Objective:To compare 5-year overall survival (OS) and disease free survival (DFS) between preoperative three dimensional conformal radiotherapy (3DCRT) and volumetric medulated arc therapy (VMAT) concurrently combined with chemotherapy for locally advanced rectum cancer (LARC), and analyze the value of induction and/or consolidation chemotherapy in these circumstances.Methods:334 patients with LARC treated with preoperative 3DCRT (172 cases) and VMAT (162 cases) concurrently combined with chemotherapy, main protocol XELOX (capecitabine plus oxaplatin), and subsequent surgery in Sun Yat-sen University from May 2007 to April 2013 were retrospectively analyzed. The radiation prescription dose for VMAT group was 50 Gy 25 fractions for planning target volume1(PTV 1), and 46 Gy 25 fractions for PTV 2. The radiation prescription dose for 3DCRT group was 46 Gy 23 fractions for PTV 2. One hundred and eighty-five cases of all received preoperative concurrent chemoradiotherapy (namely, CCRT group), 149 cases received preoperative concurrent chemoradiotherapy plus median 2 courses (1-7 courses) induction and/or consolidation chemotherapy (namely, CCRT±induction chemotherapy±consolidation chemotherapy group), whose main chemotherapy protocol was XELOX. Difference of 5-year OS and DFS between 3DCRT and VMAT group was compared. The rate differences of acute toxicity during chemoradiotherapy, postoperative complications, ypCR, and survival between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group were analyzed. Results:After a median follow-up of 62.3 months (2.4-119months) for the 334 patients, no any significant difference for 5-year OS (79.0% vs. 83.2%, P=0.442) and 5-year DFS (77.0% vs. 82.1%, P=0.231) between 3DCRT and VMAT group was observed. There was no any significant difference for the Grade 3 hematological toxicity (7.0% vs. 12.1%, P=0.114) and non-hematological toxicity (14.1% vs. 16.8%, P=0.491) during chemoradiotherapy, postoperative complications (17.3% vs. 17.4%, P=0.971), ypCR rate (25.4% vs. 30.2%, P=0.329), 5-year OS (80.5% vs. 82.0%, P=0.714) and 5-year DFS (78.8% vs. 81%, P=0.479) between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group. Conclusions:Compared with 3DCRT, the physics advantage of VMAT technique does not significantly convert into clinical benefits and improve 5-year OS and DFS, even further boosting radiation dose to the gross tumor volume. It is safe for median 2 courses of induction and/or consolidation chemotherapy before and or after preoperative concurrent chemoradiotherapy in the treatment of LARC, though it does not significantly improve ypCR rate and survival.

Objective:To develop a national secondary reference material of Urea and Creatinine in frozen human serum as a standard for metrological traceability.Methods:According to JJF1343-2012 "General and Statistical Principles for Characterization of Reference Materials" and JJF 1006-1994 " Technical Norm of Primary Reference Material ", the homogeneity, stability, and commutability were evaluated;Using the JCTLM recommended methods, the value of the reference materials was assigned through collaboration with 6 accredited reference laboratories from Guangdong Provincial Hospital of Chinese Medicine, Beijing Aerospace General Hospital, Shenzhen Mindray Bio-Medical Electronics, Maccura Biotechnology, Beijing Leadman Biochemistry, and Zhejiang MedicalSystem Biotechnology. Uncertainty components including inhomogeneity, stability and value assignment were evaluated.Results:The results of one-way analysis of variance of homogeneity for the reference materials showed P>0.05, and the stability evaluation was less than the critical value of the t-test. The measured values were in the 95% confidence interval in the four conventional detection systems for commutability, and the certified values and expanded uncertainties were urea:(14.7±0.3) mmol/L ( k=2),Cr:(313.9±14.5) μmol/L ( k=2). Conclusion:The prepared secondary reference materials of urea and creatinine had promising homogeneity, stability, and commutable, the values of urea and creatinine concentration in reference materials were accurate and reliable.

Objective To investigate the association between short-term exposure to ambient air pollution and hospital admission for ischemic stroke among older adults. Methods Using clinical monitoring data from China National Health Commission, we identified 124 297 individuals from Guangzhou, Guangdong province, China who were 60 years or older and were admitted to hospital for ischemic stroke in 2016-2019. We used a time-stratified case-crossover design and employed the conditional logistic regression model to investigate the exposure-response association between short-term exposure to air pollution and hospital admission for ischemic stroke. Based on each subject's residential address and pollutant data from its neighboring air quality monitoring stations, we used an inverse distance weighting method to assess individual-level exposure to PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ on each of the case and control days. Results In single-pollutant models, each 10 µg/m₃ increase of PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃ was associated with a 0.46% (95% confidence interval [CI]: 0.13-1.36%, lag 2 d), 0.66% (1.38-2.93%, lag 02 d), 3.39% (0.07-0.21%, lag 2 d), 1.47% (0.07-0.21%, lag 02 d), 0.06% (0.07-0.21%, lag 02 d) and 0.18% (0.07-0.21%, lag 3 d) increase in odds of hospital admission, respectively. The results of 2-pollutant models showed that the association of exposure to SO₂, NO₂ and O₃ with hospital admission for ischemic stroke remained stable with adjustment for each of the other air pollutants. Conclusions Short-term exposure to ambient air pollution, especially SO₂, NO₂ and O₃, was associated with increased risk of hospital admission for ischemic stroke in older adults.

Objective: To identify the definition of heat wave based on mortality risk assessment in different regions of China. Methods: Daily mortality (from China Information System for Disease Control and Prevention) and meteorological data (from National Meteorological Information Center in China) from 66 counties with a population of over 200 000 were collected from 2006-2011. With the consideration of climate type and administrative division, China was classified as seven regions. Firstly, distributed lag non-linear model (DLNM) was used to estimate community-specific effects of temperature on non-accidental mortality. Secondly, a multivariate meta-analysis was applied to pool the estimates of community-specific effects to explore the region-specific temperature threshold and the duration for definition of heat wave. Results: We defined regional heat wave of Northeast, North, Northwest, East, Central and Southwest China as being two or more consecutive days with daily mean temperature higher than or equal to the P₆₄, P₇₁, P₈₅, P₆₇, P₇₅ and P₇₇ of warm season (May to October) temperature, respectively, while the thresholds of temperature were 21.6, 23.7, 24.3, 25.7, 28.0 and 25.3 ℃. The heat wave in South China was defined as five or more consecutive days with daily mean temperature higher than or equal to the P₉₃ (30.4 ℃) of warm season (May to October) temperature. Conclusion The region-specific definition of heat wave developed in our study may provide local government with the guidance of establishment and implementation of early heat-health response systems to address the negative health outcomes due to heat wave.

Objective To quantitatively evaluate the association of short-term exposure to ambient submicron particulate matter (PM₁) with hospital admissions for angina in older adults. Methods A case-crossover study was conducted among 46 687 older adults hospitalized for angina from 2016 to 2019 in Guangzhou medical institutions. Grid data on ambient PM₁ concentrations in Guangzhou were obtained from the ChinaHighAirPollutants (CHAP) dataset. Exposure to PM₁ was assessed according to each subject's residential addresses. Conditional logistic regression model was used to analyze the the exposure-response association between PM₁ and hospital admissions for angina. Results From 2016 to 2019, the average exposure level of PM₁ on the same day of hospital admissions (lag 0) for angina was 21.0 ± 11.5 μg/m³. The results of main model analysis showed that lag 0 day exposure to ambient PM₁ was significantly associated with a higher odds of hospital admissions for angina in older adults. Each 10 μg/m³ increase of PM₁ exposure level was significantly associated with a 1.31% (95% CI: 0.05%, 2.59%) increased odds of angina admissions. Results from a two-pollutant model adjusting for O₃ showed that the association between short-term exposure to PM₁ and odds of hospitalization for angina remained stable. According to the results of the above model, it was estimated that the excess hospitalization attributable to ambient PM₁ exposure accounted for 2.46% (95% CI: 0.09%, 4.76%) of the total admissions in Guangzhou during 2016-2019, corresponding to 1539 (95% CI: 54, 2976) admissions. No significant effect modification on the associations was observed by sex, age, or season. Conclusion Short-term exposure to ambient PM₁ was significantly associated with an increased odds of hospital admissions for angina in older adults.