GSN gene frameshift mutations in Alzheimer's disease

BACKGROUND

The pathogenic missense mutations of the gelsolin (GSN) gene lead to familial amyloidosis of the Finnish type (FAF); however, our previous study identified GSN frameshift mutations existed in patients with Alzheimer's disease (AD). The GSN genotype-phenotype heterogeneity and the role of GSN frameshift mutations in patients with AD are unclear.

METHOD

In total, 1192 patients with AD and 1403 controls were screened through whole genome sequencing, and 884 patients with AD were enrolled for validation. Effects of GSN mutations were evaluated in vitro. GSN, Aβ42, Aβ40 and Aβ42/40 were detected in both plasma and cerebrospinal fluid (CSF).

RESULTS

Six patients with AD with GSN P3fs and K346fs mutations (0.50%, 6/1192) were identified, who were diagnosed with AD but not FAF. In addition, 13 patients with AD with GSN frameshift mutations were found in the validation cohort (1.47%, 13/884). Further in vitro experiments showed that both K346fs and P3fs mutations led to the GSN loss of function in inhibiting Aβ-induced toxicity. Moreover, a higher level of plasma (p=0.001) and CSF (p=0.005) GSN was observed in AD cases than controls, and a positive correlation was found between the CSF GSN and CSF Aβ42 (r=0.289, p=0.009). Besides, the GSN level was initially increasing and then decreasing with the disease course and cognitive decline.

CONCLUSIONS

GSN frameshift mutations may be associated with AD. An increase in plasma GSN is probably a compensatory reaction in AD, which is a potential biomarker for early AD.

Association of Dental Caries with Muscle Mass, Muscle Strength, and Sarcopenia: A Community-Based Study

OBJECTIVES

Changes in the oral cavity can reflect other changes throughout the body. This study aimed to investigate the association of dental caries with muscle mass, muscle strength, and sarcopenia, and also to describe the microbial diversity, composition, and community structure of severe dental caries and sarcopenia.

DESIGN

Cross-sectional study based on a Chinese population aged from 50 to 85 years.

SETTING

Communities from Lanxi City, Zhejiang Province, China.

PARTICIPANTS

A total of 1,442 participants aged from 50 to 85 years from a general community (62.8% women; median age 61.0 [interquartile range: 55.0, 68.0]).

MEASUREMENTS

Dental caries was assessed by the decayed, missing, and filled teeth (DMFT) index. Sarcopenia was defined as the presence of both low muscle mass (assessed by dual-energy X-ray absorptiometry scanning) and low muscle strength (assessed by handgrip strength). Multivariate logistic regression models were used to analyze the association of dental caries with muscle mass, muscle strength, and sarcopenia. Fecal samples underwent 16S rRNA profiling to evaluate the diversity and composition of the gut microbiota in patients with severe dental caries and/or sarcopenia.

RESULTS

In the fully adjusted logistic models, dental caries was positively associated with low muscle strength (DMFT ≥ 7: OR, 1.61; 95% CI, 1.25-2.06), and sarcopenia (DMFT ≥ 7: OR, 1.51; 95% CI, 1.01-2.26), but not low muscle mass. Severe dental caries was positively associated with higher alpha-diversity indices (richness, chao1, and ACE, all p < 0.05) and associated with beta-diversity based on Bray-Curtis distance (p = 0.006). The severe dental caries group and the sarcopenia group overlapped with 11 depleted and 13 enriched genera.

CONCLUSION

Dental caries was positively associated with low muscle strength and sarcopenia but not muscle mass, and this association was more pronounced in male individuals. Significant differences were observed in gut microbiota composition both in severe dental caries and sarcopenia, and there was an overlap of the genera features. Future longitudinal studies are needed to clarify causal relationships.

