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Biomedical subjects

B Rachet

Publications and source records attributed to B Rachet.

11 recordsLinked to original sources
PubMed2005

Origins of socio-economic inequalities in cancer survival: a review.

BACKGROUND: Cancer survival is known to vary by socio-economic group. A review of studies published by 1995 showed this association to be universal and resilient to the many different ways in which socio-economic status was determined. Differences were most commonly attributed to differences in stage of disease at diagnosis. MATERIALS AND METHODS: A review of research published since 1995 examining the association of cancer survival with socio-economic variables. RESULTS: An association between socio-economic status and cancer survival has continued to be demonstrated in the last decade of research. Stage at diagnosis and differences in treatment have been cited as the most important explanatory factors. Some research has evaluated the psychosocial elements of this association. CONCLUSIONS: Socio-economic differences in cancer survival are now well documented. The explanatory power of stage at diagnosis, although great, should not detract from the evidence of differential treatment between social groups. Neither factor can completely explain the observed socio-economic differences in survival, however, and the importance of differences in tumour and patient factors should now be quantified.

Health Status Indicators↗
PubMed2004

Trends and socioeconomic inequalities in cancer survival in England and Wales up to 2001.

We examined national trends and socioeconomic inequalities in cancer survival in England and Wales during the 1990s, using population-based data on 2.2 million patients who were diagnosed with one of the 20 most common cancers between 1986 and 1999 and followed up to 2001. Patients were assigned to one of five deprivation categories (from 'affluent' to 'deprived') using characteristics of their electoral ward of residence at diagnosis. We estimated relative survival up to 5 years after diagnosis, adjusting separately in each deprivation category for background mortality by age, sex and calendar period. We estimated trends in survival and in the difference in survival between deprivation categories ('deprivation gap') over the periods 1986-90, 1991-95 and 1996-99. We used period analysis to examine likely survival rates in the near future. Survival improved for most cancers in both sexes during the 1990s, and appears likely to continue improving for most cancers in the near future. The deprivation gap in survival between rich and poor was wider for patients diagnosed in the late 1990s than in the late 1980s. Increases in cancer survival in England and Wales during the 1990s are shown to be significantly associated with a widening deprivation gap in survival.

England↗
PubMed2004

[Intractable postpartum haemorrhages: where is the place of vascular ligations, emergency peripartum hysterectomy or arterial embolization?].

OBJECTIVE: Update of knowledge on the various methods of management of intractable postpartum haemorrhage. METHOD: PubMed, MEDLINE were the electronic sources, in English and French languages, used for data retrieval. Uterine atony and abnormal placental insertions (placenta praevia or accreta) are the major causes of primary postpartum haemorrhages. To preserve fertility, we dispose of angiographic selective embolization or surgical vascular ligations. Embolization is a non-invasive method practicable by simple catheterization under local anesthesia. Vascular ligations of the uterine vessels or internal iliac arteries require mostly laparotomy. New and easier surgical methods, such as uterine compression or hemostatic suturing techniques have been described for which we lack experience. RESULTS: For uterine atony, the success rate of arterial embolization and uterine artery ligations is close to 100%. Ligation of internal iliac arteries is a little less effective and technically more difficult to carry out. It remains interesting in obstetrical traumatic hurts, which do not concern the uterus. If bleeding from the lower segment occurs during caesarean section, low uterine artery ligatures are necessary. These methods are all the more effective than they are prematurely implemented before the rise of major coagulopathy. In this case, uterine devascularization has also to be applied to ovarian vessels. With placenta accreta, accreta portion of the placenta can be left in place and arterial embolization or vascular ligations can be done. Nevertheless the main cause of failure with conservative treatments is placenta accreta. CONCLUSION: The simplest and the least morbid methods must be retained. After vaginal birth, arterial embolization can be done, if there is no maternal haemodynamic disorder nor interventional vascular radiology unit nearby. During caesarean section, progressive uterine artery ligation can be done adapted to the bleeding cause. In case of failure of a conservative treatment, it would be dangerous to multiply techniques. Emergency peripartum then should remain the choice procedure.

Arteries↗
PubMed2004

A flexible modeling approach to estimating the component effects of smoking behavior on lung cancer.

