Lung cancer and use of cigarettes: a French case-control study.

A case-control study of 1,625 cases and 3,091 controls was conducted in France from 1976 to 1980 to compare the effects of different smoking habits, especially the use of filter cigarettes, tobacco types (light or dark), and the use of hand-rolled or manufactured cigarettes on the occurrence of lung cancer. All cases had histologically confirmed lung cancer; the controls were matched by sex, age, hospital of admission, and interviewer. The reported results concern only male nonsmokers and males who smoked (or had smoked) cigarettes exclusively, i.e., a total of 1,217 Kreyberg I and Kreyberg II cancer cases and 1,915 controls. Cigarette smoking was associated with both Kreyberg I and Kreyberg II cell categories although with different relative risks (RR) (17.2 and 3.6, resp.). Within the Kreyberg I category, RR were significantly increased (P less than .0001) with certain indices of duration and intensity of cigarette exposure, such as early age at first cigarette smoked, daily consumption, depth of inhalation, and duration of smoking. A significant difference in risk was found within the Kreyberg I category for nonfilter versus filter cigarette smokers (RR = 18.1 and 10.9, resp.) and dark versus light tobacco smokers (RR = 18.1 and 4.9, resp.) but not for hand-rolled versus manufactured cigarette smokers (RR = 19.8 and 16.0, resp.). When all the covariates were taken into account in a matched logistic regression, lung cancer risks for nonfilter versus filter cigarette smokers was RR = 1.23, for hand-rolled versus manufactured cigarette users RR = 1.22, and for dark versus light tobacco users RR = 1.94.

Association between breast cancer and family malignancies.

In a case-control study, the relationship between a family history of cancer of the breast, ovary, colon, uterus or prostate and the risk of breast cancer was investigated. The data consisted of family histories from 495 breast cancer cases and 785 controls aged 20-56 years. A positive association was found between the occurrence of breast cancer and a history of breast cancer in the families of the subjects affected. This relationship increased linearly with both the degree of kinship of the affected relatives and with their number. The risk of breast cancer associated with other types of cancer in the family was not significantly different from unity.

Cancer epidemiology: implications for prevention and treatment.

Due to the results achieved in epidemiological research for the last 30 years, we are able to reduce considerably mortality from cancer through prevention and early diagnosis. The data required to accomplish these actions have been provided by epidemiology: (a) Descriptive epidemiology is the study of the frequency and the distribution of cancers, based on data concerning mortality and morbidity. These frequencies vary according to different parameters (i.e., sex, age, geographical situation). (b) Analytical epidemiology is able to pinpoint different risk factors (i.e., alcohol, tobacco, iatrogenic factors) through adequately conducted surveys. Primary prevention can attenuate the incidence of cancers by the suppression or reduction of certain risk factors. Secondary prevention permits the screening and treatment of precancerous lesions and avoids the secondary emergence of cancer (cervix uteri, colon). Early diagnosis is able to detect lesions at an early stage in their evolution where treatment is facilitated and where there are optimal chances of survival (breast). All of these measures for prevention and early diagnosis are being organized as large-scale strategic campaigns (e.g., National Cancer Institute, European Communities).

Variations in the risk of breast cancer associated with a family history of breast cancer according to age at onset and reproductive factors.

In a case-control study of 495 breast cancer patients and 785 controls between 20 and 56 years of age, the risk of breast cancer associated with a family history of breast cancer was studied according to age and reproductive factors. The familial risk of breast cancer was not significantly modified by age at onset, age at menarche, number of children, age at first full-term pregnancy, menstrual cycle length or age at menopause. However, the familial risk significantly increased with the number of abortions (p < 0.05) and seemed to decrease after a natural menopause (p = 0.08). These results suggest that a familial predisposition to breast cancer exerts the same influence during the first six decades of life, except maybe when there are isolated or repeated events such as abortions or artificially imposed menopause, in which case the risk is apparently greater.

Differential effects of tar content, type of tobacco and use of a filter on lung cancer risk in male cigarette smokers.

