1. Department of Surgery and University of California, San Francisco, San Francisco, California, USA.
2. Department of Surgery, Clarunis – St. Clara Hospital and University Hospital Basel, Basel, Switzerland.
3. Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA.
4. Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA.