The Japanese Nationwide Cohort Data of Particle Beam Therapy for Liver Oligometastasis in Esophagogastric Cancer Patients

PURPOSE/OBJECTIVE(S)

A nationwide multicenter cohort study on particle therapy was launched by the Japanese Society for Radiation Oncology (JASTRO) in Japan in May 2016. We analyzed the outcome of proton beam therapy (PBT) for liver oligometastasis of esophagogastric cancers.

MATERIALS/METHODS

Cases in which PBT was performed at all PBT facilities in Japan between May 2016 and February 2019 were enrolled. The patients were selected based on the following criteria: controlled primary cancer; liver recurrence without extrahepatic tumors; and no more than three liver lesions. The dose and fraction of PBT were determined using unified treatment policy established by JASTRO. We used the following protocol, 64 gray (relative biological effect) (Gy (RBE))/8 fractions (fr) for the peripheral region, and 72.6 GyE/22fr for the central region. For safety aspect, the hepatocellular carcinoma irradiation protocols of 66 Gy (RBE)/10fr, 72.6-76 Gy (RBE)/20-22fr, and 74-76 Gy (RBE)/37-38fr could be allowed. The overall survival (OS), local control (LC), and adverse events (AEs) were examined. The OS and LC rates were calculated using the Kaplan-Meier method. Factors possibly related to OS, such as tumor size (for multiple lesions, the largest size), number of liver tumors, as well as the presence or absence of prior, concurrent, and post-PBT chemotherapy, were investigated. The cut-off values were estimated using the receiver operating characteristic curve and area under the curve. Univariate analysis was performed using the log-rank test. Statistical significance was P-values < 0.05.

RESULTS

Twenty-three males and two females with a median age of 69 (range, 52-80) years and 36 lesions were included. This study included six patients with esophageal and 19 patients with gastric cancer. The median lesion size, fraction size, and biological effective dose (BED)10 were 31 (7-104) mm, 3.8 gray (relative biological effect)/fractions (Gy (RBE)/fr) (2-8 Gy (RBE)/fr), and 96.9 (88.8-115.2) Gy, respectively. The median follow-up period was 18 (4-47) months. The 1-, 2-, and 3-year OS rates were 76.0, 49.5, and 43.3%, respectively, and the median OS was 19 months. The 1-, 2-, and 3-year OS rates of esophageal cancer were 83.3% for all. The 1-, 2-, and 3-year OS rates of gastric cancer were 73.7, 40.2, and 32.2%, respectively, and the median OS was 18 months. The 1-, 2-, and 3-year LC rates were 96.3, 91.5, and 91.5%, respectively. The 1-, 2-, and 3-year LC rates of esophageal cancer were 100% for all. The 1-, 2-, and 3-year LC rates of gastric cancers were 94.7, 88.0, and 88.0%, respectively. Tumor size was the only significant OS-related factor (P < 0.01). No grade 3 or higher adverse events were observed.

CONCLUSION

Owing to the low incidence of adverse events and the high LC rate, PBT is a feasible option for liver oligometastasis of esophagogastric cancers.

The Japanese Nationwide Cohort Data of Proton Beam Therapy for Liver Oligometastasis in Breast Cancer Patients

PURPOSE/OBJECTIVE(S)

A nationwide multicenter cohort study on particle therapy was launched by the Japanese Society for Radiation Oncology (JASTRO) in Japan. We analyzed the outcome of proton beam therapy (PBT) for liver oligometastasis in breast cancers.

