, Ohio (which includes Cincinnati). A total of 731 bladder cancer cases who died during 1960-1982 were matched on age, sex, race, date-of-death, and residence at death to two controls per case. Risks of bladder cancer death were calculated by occupation, industry, and specific employer, using both city directories (multiple statements) and death certificates (single statement). Four companies showed a significant excess bladder cancer risk when using city directories. Only one would have been identified using death certificates, which ask for usual lifetime type of industry rather than a specific company name. Using city directories, significant positive associations were found between bladder cancer and occupation as an engineer, tailor, carpenter, furnace operator, blending machine operator, chemist, pressing machine operator, house cleaner, or salesman. For industry, the authors found significant positive associations for the textile, chemical, grain mill, foundry, petroleum, building service, entertainment, and advertising industries. A significant increase in risk for those with 20 or more years of employment was seen for those employed as truck drivers and furnace operators, or those employed in the railroad industry. A check of the validity of city directory data indicated that 77 per cent of the listings agreed with Social Security earnings reports for employer in any given year. One limitation of Hamilton County city directory data was the fairly large number of yearly listings without any occupational data (15 per cent for occupation, 36 per cent for employer). While city directory data do provide work history over time, unlike death certificates, such data are available only for years of residence in the city in question.

Occupation and bladder cancer in males: a case-control study.

A case-control study of 512 male cases of bladder cancer and 596 male hospital controls (all living in the province of Turin, Northern Italy, an area with a high proportion of car workers) has been analyzed for occupations. Relative risks were 1.8 (95% c.l. 0.9-3.6) for the textile industry, 3.8 (1.3-11.5) for the leather industry, 1.8 (0.8-4.0) for printing, 8.8 (2.7-28.6) for dyestuff production, 1.2 (0.6-2.4) for tire production and 2.5 (1.0-6.0) for other rubber goods, 2.0 (0.9-4.5) for brickyards and related activities. A relative risk of 3.1 (0.9-10.5) was found for turners having started work before 1940 and with at least 10 years of activity. For truck drivers the relative risk was 1.2 (0.6-2.5). A job-exposure matrix was developed for the development of new hypotheses; an association with bladder cancer was found for aromatic amines only. The attributable risk percent in the population was estimated as 10%, when only those occupations consistently associated with bladder cancer were considered.

Increased risk for male bladder cancer among a cohort of male and female hairdressers from Geneva.

A cohort of 703 male and 677 female hairdressers born from 1880 onwards, who started to run salons in Geneva between 1900 and 1964 was followed-up to the end of 1982. Cause-specific mortality was analysed from 1942 to 1982 and a significant excess mortality from bladder cancer (observed deaths = 10, expected deaths = 3.9) was found among males. Cancer incidence recorded for the years 1970 to 1980 showed a significant increase among males for all neoplasms (O = 65, E = 51.4), cancer of the buccal cavity and pharynx (O = 6, E = 2.5), cancer of the prostate (O = 12, E = 6.1), and bladder cancer (O = 11, E = 5.3). Among female hairdressers no significant increase in mortality or in cancer incidence was found. Mean age at diagnosis of the 18 deaths and/or incident cases from bladder cancer found among the male hairdressers was 68.6 years (range 51-88) and mean latency period since first exposure was 52.2 years (range 24-73). Occupational history was obtained for most of the 18 cases and of 54 controls randomly selected from the cohort. Little evidence was found of a causal relationship between exposure to hair dyes and the excess risk for bladder cancer among the male hairdressers. It is a suggestion that this excess might be related to some colouring agent(s) in brilliantines which were widely used in men's hairdressing salons in Geneva until about 1950.

Data Analytic Methods for Matched Case-Control Studies

The recent introduction of complex multivariate statistical models in matched case-control studies is a mixed blessing. Their use can lead to a better understanding of the way in which many variables contribute to the risk of disease. On the other hand, these powerful methods can obscure salient features in the data that might have been detected by other, less sophisticated methods. This shortcoming is due to a lack of support methodology for the routine use of these models. Satisfactory computation of estimated relative risks and their standard errors is not sufficient justification for the fitted model. Goodness of fit must be examined if inferences are to be trusted. This paper is concerned with the analysis of matched case-control studies with logistic models. Analogies of these models to linear regression models are emphasized. In particular, basic concepts such as analysis of variance, multiple correlation coefficient, one-degree-of-freedom tests, and residual analysis are discussed. The fairly new field of regression diagnostics is also introduced. All procedures are illustrated on a study of bladder cancer in males.