Observation of Stark many-body localization without disorder.

Thermalization is a ubiquitous process of statistical physics, in which a physical system reaches an equilibrium state that is defined by a few global properties such as temperature. Even in isolated quantum many-body systems, limited to reversible dynamics, thermalization typically prevails1. However, in these systems, there is another possibility: many-body localization (MBL) can result in preservation of a non-thermal state2,3. While disorder has long been considered an essential ingredient for this phenomenon, recent theoretical work has suggested that a quantum many-body system with a spatially increasing field-but no disorder-can also exhibit MBL4, resulting in 'Stark MBL'5. Here we realize Stark MBL in a trapped-ion quantum simulator and demonstrate its key properties: halting of thermalization and slow propagation of correlations. Tailoring the interactions between ionic spins in an effective field gradient, we directly observe their microscopic equilibration for a variety of initial states, and we apply single-site control to measure correlations between separate regions of the spin chain. Furthermore, by engineering a varying gradient, we create a disorder-free system with coexisting long-lived thermalized and non-thermal regions. The results demonstrate the unexpected generality of MBL, with implications about the fundamental requirements for thermalization and with potential uses in engineering long-lived non-equilibrium quantum matter.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources.

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Constraints on Ultraheavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations.

In this Letter we try to search for signals generated by ultraheavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible γ rays by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of the LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter that have low fluxes of astrophysical γ-ray background while having large amount of dark matter. By analyzing more than 700 days of observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultraheavy dark matter annihilation cross section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived.

Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A.

On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.

Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A.

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

[Ultrasound-guided percutaneous thermal ablation assisted by artificial ascites and soft tissue edema in the treatment of special-region hepatic tumors].

Objective: To explore the application value and operation skills of ultrasound-guided percutaneous thermal ablation assisted by artificial ascites or/and soft tissue edema in the treatment of special hepatic tumors located nearby the diaphragm, heart, stomach, gastrointestinal tract, gall bladder, kidney, and other organs. Methods: The clinical data of 132 patients with special-region hepatic tumors treated with ultrasound-guided percutaneous thermal ablation aided by artificial ascites and/or artificial soft tissue edema were retrospectively analyzed. Intraoperative contrast-enhanced ultrasound was used to guide ablation when necessary. During the operation, the ablation needle was lifted or pressed down, or the direction of the needle handle was changed to protect vital organs. The technical success rate of artificial ascites and/or soft tissue edema formation, the complete in activation rate of the tumor, and the complications were observed. Results: There were 74 patients (108 lesions) treated with radiofrequency ablation and 58 patients (82 lesions) treated with microwave ablation. Among them, 81 cases was successfully injected artificial abdominal ascites, with a water volume of (1 301±685) ml; artificial soft tissue edema was successfully formed for 19 patients, with a water volume of (534±258) ml. Both artificial ascites and artificial soft tissue edema were built for 30 patients. The success rate of this hydro-isolation technique was 98.5% (130/132). 129 patients successfully completed the treatment, and the complete inactivation rate of the tumor was 92.5% (172/186). The average postoperative hospital stay was three days. No patient had serious complications, such as surface tumor rupture, gastrointestinal injury, or diaphragm perforation. Conclusions: For hepatic tumors located adjacent to other organs such as the diaphragm, heart, gastrointestinal tract, gallbladder, and kidney, the application of artificial ascites and/or artificial soft tissue edema can reduce the damage to these organs, as well as reduce the possibility of tumor rupture and diaphragm perforation. These methods are safe and effective in ultrasound-guided percutaneous thermal ablation.

[Epidemic trends and prevention and control of seasonal influenza in China after the COVID-19 pandemic].