MATERIALS/METHODS

Cases in which PBT was performed at all Japanese proton therapy facilities between May 2016 and February 2019 were enrolled. The patients were selected based on the following criteria: the primary cancer was controlled, liver recurrence without extrahepatic tumors, and no more than three liver lesions. The treatment indication and strategy were discussed at cancer boards in each institution. The dose and fraction of PBT were determined by referring to the unified treatment policy established by JASTRO. We used the following protocol: 64 gray (Gy) (relative biological effectiveness [RBE])/8 fraction (fr) for the hepatic periphery area away from the GI tract, and 72.6 GyE/22 fr for the adjacent hilar region type. Regarding safety, the HCC irradiation protocols of 66 GyE/10 fr, 72.6-76 GyE/20-22 fr, and 74-76 GyE/37-38 fr could be used. The local control (LC), overall survival (OS), and progression free survival (PFS) rates were calculated using the Kaplan-Meier method. Factors possibly related to OS, such as tumor size, number of liver tumors, intervention of chemotherapy, and/or hormone therapy, were investigated. The cut-off values were estimated using the receiver operating characteristic curve and area under the curve. Univariate analysis was performed using the log-rank test.

RESULTS

Fourteen females, with a median age of 57 (range, 44-73) years and twenty-two lesions were included. Nine patients had one lesion, two patients had two lesions, and three patients had three lesions. PBT was selected because nine patients had underlying disease and five patients had general conditions (age, etc.). The median lesion size, fraction size, and biological effective dose using the linear-quadratic model with α/β = 10 Gy ((BED)10) were 44 (20-130) mm, 6.6 (2-8) (relative biological effectiveness [RBE])/fraction (fr), and 109.6 (52.7-115.2) Gy, respectively. The median follow-up period of breast cancers was 22.8 (4-54) months. The 1-, 2-, and 3-year LC rates of liver metastasis from breast cancers were 100% for all. The 1-, 2-, and 3-year OS rates were 85.7%, 62.5%, and 62.5%, respectively. The 1-, 2-, and 3-year PFS rates were 50.0%, 33.3%, and 16.7%, respectively, and median PFS time was 16 months. Tumor size, the number of liver tumors, and the intervention of chemotherapy and/or hormone therapy at any time were not significantly related to the OS. Only one patient did not complete PBT due to current disease progression. The other patients completed PBT without interruption. One patient had grade 3 radiation-induced dermatitis.

CONCLUSION

Based on the low incidence of adverse events and the high LC rate, PBT appears to be a feasible option for liver oligometastasis in breast cancer patients.

Phase II Clinical Trial of Hypofractionated Image-Guided Proton Therapy with 12 Fractions for Prostate Cancer

PURPOSE/OBJECTIVE(S)

Towards hypofractionated proton therapy for prostate cancer for improving convenience for patients to receive treatment and improving therapeutic efficacy, image-guided technique with hydrogel spacer solved the late gastrointestinal toxicity, but it is unclear whether acute genitourinary (GU) toxicity is acceptable. The aim of this phase II study was to evaluate the safety and efficacy of hypofractionated image-guided proton therapy (IGPT) with 12 fractions for prostate cancer.

MATERIALS/METHODS

Eligibility criteria were as follows: (1) histologically confirmed primary prostate cancer; (2) T1-T3bN0M0 staged by (UICC TNM8th); (3) ECOG-PS ≤ 2; (4) age ≥ 20 years; (5) no serious underlying disease or other cancers; (6) technically capable of proton therapy, and (7) written informed consent. Primary endpoint was the ratio of grade 2 or more acute genitourinary toxicity. We used the modified CTCAE grading of grade 2 GU toxicities, in which prescribing two and more types of drugs for dysuria within 3 months of the start of radiation was considered to indicate grade 2 GU toxicity. A phase II trial was planned based on the minimax Simon's two-stage design with a significance level of 0.05 and a power of 90%. The acceptable incidence is considered to be less than 5%, and the unacceptable incidence is considered to be more than 15%. A total of 83 patients is required for completion of the trial (7 patients or fewer). After evaluating the primary endpoint in 83 patients, 217 additional patients were registered and a total of 300 patients were registered in order to further examine the safety and efficacy. The prescribed dose to the isocenter was 51.6 GyRBE in 12 fractions (4 days a week).

