Japanese Journal of Clinical Oncology 34:29-36 (2004)
© 2004 Foundation for Promotion of Cancer Research
Radical External Beam Radiotherapy for Prostate Cancer in Japan: Preliminary Results of the 1999–2001 Patterns of Care Process Survey
1 Department of Radiology, University of the Ryukyus, Okinawa, 2 Department of Surgical and Molecular Oncology, Medical Institute of Bioregulation, Kyushu University, Beppu, 3 Department of Clinical Radiology, Kyushu University, Fukuoka, 4 Department of Medical Physics and Engineering, Osaka University, Osaka, 5 Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka and 6 Department of Radiation Oncology, Osaka University, Osaka, Japan
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
Background: A Patterns of Care Study (PCS) has been conducted to evaluate the standards of practice for prostate cancer patients treated with radiotherapy in Japan. This study examines the influence of institutional stratification on the process of care for patients receiving radical external beam radiotherapy for prostate cancer in the 1999–2001 PCS in Japan. These PCS results were compared with those of the 1999 PCS in the USA.
Methods: A national survey of 36 institutions was conducted using two-stage cluster sampling and detailed information was accumulated on 305 clinically localized prostate cancer patients who received radiotherapy between 1999 and 2001. Of these, 181 patients treated with radical external beam radiotherapy were selected and the preliminary results were analyzed. Institutions were classified as A1 (academic institutions treating 
430 patients a year) or B1 (non-academic institutions treating 130 patients a year).
Results: In both A1 and B1 institutions, more than 80% of the patients had intermediate or unfavorable risk diseases. There were no significant differences in the patients’ disease characteristics between A1 and B1 institutions, while the institutional stratification significantly affected the patterns of radiotherapy; such as the beam energy (10 MV, A1 89.9%, B1 72.2%; P = 0.0022), the use of a CT simulator (A1 91.0%, B1 80.0%; P = 0.0340) and the administration of conformal therapy (A1 85.0%, B1 20.5%; P < 0.0001). The median number of full-time equivalent (FTE) radiation oncologists was 2.7 in A1 institutions and only 0.7 in B1 institutions. Median radiation doses of 66.00 Gy (A1 institutions) and 69.00 Gy (B1 institutions) were delivered and hormonal therapy was commonly used before, during and after radiotherapy, with a mean duration of 1.3 years (88.0% in A1 institutions; 90.0% in B1 institutions). In comparing the results of PCS in Japan (1999–2001) with those in the USA (1999), patients in Japan were found to have more advanced primary diseases with higher PSA levels than those in the USA. The median prescribed dose to the primary tumor was not significantly different between the two countries (69.00 Gy in Japan and 70.45 Gy in the USA). Conversely, almost half of the patients in the USA were treated with higher prescription dose levels (72 Gy), whereas only 9.4% of the Japanese patients received these dose levels. Hormonal therapy was used more frequently in Japan (88.1% of the patients) than in the USA (50% of the patients). Most of the Japanese patients with a favorable prognosis (72.0%) were treated with hormonal therapy, compared with 30% in the USA. On the other hand, most of the patients in the unfavorable risk group were treated with radiotherapy in conjunction with hormonal therapy both in Japan (91.1%) and the USA (81%).
Conclusions: During the period 1999–2001, the majority of the prostate cancer patients treated in Japan with radical external beam radiotherapy had advanced diseases and institutional stratification significantly affected the patterns of radiotherapy. In both academic and non-academic institutions, radiotherapy in conjunction with long-term hormonal therapy was commonly used. In comparison with the 1999 PCS in the USA, Japanese patients had more advanced diseases, but the higher prescribed doses (72 Gy) were less common in Japan. Administration rates of hormonal therapy for favorable risk patients were different between Japan and the USA. On the other hand, for unfavorable risk patients, radiotherapy in conjunction with hormonal therapy appeared to be an accepted approach both in Japan and in the USA.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
The Patterns of Care Study (PCS) national survey is a retrospective study designed to establish national practice processes for selected malignancies over a specific time period (1–3). In addition to documenting practice process, the PCS is important in developing and spreading national guidelines for cancer treatment. This helps to promote a more uniform care process in the country. The PCS is also designed to complement clinical trials that enhance the standard of care for cancer patients (1,4).