During the COVID-19 pandemic, a series of non-pharmaceutical interventions, which were implemented to curb the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), significantly modified the seasonal pattern of influenza. The intensity of influenza activity markedly decreased and B/Yamagata lineage was no longer detected. As the national influenza sentinel surveillance data shown, clear seasonal patterns were observed for influenza between 2012-2019, annually with an average of 14.57% of specimens tested positive for influenza virus. However, the seasonal pattern of influenza was disrupted after the outbreak of COVID-19. In the 2020-2021 season, influenza demonstrated an extremely low activity (yearly positivity rate<1.0%), followed by a resurgence of winter peak in the 2021-2022 season. Following the downgrade of management of COVID-19 to Class B in China in December 26, 2022, social activities gradually resumed, leading to the rebound of influenza activity with an out-of-season ciculation. After COVID-19 pademic, other respiratory infectious diseases caused by SARS-CoV-2, respiratory syncytial virus, and mycoplasma pneumonia were alternatively or concurrently circulated with influenza. The prevention and control of influenza and other respiratory infectious diseases emphasizes a multi-disease prevention strategy, including long-term and continuous monitoring the epidemic trends in influenza virus and SARS-CoV-2, promoting influenza and COVID-19 vaccination among key populations, and strengthening the knowledge and public awareness of prevention and control for respiratory infectious diseases, etc.

[Reflections on the positioning and implementation pathways of adult vaccine prescriptions].

The innovation of integrating medical treatment and prevention mechanisms is a key task deployed by the government, aiming to promote the construction of a Healthy China and address the prevalent "treatment over prevention" mindset in healthcare services and society. Vaccination is an effective strategy for preventing and controlling infectious diseases; however, adult vaccination rates in China remain low due to insufficient awareness and enthusiasm among the public and healthcare professionals. In recent years, various regions have begun to explore the model of physicians in medical institutions prescribing vaccines to improve vaccination rates. This article analyzes the positioning, current implementation status, and challenges of vaccine prescriptions, and proposes recommendations advocating policy formulation, improving service models and supporting measures, improving funding mechanisms, and strengthening publicity and education to promote the widespread implementation and effectiveness of vaccine prescriptions.

[The international cases of vaccinology education and its enlightenment to the discipline development in China].

Vaccination is an effective public health measure to prevent and control vaccine-preventable diseases for individual and society. However, China currently confronts significant challenges, including a dearth of skilled professionals in the field of vaccination and disparities in the capacity for immunization services. This review introduced the experiences of four prime international vaccinology education models, including London School of Hygiene & Tropical Medicine, Johns Hopkins University, Leading International Vaccinology Education, and the Bill & Melinda Gates Foundation, in the aspect of personnel development, academic research and communication platforms establishment. It is supposed to give some insights and feasible suggestions on the establishment and advancement of vaccinology as a sub-discipline within high-level public health school in China, with the aim of development of a robust vaccinology education framework in China, which is essential for nurturing the next generation of public health leaders and practitioners for our country.

[Epidemiological characteristics and clinical features of pertussis in Shandong Province from 2007 to 2022].

Objective: To analyze the epidemiological characteristics and clinical features of pertussis cases reported in Shandong Province of China. Methods: Data on pertussis cases in Shandong Province from 2007 to 2022 were collected from China Information System for Disease Control and Prevention. At the same time, some case information was collected from the database of notifiable pertussis in Shandong Province from 2007 to 2022. The distribution characteristics and clinical features of pertussis were analyzed. A spatial distribution map of pertussis cases in Shandong Province was drawn. Results: A total of 26 122 pertussis cases were reported in Shandong Province during 2007-2022, with an annual incidence rate ranging from 0.11 to 5.77 cases per 100 000 people. Cases occurred throughout the whole year, with a seasonal peak occurring in spring and summer, especially in July and August. In recent years, reported cases were mainly distributed in the central and western regions of Shandong Province, with fewer cases in the eastern region. The hot spots of the disease shifted from Heze and Dezhou City in 2007-2013 to Jinan and Tai'an city in 2014-2022. The age range of onset was from 1 day to 93 years old. The proportion of cases with age≤1 year was the largest (41.81%, 10 922/26 122), and the proportion of cases aged 0-6 months decreased from 32.21% (67/208)-55.67% (157/282) within the period of 2007 to 2013 to 16.78% (883/5 263)-41.97% (444/1 058) within the period of 2014 to 2022, with a statistically significant trend (χ² trend=670.01, P<0.001). There were 13 682 male cases and 12 440 female cases, with a male-female ratio of 1.10∶1. The male-female ratio was 1.45∶1 (806∶556) from 2007 to 2013 and 1.08∶1 (12 876∶11 884) from 2014 to 2022. The proportion of women increased from 42.31% (88/208) in 2007 to 47.84% (2 518/5 263) in 2022, and with a significant trend (χ² trend=22.25, P<0.001). In pertussis cases, the proportions of scattered children, kindergarten children and students were 71.38% (18 645/26 122), 15.13% (3 951/26 122), and 11.60% (3 031/26 122), respectively. The top five clinical symptoms of pertussis cases were paroxysmal spasmodic cough (86.33%, 21 411 cases), flushing (39.61%, 9 824 cases), restless sleep (34.51%, 8 558 cases), fever (30.80%, 7 638 cases), and crowing (27.53%, 6 829 cases). Among 24 802 cases, there were 15 542 cases (62.66%) with a history of immunization against pertussis vaccine. Conclusion: From 2007 to 2022, the incidence rate of pertussis cases in Shandong Province shows an upward trend, with the majority being young children, and the clinical symptoms are relatively typical.