RESULTS

From January 2020 to March 2021, 30, 53, and 217 patients (total 300) were enrolled. The patient characteristics were as follows: median age, 70 (48-83) years; low/intermediate/high risk, 44/132/124. Forty-nine and 38 patients had benign prostatic hyperplasia and diabetes mellitus, respectively. Grade 2 acute GU toxicities were observed in 1, 5 and 13 patients, respectively (total 6.3%). No grade 3 or higher acute GU toxicities were observed. However, urinary retention during IGPT, which was not previously observed, was observed in 3 cases, and temporary urethral catheterization was performed (Grade 2). Most of the acute GU toxicity tended to improve at 1 month after IGPT, and almost improved at 3 months. Mean score deteriorations beyond the minimum clinically important difference threshold (1/2 SD) were observed only at 1 month in the following scales: summary (-6.0), bother (-7.0), and irritative/obstructive (-6.3).

CONCLUSION

Hypofractionated IGPT with 12 fractions for prostate cancer is well tolerated in acute GU toxicities. Longer follow-up is necessary to evaluate the efficacy and late toxicities. Further investigation of hypofractionated IGPT with 12 fractions for prostate cancer is warranted. Since April 2021, an additional 1000 cases of prospective registration study have been conducted.

The 2021 Bo Lindell Lecture: Inclusive, accountable, transparent: the direction we should take for the benefit of present and future generations

The International Commission on Radiological Protection (ICRP) is recognised as the de-facto world authority in the field of radiological protection. The ICRP Recommendations have been used as a basis for regulations and policy in almost every country, and with the current review and revision of the System of Radiological Protection, it will continue to make significant contributions in radiation safety for patients, workers, the public, and the environment. In a society undergoing significant change, it is necessary to give careful thought to which groups will be perceived as authoritative organisations by the constituents of the future. The ideal form of an authoritative organisation in the new society of the future is to continue to show how it came to make such recommendations, how it reflected the opinions of interested parties in the process, and how it discloses its records with as much transparency as possible. The question now is what we must do to ensure that decision-making advances in a way that not only makes sense to the present generation, but will be easily consumed by future generations. The path that ICRP is taking to formulate the next set of General Recommendations is doing just that, in line with the key procedural values of INCLUSIVE, ACCOUNTABLE, AND TRANSPARENT.

Population-based incidence and outcomes of acute aortic dissection in Japan

Background

The population-based incidence and outcomes of acute aortic dissection (AAD) are still unknown because some patients are already dead on arrival at the hospital, and the accurate diagnosis of AAD is difficult due to the low autopsy rate for patients with cardiopulmonary arrest outside of the hospital. We performed a population-based review of all patients with AAD in a well-defined geographical area in the southern part of Japan between 2016 and 2018.

Methods

Data of all patients with AAD at our Hospital, which performs medical care for 120,000 residents, were collected retrospectively. The emergency medical service is dedicated to the transfer of all patients in this area to the MPNH. For all patients who were dead on arrival, the diagnosis of AAD was made by autopsy imaging (AI) using computed tomography. The age-adjusted incidence and mortality per 100,000 population were calculated using the Japanese population distribution model in 2015.

Results

The total incidence of AAD was 79 (type A: 64.5%, n=51). Of those, 60.8% (31/51) of patients with type A and 21.4% (6/28) with type B were dead on arrival and diagnosed by AI. The 30-day mortality rates after the onset of AAD were 74.5% (38/51) in type A and 25.0% (7/28) in type B. Excluding the dead-on-arrival patients, the 30-day mortality rates were 35.0% (7/20) in type A and 4.5% (1/22) in type B. The age-adjusted incidence and mortality of AAD per 100,000 inhabitants were 17.3 (type A: 11.3, type B: 6.0) and 9.6 (type A: 8.4, type B: 1.2), respectively. Both values were significantly higher in men than in women.

Conclusions

The population-based survey of emergency medical care for AAD showed that the age-adjusted incidence of AAD was two-fold higher than in previous reports, and the actual mortality rates after AAD onset were markedly higher due to the high incidence of dead-on-arrival.

Funding Acknowledgement

Type of funding sources: None. Representative CT images of type A AAD

Impact of endovascular repair on the outcomes of octogenarians with ruptured abdominal aortic aneurysms: a nationwide Japanese study

Objective

This study aimed to clarify the impact of endovascular aneurysm repair (EVAR) on clinical outcomes in Japanese patients of advanced age with ruptured abdominal aortic aneurysm (rAAA).

Methods

This was a national registry based retrospective comparative study, using data from the Japanese Registry Of All cardiac and vascular Diseases-Diagnostic Procedure Combination (JROAD-DPC), a nationwide claim based database from more than 600 hospitals. Patients admitted with rAAA between April 1, 2012, and March 31, 2015 were included in the study. Patient characteristics, management, and outcomes were compared between the elderly (aged ≥80 y) and the less old. The primary endpoint was in hospital mortality; the secondary endpoint was the functional status at discharge.

Results

Of 3 969 eligible patients, 49.9% were categorised as elderly. Elderly patients had a higher prevalence of female gender (41.8% vs. 17.0%, p&lt;0.001) and disturbance of consciousness on admission (28.6% vs. 20.7%, p&lt;0.001). They were less likely to undergo open surgical repair (31.6% vs. 56.7%, p&lt;0.001), although EVAR was performed similarly in both groups (13.7% vs. 14.8%, p&lt;0.33). The unadjusted mortality rate (61.8% vs. 37.6%, p&lt;0.001) and mean Barthel index at discharge (73.0 vs. 91.8, p&lt;0.001) were statistically significantly worse in the elderly. Multilevel mixed effect logistic regression analyses showed that old age was detected as an independent predictor of in hospital death (odds ratio 2.75; 95% confidence interval, 2.39–3.17; p&lt;0.001). However, for patients who received EVAR, old age was not statistically significant (odds ratio 1.13; 95% confidence interval, 0.77–1.66; p&lt;0.53).

Conclusion

Elderly patients with rAAA were less likely to be offered open surgical repair, and the mortality among those who received surgery was high. However, for the small subgroup of elderly patients currently selected for EVAR there was a favourable outcome. The further implementation of EVAR for rAAA in Japan, especially for elderly patients with suitable anatomy, may be justified.

Funding Acknowledgement

Type of funding source: None

Sex-related differences in clinical features and in-hospital outcomes of acute aortic dissection type b

Background

Acute aortic dissection (AAD) is a life-threatening medical condition with high morbidity and mortality. The association between female sex and poorer outcomes following surgery for AAD type A has been reported; however, the sex-related differences in clinical features and in-hospital outcomes of AAD type B remain to be elucidated.

Methods

We studied a total of 1877 patients with AAD type B who were enrolled in the Tokyo Acute Aortic Super-network from January 2013 to December 2016. Clinical features and in-hospital outcomes were compared between sexes. Independent predictors of in-hospital mortality were assessed using a multivariable analysis.

Results

The mean age of the patients was 69±13 years and 549 (29%) were females. Female patients were older than males (74±13 years vs 67±13 years; p&lt;0.001). Females had lower systolic blood pressure on admission (158±37 mmHg vs 164±38 mmHg; p=0.007) and were more likely to have altered consciousness level at presentation (8.7% vs 3.9%; p&lt;0.001), intramural hematoma (IMH)-type AAD (62.7% vs 53.6%; p&lt;0.001), and DeBakey type IIIa (28.4% vs 21.8%; p=0.002) compared with males. Females were treated with medical therapy alone more frequently (90.3% vs 85.9%; p=0.009) and had a higher in-hospital mortality rate (5.3% vs 2.6%; p=0.036). A multivariable analysis revealed that age [per year, odds ratio (OR) 1.06; 95% CI 1.04–1.09; p&lt;0.001], altered consciousness level (OR 3.28; 95% CI 1.54–6.98; p=0.002), shock/hypotension (OR 14.0; 95% CI 5.92–33.1; p&lt;0.001), classic-type AAD (OR 2.54; 95% CI 1.36–4.73; p=0.003), and medical therapy alone (OR 0.28; 95% CI 0.15–0.54; p&lt;0.001) were independent predictors of in-hospital mortality, whereas female sex was not predictive of in-hospital mortality (OR 1.64; 95% CI 0.91–2.96; p=0.10).

Conclusion

In AAD type B, females were older and had altered consciousness level, IMH-type, and a less widespread dissection more frequently than males. The overall in-hospital mortality was higher in females; however, female sex was not associated with in-hospital mortality after multivariable adjustment.

Funding Acknowledgement

Type of funding source: None

Diagnostic markers for discriminating between acute aortic dissection and acute myocardial infarction during the pre-hospital phase: analysis of 3,195 cases

 

Both acute aortic dissection (AAD) and acute myocardial infarction (AMI) present with chest pain and are life-threatening diseases that require early diagnosis and treatment for better clinical outcome. However, two critical diseases in the very acute phase are sometimes difficult to differentiate, especially prior to arrival at the hospital for urgent diagnosis and selection of specific treatment.

The aim of our study was to clarify the diagnostic markers acquired from the information gathered from medical history taking and physical examination for discriminating AAD from AMI by using data from the Tokyo Cardiovascular Care Unit (CCU) Network database.

We examined the clinical features and laboratory data of patients with AAD and AMI who were admitted to the hospital in Tokyo between January 2013 and December 2015 by using the Tokyo CCU Network database. The Tokyo CCU Network consists of &gt;60 hospitals that fulfil certain clinical criteria and receive patients from ambulance units coordinated by the Tokyo Fire Department. Of 15,061 patients diagnosed as having AAD and AMI, 3,195 with chest pain within 2 hours after symptom onset (537 AAD and 2,658 AMI) were examined. The patients with out-of-hospital cardiac arrest were excluded.

We compared the clinical data of the patients with chest pain who were diagnosed as having AAD and AMI. The following indicators were more frequent or had higher values among those with AAD: female sex (38% vs. 20%, P&lt;0.001), systolic blood pressures (SBPs) at the time of first contact by the emergency crew (142 mmHg vs. 127 mmHg), back pain in addition to chest pain (54% vs. 5%, P&lt;0.001), history of hypertension (73% vs. 58%, P&lt;0.001), SBP ≥150 mmHg (39% vs. 22%, P&lt;0.001), back pain combined with SBP ≥150 mmHg (23% vs. 0.8%, P&lt;0.001), and back pain with SBP &lt;90 mmHg (4.5% vs. 0.1%, P&lt;0.001). The following data were less frequently observed among those with AAD: diabetes mellitus (7% vs. 28%, P&lt;0.001), dyslipidaemia (17% vs. 42%, P&lt;0.001), and history of smoking (48% vs. 61%, P&lt;0.001). The multivariate regression analysis suggested that back pain with SBP ≥150 mmHg (odds ratio [OR] 47; 95% confidence interval [CI] 28–77; P&lt;0.001), back pain with SBP &lt;90 mmHg (OR 68, 95% CI 16–297, P&lt;0.001), and history of smoking (OR 0.49, 95% CI 0.38–0.63, P&lt;0.001) were the independent markers of AAD. The sensitivity and specificity of back pain with SBPs of ≥150 mmHg and back pain with SBPs &lt;90 mmHg for detecting AAD were 23% and 99%, and 4% and 99%, respectively.

In patients with chest pain suspicious of AAD and AMI, “back pain accompanied by chest pain with SBP ≥150 mmHg” or “back pain accompanied by chest pain with SBP &lt;90 mmH” is a reliable diagnostic marker of AAD with high specificity, although the sensitivity was low. The two SBP values with back pain are markers that may be useful for the ambulance crew at their first contact with patients with chest pain.

Funding Acknowledgement

Type of funding source: None

P5599Prognostic impact of quality indicators on outcomes of acute aortic dissection in Japan

Background

Despite recent advances in diagnosis and management, the mortality of acute aortic dissection (AAD) remains high.

Purpose

This study aims to develop quality indicators (QIs) for the management of AAD, and to evaluate the associations between QIs and outcomes of AAD in a Japanese nationwide administrative database.

