Conduct of epidemiologic studies in French cancer survivors: Methods, difficulties encountered and solutions provided. Lessons learned from the SIMONAL study on long-term toxicities after non-Hodgkin lymphoma treatment

Introduction > Since the introduction of targeted therapies, specific lymphoma mortality has decreased. Possible long-term toxicities, however, are not known yet. This article describes the implementation of the SIMONAL study that investigates the hypothesis of an overconsumption of care after lymphoma treatment with a 10-year follow-up. Methods > After the mandatory regulatory steps (CCTIRS and CNIL) the vital status and address of 5247 patients treated in 131 French centers were retrieved using a secure web portal, in order to send a quality of life after lymphoma questionnaire. After an additional vital status validation request at the center for epidemiologic research and population health (CESP), the questionnaires were sent. Double data entry was performed on the collected data and a request to access data from France's public health insurance scheme information system (SNIIRAM) was formulated. Results > Retrieval of the addresses via the portal has been slow and multiple reminders were needed. The CESP identified 9.4 % additional deaths not known by the treatment centers. Of the 3391 questionnaires sent, the response rate was 50%. A comparison between the responders and non-responders revealed no demographic differences but showed that the responders were more often treated with targeted drugs as they were included in more recent trials. Discussion > Logistic and information technology (IT) aspects rendered the implementation of the SIMONAL study more complex, time consuming and costly. However, using the collected data, many future research questions will be addressed.