OBJECTIVE: Despite the established causal association between cigarette smoking and lung cancer, the relative contributions of age started, duration, years since quitting, and daily amount smoked have not been well characterized. We estimated the contribution of each of these aspects of smoking behavior. STUDY DESIGN AND SETTING: A case-control study was conducted in Montreal on the etiology of lung cancer. There were 640 cases and 938 control subjects for whom lifetime smoking histories were collected. We used generalized additive models, incorporating cubic smoothing splines to model nonlinear effects of various smoking variables. We adopted a multistep approach to deal with the multicollinearity among time-related variables. RESULTS: The main findings are that (1) risk increases independently by daily amount and by duration; (2) among current smokers, lung cancer risk doubles for every 10 cigarettes per day up to 30 to 40 cigarettes per day and tails off thereafter; (3) among ex-smokers, the odds ratio decreases with increasing time since quitting, the rate of decrease being sharper among heavy smokers than among light smokers; and (4) absolute risks demonstrate the dramatic public health benefits of long-term smoking cessation. CONCLUSION: Our results reinforce some previous findings on this issue.

Adult↗
PubMed2003

Estimating the distribution of lag in the effect of short-term exposures and interventions: adaptation of a non-parametric regression spline model.

Information on the distribution of lag duration between exposure or intervention and the subsequent changes in risk can help in assessing the impact of exposure, predicting cost-effectiveness of intervention, and understanding the underlying biological mechanisms. Previous approaches focused more on optimizing the strength of the exposure-disease association than on directly estimating lag duration. We propose an alternative approach applicable to the analysis of the lagged effects of binary exposure variables. The density function of the distribution of lags is estimated based on flexible modelling of changes in hazard ratio of exposed versus unexposed subjects. The methodology is evaluated in a simulation study and is applied to the Framingham data to investigate the lagged effect of smoking cessation on coronary heart disease risk.

Biometry↗
PubMed2000

Cancer risk in laboratory workers: an emphasis on biological research.

BACKGROUND: At the end of the 1980s, several cancer clusters were observed in biological research laboratories. Over time, biological research and the technologies used have been diverse and have involved a wide range of mutagenic or carcinogenic chemical, physical and biological agents. METHODS: We reviewed 45 published studies on cancer risk among biological research personnel and workers in closely related fields, and numerous reports based on routinely collected data. RESULTS: Biological research could be associated with an elevated risk for pancreatic cancer, brain tumors, and certain hemopathies. A common limitation of available studies was low statistical power and the absence or inaccuracy of data on individual past exposure. CONCLUSIONS: Overall, this study suggests a low overall risk of cancer, albeit a higher risk may be suggested for cancers of the pancreas (risk ratios ranging from 0.5 to 6.3) and brain (0.7-9.4), and for non-Hodgkin's lymphoma (0.6-51.5). We suggest ways in which multiple past exposures could be assessed more precisely and emphasize a pressing need to take into account known confounders.

Biological Science Disciplines↗
PubMed1998

Prognostic factors for mortality in nasopharyngeal cancer: accounting for time-dependence of relative risks.

BACKGROUND: Few studies have assessed the role of prognostic factors for mortality from nasopharyngeal cancer and even fewer used multivariable methods. Most of these studies relied on the Cox model without testing the proportional hazards assumption. METHODS: A cohort of 76 cases of nasopharyngeal cancer recorded in the Rhône, France, between 1980 and 1985, was followed until 1995. Proportional hazards assumption was tested for each putative prognostic factor. Two multivariable models were built using forward selection of prognostic factors: the Cox model and a flexible model in which variables not meeting the proportional hazards assumption were represented by a time-varying hazard ratio. RESULTS: Only Epstein Barr Virus Nuclear Antigen (EBNA) serology, a marker of infection by the Epstein-Barr virus, and tumoral extent were selected in the analysis based on the Cox model. In contrast, four prognostic factors were significant at alpha = 0.05 level in the flexible model: initial EBNA serology, tumoral histology, age and tumoral extent, the last two not verifying the proportional hazards assumption. The relative risk of age increases with duration of follow-up whereas the effect of tumoral extent changes in a non-monotonic pattern. CONCLUSION: We showed the importance of taking into account the non-proportionality of hazards which can influence results and yield new insights about the role of prognostic factors in nasopharyngeal cancer. Because of the small size of our cohort, our results have to be confirmed in an independent study.

Adult↗
PubMed1997

[Late post-partum hemorrhage after cesarean section due to rupture of a false aneurysm of the uterine pedicle].

We report a recent case of late post-partum hemorrhage attributed to a consecutive aneurysm breaking in the uterine cavity. Childbirth by cesarean section was the main cause of the consecutive aneurysm which was maintained by a wound from the uterine vessels. The diagnosis was confirmed by the angiography. This procedure permits treatment by fistula embolization with decreased morbidity, while preserving future prospects of pregnancy. Consecutive aneurysm is of an unknown etiology and not as rare as commonly thought. Wounds of the uterine vessels caused by cesarean section may occur spontaneously.

Adult↗