Methods

A total of 18,348 patients suffered from AAD (Type A: 10,131, Type B: 8,217) in the Japanese Registry of All Cardiac and Vascular Diseases database between 2012 and 2015 were studied. A systematic review was performed to establish initial index items for QIs. Evaluation was performed through the expert consensus meeting using a Delphi method. Associations between developed QIs and the mortality were determined by multivariate mixed logistic regression analyses.

Results

A total of nine QIs (five structural and four processatic) were developed. Achievements of developed QIs (High: 7–9, Middle: 4–6, Low: 0–3) were significantly associated with lower in-hospital mortality even after adjustment for covariates in both type A (Middle: odds ratio [OR], 0.257; 95% confidence interval [CI], 0.211–0.312; P<0.001; High: OR, 0.064; 95% CI, 0.047–0.086; P<0.001 vs. Low) and type B (Middle: OR, 0.447; 95% CI, 0.338–0.590; P<0.001; High: OR, 0.128; 95% CI, 0.077–0.215; P<0.001 vs. Low). Additionally, achievements of structural and processatic QIs were consistently associated with reduced in-hospital mortality.

QIs and in-hospital mortality

Conclusions

Developed QIs for AAD management were significantly associated with lower in-hospital mortality. Evaluation of each hospital's management with QIs could be helpful to equalize quality of treatment and to fill the evidence-to-practice gaps in the real-world treatment.

P5607Clinical characteristics and treatment strategy for acute aortic dissection in Tokyo Acute Aortic Disease Super-Network System

Introduction

Acute aortic dissection (AAD) is one of the most fatal cardiovascular diseases. The prevalence of AAD is reported to be low. The clinical data of AAD from representative cardiovascular centers are not enough to show the whole range of clinical feature of AAD. We have to know the exact prevalence and clinical pictures of AAD under the new system, the Tokyo AAD Super-Network System (TAAD-SNS), for strategy of emergency transport and treatment of AAD which would cover the entire metropolitan area of Tokyo. TAAD-SNS started in 2011, and after slight modification, the new system of AAD re-started in 2013. The aim of this study is to elucidate the whole range of clinical characteristics and recent trends of treatment of AAD.

Methods

Out of 73 hospitals included in Tokyo CCU Network system, 41 hospitals are chosen for TAAD-SNS. These hospitals provide around-the-clock surgery. In this system, the availability of surgical division is monitored in real time. All of the patients suspected of AAD are transferred directly or from primary care hospital to the hospitals of TAAD-SNS.

Results

After exclusion of 237 patients with cardiopulmonary arrest on arrival, 4877 consecutive patients (2923 male, mean age of 69±14 y/o) were admitted to the hospitals with diagnosis of AAD from 2013 to 2016. Prevalence of AAD in Tokyo was about 10 patients per 100,000 populations in every year. After exclusion of 37 patients undetermined into type A or B, 4840 patients (2694 with type A and 2146 with type B) were analyzed. Among the type A patients, 1752 (65%) were classified into type of patent false lumen (classic-type), 721 (27%) of closed false lumen (intramural hematoma: IMH-type), and 221 (8%) were undetermined. Among the type B, 880 (41%) were classified into classic-type, 1129 (53%) of IMH-type, and 137 (6%) were undetermined. Both among type A and B, mean ages were younger in classic-type than in IMH-type (type A: 66±14 vs. 73±12 y/o, p<0.05; type B: 64±15 vs. 72±12 y/o, p<0.05). Prevalence of male population and risk factor of hypertension was higher in type B than in type A both among classic-type and IMH-type. Systolic blood pressure at the emergency room was lower in type A than in type B among both classic-type and IMH-type (classic-type: 124±34 vs. 161±38 mmHg, IMH-type: 130±51 vs. 163±56 mmHg). In-hospital mortality of surgical treatment for type A classic-type and type A IMH-type, conservative strategy for type B classic-type and type B IMH-type was 9.6%, 4.2%, 3.1% and 1.7%, respectively. Stentgraft implantation for type B AAD started and shows a favorable in-hospital mortality compared to the operative treatment (Stentgraft vs. surgery in type B classic-type: 7.8% vs. 6.5%, in type B IMH-type: 10.7% vs. 11.8%, respectively).

