Biomedical subjects

Teruki Teshima

Publications and source records attributed to Teruki Teshima.

30 records · Page 2Linked to original sources

PubMed2003

Radical radiation therapy for prostate cancer in Japan: a Patterns of Care Study report.

BACKGROUND: The patterns of radical radiation therapy for prostate cancer are unclear in Japan. A Patterns of Care Study was performed throughout Japan to examine the patterns of radiation therapy for prostate cancer. METHODS: From 1999 to 2000, extramural audits were performed on 50 randomly selected institutions (approximately 7% of all institutions in Japan). Detailed information was collected on a total of 311 prostate cancer patients without evidence of distant metastases, who were treated by radiation therapy between 1996 and 1998. Of these 311 patients, 162 treated radically using photon beams were analyzed in this study. RESULTS: Eighty percent of the patients had high-risk diseases defined as T3 or T4 tumors, a pretreatment prostate-specific antigen level >20 ng/ml or poorly differentiated adenocarcinoma. Androgen ablation was performed in 85.8% of patients and the median duration of hormonal therapy before and after radiation therapy was 5.3 and 21.4 months, respectively. The median total dose of radiation therapy to the prostate was 65.0 Gy (range: 20-74 Gy). The 3-year overall and biochemical relapse-free survival rates were 86.7 and 86.1%, respectively. Late toxicity was mild, with only nine patients (5.6%) exhibiting grade 2 late morbidity. CONCLUSIONS: The majority of the patients who received radical radiation therapy in Japan have high-risk disease. Androgen ablation plus radiation therapy was commonly used to treat these patients and resulted in high rates of initial control with a low risk of complications.

Adenocarcinoma↗

PubMed2003

Patterns of care study in Japan: analysis of patients subjected to mastectomy followed by radiotherapy.

BACKGROUND: Two prospective studies reported in 1997 demonstrated that postoperative radiotherapy after mastectomy was not only associated with a higher loco-regional control rate but also with a higher overall survival rate. The purpose of this study is to clarify the processes of care for patients undergoing mastectomy and postoperative radiotherapy in Japan. METHODS: A national survey carried out in 1998-2000, involving 79 Japanese institutions by two-stage cluster sampling of institutions and patients, disclosed that 1124 patients with breast cancer had been treated between 1995 and 1997. Mastectomy followed by radiotherapy was performed on 258 patients. RESULTS: The compliance rates for pre-treatment evaluation, including history, physical examination and mammography, averaged approximately 50% (24-81%). The chest wall was irradiated in only 19% of the patients and regional node irradiation was carried out for 70-86%. Radiation treatment planning with the aid of computed tomography was done in only 29% of patients (university hospitals or cancer centers, 39%; other hospitals, 17%; P = 0.001). Hormonal therapy was administered to 56% of the patients who showed no endocrine responsiveness. Non-intensive chemotherapy, which did not include the use of anthracycline or taxol, was used in 55% of the patients who received chemotherapy. CONCLUSIONS: There is room for improvement regarding some aspects of radiotherapy and adjuvant systemic therapies. Especially in the field of radiotherapy, significant differences were found among the treatment techniques employed in various institutions.

Adult↗

PubMed2003

Patterns of care study: comparison of process of post-mastectomy radiotherapy (PMRT) in Japan and the USA.

BACKGROUND: The Patterns of Care Study (USPCS) by the American College of Radiology (ACR) has made significant contributions to improvements in the procedures of care for patients with breast cancer in the USA. The purpose of this study was to identify problems associated with the process of care for patients undergoing post-mastectomy radiotherapy (PMRT) in Japan compared with those in the USA. METHODS: The Japanese Patterns of Care Study Subgroup (JPCS) conducted a national survey in 1998-2000, involving 79 institutions and using two-stage cluster sampling of institutions and patients, which showed that between 1995 and 1997 PMRT was performed on 258 patients. The survey of the USPCS, involving 55 institutions, found that 407 patients received PMRT between 1998 and 1999. RESULTS: More than three axillary positive nodes were detected in 54% of the patients covered by the JPCS and in 46% of those covered by the USPCS. The clinical set-up of radiation treatment was planned without the aid of computed tomography or X-ray simulation for 25% of the JPCS patients and for 6% of the USPCS patients. The chest wall of 31% of the JPCS patients and of 98% of the USPCS patients was irradiated. The JPCS showed that inappropriate radiation techniques such as parallel opposed fields for chest wall irradiation were used for 3% of the patients in academic facilities, but for 25% of those in non-academic facilities (P = 0.0002). CONCLUSION: There is ample room for improvement in radiation treatment planning and chest wall irradiation techniques in Japan.

Breast Neoplasms↗

PubMed2003

Trends in the practice of radiotherapy for localized prostate cancer in Japan: a preliminary patterns of care study report.

