To appraise the existing literature on cancer risk among patients with Parkinson's disease (PD), determine the overall cancer risk ratio among patients with PD, explore reasons for variations in study results, and assess the potential for publication bias.
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA. n2baj@channing.harvard.edu