To improve the quality of radiation oncology nationwide in Japan, the PCS has been imported from the USA and the first Japanese version of a PCS for esophageal and uterine cervical cancer has been functioning since July 1996 (5–7). In September 1998, the Japanese PCS started a nationwide survey of patients with breast, lung, esophageal and uterine cervical cancer who were treated between 1995 and 1997 (8–10). One year later, the Japanese PCS began the first nationwide process survey of prostate cancer patients who underwent radiotherapy between 1996 and 1998. This involved 162 prostate cancer patients who were treated by radical external beam radiotherapy between 1996 and 1998. The results revealed that there were significant proportions of high-risk diseases in the patient group and that hormonal therapy was prescribed frequently in Japan (11).
Since entering the PSA era, it is possible to detect earlier stages of prostate cancer and there is a better chance of successfully treating early-stage patients with prostate cancer than ever before. Moreover, the use of radiotherapy to treat prostate cancer recently has become much more common, because a significant amount of new radiation treatment planning technology and methodology has become available. Therefore, the optimal management of radiotherapy for prostate cancer patients has been a major concern in Japan. However, we have not been able to evaluate properly the updated national practice processes of radiotherapy for prostate cancer in Japan owing to the limited information available. In July 2002, PCS audits for prostate cancer patients treated between 1999 and 2001 were started in Japan. The preliminary results of this PCS were evaluated in May 2003 and detailed information regarding 181 patients who underwent radical external beam radiotherapy has already been collected, even though the 1999–2001 PCS survey is still ongoing. Therefore, we analyzed these preliminary results of radical external beam radiotherapy for clinically localized prostate cancer, focusing especially on the influence of institutional stratification on the process of care and also comparing the PCS results with the 1999 PCS reported in the USA (12).
|
SUBJECTS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
The preliminary results of the 1999–2001 PCS concerning radiotherapy for Japanese prostate cancer patients were evaluated. The PCS involved an extramural audit survey of 36 institutions using stratified two-stage cluster sampling and collected specific information on 305 patients with prostate cancer who were treated with radiotherapy between 1999 and 2001. The Japanese PCS developed an original data format in collaboration with the American College of Radiology (ACR, Philadelphia, PA). The following eligibility criteria were used in this survey: the patients were required to have adenocarcinoma of the prostate without evidence of distant metastasis; they must have been treated with radiotherapy between 1999 and 2001; and they must not have been diagnosed with any other malignancy or have been previously treated with radiotherapy. The PCS surveyors consisted of 20 radiation oncologists from academic institutions. For each institution surveyed, one radiation oncologist visited and surveyed data by reviewing patients’ charts. In order to validate the quality of the collected data, the PCS utilized an Internet mailing list including all the surveyors. In-site real time checks and adjustments of the data input were available to each surveyor to the PCS committee (13).
On the basis of the Japanese facility master list of 1999 (14), the 1999–2001 PCS stratified the institutions as follows: A1, academic institutions treating 430 patients a year; A2, <430 patients; B1, non-academic institutions treating 130 patients a year; and B2, <130 patients. The 1999–2001 PCS was scheduled to collect the data for 80 institutions, including A1, A2, B1 and B2 institutions, with two-stage cluster sampling. However, at the time of analysis, the PCS had collected the data on 36 institutions, including only those with A1 and B1 stratifications. Therefore, in the current study, we analyzed the data concerning the A1 and the B1 institutions. Among the 305 patients surveyed in the current PCS, 181 patients who were treated with radical external beam radiotherapy were selected for analysis and preliminary results for these patients were reported. Patients who had received prior prostatectomy and patients with hormone-refractory prostate cancer were excluded from this analysis.