BACKGROUND: To date, the effect of tar exposure, the use of a filter and the type of tobacco (light or dark) on the risk of lung cancer have not been studied together. METHODS: Data from a case-control study on lung cancer were used to evaluate the specific effects of these three parameters. Cases of lung cancer and controls were interviewed in hospitals in France from 1976 to 1980. The past tar content of cigarettes distributed by the French Tobacco Monopoly was obtained. The results presented concern an exclusively male population of lifelong smokers of French cigarettes and lifelong smokers of light imported cigarettes. The population comprised 1114 cases of histologically confirmed lung cancer and 1466 hospitalized controls. RESULTS: An increase in risk was found among smokers of both dark and light cigarettes (relative risk [RR] = 2.6, 95% confidence interval [CI]:1.1-6.5) and among lifelong smokers of dark cigarettes (RR = 1.7, 95% Cl: 0.9-3.2) compared to lifelong smokers of light cigarettes. Similarly, the risk of lung cancer was higher among smokers of both non-filter and filter cigarettes (RR = 1.6, 95% Cl: 0.9-2.7) and among lifelong smokers of non-filter cigarettes (RR = 1.6, 95% Cl: 0.9-2.8) than among lifelong smokers of filter cigarettes. A borderline significant increase in risk was observed for smokers of French cigarettes compared to smokers of light imported cigarettes (RR = 2.6, 95% Cl: 0.9-7.7). No significant difference in the risk of lung cancer was observed among smokers of French cigarettes according to the proportion of years of smoking high tar cigarettes. CONCLUSION: This study tends to demonstrate a separate effect of type of tobacco, use of a filter and tar content in addition to the usual characteristics of cigarette smoking on lung cancer risk.

Oral contraceptives and breast cancer: a French case-control study.

The relationship between the risk of breast cancer and oral contraceptive use was investigated in a case-control study conducted in France between 1983 and 1987 in five public hospitals. Some 464 cases aged 25 to 56 years and 542 matched controls were interviewed about their history of the use of oral contraceptives (OC). Results are given for the entire population and for the subgroup of 358 and 379 premenopausal cases and controls. The multivariate relative risk estimate, for ever user, was 1.5 (p less than 0.01) in the whole group as well as in the premenopausal subgroup (p less than 0.02). However, there was no evidence that the effect varied appreciably according to duration of use, age at first use, use before first full-term pregnancy (FFTP) and time since first or last use. The risk was not altered for any particular brand of OC. We conclude that, because of the widespread attention given to the relationship between OC use and breast cancer, information bias might be responsible for part of the excess in risk observed among OC ever users.

PIP: The relationship between the risk of breast cancer and oral contraceptive (OC) use was investigated in a case-control study conducted in France between 1983-87 in 5 public hospitals. Some 464 cases ages 25-56 years and 542 matched controls were interviewed about their history of OC use. Results are provided for the entire population and for the subgroups of 358 and 379 premenopausal cases and controls. The multivariate relative risk estimate, for ever-use, was 1.5 (p0.01) in the entire group as well as in the premenopausal subgroup (p0.02). However, there was no evidence that the effect varied appreciably according to the duration of use, age at 1st use, use prior to 1st fullterm pregnancy, and time since 1st or last use. The risk was not altered for any particular OC brand. The authors conclude that because of the widespread attention given to the relationship between OC use and breast cancer, information bias might be responsible for a part of the excess of risk observed among OC ever-users.

Breast cancer and oral contraceptives: a review.

The relationship between oral contraceptive use and breast cancer was investigated in 22 major epidemiological studies, which are reviewed in this paper. The overall risk ratio was never found to increase when computed among all users vs. nonusers. Risk increases were found in some studies within specific subgroups; but in general, if any risk exists, it is not much more than one. Future studies should focus specifically on women under age 25, on women before a first full-term pregnancy and, to a lesser extent, on perimenopausal women and on women who have had a benign breast disease.

PIP: This paper reviews the findings of the 22 major epidemiologic studies that have investigated the relationship between breast cancer and oral contraceptive (OC) use. Although the findings are discrepant, they tend to rule out the hypothesis of a large increase in the risk of breast cancer in OC users compared to nonusers, at least among women over 25 years of age. Moreover, rates of breast cancer have not been shown to increase with increasing duration of OC use. In general, if a risk has been found, it has not exceeded 1. In certain specific subgroups, particularly women under age 25 years and women who used OCs before 1st pregnancy, the risk of breast cancer has been found to be increased in selected studies but not in other studies. To clarify these discrepant findings, it is recommended that future studies focus on women under age 25 years, on women before a 1st full-term pregnancy, and, to a lesser extent, on perimenopausal women and those who have had a benign breast disease. It should be kept in mind that widespread use of OCs may be too recent to assess possible carcinogenic effects. The absence of a consistent pattern of risk findings in the literature may in part reflect methodological inadequacies, including an sufficient number of cases or biased selection of subjects.

[From the explanatory to the pragmatic]. / De l'explicatif au pragmatique.

The classical methodology of clinical trials has been conceived for improving scientific knowledge in therapeutic research. This methodology is often unsuitable for evaluating a treatment in clinical practice, i.e. taking into account all its advantages and disadvantages. For that very reason two approaches, explanatory and pragmatic, which differ in many aspects, were developed during the 1970's. This distinction is very useful in the design of a trial, but two main difficulties are related to the assessment criteria and the method of analysis. A possible solution is to use the decision-making procedures but it's still a research problem.

