A Japanese multi-institutional phase II study of moderate hypofractionated intensity-modulated radiotherapy with image-guided technique for prostate cancer.

BACKGROUND: The aim of this multi-institutional phase II study was to confirm the safety and the potential efficacy of moderately hypofractionated intensity-modulated radiotherapy (IMRT) with prostate-based image-guidance for Japanese patients. METHODS: Patients with low- or intermediate-risk localized prostate cancer were eligible. Patients with a part of high risk (having only one of the following factors, cT3a, 20 < PSA ≤ 30, or GS = 8 or 9) were also included. Hypofractionated IMRT using daily image-guided technique with prostate matching was performed with a total dose of 70 Gy in 28 fractions. Neoadjuvant hormonal therapy for 4-8 months was mandatory for patients with intermediate or high-risk prostate cancer. RESULTS: From 20 institutions, 134 patients enrolled. The median follow-up was 5.16 years (range, 1.43-6.47 years). The number of patients with low, intermediate, and high-risk prostate cancer was 20, 80, and 34, respectively. The 5-year overall, biochemical failure-free, and clinical failure-free survival was 94.5%, 96.0%, and 99.2%, respectively. The 5-year biochemical failure-free survival for patients with low-, intermediate-, and high-risk disease was 94.1%, 97.4%, and 93.9%, respectively. The incidences of grade 2 gastrointestinal (GI) and genitourinary (GU) late toxicities at 5 years were 5.3% and 5.3%, respectively. There are no acute or late toxicities ≥ grade 3. Of 124 patients who were followed for up to 5 years, the grade 2 late GU or GI toxicities were 10.5% (90% confidence intervals, 6.3-16.2%, p = 0.0958). CONCLUSION: The safety and efficacy of moderately hypofractionated IMRT with prostate-based image-guidance was confirmed among Japanese patients with prostate cancer.

Plastic brain structure changes associated with the division of labor and aging in termites.

Division of labor is a prominent feature of social insect societies, where different castes engage in different specialized tasks. As brain differences are associated with behavioral differences, brain anatomy may be linked to caste polymorphism. Here, we show that termite brain morphology changes markedly with caste differentiation and age in the termite, Reticulitermes speratus. Brain morphology was shown to be associated with reproductive division of labor, with reproductive individuals (alates and neotenic reproductives) having larger brains than nonreproductives (workers and soldiers). Micro-computed tomography (CT) imaging and dissection observations showed that the king's brain morphology changed markedly with shrinkage of the optic lobes during their long life in the dark. Behavioral experiments showed that mature primary kings lose visual function as a result of optic lobe shrinkage. These results suggested that termites restructure their nervous systems to perform necessary tasks as they undergo caste differentiation, and that they also show flexible changes in brain morphology even after the final molt. This study showed that brain morphology in social insects is linked to caste and aging, and that the evolution of the division of labor is underpinned by the development of diverse neural systems for specialized tasks.

Radiotherapy for ductal carcinoma of the prostate: an analysis based on the Japanese radiation oncology study group survey.

BACKGROUND: The clinical characteristics of prostate ductal carcinoma is still unclear, and treatment strategy has not yet been established due to its rarity. Therefore, we conducted a multicenter survey of radiation therapy for prostate ductal carcinoma in Japan. METHOD: Data of patients with ductal carcinoma of the prostate treated with radiation therapy between 1996 and 2018 were extracted from the database of each facility. RESULTS: Fifty-two treatment records of 41 patients were collected from nine institutions. The treatment purpose and situations were varied curative intent to palliation. Twenty-eight patients received curative treatments. The median follow-up period of these patients was 68 months. Androgen deprivation therapy was combined with radiation therapy in 26 cases (93%). X-ray and particle irradiation was used. Radiation dose range was 63-78 Gy; 5-year overall survival, progression-free survival and biochemical relapse-free survival were 87.0, 79.3 and 79.3%, respectively. One patient experienced Grade 3 radiation proctitis and one experienced Grade 3 radiation cystitis. There were no Grade 4 or worse adverse events. CONCLUSION: Most patient received similar treatment with adenocarcinoma of prostate, and the clinical results were compatible. For more reliable evidence, further studies are required.

