Radical External Beam Radiotherapy for Clinically Localized Prostate Cancer in Japan: Differences in the Patterns of Care between Japan and the United States

Abstract

The current study focused on the differences in the patterns of care between Japan and the United States for clinically localized prostate cancer patients treated with radical external beam radiotherapy. Materials and Methods: Results from the 1999-2001 Japanese Patterns of Care Study (PCS) survey were compared with those of the 1999 PCS in the United States. In addition, the changing trends in the patterns of care between Japan and the United States were also analyzed. Results: Patients in Japan were found to have more advanced primary disease than patients in the United States: with higher PSA levels, advanced T stages and a Gleason combined score of 8-10. These patient characteristics in both countries have not changed from previous PCS studies. The prescribed dose of radiotherapy to the primary tumor was significantly higher in the United States and there was a rapid increase in patients treated with higher prescription dose levels (≥72 Gy) in the United States, while only a small number of patients received these dose levels in Japan. Hormonal therapy was used more frequently in Japan than in the United States, and the percentage of patients receiving hormonal therapy has remained high for several years in Japan. Furthermore, most of the patients in the favorable risk group in Japan were treated with hormonal therapy, contrary to those in the United States. Conclusion: Japanese prostate cancer patients treated with radical external beam radiotherapy were found to have more advanced disease than those in the United States and these trends have continued for the last few years. Patterns of care for prostate cancer in Japan are considerably different from those in the United States, especially in terms of the radiation dose and the use of hormonal therapy. Moreover, the changing trends in the patterns of care are also different between the two countries.