With regard to the risk groups for prostate cancer, the 1999 PCS in the USA categorized patients into the following risk groups: favorable – absence of adverse features (PSA <10, Gleason score <6 and T stage <3); the presence of one or more of these features classified patients into the intermediate and unfavorable groups, respectively (12). In the current study, because 35% (64 of 176 patients) of the data regarding the Gleason combined score were missing, we used the tumor differentiation instead of the Gleason combined score as a factor to evaluate the risk group. Therefore, Japanese patients were categorized into the following risk groups: favorable – absence of adverse features (PSA <10, not poorly differentiated and T stage <3); the presence of one or more of these features classified patients into the intermediate and unfavorable groups, respectively.
Statistical analyses were performed using the Statistical Analysis System at the PCS statistical center (15). Statistical significance was tested using the chi-squared test and Student’s t-test. A probability level of 0.05 was chosen for statistical significance.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
Patient and Disease Characteristics
Patient and disease characteristics were separated according to the stratified institutions, as shown in Table 1. There were no significant differences in the disease characteristics, such as pretreatment PSA level, tumor differentiation, Gleason combined score and T stage. In both A1 and B1 institutions, >80% of the patients had intermediate or unfavorable risk diseases. The main reasons given for selection of radiotherapy were patient preference, advanced or high-risk disease, medical contraindication and old age.
|
Treatment Characteristics
Treatment characteristics of the stratified institutions are shown in Table 2. Institutional stratification was closely related to the infrastructure of radiation oncology such as equipment and personnel and significantly affected the patterns of radiotherapy, such as beam energy (
10 MV, A1 89.9%, B1 72.2%; P = 0.0022), the use of a CT simulator (A1 91.0%, B1 80.0%; P = 0.0340) and the administration of conformal therapy (A1 85.0%, B1 20.5%; P <0.0001). Median radiation doses of 66.00 Gy (A1 institutions) and 69.00 Gy (B1 institutions) were delivered and the proportion of patients who received total doses of <60 Gy was 2.8% (A1 4.0%, B1 1.3%). Pelvic irradiation was performed in 29.7% of the patients in the A1 institutions and 53.8% in the B1 institutions (P = 0.0011). The median number of full-time equivalent (FTE) radiation oncologists was 2.7 in A1 institutions and only 0.7 in B1 institutions.
|
Hormonal therapy was commonly used before, during and after radiotherapy with a mean duration of 1.3 ± 1.0 years (88.0% in A1 institutions; 90.0% in B1 institutions). Luteinizing hormone-releasing hormone (LH-RH) agonist and antiandrogen were frequently used as hormonal agents. In contrast, chemotherapy in general was not administered in both institutions (9.0% in A1 institutions; 4.2% in B1 institutions).
Comparison Between the Results in Japan and Those in the USA
Comparisons of PCS results between Japan (1999–2001) and the USA (1999) (12) are shown in Table 3. Patients in Japan were found to have more advanced primary diseases with higher PSA levels than those in the USA. In Japan, the percentage of patients with favorable, intermediate and unfavorable tumors were 15.2, 37.0 and 47.9%, respectively, compared with 40, 39 and 21%, respectively, in the USA. Conformal radiotherapy was administered to 56.7% of the patients in Japan and 85% in the USA. The median prescribed dose was not significantly different between the two countries (Japan 69.00 Gy, USA 70.45 Gy). In contrast, almost half of the patients in the USA (48%) were treated with higher prescription dose levels (72 Gy), while only 9.4% of the Japanese patients received these dose levels. With regard to hormonal therapy, 88.1% of the patients in Japan and 50% in the USA were treated with hormonal therapy. In Japan, the percentages of patients with favorable, intermediate and unfavorable tumors treated in conjunction with hormonal therapy were 72.0, 91.8 and 91.1%, respectively, compared with 30, 54 and 81, respectively, in the USA (Fig. 1). For the favorable risk group, most of the patients (72.0%) in Japan were treated with hormonal therapy, whereas only 30% of these patients received hormonal therapy in the USA. On the other hand, for the unfavorable risk group, >80% of the patients were treated with radiotherapy in conjunction with hormonal therapy both in Japan (91.1%) and in the USA (81%).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