Lipid Polyunsaturated Fatty Acid Chains in Mouse Kidneys Were Increased within 5 min of a Single High Dose Whole Body Irradiation.

To understand the ultra-early reaction of normal organ lipids during irradiation, we investigated the response of lipids, including polyunsaturated fatty acid (PUFA) chains, which are particularly susceptible to damage by ROS, in mice's kidneys, lungs, brains, and livers within 5 min of single high-dose irradiation. In this study, we set up three groups of C56BL/6 male mice and conducted whole-body irradiation with 0 Gy, 10 Gy, and 20 Gy single doses. Kidney, lung, brain, and liver tissues were collected within 5 min of irradiation. PUFA-targeted and whole lipidomic analyses were conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that PUFA chains of kidney phosphatidylcholine (PC), phosphatidylethanolamine (PE), and triacylglycerol (TG) significantly increased within 5 min of 10 Gy and 20 Gy irradiation. The main components of increased PUFA chains in PC and PE were C18:2, C20:4, and C22:6, and in TG the main component was C18:2. The kidney lipidomes also showed significant changes from the perspective of lipid species, mainly dominated by an increase in PC, PE, TG, and signal lipids, while lipidomes of the lung, brain, and liver were slightly changed. Our results revealed that acute PUFA chains increase and other lipidomic changes in the kidney upon whole-body irradiation within 5 min of irradiation. The significantly increased lipids also showed a consistent preference for possessing PUFA chains. The lipidomic changes varied from organ to organ, which indicates that the response upon irradiation within a short time is tissue-specific.

National survey of radiation oncologists' practice patterns regarding hormone-naïve prostate cancer with bone metastases.

OBJECTIVE: To explore radiation oncologists' attitudes and practice patterns of radiotherapy for hormone-naïve prostate cancer with bone metastases in Japan. METHODS: An internet-based survey was distributed to board-certified radiation oncologists of the Japanese Society of Radiation Oncology. Three hypothetical cases were assumed: hormone-naïve prostate cancer with single, three or multiple non-symptomatic bone metastases. The respondents described their attitude regarding such cases, treatment methods and the radiotherapy dose fractionation that they would recommend. RESULTS: Among the 1013 board-certified radiation oncologists in Japan, 373 (36.8%) responded to the questionnaire. Most of the respondents (85.0%) believed that radiotherapy may be applicable as a primary treatment for hormone-naïve prostate cancer with bone metastases in some circumstances. For Case 1 (single bone metastasis), 55.0% of the respondents recommended radiotherapy for the prostate and bone metastasis. For Case 2 (three bone metastases), only 24.4% recommended radiotherapy for all lesions, and 31.4% recommended radiotherapy for the prostate only. For Case 3 (multiple bone metastases), 49.1% of the respondents stated that there was no indication for radiotherapy. However, 34% of the respondents still preferred to administer radiotherapy for the prostate. The radiotherapy techniques and dose fractionations varied widely among the respondents. CONCLUSION: Most of the respondent radiation oncologists believed that radiotherapy may be beneficial for hormone-naïve prostate cancer with bone metastases.

[Clinical Complete Response to Definitive Chemoradiotherapy for Advanced Lower Rectal Cancer-A Case Report].

A man in his 80s was admitted to our hospital with a chief complaint of bloody stools. He was diagnosed with cT2N0M0, cStage Ⅰ rectal cancer. As the patient was of advanced age and had multiple comorbidities, definitive chemoradiotherapy was administered. Immediately after treatment, the patient achieved a complete clinical response, and recurrence has not been detected for 2 years and 3 months since treatment.

Institutional patient accrual volume and the treatment quality of I­125 prostate seed implantation in a Japanese nationwide prospective cohort study.