[Influencing factors of hypertension and diabetes care cascade: a qualitative study].

Objective: Employing the cascade care model, this qualitative study explores determinants influencing the cascading care stages of hypertension and diabetes by interviewing various stakeholders. Methods: In July 2023, purposive sampling was employed to recruit participants from Gongyi and Wugang cities in Henan Province, and Linqu County in Weifang City, Shandong Province. Semi-structured in-depth interviews were conducted with representatives of policymakers, healthcare institution managers, providers, and patients with hypertension and diabetes.And thematic analysis was performed using both inductive and deductive approaches. Results: A total of 82 individuals were interviewed, with an age range of (53.8±12.0) years, among which 48 (58.5%) were male; including 5 policymakers, 10 institutional managers, 20 healthcare providers, and 47 patients with hypertension and diabetes. The study identified both barriers and facilitating factors at the patient, healthcare provider, and system levels across various stages: awareness, screening, diagnosis, treatment, long-term management, and control of hypertension and diabetes. Conclusion: By delineating and analyzing the barriers and facilitators at each stage of hypertension and diabetes care, this study lays the groundwork for the development of effective, feasible, and sustainable implementation pathways, with significant implications for the enhanced management of hypertension and diabetes in China.

[Early experience with mechanical hemodynamic support for catheter ablation of malignant ventricular tachycardia].

Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

[Total knee replacement in different age groups]. / Sravnenie lechebnogo effekta total'nogo endoprotezirovaniya kolennogo sustava v raznykh vozrastnykh gruppakh.

OBJECTIVE: To evaluate the efficacy and quality of life in long-term period (1 year) after total knee replacement in various age groups. MATERIAL AND METHODS: We studied 134 patients after unilateral primary total knee replacement. The KOOS and SF-36 questionnaires were used to assess the therapeutic effect (functionality and symptoms) and quality of life in patients with knee osteoarthritis. RESULTS: At baseline, group I (young patients) had low KOOS pain scores (39.42±16.42), function scores (50.18±19.16) and QoL scores (18.2±15.9) compared to other age groups. A year after surgery, group I (<55 years) had significantly lower KOOS scores of pain, function and quality of life compared to group III (>65 years). Multiple regression analysis showed that age was a significant predictor of pain, but not a function after a year. CONCLUSION: Total knee replacement gives a noticeable improvement in pain, functionality and quality of life in all age groups. However, there are significant age-related differences in preoperative assessment of pain, quality of life and mental health, as well as in final indicators of postoperative pain and quality of life. Indeed, young patients (<50 years) report more intense pain and worse quality of life. These data may be used in clinical practice to improve decision-making and patient expectations before total knee replacement.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A.

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

[The value of vaccines from the perspective of population medicine].

Vaccination is one of the most effective, broad-reach, and cost-effective public health initiatives to fight against infectious diseases. From the perspective of population medicine, this article systematically elaborates on the value of vaccines in preventing infections, reducing disease incidence, decreasing disability and severe cases, lowering mortality rates, improving population health and life expectancy, reducing antibiotic use and resistance, as well as promoting fairness in public health services. Based on the current situation, the following recommendations are proposed: first, strengthen scientific research to provide a solid foundation for related policy-making; second, increase the coverage rate of non-national immunization program vaccines; third, promote the inclusion of more appropriate vaccines in the national immunization program; fourth, strengthen the research and development of new vaccines; and fifth, increase talent training in the field of vaccinology.

