Epidemiological study of cardiovascular risk after breast cancer therapy

 

Objective of the PASSOS Heart Study

The PASSOS Heart Study is an epidemiological cohort study on the relationship between radiotherapy in breast cancer patients with good prognosis and the long-term risk for cardiovascular morbidity and mortality, taking into account individual risk factors. The following issues are investigated:

• How does radiotherapy affect the long-term mortality risk in breast cancer patients? Is there a higher risk due to cardiovascular incidents?
  
  
• How does radiotherapy affect the cardiovascular incidence risk in breast cancer patients? How important are individual risk factors (lifestyle factors, co-morbidities)?
  
  
• What is the dose-response relationship between the heart dose and the cardiovascular mortality / morbidity risk?

The objective of the PASSOS Heart Study is to acquire substantiated German data, showing the relationship between radiotherapy in breast cancer patients and cardiovascular late effects. Detailed knowledge of the attending physicians regarding the exact dose-response relationship between radiation and possible late health effects, taking into consideration the laterality, the age of the patient, and her medical history may allow for a more personalized therapy.

 

Study design

The PASSOS Heart Study is a retrospective cohort study. It includes approximately 13,000 patients at two centers, Ulm and Mainz, with initial diagnosis between 1998 and 2008. Patients with bilateral tumors and/or primary metastatic disease at first diagnosis are not included. The patients are followed-up until December 31^st 2012. Studied endpoints are mortality (of all causes) and morbidity due to radiation induced secondary diseases (coronary heart disease, valvular defects, conduction abnormalities).

At both centers the vital status of the patients is assessed and if applicable, the cause of death is ascertained.

A retrospective survey is planned regarding morbidity due to radiation induced secondary diseases. Patients of the cohort will therefore be asked if and when a cardiovascular incident has occurred. Since cardiovascular diseases are not only induced by radiotherapy, further variables need to be collected in the course of this survey. The self-reported data will be validated via the family physicians as well as clinical data.

The individual dose data (mean heart dose, dose distribution in the tissue, dose-volume histogram) will be determined for a random sampling of the patients at the corresponding university clinics at Ulm and Mainz. Individual dose data will be determined for each patient of the random sample and will be extrapolated for the full cohort. This is a requirement for the statistical analysis of the dose-response relationship.

 

Involved Partners:
Institut für Medizinische Biometrie, Epidemiologie und Informatik, Johannes-Gutenberg Universität Mainz
Klinik und Poliklinik für Radioonkologie und Strahlentherapie, Johannes-Gutenberg Universität Mainz
Klinik für Frauenheilkunde und Geburtshilfe, Universitätsklinikum Ulm
Klinik für Strahlentherapie und Radioonkologie, Universitätsklinikum Ulm