PURPOSE: It is unclear whether experience at high-volume institute improves the treatment quality of prostate seed implantation. The aim of this study was to evaluate the effect of institutional experience on postimplant dosimetric parameters in a nationwide prospective cohort study. METHODS: From July 2005 to June 2007, 2354 patients were registered in the Japanese Prostate Cancer Outcome Study of Permanent I­125 Seed Implantation (J-POPS), and 1126 patients treated with seed implantation alone were evaluated. As a surrogate for institutional experience, we classified the J­POPS institutions as high-volume (patient accrual volume was ≥120 patients per institution) or low-volume institutions (patient accrual volume was <120 patients per institution). To compare treatment quality between institutions, we evaluated the postimplant dosimetric parameters including D90, V100/150 (prostatic dose parameters), UD5/90, U200 (urethral dose parameters), and rectum R100/150 (rectal dose parameters). RESULTS: In the 5 high-volume institutions (n = 601 patients), most of the patients were treated with >144 Gy of D90, whereas in the 20 low-volume institutions (n = 525) some of the patients were treated with <144 Gy. The V100 of most of the high-volume institution patients were >90%, whereas in the low-volume institutions a considerable percentage of patients showed lower V100. Although there was no correlation between D90 and rectal dose parameters, UD90 had a moderate positive correlation with D90 in both the high- and low-volume institutions. U200 varied more widely in the low-volume institutions. CONCLUSIONS: Our findings indicate that the institutional patient accrual volume is associated with the treatment quality of I­125 prostate seed implantation.

Comparison of radiotherapy infrastructure between Korea and Japan.

BACKGROUND: Patterns of cancer incidence and radiotherapy use are similar in Korea and Japan, with differences in radiotherapy infrastructure. METHODS: The authors surveyed the megavoltage machines in 91 radiotherapy centers in Korea and published data in Japan. The number of megavoltage machines per center was used as an indicator of the fragmentation of radiotherapy services using four as the threshold, and the number of megavoltage machines per million people was compared. The practice pattern of intensity-modulated radiation therapy was analyzed. RESULTS: There were 91 centers in Korea and 825 in Japan. The number of megavoltage machines per center was 1.3 in Japan and 2.3 in Korea. Radiotherapy infrastructure showed fragmentation in Korea and hyperfragmentation in Japan. In Japan, 75% of radiotherapy centers operated with one megavoltage machine, whereas in Korea, 47% megavoltage machines per center was 3.2 in Seoul, while that in the non-capital area was 1.8, constituting a mixed pattern of centralization and fragmentation. In Japan, megavoltage machines per center in Tokyo, Kanagawa and Osaka, was 1.5, 1.3 and 1.2, respectively, indicating no concentration in the metropolis. The number of megavoltage machines per million in Korea was 4.0, whereas that in Seoul was 8.7, constituting capital concentration. In Japan, the number of megavoltage machines per million was 8.7, whereas in Tokyo, Kanagawa and Osaka, it was is 9.3, 6.3 and 9.0, showing uniform distribution. intensity-modulated radiation therapy utilization is increasing, accounting for 15% and 23% of radiotherapy patients in Japan and Korea, respectively. CONCLUSIONS: The fragmentation of radiotherapy services in Korea and Japan might affect radiotherapy quality.

Quality of life after external beam radiotherapy for localized prostate cancer: Comparison with other modalities.

In external beam radiotherapy for localized prostate cancer, acute toxicities are typically transient and mild. These symptoms will disappear within 4-8 weeks after external beam radiotherapy. Some patients might suffer from proctitis with bloody stools as late rectal toxicity. Therefore, it has been shown that external beam radiotherapy has a more pronounced negative impact on bowel function compared with other treatment modalities. However, the recent development of modern beam delivery techniques, including intensity-modulated radiotherapy, allows us not only to deliver higher doses to the prostate, but also to decrease the doses to the critical organs, resulting in the maintenance of patients' quality of life within satisfactory levels. Patients' quality of life after external beam radiotherapy is also strongly related to the total dose, fractionation regimens, dose parameters of the critical organs and treatment plan quality, with a trade-off between the radicality of external beam radiotherapy and potentially increased toxicity. Radiation oncologists should choose treatment parameters carefully to achieve a reasonable balance between a good oncological outcome and the patient's quality of life.

