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Diaporama de l\u27intervention de Jean-Baptiste de Vathaire dans le cadre de la Biennale du numérique 2023 " Intelligence artificielle : écosystèmes, enjeux, usages

Exploring the Performance of Methods to Deal Multicollinearity: Simulation and Real Data in Radiation Epidemiology Area

The issue of multicollinearity has long been acknowledged in statistical modelling; however, it is often untreated in the most of published papers. Indeed, the use of methods for multicollinearity correction is still scarce. One important reason is that despite many proposed methods, little is known about their strength or performance. We compare the statistical properties and performance of four main techniques to correct multicollinearity, i.e., Ridge Regression (R-R), Principal Components Regression (PC-R), Partial Least Squares Regression (PLS-R), and Lasso Regression (L-R), in both a simulation study and two real data examples used for modelling volumes of heart and Thyroid as a function of clinical and anthropometric parameters. We find that when the statistical approaches were used to address different levels of collinearity, we observed that R-R, PC-R and PLS-R appeared to have a somewhat similar behavior, with a slight advantage for the PLS-R. Indeed, in all implemented cases, the PLS-R always provided the smallest value of root mean square error (RMSE). When the degree of collinearity was moderate, low or very low, the L-R method had also somewhat similar performance to other methods. Furthermore, correction methods allowed us to provide stable and trustworthy parameter estimates for predictors in the modelling of heart and Thyroid volumes. Therefore, this work will contribute to highlighting performances of methods used only for situations ranging from low to very high multicollinearity

Risk of a second kidney carcinoma following childhood cancer:role of chemotherapy and radiation dose to kidneys

International audiencePurpose: Kidney carcinoma is a rare second malignancy following childhood cancer.Materials and methods: We sought to quantify risk and assess risk factors for kidney carcinoma following treatment for childhood cancer. We evaluated a cohort of 4,350 patients who were 5-year cancer survivors and had been treated for cancer as children in France and the United Kingdom. Patients were treated between 1943 and 1985, and were followed for an average of 27 years. Radiation dose to the kidneys during treatment was estimated with dedicated software, regardless of the site of childhood cancer.Results: Kidney carcinoma developed in 13 patients. The cumulative incidence of kidney carcinoma was 0.62% (95% CI 0.27%-1.45%) at 40 years after diagnosis, which was 13.3-fold higher (95% CI 7.1-22.3) than in the general population. The absolute excess risk strongly increased with longer duration of followup (p <0.0001). Compared to the general population, the incidence of kidney carcinoma was 5.7-fold higher (95% CI 1.4-14.7) if radiotherapy was not performed or less than 1 Gy had been absorbed by the kidney but 66.3-fold higher (95% CI 23.8-142.5) if the radiation dose to the kidneys was 10 to 19 Gy and 14.5-fold higher (95% CI 0.8-63.9) for larger radiation doses to the kidney. Treatment with chemotherapy increased the risk of kidney carcinoma (RR 5.1, 95% CI 1.1-22.7) but we were unable to identify a specific drug or drug category responsible for this effect.Conclusions: Moderate radiation dose to the kidneys during childhood cancer treatment increases the risk of a second kidney carcinoma. This incidence will be further increased when childhood cancer survivors reach old age

Second primary malignancies in thyroid cancer patients

The late health effects associated with radioiodine ((131)I) given as treatment for thyroid cancer are difficult to assess since the number of thyroid cancer patients treated at each centre is limited. The risk of second primary malignancies (SPMs) was evaluated in a European cohort of thyroid cancer patients. A common database was obtained by pooling the 2-year survivors of the three major Swedish, Italian, and French cohorts of papillary and follicular thyroid cancer patients. A time-dependent analysis using external comparison was performed. The study concerned 6841 thyroid cancer patients, diagnosed during the period 1934-1995, at a mean age of 44 years. In all, 17% were treated with external radiotherapy and 62% received (131)I. In total, 576 patients were diagnosed with a SPM. Compared to the general population of each of the three countries, an overall significantly increased risk of SPM of 27% (95% CI: 15-40) was seen in the European cohort. An increased risk of both solid tumours and leukaemias was found with increasing cumulative activity of (131)I administered, with an excess absolute risk of 14.4 solid cancers and of 0.8 leukaemias per GBq of (131)I and 10(5) person-years of follow-up. A relationship was found between (131)I administration and occurrence of bone and soft tissue, colorectal, and salivary gland cancers. These results strongly highlight the necessity to delineate the indications of (131)I treatment in thyroid cancer patients in order to restrict its use to patients in whom clinical benefits are expected