The 1999–2001 PCS revealed that in Japan, more than 80% of the patients treated with radical external beam radiotherapy had intermediate or unfavorable risk diseases and institutional stratification did not significantly affect the disease characteristics, such as pretreatment PSA levels, Gleason combined score and T stage. Conversely, the current study has demonstrated significant differences in the practice process of radiotherapy for prostate cancer, according to the stratification of the institutions. Significant differences were found in the beam energy, the use of a CT simulator and the administration of conformal therapy. These differences in process indicate that the quality of radiotherapy in academic institutions was significantly higher than that in non-academic institutions. Results of a process survey carried out to evaluate treatment of cancers at different disease sites, such as cancer of the esophagus and uterine cervix, have also been reported and significant differences in the patterns of process were found according to the stratification of the institutions (6,7). The processes in the non-academic institutions in Japan were closely related to structural immaturity, especially in terms of equipment and personnel. In the non-academic institutions, CT simulators and conformal therapy were used for only 80.0 and 20.5% of the patients, respectively, compared with 91.0 and 85.0%, respectively, in the academic institutions. Moreover, in these non-academic institutions, less than one full-time equivalent radiation oncologist has been managing many of these patients (6,7). This PCS survey revealed that the median number of FTE radiation oncologists was 2.7 in A institutions, but only 0.7 in B institutions. Therefore, in order to provide good-quality radiotherapy, facilities need appropriate treatment planning capabilities. Modern radiotherapy requires a CT simulator or conformal therapy in order to improve the target dose distribution, while concomitantly reducing the normal tissue dose (16). Moreover, the number of patients treated with radiotherapy has increased in every institutional stratification, with an overall increase of 1.4-fold over the past 10 years (17). Therefore, the number of FTE radiation oncologists on duty must be increased, especially in non-academic institutions in Japan.
This study indicates that radiotherapy in conjunction with long-term hormonal therapy was almost routinely (88.1% of the patients surveyed) administered to Japanese patients who were treated between 1999 and 2001. In the 1996–1998 PCS reported by Nakamura et al. (11), the administration rate of hormonal therapy was also high (85.8% of the patients surveyed). These results indicate that the administration rate of hormonal therapy continues to be high during these periods. However, it has been acknowledged that conventional radiotherapy alone has little curative potential in high-risk prostate cancer (18). Taking into account the high percentage of high-risk patients in the current study, the therapeutic strategy of long-term hormonal therapy with radiotherapy may be appropriate for most Japanese patients. However, prolonged hormonal therapy may lead to side effects such as impotence, hot flushes, fatigue and osteoporosis. Investigation into the optimal timing and duration of hormonal therapy should be carried out in the future.
When compared with the PCS results in the USA, patients in Japan had more advanced diseases than did those in the USA. Japanese patients had higher pretreatment PSA levels and an advanced T stage and the incidence of unfavorable risk patients in Japan was 47.9%, compared with 21% in the USA. However, it is not known whether these differences were caused by the differences in access to care or to biological difference in the tumors themselves, between the patients in Japan and in the USA. Further investigation of the different disease characteristics between individuals into the two countries would be worthwhile.
The median radiation dose employed in Japan (69.00 Gy) was not significantly different from that used in the USA (70.45 Gy). However, almost half of the patients in the USA were treated with higher prescription dose levels (72 Gy), whereas only 9% of the Japanese patients received these higher doses. Moreover, the proportion of Japanese patients who received total doses of <60 Gy was only 2.8%. These results indicate that most Japanese patients received the irradiation doses with a small range just around 69 Gy. One reason for this may be the lower incidence of conformal therapy in Japan, especially in B1 institutions. Conformal radiotherapy was administered to 85% of the patients in the USA, whereas only 20.5% of the patients in the B1 institutions received this treatment in Japan. Another reason may be the high incidences of hormonal therapy in Japan. At present, many Japanese radiation oncologists may consider the higher dose levels (72 Gy) unnecessary for prostate cancer patients when combined with long-term hormonal therapy.