[Efficacy and safety of epidermal growth factor receptor tyrosine kinase inhibitors combined with chemotherapy as first-line treatment for epidermal growth factor receptor-mutant advanced non-small cell lung cancer].

Objective: To observe the clinical efficacy and safety of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) combined with chemotherapy as first-line treatment for EGFR mutant advanced non-small cell lung cancer (NSCLC). Methods: It was a retrospective, single-arm real-world study and a total of 39 patients with stage ⅢB to Ⅳ EGFR mutant NSCLC diagnosed in Cancer Hospital of Chinese Academy of Medical Sciences from July 2018 to December 2020 were collected. There were 16 males and 23 females, the age ranged from 25 to 73 years, with a median age of 53 years. All patients received EGFR-TKIs synchronously combined with pemetrexed and platinum-containing chemotherapy for 4-6 cycles as first-line treatment, followed by EGFR-TKI monotherapy with or without pemetrexed maintenance therapy. The objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and adverse reactions were evaluated. Median follow-up time was 18.6 months (95%CI: 16.2-21.0 months). The Kaplan-Meier method was used for survival analysis. Results: The ORR was 61.5% (24/39), the DCR was 94.9% (37/39) and the median PFS was 16.4 months (95%CI: 12.1-20.7 months). The main adverse reactions were liver function injury (59.0%, 23/39), myelosuppression (43.6%, 17/39), skin reaction (25.6%, 10/39), gastrointestinal reaction (17.9%, 7/39), fatigue (12.8%, 5/39) and kidney injury (5.1%, 2/39). Most of the patients had grade 1-2 adverse reactions, and the rate of grade 3 adverse events were 12.8%(5/39), which were effectively alleviated after symptomatic support treatment, no grade 4 serious adverse events occurred. Conclusion: EGFR-TKIs synchronously combined with chemotherapy followed by EGFR-TKI monotherapy with or without pemetrexed maintenance therapy has a certain therapeutic effect and fairly good safety, which can prolong PFS in patients with EGFR mutated advanced NSCLC.

[Prevalence and related factors of visual disability, hearing disability and comorbidity of visual and hearing disability among the elderly in China].

Objective: To estimate the prevalence of visual disability, hearing disability and comorbidity of visual and hearing disability among the elderly in China, and explore the related factors of comorbidity of visual and hearing disability in the elderly. Methods: This was a cross-sectional study. Based on the Second China National Sample Survey on Disability in 2006, the data of the elderly with visual and hearing disability were extracted and combined for descriptive analysis. Meanwhile, multivariate logistic regression model was used to analyze the related factors of comorbidity of visual and hearing disability among the elderly. Results: A total of 250 752 cases were in the final analysis (119 120 males and 131 632 females), and there were 164 003, 74 156 and 12 593 cases with the age of 65-<75, 75-<85 and ≥ 85 years, respectively. The prevalence of visual disability and hearing disability of the elderly in China was 8.10% (95%CI: 8.00%-8.21%), 13.41% (95%CI: 13.29%-13.54%), respectively, while the prevalence of comorbidity of visual and hearing disability was 1.97% (95%CI: 1.92%-2.02%). The severity of disability of the elderly with comorbidity of visual and hearing disability was higher, and the percentage of mild disabilities (18.31%, 966/5 277) was lower than those with visual (53.06%, 11 208/21 123) or hearing disabilities (32.96%, 11 536/34 995). Moreover, 19.40% (1 024/5 277) of visual or hearing disability occurred in the same year. Multivariate logistic regression analysis showed that education level below primary school (OR=0.65, 95%CI: 0.61-0.70, P<0.001), having a spouse (OR=0.68, 95%CI: 0.64-0.72, P<0.001), living in an urban area (OR=0.77, 95%CI: 0.71-0.82, P<0.001) and having a per capita household income higher than the national average (OR=0.73, 95%CI: 0.68-0.78, P<0.001) were protective factors for comorbidity of visual and hearing disability among the elderly. Conclusions: Visual disability is correlated with hearing disability in the elderly. Attention should be paid to the prevention and control of associated disabilities such as visual and hearing co-disabilities in the elderly population, with emphasis on strengthening publicity and education on prevention and control of visual and hearing disabilities for the elderly who are economically disadvantaged, have no spouse and live in remote areas.