Response of sugar metabolism in the cotyledons and roots of Ricinus communis subjected to salt stress

Ricinus communis is an important oilseed crop worldwide and is also considered one of the best potential plants for salt-affected soil improvement in northeast China. However, little is known about photosynthesis and carbohydrate metabolism in this plant, nor the distribution of carbohydrates in cotyledons and roots under salinity stress. In the present study, seedling growth, gas exchange parameters (P_N , E, g_s and C_i ), carbohydrate (fructose, sucrose, glucose, soluble sugar and starch) metabolism and related enzymes and genes were measured in Ricinus plants. Under salt stress, P_N of cotyledons decreased significantly (P < 0.05), resulting in weak photosynthetic capacity. Furthermore, salt stress increased sucrose and glucose content in cotyledons, but decreased soluble sugar and starch content. However, sucrose increased and starch decreased in roots. This may be correlated with the increasing sugar metabolism under salinity, including notable changes in sugar-related enzyme activities (SPS, SuSy, α-amylase and β-amylase) and gene expression of RcINV, RcSUS, RcAmY, RcBAM and RcGBE1. The results suggest that salinity reduces photosynthesis of cotyledons, alters carbohydrate allocation between cotyledons and roots and also promotes starch utilization in cotyledons and starch biosynthesis in roots, leading to a functional imbalance between cotyledons and roots. Together, these findings provide insights into the crucial role of sugar metabolism in improving salt-tolerance of Ricinus during the early seedling growth stage.

Assessing single-locus CRISPR/Cas9-based gene drive variants in the mosquito Aedes aegypti via single-generation crosses and modeling

The yellow fever mosquito Aedes aegypti is a major vector of arthropod-borne viruses, including dengue, chikungunya, and Zika viruses. A novel approach to mitigate arboviral infections is to generate mosquitoes refractory to infection by overexpressing antiviral effector molecules. Such an approach requires a mechanism to spread these antiviral effectors through a population, for example, by using CRISPR/Cas9-based gene drive systems. Critical to the design of a single-locus autonomous gene drive is that the selected genomic locus is amenable to both gene drive and appropriate expression of the antiviral effector. In our study, we used reverse engineering to target 2 intergenic genomic loci, which had previously shown to be highly permissive for antiviral effector gene expression, and we further investigated the use of 3 promoters (nanos, β2-tubulin, or zpg) for Cas9 expression. We then quantified the accrual of insertions or deletions (indels) after single-generation crossings, measured maternal effects, and assessed fitness costs associated with various transgenic lines to model the rate of gene drive fixation. Overall, MGDrivE modeling suggested that when an autonomous gene drive is placed into an intergenic locus, the gene drive system will eventually be blocked by the accrual of gene drive blocking resistance alleles and ultimately be lost in the population. Moreover, while genomic locus and promoter selection were critically important for the initial establishment of the autonomous gene drive, it was the fitness of the gene drive line that most strongly influenced the persistence of the gene drive in the simulated population. As such, we propose that when autonomous CRISPR/Cas9-based gene drive systems are anchored in an intergenic locus, they temporarily result in a strong population replacement effect, but as gene drive-blocking indels accrue, the gene drive becomes exhausted due to the fixation of CRISPR resistance alleles.

[Efficacy analysis of lidocaine plaster combined with gabapentin in the treatment of herpes zoster neuralgia]