As for the risk groups and the incidences of hormonal therapy, the administration of hormonal therapy for favorable risk patients was found to be different in Japan and the USA. Only 30% of these patients were treated with hormonal therapy in the USA (Fig. 1). Several studies in the USA have indicated that radical radiotherapy alone could control the disease in patients with a favorable risk status. Zietman et al. indicated that total doses of <71 Gy were sufficient to control the disease when the pretreatment PSA level was <10 ng/ml (19). Hanks et al. found that prostate cancer patients with pretreatment PSA <10 ng/ml did not benefit from dose escalation above 70 Gy (20). Therefore, radical external beam radiotherapy without hormonal therapy has been a primary treatment for patients with favorable risk diseases in the USA. On the other hand, 72% of the patients in the favorable risk group were treated with long-term hormonal therapy in Japan (Fig. 1). The high rate of health insurance coverage (21,22) and fewer side effects of estrogen therapy (23,24) for Japanese people may explain the frequent administration of hormonal therapy in Japan. However, hormonal therapy was found to be unnecessary for favorable risk patients in the USA (19,20). Therefore, radical external beam radiotherapy without hormonal therapy should be a treatment of choice for favorable risk patients also in Japan.
On the other hand, the significantly increased use of hormonal therapy for high-risk patients in the USA reflects the penetration and growing acceptance of clinical trial results that have demonstrated the efficacy of these treatment approaches (25). The randomized trial RTOG 8610 (26,27) showed an increase in disease-free survival at 2 years of 76 vs 62% survival for locally advanced prostate cancer patients treated with neoadjuvant total androgen blockade plus radiation vs radiation therapy alone. In Japan, hormonal therapy was administered to >90% of the patients with unfavorable risk diseases. Therefore, for the unfavorable risk group, radiotherapy in conjunction with hormonal therapy appears to be an accepted approach both in Japan and in the USA.
The analysis of these 1999–2001 PCS results delineates the patterns of radiotherapy for prostate cancer patients treated with radical external beam radiotherapy between 1999 and 2001 in Japan. Moreover, we compared the Japanese results with those in the USA and these data will be informative to establish where we stand now and where we should go in the future. However, this report analyzes preliminary results of a survey of only 36 A1 and B1 institutions. In the meantime, the same PCS survey is still collecting more information on prostate cancer patients including A2 and B2 institutions. When we have analyzed the data from the additional institutions, we will report the updated results. The national Practice of Care Standard will be represented more accurately when data from a larger number of prostate cancer patients are included.
|
Acknowledgments |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
This paper was presented in part at the 2nd Japan/USA PCS Workshop, Tokyo, February 17–19, 2003. This work was supported by a Grant-in-Aid for Cancer Research (Grant No. 14-6) from the Ministry of Health, Labor and Welfare of Japan, the Japanese Foundation of Aging and Health, the Japan Society for the Promotion of Science, Japanese Cancer Research, Siemens Medical, Toshiba Medical and CMS Japan. We thank all radiation oncologists who participated in this study. Their efforts to provide information to us make these surveys possible. We are grateful for the continuous and thoughtful support we have received from the US PCS Committee for 9 years.
|
FOOTNOTES |
|---|
+ For reprints and all correspondence: Kazuhiko Ogawa, Department of Surgical and Molecular Oncology, Medical Institute of Bioregulation, Kyushu University, Tsurumihara 4546, Beppu 874-0838, Japan. E-mail: kogawa{at}med.u-ryukyu.ac.jp
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONSUBJECTS AND METHODSRESULTSDISCUSSIONAcknowledgmentsREFERENCES |
|---|
1 Hanks GE, Coia LR, Curry J. Patterns of care studies: past, present and future. Semin Radiat Oncol 1997;7:97–100.[CrossRef][Web of Science][Medline]
2 Owen JB, Sedransk J, Pajak TF. National averages for process and outcome in radiation oncology: methodology of the patterns of care study. Semin Radiat Oncol 1997;7:101–7.[CrossRef][Web of Science][Medline]
3 Tanisada K, Teshima T, Ohno Y, Inoue T, Abe M, Ikeda H, et al. Patterns of care study quantitative evaluation of the quality of radiotherapy in Japan. Cancer 2002;95:164–71.[CrossRef][Web of Science][Medline]