[Epidemiologic studies on the role of tobacco in various human cancers]. / Etudes épidémiologiques sur le rôle du tabac dans les différents cancers humains

The totality of epidemiological research over the last 25 years in the field of the relationship between tobacco consumption and the chance of developing certain cancers has demonstrated beyond reasonable doubt that the use of tobacco is implicated in the genesis of a certain number of cancers of the respiratory tract and the upper air and food passages. The most important relationship concerns carcinoma of the bronchus, currently the most frequently encountered in men, for which the incidence risk is directly related to the use of cigarettes and which rises with the amount smoked and with inhaling. Other possible aetiological factors, particularly occupational exposure to chemical and radio active agents, whilst interesting are none the less marginal. The ramifications of epidemiologic and experimental researchs lead us to envisage a multifactorial aetiology in which tobacco is a constant element. Avoidance of exposure would play a major role in prevention.

[Nutrition and carcinoma of the breast: presentation of a french investigation (author's transl)]. / Nutrition et cancer du sein: présentation d'une enquête française.

The existence of dietary risk factors in breast cancer of post-menopausal women is a recent, and yet unproven hypothesis. A French survey made possible by the cooperation of general surgeons and radiotherapists practising in private clinics is currently in progress in a number of metropolitan departments. A preliminary evaluation of the first 654 questionnaires has proved entirely negative. There was no difference between women with breast cancer and a population of age-matched controls with regard to weight, height or the various traditionnal indices of obesity. However, the number of patients studied is too small to allow this hypothesis to be still rejected.

[Small cell bronchial cancer: epidemiology]. / Cancer bronchique à petites cellules: épidémiologie.

Small cell lung carcinoma is the most frequent cancer in man. In France, the geographic distribution is not homogenous and the frequency is time-dependent. The main risk factors are smoking and some professional exposures.

Knowledge acquisition in oncology from randomized therapeutic trials.

Appreciating the impact, on the progress of our knowledge, of randomized therapeutic trials performed over a period of thirty years leads to a two-fold approach: a) Drawing up the list of randomized trials and assessing the impact of their conclusions on the progress of our knowledge and on the improvement of standard therapy; b) from recognised progress in oncology, appraising the part played by randomized trials in the acquisition of that knowledge.

[Estimation of survival rates: technics used (author's transl)]. / Etablissement des courbes de survie: mise au point.

The direct method and life-table methods (actuarial and Kaplan-Meier) for estimating survival rates are described here. The difference between direct method and lifetable method is the use of information about the patients who are still alive. Practical examples of calculation are given with recommandations for graphical displays.

PIP: The authors describe the direct and life table methods used to estimate survival rates and provide some practical examples of calculations and recommendations for graphical display (SUMMARY IN ENG)

[Carcinogenic risks and prevention of cancer (author's transl)]. / Risques carcinogènes et prévention des cancers

Epidemiologic studies supported by experimental research have made it possible to draw up an epidemiological outline of the different types of cancer. From the standpoint of prevention, carcinogenic factors can be investigated according as they apply to collective or individual life, according to their relative etiological importance, and to the incidence rate and gravity of cancers involved. The most efficient procedures concerning about more than 50% of human cancers appear to be the campaigns against tobacco and alcohol consumption, systematic screening and treatment of precancerous lesions of uterine cervix and changes in the nutritional habits.

[A major cause of epidemics: the increase in tobacco consumption in France]. / Une cause d'épidémie majeure: l'augmentation de la consommation de tabac en France.

There are conflicting reports on trends in tobacco consumption for France. We present here a synthesis of the available evidence from total sales and from population surveys. The consequences on future lung cancer death rates are briefly discussed and some possible actions are suggested.

[Study of the distribution of HLA antigens within a population and a comparison between 2 populations]. / Etude de la distribution des antigènes HLA dans une population et comparaison de deux populations.

HLA complex is made up of numerous loci whose alleles are codominant. Several associations between HLA antigens and diseases have been identified. Analysis of these associations require statistical methods taking into account the number of tests and the existence of alleles which have not yet been identified. Statistical methods for the estimation and the comparison of alleles frequencies are presented for genotypic, phenotypic and marginal data. An example concerning patients with medullary thyroid carcinoma illustrates these methods.

[Methodological framework of the evaluation of systematic screening and treatment of preexistent lesions of the colon and the rectum]. / Cadre méthodologique de l'évaluation de dépistage systématique et du traitement des lésions pré-existantes du côlon et du rectum.

Among the conditions which need to be filled when generalizing the mass screening of polyps in view of the secondary prevention of colorectal cancers, three are already present: 1) it is a frequent and serious cancer; 2) there is an affiliation between benign tumours and cancer; 3) an effective non-mutilating treatment of benign tumours is available. On the other hand, two additional conditions remain unfilled and yet lie within the domain of research by methodologically rigorous studies: the setting up of a screening test with a high cost-effectiveness relationship; the epidemiological demonstration of the decreasing incidence of colorectal cancers following screening and treatment of precancerous lesions.