BACKGROUND: This is the first study to examine the characteristics and changes of the patterns of radiotherapy for prostate cancer in Japan. METHODS: The Japanese Patterns of Care Study (PCS) conducted a random survey of 84 institutions nationwide. Detailed information was collected on prostate cancer patients without distant metastases, who received radiotherapy during 1996-1998 and 1999-2001. RESULTS: The patients were divided into three groups: The Fresh Group (n = 338) was treated with radical radiotherapy with photon beams; the Surgery Group (n = 115) was treated after prostatectomy; and the Hormone-Refractory Group (n = 117) was treated after progression from hormonal therapy. In the Fresh Group, there was a decline in the fraction of patients with T3-4 tumors, from 65.2% in 1996-1998 to 43.9% in 1999-2001. In 1999-2001, a higher median dose of 69 Gy was irradiated as compared to 65 Gy in 1996-1998. In particular, the fraction of the patients treated with doses >or=70 Gy increased from 16.4% to 46.3%. In the Surgery Group, the percentage of clinical T3-4 tumors before prostatectomy decreased from 71.4% in 1996-1998 to 16.2% in 1999-2001. The median radiation dose of 60 Gy did not change, but the 1999-2001 results showed a decrease in the use of doses <60 Gy. In the Hormone-Refractory Group, the median dose increased from 60 Gy in 1996-1998 to 67 Gy in 1999-2001. CONCLUSION: These data suggest that radiation doses for prostate cancer in Japan have increased dramatically within a short period of time.

Aged↗

PubMed2002

Patterns of Care Study quantitative evaluation of the quality of radiotherapy in Japan.

BACKGROUND: Quality assurance (QA) of clinical practice is important for any medical specialty. Programs based on the Patterns of Care Study (PCS) have been developed to compare the quality of radiotherapeutic care at individual institutions, with the national average representing the process and outcome of radiotherapy. The feasibility of these programs was analyzed. METHODS: Calculation programs for the national average and standard score were developed to evaluate quantitatively the process and outcome of radiotherapy at individual institutions as well as at the national level. The programs were used to evaluate the quality of radiotherapy for 561 esophageal carcinoma patients surveyed in the Japanese PCS. RESULTS: As a representative example of QA measurement, the national average for the 5-year survival rate for these patients in the nonsurgery group was 5%. The regional averages for those in academic and nonacademic institutions were 9% and 1%, respectively (P = 0.0142), showing a significant difference between these two institutional strata. The standard score compared with the national average for institution No.105, for example, was 16.3 (P < 0.0001), with the positive value indicating that the outcome at this institution was significantly higher than the national average. The corresponding figure compared with the regional average was -0.3 (P = 0.7391), with the negative value indicating the outcome is not superior to the regional average of academic institutions. CONCLUSIONS: These programs make it possible to compare quantitatively the quality of radiation therapy at individual institutions with the national and regional averages. They should also be useful for nationwide QA projects in radiation oncology as well as in other medical specialities.

Aged↗

PubMed2002

Radiation therapy for small-cell lung cancer: results of the 1995-1997 patterns of care process survey in Japan.

The Patterns of Care Study (PCS) conducted a nationwide audit survey in order to establish the national practice process of radiation therapy for small-cell lung cancer (SCLC) and examined the influence of institutional stratification on the process of care in Japan. The PCS randomly sampled institutions and patients using a two-stage cluster method and surveyed the process of radiation therapy for 174 stage I-III SCLC patients according to the category of institution, stratified as follows: A1, academic institutions treating > or = 300 patients a year; A2, <300 patients; B1, non-academic institutions treating > or = 120 patients a year; and B2, <120 patients. Karnofsky performance status distributions showed significant variance by stratification of institutions (P=0.013). Patients treated on an outpatient basis accounted for 32% in A1, 23% in A2, 8% in B1, but only 5% in B2 (P=0.007). A photon energy > or = 10 MV was used for 87% of patients in A1, 69% in A2, 54% in B1 and 23% in B2 (P=0.001). Contralateral hilus was irradiated for 11% of patients in A1, 17% in A2, 29% in B1 and 3% in B2 (P=0.001). Field size reduction during the treatment course was done for 77% of patients in A1, 54% in A2, 60% in B1 and 42% in B2 (P=0.007). Ninety-two percent of patients received combined chemotherapy and radiation therapy, and the most frequently used drugs were etoposide (91%) and cisplatin (69%). The results of clinical studies on SCLC had favorably penetrated into the clinical practice. However, the stratification of institutions significantly affected the process of radiation therapy in Japan.

Adult↗

PubMedDate not supplied

Monte Carlo calculation of depth doses for small field of CyberKnife.