4 Inoue T. Quality assurance of radiotherapy and its clinical assessment. Jpn J Clin Oncol 2002;32:497–505.
5 Tanisada K, Teshima T, Ikeda H, Abe M, Owen JB, Hanks GE, et al. A preliminary outcome analysis of the patterns of care study in Japan for esophageal cancer patients with special reference to age: non surgery group. Int J Radiat Oncol Biol Phys 2000;46:1223–33.[CrossRef][Web of Science][Medline]
6 Teshima T, Abe M, Ikeda H, Hanks GE, Owen JB, Yamada S, et al. Patterns of care study of radiation therapy for cervix cancer in Japan: the influence of the stratification of institution on the process. Jpn J Clin Oncol 1998;28:388–95.
7 Teshima T, Abe M, Ikeda H, Hanks GE, Owen JB, Hiraoka M, et al. Patterns of care study of radiation therapy for esophageal cancer in Japan: influence of the stratification on the process. Jpn J Clin Oncol 1998;28:308–13.
8 Uno T, Sumi M, Ikeda H, Teshima T, Yamashita M, Inoue T. Radiation therapy for small-cell lung cancer: results of the 1995–1997 patterns of care process survey in Japan. Lung Cancer 2002;35:279–85 .[CrossRef][Web of Science][Medline]
9 Uno T, Sumi M, Sawa Y, Teshima T, Hara R, Ikeda H, et al. Process of care and preliminary outcome in limited-stage small-cell lung cancer: results of the 1995–1997 patterns of care study in Japan. Int J Radiat Oncol Biol Phys 2003;55:626–32.[CrossRef][Web of Science][Medline]
10 Gomi K, Oguchi M, Hirokawa Y, Kenjo M, Ogata T, Takashima Y, et al. Process and preliminary outcome of a patterns-of-care study of esophageal cancer in Japan: patterns treated with surgery and radiotherapy. Int J Radiat Oncol Biol Phys 2003;56:813–22.[CrossRef][Web of Science][Medline]
11 Nakamura K, Teshima T, Takahashi Y, Imai A, Koizumi M, Mitsuhashi N, et al. Radical radiotherapy for prostate cancer in Japan: a patterns of care study report. Jpn J Clin Oncol 2003;33:122–6.
12 Zelefsky MJ, Moughan J, Owen J, Zietman A, Hanks GE. Changing trends in the national practice for external beam radiotherapy for clinically localized prostate cancer: the 1999 patterns of care survey for prostate cancer. Int J Radiat Oncol Biol Phys 2002;54(Suppl):8.
13 Kinoshita K, Teshima T, Ohno Y, Inoue T, Yamashita T, Hiraoka M, et al. Logical checking function increases the accuracy of data entry in the patterns of care study. Strahlenther Onkol 2003;179:107–12.[CrossRef][Web of Science][Medline]
14 JASTRO Database Committee. Present status of radiotherapy in Japan – the regular structure survey in 1999. J Jpn Soc Ther Radiol Oncol 2001;13:227–35 (in Japanese).
15 SAS Procedure Reference, Version 6, 1st edition. Tokyo: SAS Institute 1995.
16 Sumi M, Ikeda H, Tokuuye K, Kagami Y, Murayama S, Tobisu K. et al. External radiotherapy with three-dimensional conformal boost after neoadjuvant anfrogen suppression for patients with locally advanced prostatic carcinoma. Int J Radiat Oncol Biol Phys 2000;48:519–28.[CrossRef][Web of Science][Medline]
17 Iami A, Teshima T, Ohno Y, Inoue T, Yamashita T, Mitsuhashi N, et al. The future demand for and structural problems of Japanese radiotherapy. Jpn J Clin Oncol 2001;31:135–41.
