Découpage de courbes de densité : Application au dépistage du cancer

International audienceLe dépistage actuel du cancer broncho-pulmonaire est effectué à l'aide d'une radiographie pulmonaire, d'un scanner thoracique et d'un examen cytologique des expectorations. La cytologie automatisée des expectorations est une méthode permettant l'analyse informatique des cellules d'un crachat sur la lame d'un microscope. Comme une personne est représentée par l'ensemble des cellules de sa lame, il nous a paru intéressant d'utiliser la densité de probabilité comme unité statistique. La modélisation fonctionnelle des données, méthode pour laquelle l'unité statistique est à valeurs dans un espace infini, répond bien à cette problématique statistique puisque, par définition, une densité de probabilité est une fonction. Lors de cet exposé nous présenterons la méthode de classification supervisée de courbes de densité que nous avons développée, pour discriminer des personnes ayant un cancer et des personnes saines, et nous vous donnerons quelques résultats issus de données réelles

Développements statistiques pour l'évaluation de techniques innovantes dans le dépistage du cancer broncho-pulmonaire

L objectif général de ce travail de thèse est de proposer des développements statistiques propres à améliorer les outils de dépistage du cancer broncho-pulmonaire. Nous avons comparé les performances du dépistage du cancer broncho-pulmonaire par radiographie pulmonaire et par scanner thoracique faiblement irradiant. Nous avons quantifié le coût en termes de faux positifs associés à la découverte d'un vrai positif supplémentaire au scanner thoracique faiblement irradiant comparativement à la radiographie pulmonaire. Pour prendre en compte toute l'information disponible sur les cellules de l expectoration bronchique d'un individu, nous avons proposé deux méthodes statistiques d'évaluation des données cytologiques. Ces méthodes considèrent que l'individu est représenté par la densité de probabilité des mesures effectuées sur ces cellules. La première méthode compare les quantiles de la distribution, la seconde les courbes de densité de probabilité à travers le développement d'une méthode de discrimination pour données fonctionnelles. Ces deux méthodes ont été mise en œuvre dans la cadre d une étude cas-témoin constituée de 22 prélèvements de personnes ayant un cancer broncho-pulmonaire et de 25 prélèvements de personnes saines de cancer.The main objective of this thesis is to propose new statistical methods for improving lung cancer screening tools. We compared the performance of lung cancer screening by chest radiograph and by low radiation chest CT scan. We quantified the cost associated with extra false positives generated by chest CT scan in order to detect one extra true positive compared with chest radiograph. In order to comprehensively account for available information on sputum cell samples, we proposed two statistical methods for evaluating cytological data. These methods consider that an individual is represented by the probability density of measurements conducted on his/her sputum cells. The first method compares the quantiles of probability density. The second method compares density curves through the development of a functional data analysis discrimination model. These two methods were tested on a case-control study composed of 22 sputum samples from subjects presenting with lung cancer and on 25 sputum samples from healthy subjects.CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Socioeconomic Determinants for Compliance to Colorectal Cancer Screening. A Multilevel Analysis.

International audienceBACKGROUND: Compliance in cancer screening among socially disadvantaged persons is known to be lower than among more socially advantaged persons. However, most of the studies regarding compliance proceed via a questionnaire and are thus limited by self reported measures of participation and by participation bias. This study aimed at investigating the influence of socioeconomic characteristics on compliance to an organised colorectal cancer screening programme on an unbiased sample based on data from the entire target population within a French geographical department, Calvados (N=180,045). METHODS: Individual data of participation and aggregate socioeconomic data, from respectively the structure responsible for organising screening and the French census, were analysed simultaneously by a multilevel model. RESULTS: Uptake was significantly higher in women than in men; odds ratio (OR=1.33; 95%CI: 1.21-1.45); and significantly lower in the youngest (50-59 years) and in the oldest (70-74 years) persons, compared with intermediate ages 60-69 years with respectively OR=0.70 (95%CI: 0.63-0.77) and OR=0.82 (95%CI: 0.72-0.93). Uptake fell with increasing level of deprivation, there was a significant difference of uptake probability between the least deprived and the most deprived areas (OR=0.68; 95%CI: 0.59-0.79). No significant influence of the general practitioners density was found. CONCLUSION: Multilevel analysis allowed to detect areas of weak uptake linked to areas of strong deprivation. These results suggest that targeting populations with a risk of low compliance, as identified both socially and geographically in our study, could be adopted to minimise inequalities in screening