Objective: To evaluate the efficacy and safety of lidocaine plaster combined with gabapentin in the treatment of herpes zoster neuralgia (HZN). Methods: A total of 93 patients diagnosed with HZN from June 4, 2021 to January 5, 2022 in the Department of Pain Clinic of Nanjing Drum Tower Hospital were selected, and their gender was not limited. They were divided into 3 groups by random number table method: group A (n=32) prescribed gabapentin alone, group B (n=30) lidocaine plaster alone, and group C (n=31) lidocaine plaster combined with gabapentin. After excluding patients who did not meet the criteria, there were 28 cases in group A, 28 cases in group B, and 29 cases in group C. The visual analogue scale (VAS), the short-form McGill pain questionnaire (SF-MPQ) score, and drug dosage and adverse reaction in each group at pre-treatment (T0), post-treatment in one week (T1), in two weeks (T2), in four weeks (T4), and in 12 weeks (T12) were recorded and evaluated; Pittsburgh Sleep Quality Index (PSQI) score and Medical Outcomes Study short-form 36 (SF-36) score at T0, T4, and T12 were recorded. Adverse reactions and drug dosage in each group were documented. Repeated measures ANOVA was used to compare the curative effects of the three groups at different time points before and after treatment. Results: The ages of the three groups of patients were (67.8±10.0), (60.9±11.4) and (63.5±12.5) years old respectively (P=0.318), and the proportions of men were 46.4 % (13 cases), 35.7% (10 cases) and 44.8 % (13 cases), respectively (P=0.472). After treatment, the VAS scores and SF-MPQ scores of patients in the three groups were decreased at each time point compared with those before treatment (all P<0.05), the VAS and SF-MPQ scores of patients in group C at T12 time point were 1.2±0.4 and 5.2±2.4 respectively, which were lower than those of patients in groups A and B (both P<0.05). The dosages of gabapentin and lidocaine plaster in group C were lower than those in groups A and B at each time point after treatment (all P<0.05). The PSQI scores of patients in the three groups at T4 and T12 were lower than those before treatment (all P<0.05). The PSQI scores of patients in group C at T4 and T12 were 5.7±1.2 and 4.5±1.2, which were lower than those of patients in groups A and B. (all P<0.05), The SF-36 scores of patients in three groups at T4 and T12 were higher than those before treatment (all P<0.05), and the SF-36 scores of group C at T4 and T12 were 91.7±8.5, 93.1±6.3, which were higher than that of patients in groups A and B (both P<0.05). The incidence of adverse reactions in the three groups were 35.7% (9 cases), 10.7% (3 cases), and 13.8% (4 cases) respectively (P<0.05), the adverse reactions in groups B and C were less than those in group A (P<0.05), and there was no statistical difference between groups B and C (P>0.05). Conclusion: Lidocaine plaster combined with gabapentin has better analgesic effect in the treatment of HZN, with less incidence of adverse reactions, and can reduce the dosage of systemic drugs, improve patients' sleep and quality of life, and thus could provide a safe and effective method for the treatment of HZN.

Hysteresis analysis reveals dissolved carbon concentration - discharge relationships during and between storm events

The dissolved carbon concentration, which is responsible for aquatic ecosystem productivity and water quality, is tightly coupled with hydrological processes. Excess dissolved carbon may exacerbate eutrophication and hypoxia in aquatic ecosystems and lead to deterioration of water quality. Storm events dominate the dynamics of dissolved carbon concentrations, and this nonlinear behavior exhibits significant time scale dependence. Here, we identified inter- and intra-event variability in the dissolved carbon concentration-discharge (C-Q) relationship in an agriculture-intensive catchment. The driving factors of C-Q hysteresis patterns for dissolved inorganic carbon (DIC) and organic carbon (DOC) were quantified by redundancy analysis combined with hierarchical partitioning. At the inter-event scale, DIC exhibited mainly clockwise hysteresis, indicating an exhaustible, proximal source (e.g., groundwater). However, DOC hysteresis was generally counter-clockwise, indicating distal and plentiful sources (e.g., soil water) in the agricultural catchment. Hierarchical partitioning showed that total rainfall, peak discharge and flood intensity explained 28.38% of the total variation in C-Q hysteresis for DIC and 39.87% for DOC at the inter-event scale. At the intra-event scale, time series analysis of dissolved carbon concentration and discharge indicated the interconversion of supply limitation to transport limitation, which depends on the activation of the specific DIC or DOC source zones. These findings provide significant insights into understanding the dynamics of dissolved carbon during storm periods and are important for targeted watershed management practices aimed at reducing carbon loading to surface waters.