18 Pollack A, Zagars GK. Androgen ablation in addition to radiation therapy for prostate cancer: is there true benefit? Semin Radiat Oncol 1998;8:95–106.[CrossRef][Web of Science][Medline]
19 Zietman AL. Radiation therapy or prostatectomy: an old conflict revisited in the PSA era; a radiation oncologist’s view-point. Semin Radiat Oncol 1998;8:81–6.[CrossRef][Web of Science][Medline]
20 Hanks GE, Schultheiss TE, Hanlon AL, Hunt M, Lee WR, Epstein BE, et al. Optimization of conformal radiation treatment of prostate cancer: report of a dose escalation study. Int J Radiat Oncol Biol Phys 1997;37:543–50.[CrossRef][Web of Science][Medline]
21 Takara K. The origins and development of public health in Japan. In: Detels R, McEwen J, Omenn GS, editors. Oxford Textbook of Public Health, 3rd edition, vol 1. The Scope of Public Health. New York: Oxford University Press 1997;55–72.
22 OECD Health Data 2001. A Comparative Analysis of 30 OECD Countries. http://www.oecd.org/els/health/.
23 Kumamoto Y, Tsukamoto T, Umehara T. Shimazaki J, Fuse H, Oshima H, et al. Clinical studies on endocrine therapy of prostatic carcinoma (2): prognosis of patients with prostatic carcinoma given endocrine therapy and analyses of causes of death and side effects of endocrine therapy. Hinyokika Kiyo 1990;36:285–93 (in Japanese).[Medline]
24 Sakai H, Minami Y, Kanetaka H, Saito Y, Ito K, Suzuki T, et al. Endocrine therapy for prostate cancer: 1980–1989. Nishinihon J Urol 1995;57:592–5 (in Japanese).
25 Bolla M, Gonzalez D, Warde P, Dubois JB, Mirimanoff RO, Storme G, et al. Improved survival in patients with locally advanced prostate cancer treated with radiotherapy and goserelin. N Engl J Med 1997;337:295–300.
26 Pilepich MV, Krall JM, al-Sarraf M, John MJ, Doggett RL, Sause WT, et al. Androgen deprivation with radiation therapy compared with radiation therapy alone for locally advanced prostatic carcinoma: a randomized comparative trial of the Radiation Therapy Oncology Group. Urology 1995;45:616–23.[CrossRef][Web of Science][Medline]
27 Pilepich MV, Caplan R, Byhardt RW, Lawton CA, Gallagher MJ, Mesic JB, et al. Phase III trial of androgen suppression using goserelin in unfavorable-prognosis carcinoma of the prostate treated with definitive radiotherapy: report of Radiation Therapy Oncology Group Protocol 85-31. J Clin Oncol 1997;15:1013–121.
Received September 20, 2003; accepted November 28, 2003
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Sasaki, K. Nakamura, K. Ogawa, H. Onishi, Y. Otani, M. Koizumi, Y. Shioyama, T. Teshima, and The Japanese Patterns of Care Study Working Subgro Postoperative Radiotherapy for Patients with Prostate Cancer in Japan; Changing Trends in National Practice between 1996-98 and 1999-2001: Patterns of Care Study for Prostate Cancer Jpn. J. Clin. Oncol., October 1, 2006; 36(10): 649 - 654. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Ogawa, K. Nakamura, H. Onishi, T. Sasaki, M. Koizumi, Y. Shioyama, T. Komiyama, Y. Miyabe, T. Teshima, and Japanese Patterns of Care Study Working Subgroup o Radical External Beam Radiotherapy for Prostate Cancer in Japan: Results of the 1999-2001 Patterns of Care Process Survey Jpn. J. Clin. Oncol., January 1, 2006; 36(1): 40 - 45. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Teshima and Japanese PCS Working Group Patterns of Care Study in Japan Jpn. J. Clin. Oncol., September 1, 2005; 35(9): 497 - 506. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Ogawa, K. Nakamura, T. Sasaki, T. Yamamoto, M. Koizumi, T. Inoue, T. Teshima, and the Japanese Patterns of Care Study Working Subgro Radical External Beam Radiotherapy for Prostate Cancer in Japan: Preliminary Results of the Changing Trends in the Patterns of Care Process Survey between 1996-1998 and 1999-2001 Jpn. J. Clin. Oncol., March 1, 2004; 34(3): 131 - 136. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||