[A long-term follow-up study on recurrence and benefit of standardized postoperative chemotherapy of rectal cancer patients with complete pathological response after neoadjuvant chemoradiotherapy].

Objective: To analyze the clinicopathological factors affecting long-term disease-free survival and the characteristics of local recurrence or distance metastasis of rectal cancer patients with complete pathological response after neoadjuvant chemoradiotherapy. Methods: The clinicopathological data and follow-up information of patients with a complete pathological response of rectal cancer after neoadjuvant chemoradiotherapy in the Cancer Hospital of Chinese Academy of Medical Sciences from June 2004 to December 2019 were retrospectively collected. The clinicopathological factors affecting the long-term disease-free survival of patients were analyzed to build a prediction model of local recurrence and distant metastasis and to evaluate the benefits of postoperative chemotherapy. Results: The age of 108 patients was(56.3±11.6) years, of which 68 were males (63.0%); The median follow-up time was 79.9 (61.8, 112.6) months. There were 12 patients (11.1%) who had a local recurrence or distant metastasis. The 5-year disease-free survival rate was 91.1% with 9 patients who experienced recurrence. Multivariate Cox proportional hazards regression analysis showed that the maximum diameter of the residual tumor or scar (HR=8.41, 95%CI: 1.08-65.22, P=0.042) and the distance from the lower edge of the tumor to the anal margin before treatment (HR=4.54, 95%CI: 1.23-16.81, P=0.023) were independent risk factors affecting the prognosis. The prognosis of patients was stratified based on relevant factors. The 5-year cumulative disease-free survival rate of those patients receiving postoperative standardized chemotherapy was 92.0%, while for patients who did not receive or complete standardized chemotherapy, the 5-year cumulative disease-free survival rate was 82.3%. Conclusions: The maximum diameter of the residual tumor or scar and the distance from the lower edge of the tumor to the anal margin before treatment were independent risk factors affecting the prognosis of patients with a complete pathological response. Patients with independent risk factors could benefit from the standardized postoperative chemotherapy.

[Study on the recurrence pattern of rectal cancer patients undergoing radical surgery after neoadjuvant chemoradiotherapy].

Objective: To analyze the recurrence pattern of rectal cancer patients with radical surgery after neoadjuvant chemoradiotherapy. Methods: The clinicopathological characteristics and follow-up information of rectal cancer patients with radical surgery after neoadjuvant chemoradiotherapy in the Cancer Hospital of the Chinese Academy of Medical Sciences from June 2004 to December 2017 were retrospectively collected. The recurrence pattern including the time and site was investigated. Results: The age of 537 patients was (55.5±11.7) years, of whom 361 were male (67.2%). The median follow-up time [M(Q1,Q3)] was 77.9 (64.5, 95.6) months. Moreover, 30.7% (165/537) of patients had distant metastasis or local recurrence; 26.8% (144/537) of patients had distant metastasis; 5.6% (30/537) of patients had local recurrence; 1.7% (9/537) of patients had both distant metastasis and local recurrence. In all the recurrent patients, 23.6% (39/165) were in the first year after surgery, followed by 27.3% (45/165) in the second year, 17.0% (28/165) in the third year, and 15.8% (26/165) after five years. According to the risk curve drawn by the life table, the highest metastasis risk of patients occurred in the second year after surgery, and the metastasis risk peak occurred again after more than five years. The lung was the most common metastatic organ, accounting for 47.9% (69/144), followed by the liver (18.8%, 27/144). The ratios of the recurrent patients in each ypTNM stage were 9.5% (8/84), 12.0% (12/100), 26.5% (41/155), 52.5% (104/198), respectively. The proportion of recurrent patients in tumor regression grade (TRG) 1-2 and TRG 3-5 patients were 19.2% (38/198) and 37.5% (127/339), respectively. Conclusions: The recurrence pattern of patients undergoing radical surgery after neoadjuvant chemoradiotherapy is mainly distant metastasis. The lung is the primary metastatic organ. The risk of distant metastasis and local recurrence is high in the first three years after surgery, and there is still high risk of recurrence after five years. For patients with ypTNM stage 2, 3 and TRG3-5, the postoperative adjuvant chemotherapy and long-term follow-up should be strengthened.