Dose evaluation indices for total body irradiation using TomoDirect with different numbers of ports: A comparison with the TomoHelical method.

TomoDirect has been reported to have some advantages over TomoHelical in delivering total body irradiation (TBI). This study aimed to investigate the relationships between the number of ports and the dose evaluation indices in low-dose TBI in TomoDirect mode using 2-12 ports and to compare these data with those for the TomoHelical mode in a simulation study. Thirteen patients underwent low-dose TBI in TomoHelical mode from June 2015 to June 2016. We used the same computed tomography data sets for these patients to create new treatment plans for upper-body parts using TomoDirect mode with 2-12 beam angles as well as TomoHelical mode. The prescription was 4 Gy in two equal fractions. For the TomoDirect data, we generated plans with 2-12 ports with approximately equally spaced angles; the modulation factor, field width, and pitch were 2.0, 5.0 cm, and 0.500, respectively. For the TomoHelical plans, the modulation factor, field width, and pitch were 2.0, 5.0 cm, and 0.397, respectively. D2, D98, D50, and the homogeneity index (HI) were evaluated to compare TomoDirect plans having 2-12 ports with the TomoHelical plan. Using TomoDirect plans, D2 with four ports or fewer, D98 with 10 ports or fewer, D50 with four ports or fewer and HI with five ports or fewer showed statistically significantly worse results than the TomoHelical plan. With the TomoDirect plans, D2 with seven ports or more, D50 with eight ports or more, and HI with eight ports or more showed statistically significant improvement compared with the TomoHelical plan. All of the dose evaluation indices of the TomoDirect plans showed a tendency to improve as the number of ports increased. TomoDirect plans showed statistically significant improvement of D2, D50, and HI compared with the TomoHelical plan. Therefore, we conclude that TomoDirect can provide better dose distribution in low-dose TBI with TomoTherapy.

Patterns of radiotherapy infrastructure in Japan and in other countries with well-developed radiotherapy infrastructures.

BACKGROUND: In high-income countries, the number of radiotherapy machine per population reaches a sufficient level. However, the patterns of infrastructure of radiotherapy in high-income countries are not well known. METHODS: Among 29 high-income countries with gross national income of $25,000 or more per capita, we selected 23 countries whose total number of newly diagnosed cancer patients in 2012 was reported in the Organisation for Economic Co-operation and Development Health Statistics 2017. The numbers of radiotherapy centers and teletherapy machines in each of these 23 countries were collected using the Dictionary of Radiotherapy Centers database. RESULTS: The number of cancer patients per teletherapy machine was 452.35-1398.22 (median 711.66) with a three-fold variation, whereas the number of cancer patients per radiotherapy center varied even more widely, from 826.16 to 5159.86 (median 2259.83) with a six-fold variation. The average number of teletherapy machines per radiotherapy center also ranged widely, from 1.24 to 8.29 (median 3.11) with a seven-fold variation. The number of teletherapy machines in each country was almost proportional to that of cancer patients, and the number of teletherapy machines per radiotherapy center was inversely related to the number of radiotherapy centers per cancer patients. The number of teletherapy machines per radiotherapy center in Japan was 1.24, the most fragmented among the high-income countries. The percentage of large radiotherapy centers having three or more teletherapy machines in Japan was the smallest among 23 high-income countries. CONCLUSIONS: Optimization of the radiotherapy infrastructure in Japan should be carefully considered.

Nationwide Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS): first analysis on survival.