Impact of head and neck cancer on partner's sociability

International audienceIntroduction: "Sociability" is defined as the range of experiences linking the subject to others. This is the first study to focus specifically on the impact of head and neck cancer on the sociability of patients' partners. Method: Data were collected via a dedicated questionnaire sent to patients' partners. The main endpoint was partner's self-assessment of the impact of the patient's disease on the partner's everyday life. The impact on sociability was analyzed with respect to: the circle of friends (friendship environment), unknown environment, known outside environment, necessary environment, and solitary activities. Results: Two hundred and seventy partners responded. Their everyday activities were impacted by the patient's disease in 71.5% of cases. The friendship environment was badly affected in 46.4% of cases. The unknown environment was affected in 44.0% of cases. Social practices related to the known outside environment were affected in 67.8% of cases, and the necessary environment in 26.0%; the number of solitary activities increased in 35.6% of cases. Social impact on patients' partners was thus considerable

Estimation of the general population and children under five years of age in France exposed to magnetic field from high or very high voltage power line using geographic information system and extrapolated field data

International audienceThe effects of extremely low-frequency magnetic fields, especially their long-term health effects, including childhood leukaemia, remain elusive. The International Agency for Research on Cancer has classified the exposure to magnetic fields >0.4 μT as 'possibly carcinogenic to humans (group 2 B)' for childhood leukaemia. However, the number of exposed individuals, particularly children, remains poorly documented in international literature. The objective of this study was to estimate the number of individuals living near a high or very high voltage line in France (≥63 kV), among the general population and children under the age of five years

First report of knockdown mutations in the malaria vector Anopheles gambiae from Cameroon.

International audienceWe report the first finding of the knockdown Leu-Phe and Leu-Ser mutations associated with resistance to pyrethroids and DDT insecticides in the malaria mosquito Anopheles gambiae from Cameroon. The Leu-Phe mutation was found in both the M and S molecular forms of An. gambiae. Importantly, two specimens of the S molecular form were found to carry both mutations in a heterozygous state

Performance of chest radiograph and CT scan for lung cancer screening in asbestos-exposed workers.

International audienceOBJECTIVES: The aim was to compare, in a cohort of asbestos-exposed workers, the sensitivity and the specificity of low-radiation helical chest CT scan with chest radiograph for the biennial screening of bronchopulmonary cancer, according to the size of detected nodules. Material and METHODS: The screening procedure consisted of biennial chest radiograph and monodetector chest CT scan, given to 972 individuals who had been highly exposed to asbestos. A total of 2555 screening procedures were performed. The study focuses on the 1230 screening procedures for which a 2-year follow-up period was available. RESULTS: Twenty-four cases of bronchopulmonary cancer were diagnosed. CT scan detected 20 cancers, 12 of which had not been detected by chest radiograph. Sensitivity of chest radiograph and CT scan were, respectively, 33% and 83%, lesions measuring over 2 mm in diameter being considered as suspect. The specificity of chest radiograph and CT scan were, respectively, 95% and 78%. Calculation of the differential false positive/true positive (FP/TP) ratio and the receiver operating characteristic curve, performed for both chest radiograph and CT scan, facilitated the determination of the best possible compromise between specificity and sensitivity, according to the diameter threshold applied for considering a nodule as suspect. CONCLUSIONS: Although this study confirms the superior sensitivity of chest CT scan compared with conventional chest radiograph, the associated loss in specificity leads to a recommended diameter of 5 mm as the threshold for considering non-calcified lesions as "suspect", for the surveillance of asbestos-exposed individuals

Digestive cancers and occupational asbestos exposure: incidence study in a cohort of asbestos plant workers

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