Determinants of diarrhoeal infections among users of shared sanitation in informal settlements in Durban, South Africa

Diarrhoeal disease continues to be a major health problem in many parts of the world, especially in developing countries, mainly due to the lack of access to sanitation, water, and hygienic living conditions. Identifying the determinants of diarrhoeal infections continues to be a challenge in developing countries. In this study, we ascertained the factors behind diarrhoea among inhabitants of informal settlements in the city of Durban, South Africa. Prevalence of diarrhoea in the study area varied between 7-year historical clinical records and data collected during the current study (primary data), with the primary data giving the highest monthly prevalence odds ratio (POR) up to 18.1 (±1.6)%. The main factors associated with diarrhoeal infections were open defaecation (POR = 1.8; 95% confidence interval (CI): 0.9-3.12), use of shared sanitation (POR = 1.7; 95%; CI: 1.05-2.26), and exposure to faecal matter around the homes (POR = 1.69; 95% CI: 1.25-3.10). Several other factors were also determined to be associated with diarrhoeal infections, such as hygiene practices in the communities, the non-treatment of water before use, and the presence of solid waste and faecal materials around the households. This study shows that diarrhoeal disease infections in informal settlements could be multifactorial; therefore, a multifactorial approach is needed to reduce these infections. These could include improving education on hygiene practices within the home setting as well as in public places, such as the community ablution blocks.

Automatic Segmentation and Measurement of Choroid Layer in High Myopia for OCT Imaging Using Deep Learning

Automatic segmentation and measurement of the choroid layer is useful in studying of related fundus diseases, such as diabetic retinopathy and high myopia. However, most algorithms are not helpful for choroid layer segmentation due to its blurred boundaries and complex gradients. Therefore, this paper aimed to propose a novel choroid segmentation method that combines image enhancement and attention-based dense (AD) U-Net network. The choroidal images obtained from optical coherence tomography (OCT) are pre-enhanced by algorithms that include flattening, filtering, and exponential and linear enhancement to reduce choroid-independent information. Experimental results obtained from 800 OCT B-scans of the choroid layers from both normal eyes and high myopia showed that image enhancement significantly increased the performance of ADU-Net, with an AUC of 99.51% and a DSC of 97.91%. The accuracy of segmentation using the ADU-Net method with image enhancement is superior to that of the existing networks. In addition, we describe some algorithms that can measure automatically choroidal foveal thickness and the volume of adjacent areas. Statistical analyses of the choroidal parameters variation indicated that compared with normal eyes, high myopia has a reduction of 86.3% of the choroidal foveal thickness and 90% of the adjacent volume. It proved that high myopia is likely to cause choroid layer attenuation. These algorithms would have wide application in the diagnosis and precaution of related fundus lesions caused by choroid thinning from high myopia in future studies.

Long-term exposure to air pollution increases hip fracture incidence rate and related mortality: analysis of National Hip Fracture Database

To explore the association of air pollution and hip fracture and related mortality in the UK. The average levels of PM2.5, PM10, and NO2 exhibited a positive association with hip fracture and short-term mortality while O₃ did not. Our study highlights the association of air pollution and hip fracture.

INTRODUCTION

Until now, the influence of air pollution on bone mineral density and associated fractures has drawn little attention, and the consequences are controversial. To investigate the association between air pollution and hip fracture incidence and related short-term mortality.

METHODS

We constructed a cohort of all the National Hip Fracture Database beneficiaries (513,540 patients) in the UK from 2013 to 2018. Per year averages of PM_2.5, PM₁₀, O₃, NO₂, and SO₂ were estimated according to the person's residence. The incidence rate ratio with 95% confidence interval and all-cause mortality within 30-day post-fracture (ACM30D) rate ratios were estimated using generalized additive models.

RESULTS

The average levels of PM_2.5, PM₁₀, and NO₂ exhibited a positive association with the incidence rate of hip fracture (IHF) and ACM30D. Whereas, this association was negative for O₃ levels. Each increase of 5 μg per cubic meter in PM_2.5, PM₁₀, and NO₂ leads to 9.5%, 9.2%, and 4.1% higher hip fracture rate, respectively, and also 9.3%, 8.3%, and 2.9% higher ACM30D, respectively. When we restricted the analysis to low-level exposure of air pollutants, similar results were obtained.