Conclusion

Our study showed that prevalence of AAD was 2–3 times higher than previous reports. We should consider to choose the treatment strategy according to the type of AAD, A or B, classic-type or IMH-type.

Acknowledgement/Funding

Tokyo Metropolitan government

P5605The impact of institutional case volume on the Ppognosis of ruptured aortic aneurysms: a Japanese nationwide study

Background

To improve outcome for ruptured aortic aneurysms (rAA), centralization of treatment is potentially effective. However, there is no nationwide survey for the current managements and outcomes of rAA in Japan.

Purpose

The aim of this study was to assess the volume-outcome relationship for rAA treatment using the nationwide claim-based database.

Methods

Using the Japanese Registry Of All cardiac and vascular Diseases- Diagnostic Procedure Combination database, we identified patients admitted to 564 certified teaching-hospitals with rAA between April 1, 2012 and March 31, 2015. Institutional case volume (cardiovascular surgeries per year) was categorized into quartiles (Lowest, Low, High, and Highest) and the odds ratios (ORs) for in-hospital mortality and neurological status at discharge were analyzed for each quartile.

Results

Of 7086 eligible patients, 3925 (55.4%) died in hospital. Mortality rates decreased from 69.4% in the lowest-volume to 43.8% in the highest-volume category (P<0.001). The favourable impact of institutional case volume was sustained even after adjustment for covariates (Low-volume: OR, 0.83; 95% confidence interval [CI], 0.65–1.07; P=0.147; High-volume: OR, 0.69; 95% CI, 0.54–0.89; P=0.005; and Highest-volume: OR, 0.55; 95% CI, 0.42–0.72; P<0.001 vs. Lowest-volume). Additionally, other three institutional parameters (increased aortic surgery volume, cardiovascular surgeons' volume, and certified cardiologists' volume) were consistently associated with reduced in-hospital mortality. The rate of coma at discharge was the lowest in the Highest-volume group (P<0.001).

Institutional volume and mortality

Conclusions

Increased institutional volume was associated with lower in-hospital mortality. Establishing regionally tailored systems to transfer patients to high-volume centers is needed to improve outcomes.

Quantitative assessment of provability of radiation-related cancers considering unavoidable existence of unadjusted risk factors

The attribution of stochastic effects to exposure to ionizing radiation has been qualitatively discussed by introducing two distinct concepts of provability and probability. This study aims to develop a method of quantitatively assessing the provability of radiation-related cancers. To this end, the 'minimum provable dose' (MPD) was developed and applied to actual cancer mortality in Japan. The background lifetime risk of cancer mortality was calculated for the esophagus, stomach, colon, liver, lungs, skin, breasts, ovaries, bladder, and bone marrow as well as the age-specific risk coefficients reproducing those given in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP). Comparing the relative ratio of MPDs, which was defined herein as the 'provability index' (PI), we quantitatively ranked radiation-related cancers for different tissues and organs predicated on provability for ages of 10, 30, 50, and 0-85+  years at exposure. We discuss the radiological protection of male emergency workers focusing on cancers highly prioritized according to the ranking (i.e. colon, bone marrow, and bladder). The present study proposed the system to quantitatively evaluate the level of radiological protection taking into account the variations of the background cancer risk on the provability of radiation-related cancers.

Discordance and accordance between patient's and physician's assessments in rheumatoid arthritis

OBJECTIVES

The American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission criteria for rheumatoid arthritis (RA) are more stringent than index-based criteria, making it more difficult to achieve a patient's global assessment (PGA) than an evaluator's global assessment (EGA). We investigated the reason for the discrepancy between the PGA and the EGA in a Japanese clinical cohort.

METHOD

We assessed clinical and laboratory variables in our clinical cohort. The frequency of remission achievement according to the ACR/EULAR remission criteria and predictors of the discrepancy between the PGA and EGA were analysed.

