Original Article Radical External Beam Radiotherapy for Prostate Cancer in Japan: Results of the 1999–2001 Patterns of Care Process Survey

Background: The Patterns of Care Study evaluated standards of practice for patients with clinically localized prostate cancer treated with radiotherapy in Japan. This study examined the influence of institutional stratification on care for patients receiving radical external beam radiotherapy. Methods: A national survey of 66 institutions was conducted using two-stage cluster sampling, and detailed information was accumulated on 283 patients who received radiotherapy between 1999 and 2001. Results: In A (academic) and B (non-academic) institutions, more than 80 % of patients had intermediate or unfavorable risk disease. Although there were no significant differences in disease characteristics between A and B institutions, institutional stratification significantly affec-ted radiotherapy practice patterns, such as the use of a CT-based treatment planning (A1: 91.5%, B: 77.1%; P = 0.0007) and the use of conformal therapy (A: 56.4%, B: 24.1%; P < 0.0001). CT-based treatment planning and conformal therapy significantly influenced total radiation dose (P < 0.0001 for each). Hormonal therapy was commonly used in both A and B institutions (A: 89.0%, B: 90.7%). Many patients with a favorable prognosis (A: 62.5%, B: 91.7%) receive