BACKGROUND: Investigating oncological outcomes in patients registered in the Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS) in terms of biochemical relapse-free survival (bRFS) by the Phoenix and the newly developed J-POPS definitions, exploration of predictive factors for bRFS, and preliminary verification of pitfalls of prostate-specific antigen (PSA) failure definitions. METHODS: Between July 2005 and June 2007, 2316 clinically localized patients underwent permanent seed implantation. The primary endpoint was bRFS. One of the secondary endpoints was overall survival (OS). RESULTS: The median age was 69 and performance status was 0 in 99.1% of participants. The median biologically effective dose (BED) was about 180 Gy2. During a median follow-up of 60.0 months, 8.4 and 5.9% had PSA failure by the Phoenix and the J-POPS definitions, respectively. The 5-year bRFSs based on the Phoenix and the J-POPS definitions were 89.1 and 91.6%, respectively. The 5-year OS was 97.3%. According to multivariate analyses, only age affected bRFS based on the Phoenix definition, whereas the risk group and BED independently affected bRFS based on the J-POPS definition. A spontaneous PSA decrease was seen in 91.1% of participants after PSA failure based on the Phoenix definition alone, but in only 22.2% after PSA failure based on the J-POPS definition alone. CONCLUSION: The world's largest registration study, J-POPS, consisted of patients with longevity, and a highly quality-controlled BED resulted in excellent bRFS and OS. The high likelihood of PSA bounce by the Phoenix definition should be taken into account, especially in younger patients. CLINICAL TRIAL INFORMATION: NCT00534196.

The Effect of Interim FDG-PET-guided Response-Adapted Therapy in Pediatric Patients with Hodgkin's Lymphoma (HL-14) : Protocol for a Phase II Study.

This trial enrolls patients with untreated Hodgkin's lymphoma aged<20 years at diagnosis and examines the effects of omitting radiation therapy if the FDG-positron emission tomography (PET) findings after two completed cycles of combination chemotherapy are negative. It thereby aims to determine whether patients who truly require radiation therapy can be identified by FDG-PET. If so, this modality could be used to omit radiation therapy for all other patients, decreasing the risk of serious long-term complications without affecting survival rates. The outcomes of patients for whom FDG-PET is used to assess early treatment response will also be determined.

Smoking effect on secondary bladder cancer after external beam radiotherapy for prostate cancer.

OBJECTIVE: Although it is well known that radiotherapy for prostate cancer increases comorbid rate of secondary bladder cancer, the effect of aging and smoking with radiotherapy on incidence rate of secondary bladder cancer remains unknown. Then, this study investigated the combinational effect of external beam radiotherapy for prostate cancer and aging or smoking on comorbid rate of secondary bladder cancer. METHODS: This study included 754 Japanese patients with prostate cancer treated with radiotherapy (n = 319) and radical prostatectomy (n = 435) from 2000 through 2013. The relationship between therapeutic modality for prostate cancer as well as age or smoking status and comorbid rate of secondary bladder cancer was examined. RESULTS: During the median follow-up period of 4.3 and 3.1 years, secondary bladder cancer occurred in 11 (3.4%) and 5 (1.1%) of patients with prostate cancer treated with external beam radiotherapy and radical prostatectomy, respectively. The 5-year bladder cancer-free survival rate was 97.3% in the external beam radiotherapy group and 99.4% in the radical prostatectomy group. Age (hazard ratio = 1.15, P = 0.027) and ever smoking (hazard ratio = 5.65, P = 0.011) were significant predictive factors of secondary bladder cancer incidence in the external beam radiotherapy cohort, but not in the radical prostatectomy cohort. Inversely, among men with ever smoking, but not among older men, external beam radiotherapy (hazard ratio = 9.64, P = 0.0052) was a significant risk factor of secondary bladder cancer. CONCLUSIONS: Taken together, these findings suggest that smoking history might be one of criteria to choose radical prostatectomy than external beam radiotherapy for prostate cancer, and that age would not be a criterion for therapeutic selection in terms of secondary bladder cancer.

Risk Factors and Preventive Effects of Laser Panretinal Photocoagulation for Neovascular Glaucoma after Ophthalmic Stereotactic Radiotherapy.