RESULTS

Of 370 patients with RA, 89 fulfilled PGA criteria and 167 patients fulfilled EGA criteria. The PGA was highly correlated with the visual analogue scale (VAS) pain score and non-inflammatory variables including Steinbrocker class and the Health Assessment Questionnaire Disability Index (HAQ-DI). Conversely, inflammatory variables, including swollen joint count (SJC), tender joint count (TJC), and C-reactive protein (CRP) levels, were significantly associated with the EGA. The main predictors of the discrepancy between the PGA and the EGA were patient's VAS pain score, SJC, and functional disability.

CONCLUSIONS

Increased pain and functional disability led to a discrepancy towards a worse PGA than EGA, whereas increased SJC led to an accordance towards a worse EGA.

Fractionated stereotactic radiotherapy using CyberKnife for the treatment of large brain metastases: a dose escalation study

AIMS

To evaluate the toxicity and efficacy of fractionated stereotactic radiotherapy (FSRT) with doses of 18-30 Gy in three fractions and 21-35 Gy in five fractions against large brain metastases.

MATERIALS AND METHODS

Between 2005 and 2012, 61 large brain metastases (≥ 2.5 cm in maximum diameter) of a total of 102 in 54 patients were treated with FSRT as a first-line therapy. Neurological symptoms were observed in 47 of the 54 patients before FSRT. Three fractions were applied to tumours with a maximum diameter ≥ 2.5 cm and <4 cm, and five fractions were used for brain metastases ≥ 4 cm. After ensuring that the toxicities were acceptable (≤ grade 2), doses were escalated in steps. Doses to the large brain metastases were as follows: level I, 18-22 Gy/three fractions or 21-25 Gy/five fractions; level II, 22-27 Gy/three fractions or 25-31 Gy/five fractions; level III, 27-30 Gy/three fractions or 31-35 Gy/five fractions. Level III was the target dose level.

RESULTS

Overall survival rates were 52 and 31% at 6 and 12 months, respectively. Local tumour control rates of the 102 total brain metastases were 84 and 78% at 6 and 12 months, respectively. Local tumour control rates of the 61 large brain metastases were 77 and 69% at 6 and 12 months, respectively. Grade 3 or higher toxicities were not observed.

CONCLUSIONS

The highest dose levels of 27-30 Gy/three fractions and 31-35 Gy/five fractions seemed to be tolerable and effective in controlling large brain metastases. These doses can be used in future studies on FSRT for large brain metastases.

PARG dysfunction enhances DNA double strand break formation in S-phase after alkylation DNA damage and augments different cell death pathways

Poly(ADP-ribose) glycohydrolase (PARG) is the primary enzyme responsible for the degradation of poly(ADP-ribose). PARG dysfunction sensitizes cells to alkylating agents and induces cell death; however, the details of this effect have not been fully elucidated. Here, we investigated the mechanism by which PARG deficiency leads to cell death in different cell types using methylmethanesulfonate (MMS), an alkylating agent, and Parg^−/− mouse ES cells and human cancer cell lines. Parg^−/− mouse ES cells showed increased levels of γ-H2AX, a marker of DNA double strand breaks (DSBs), accumulation of poly(ADP-ribose), p53 network activation, and S-phase arrest. Early apoptosis was enhanced in Parg^−/− mouse ES cells. Parg^−/− ES cells predominantly underwent caspase-dependent apoptosis. PARG was then knocked down in a p53-defective cell line, MIAPaCa2 cells, a human pancreatic cancer cell line. MIAPaCa2 cells were sensitized to MMS by PARG knockdown. Enhanced necrotic cell death was induced in MIAPaCa2 cells after augmenting γ-H2AX levels and S-phase arrest. Taken together, these data suggest that DSB repair defect causing S-phase arrest, but p53 status was not important for sensitization to alkylation DNA damage by PARG dysfunction, whereas the cell death pathway is dependent on the cell type. This study demonstrates that functional inhibition of PARG may be useful for sensitizing at least particular cancer cells to alkylating agents.