Radical external beam radiotherapy for clinically localized prostate cancer in Japan: Changing trends in the patterns of care process survey between 1996-1998 and 1999-2001

Background: This report presents results of a study delineating changing trends in radical external beam radiotherapy usage for prostate cancer between the 1996-1998 and 1999-2001 Patterns of Care Study (PCS) survey periods in Japan. Materials and Methods: Out of the 694 patients comprising the 1996-1998 and 1999-2001 PCS surveys, the current study analyzed data for 444 patients with clinically localized prostate cancer treated with external beam radiotherapy (1996-1998 PCS: 161 patients; 1999-2001 PCS: 283 patients). Results: Significantly higher percentages of patients had earlier T stages (T1-T2: 48.2%) and well-differentiated tumors (23.6%) between 1999 and 2001 than between 1996 and 1998 (T1-T2: 34.6%, well-differentiated tumors: 15.1%). Although only 5.9% of patients were treated with radiotherapy by their own choice during 1996-1998, a larger proportion (26.5%) chose this treatment during 1999-2001. The median radiation dose was 65.0 Gy during 1996-1998, increasing to 68.4 Gy during 1999-2001. Moreover, the incidence of total treatment doses of ≥70 Gy was higher during 1999-2001 (38.0%) than during 1996-1998 (17.5%). On the other hand, the percentage of patients receiving conformal therapy during 1996-1998 (49.1%) was almost the same as during 1999-2001 (50.2%). The median numbers of full-time equivalent (FTE) radiation oncologists increased in academic institutions (1.8 in 1996-1998; 2.4 in 1999-2001), while those in non-academic institutions remained low (0.5 in 1996-1998; 0.45 in 1999-2001). Conclusion: In Japan, fewer prostate cancer patients treated with radical external beam radiotherapy had advanced diseases. Increasing percentages of patients chose radiotherapy and received increased radiation doses, which might reflect the growing acceptance of radical external beam radiotherapy as a first-line treatment for prostate cancer in Japan.