Purpose: To evaluate the risk factors and the preventive effects of laser panretinal photocoagulation (PRP) for neovascular glaucoma (NVG) after ophthalmic stereotactic radiotherapy. Methods: Twenty-four patients with ocular malignant tumor (such as uveal malignant melanoma, lacrimal gland cancer) who received stereotactic radiotherapy (such as gamma knife, cyber knife) were retrospectively analyzed. Patients were divided into group A without preventive PRP (n=9), and group B with preventive PRP (n=15). Survival curves were plotted using the Kaplan-Meier method and compared between the two groups with the log-rank test. Results: In group A, NVG occurred in 3 patients. In contrast, in group B, no patient encountered NVG. The significant risk factor for NVG was dose-volumes that irradiated the optic disk (p=0.045). The incidence of NVG was significantly reduced in group B compared with group A (p=0.019). Conclusions: Dose-volumes that irradiated the optic disk were risk factors for NVG. PRP is effective in the prevention of NVG.

Clinical characteristics and outcome of pneumothorax after stereotactic body radiotherapy for lung tumors.

BACKGOUND: We retrospectively investigated the clinical characteristics and outcome of pneumothorax after stereotactic body radiotherapy (SBRT) for lung tumors. METHODS: Between April 2003 and July 2012, 473 patients with lung tumors were treated with SBRT. We identified 12 patients (2.5 %) with pneumothorax caused by SBRT, and evaluated the clinical features of pneumothorax. RESULTS: All of the tumors were primary lung cancers. The severity of radiation pneumonitis was grade 1 in 10 patients and grade 2 in two patients. Nine patients had emphysema. The planning target volume and pleura overlapped in 11 patients, and the tumors were attached to the pleura in 7 patients. Rib fractures were observed in three patients before or at the same time as the diagnosis of pneumothorax. The median time to onset of pneumothorax after SBRT was 18.5 months (4-84 months). The severity of pneumothorax was grade 1 in 11 patients and grade 3 in one patient. CONCLUSION: Although pneumothorax was a relatively rare late adverse effect after SBRT, some patients demonstrated pneumothorax after SBRT for peripheral lung tumors. Although most pneumothorax was generally tolerable and self-limiting, careful follow-up is needed.

Stereotactic body radiation therapy for primary lung cancers clinically diagnosed without pathological confirmation: a single-institution experience.

BACKGROUND: Pathological diagnosis of small lung lesions is sometimes difficult in medically inoperable patients. The purpose of this study was to evaluate the adverse events and the outcomes of stereotactic body radiation therapy (SBRT) for lung lesions which were clinically diagnosed as primary lung cancer without pathological confirmation. METHODS: Between April 2003 and April 2011, 88 patients with small lung lesions which were clinically diagnosed as primary lung cancer were treated with SBRT. The median tumor size was 19 mm (range 8-40 mm). The radiation dose was 48 Gy in four fractions in all patients. The median follow-up was 23 months (range 6-91 months). RESULTS: Recurrence was observed in 13 patients. The local control rate, progression-free survival rate, and overall survival rate at 3 years were 90, 67, and 80 %, respectively. Two patients (2.3 %) had Grade 2 radiation pneumonitis, and six patients (6.8 %) had Grade 2 rib fractures. There were no adverse events of Grade 3 or greater. CONCLUSIONS: SBRT appears to be a safe and effective treatment option for small lung lesions that are clinically diagnosed as primary lung cancer without pathological confirmation.

Particle radiotherapy for prostate cancer.

Recent advances in external beam radiotherapy have allowed us to deliver higher doses to the tumors while decreasing doses to the surrounding tissues. Dose escalation using high-precision radiotherapy has improved the treatment outcomes of prostate cancer. Intensity-modulated radiation therapy has been widely used throughout the world as the most advanced form of photon radiotherapy. In contrast, particle radiotherapy has also been under development, and has been used as an effective and non-invasive radiation modality for prostate and other cancers. Among the particles used in such treatments, protons and carbon ions have the physical advantage that the dose can be focused on the tumor with only minimal exposure of the surrounding normal tissues. Furthermore, carbon ions also have radiobiological advantages that include higher killing effects on intrinsic radio-resistant tumors, hypoxic tumor cells and tumor cells in the G0 or S phase. However, the degree of clinical benefit derived from these theoretical advantages in the treatment of prostate cancer has not been adequately determined. The present article reviews the available literature on the use of particle radiotherapy for prostate cancer as well as the literature on the physical and radiobiological properties of this treatment, and discusses the role and the relative merits of particle radiotherapy compared with current photon-based radiotherapy, with a focus on proton beam therapy and carbon ion radiotherapy.