PURPOSE: A Monte Carlo (MC) model of CyberKnife was developed as a quality assurance tool. The percentage depth dose (%dd) was verified by using this model. MATERIALS AND METHODS: An MC model was developed with Electron Gamma Shower version 4 (EGS4) in two steps: (1) a model of the CyberKnife treatment head and (2) a model of the collimator and phantom. The bremsstrahlung spectrum was calculated using the first model, and this spectrum was then used to calculate %dds with the second model. The calculated %dds for a large field (60 mm diameter) and three small fields (30, 15, and 5 mm diameter) were compared with those measured with a diamond detector. RESULTS AND DISCUSSION: The MC-calculated and measured %dd-curves for the 60 mm diameter field were in excellent agreement (<1.85%), thus confirming the validity of the model. Discrepancies between the calculated and measured %dd-curves increased with decreasing field size, with considerable discrepancy (11.62%) for the 5 mm diameter field due to lateral electron disequilibrium. Accurate dose can be determined with MC even in small fields. CONCLUSION: The MC technique can provide reliable standard data for accurate dose delivery with high-technology radiotherapies using small beams.

Humans↗

PubMedDate not supplied

Treatment results of radiotherapy with or without surgery for posterior pharyngeal wall cancer of oropharynx and hypopharynx: prognostic value of tumor extension.

PURPOSE: We have been treating posterior pharyngeal wall cancer of the oropharynx and hypopharynx with external radiotherapy according to our policy reported in the 1970s. MATERIALS AND METHODS: Between 1968 and 1995, 51 patients were treated. Treatment policy was decided on the basis of the treatment response after 40 Gy of radiotherapy. Thirty-six good responders were treated with radical radiotherapy, eight poor responders received radical surgery, and the other seven patients could not receive radical treatment because of tumor or patient factors. RESULTS: The 5-year local control and cause-specific survival rates were 56% and 48% for all 51 patients. The 5-year local control rate was 52% for radical radiotherapy. Tumors limited to the posterior wall showed better treatment results (76% for both local control and cause-specific survival) than tumors involving the postcricoid area (0% and 10%). CONCLUSION: Radiotherapy for carefully selected patients dependent on response after 40 Gy of radiotherapy is a useful policy. Tumor extension is an important prognostic factor.

Adult↗

PubMedDate not supplied

Radiotherapy for localized hormone-refractory prostate cancer in Japan.

BACKGROUND: The role of radiotherapy for patients with localized hormone-refractory cancer has not been well documented. MATERIALS AND METHODS: The Patterns of Care Study in Japan examined the records of 311 patients with prostate cancer treated with radiotherapy during the period 1996--1998. Of them, 61 patients (19.6%) with regionally localized hormone-refractory cancer were selected. Local progression or biochemical failure was observed after a median duration of 15.9 months of androgen deprivation. At the time of radiotherapy, 49 patients (80.4%) had T3-4 tumors and 15 (26.8%) had regional lymph node metastases. External beam radiotherapy was performed with a median total dose of 60 Gy. RESULTS: Although distant metastases or regional lymph node metastases were seen in 22 patients (36.1), local progression was observed in one patient (1.6%). The five-year overall and progression-free survival rates were 51.6% and 43.5%, respectively. CONCLUSION: Radiotherapy had an excellent local control rate for hormone-refractory cancer.

Aged↗

PubMedDate not supplied

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 > or = 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.

Aged↗

PubMedDate not supplied

Influence of age on the pattern and outcome of external beam radiotherapy for clinically localized prostate cancer.

BACKGROUND: The influence of age on the patterns and outcomes of external beam radiotherapy for clinically localized prostate cancer patients was examined. MATERIALS AND METHODS: The Japanese Patterns of Care Study surveys were used to compare the processes and outcomes of radical external beam radiotherapy in 140 elderly patients (>75 years old) and 304 younger patients (<75 years old). RESULTS: Although the Karnofsky performance status was significantly different between elderly and younger patients, there were no significant differences in disease characteristics such as pretreatment PSA level, differentiation, Gleason combined score and clinical T stage. There were also no significant differences in the treatment characteristics such as CT-based treatment planning, conformal therapy, total radiation doses (both a median of 66.0 Gy) and hormonal therapy usage. Moreover, no significant differences in overall survival, biochemical relapse-free survival and late toxicity rates were observed between elderly and younger patients. CONCLUSION: Age did not influence the disease characteristics, patterns of external beam radiotherapy, survival and late toxicities for clinically localized prostate cancer patients. Therefore, radiotherapy could represent an important treatment modality for elderly patients as well as for younger ones.

Adenocarcinoma↗

PubMedDate not supplied

Radical external beam radiotherapy for clinically localized prostate cancer in Japan: differences in the patterns of care between Japan and the United States.

UNLABELLED: 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 (> or = 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.

Adult↗