[Effect of prostate matching on dose distribution by on board imager kV-CBCT image].

PURPOSE: The purpose of this study was to evaluate the effect of prostate matching on dose distribution using kilovolt cone beam computed tomography (kV-CBCT) with image guided radiation therapy for prostate cancer. MATERIALS AND METHOD: Sixteen prostate cancer patients were treated with intensity modulated radiation therapy to 76 Gy at 2 Gy per fraction in 38 fractions. Daily target localization was performed using "bone matching" and "prostate matching" based on planning CT and kV-CBCT. Prostate dose coverage was assessed by the proportion of the CTV fully encompassed by 95%, 98% isodose lines, and mean dose lines. As for rectal and bladder, dose coverage was assessed by volumes which received 40 Gy, 60 Gy, 70 Gy, 75 Gy and mean dose at treatment. And we calculated the tumor control probability (TCP) and normal tissue complication probability (NTCP), accordingly. They were compared to the bone and prostate matching image. RESULT: Our study found an improvement in dose usage in CTV and bladder which enabled us to compare the bone matching image and the prostate matching image. However, it did not improve dose usage in the rectal. Then we chose patients who were a large shift from bone matching image to prostate matching image. As a result, rectal dose and NTCP were reduced. DISCUSSION: Prostate matching is useful and safe when compared to bone matching because of improving CTV dose usage and reducing dose rectal and bladder.

Survey of advanced radiation technologies used at designated cancer care hospitals in Japan.

OBJECTIVE: Our survey assessed the use of advanced radiotherapy technologies at the designated cancer care hospitals in Japan, and we identified several issues to be addressed. METHODS: We collected the data of 397 designated cancer care hospitals, including information on staffing in the department of radiation oncology (e.g. radiation oncologists, medical physicists and radiation therapists), the number of linear accelerators and the implementation of advanced radiotherapy technologies from the Center for Cancer Control and Information Services of the National Cancer Center, Japan. RESULTS: Only 53% prefectural designated cancer care hospitals and 16% regional designated cancer care hospitals have implemented intensity-modulated radiotherapy for head and neck cancers, and 62% prefectural designated cancer care hospitals and 23% regional designated cancer care hospitals use intensity-modulated radiotherapy for prostate cancer. Seventy-four percent prefectural designated cancer care hospitals and 40% regional designated cancer care hospitals employ stereotactic body radiotherapy for lung cancer. Our multivariate analysis of prefectural designated cancer care hospitals which satisfy the institute's qualifications for advanced technologies revealed the number of radiation oncologists (P = 0.01) and that of radiation therapists (P = 0.003) were significantly correlated with the implementation of intensity-modulated radiotherapy for prostate cancer, and the number of radiation oncologists (P = 0.02) was correlated with the implementation of stereotactic body radiotherapy. There was a trend to correlate the number of medical physicists with the implementation of stereotactic body radiotherapy (P = 0.07). Only 175 (51%) regional designated cancer care hospitals satisfy the institute's qualification of stereotactic body radiotherapy and 76 (22%) satisfy that of intensity-modulated radiotherapy. Seventeen percent prefectural designated cancer care hospitals and 13% regional designated cancer care hospitals had a quality assurance committee. CONCLUSIONS: The numbers of radiation oncologists and other operating staff might be essential factors in the implementation of advanced radiotherapy technologies. Small proportions of regional designated cancer care hospitals satisfy the institute's qualifications of advanced technologies.