CONCLUSION

Our study found a moderate, positive association between IHF, ACM30D, and the levels of specific air pollutants in the entire National Hip Fracture Database population. A reduction in the levels of PM_2.5, PM₁₀, and NO₂ may decrease the hip fracture incidence rate and associated short-term mortality in older adults. Our study highlights the influence of air pollution on hip fracture.

Novel MSH6 mutation predicted metastasis in eyelid and periocular squamous cell carcinoma

BACKGROUND

Our previous research revealed the relative local aggressiveness of eyelid and periocular squamous cell carcinoma (EPSCC), but its distinct genetic characteristics involved remain unknown.

OBJECTIVES

We conducted this study based on next-generation sequencing to identify the genetic distinctiveness of EPSCC and damaging mutations for possible etiology and poor prognosis.

METHODS

We performed sequencing using a 556-gene panel (smartonco) in 48 EPSCCs. Cox hazards model was applied to explore mutated genes that increase risk of metastasis and death. Pathogenesis of the mutations was predicted by sequence alignment algorithms.

RESULTS

The most commonly mutated genes were KMT2C (N=17, 35%), LRP1B (N=14, 29%), KMT2D (N=12, 25%), PTCH1(N=10, 21%) and TP53(N=10, 21%). DNA mismatch repair (MMR) genes (42%) like MSH6(19%) and MLH3(12%) were among the most frequently mutated genes. Cell cycle regulators including TP53(21%) and CDKN2A (10%) were less frequently mutated than in other squamous cell carcinomas (SCCs). Ultra violet exposure, MMR deficiency and aging were the main etiology. Of note, KMT2C has a deleterious mutation hotspot. Patients burdened with MSH6 mutation has a higher risk of overall metastasis (P=0.045, HR=5.165) and nodal metastasis (P=0.022, HR=14.038). Moreover, a hotspot mutation MSH6^E52A brought an even higher risk of nodal metastasis (P=0.011, HR=18.745).

CONCLUSIONS

EPSCCs displayed a unique mutation profile from cutaneous SCCs and mucosal SCCs. We have identified novel damaging mutations in epigenetic regulators like KMT2C boosted early onset of EPSCCs in addition to UVR, aging or MMR deficiency. And malfunction of MMR genes worsened prognosis.

Rapid detection of viruses: Based on silver nanoparticles modified with bromine ions and acetonitrile

Nearly 200 million people have been diagnosed with COVID-19 since the outbreak in 2019, and this disease has claimed more than 5 million lives worldwide. Currently, researchers are focusing on vaccine development and the search for an effective strategy to control the infection source. This work designed a detection platform based on Surface-Enhanced Raman Spectroscopy (SERS) by introducing acetonitrile and calcium ions into the silver nanoparticle reinforced substrate system to realize the rapid detection of novel coronavirus. Acetonitrile may amplify the calcium-induced hot spots of silver nanoparticles and significantly enhanced the stability of silver nanoparticles. It also elicited highly sensitive SERS signals of the virus. This approach allowed us to capture the characteristic SERS signals of SARS-CoV-2, Human Adenovirus 3, and H1N1 influenza virus molecules at a concentration of 100 copies/test (PFU/test) with upstanding reproduction and signal-to-noise ratio. Machine learning recognition technology was employed to qualitatively distinguish the three virus molecules with 1000 groups of spectra of each virus. Acetonitrile is a potent internal marker in regulating the signal intensity of virus molecules in saliva and serum. Thus, we used the SERS peak intensity to quantify the virus content in saliva and serum. The results demonstrated a satisfactory linear relationship between peak intensity and protein concentration. Collectively, this rapid detection method has a broad application prospect in clinical diagnosis of viruses, management of emergent viral infectious diseases, and exploration of the interaction between viruses and host cells.

[Correlation of periodontitis and oculopathy]

With the development of researches on the relationship between periodontal health and general health, more and more evidences showed that periodontitis was closely related to oculopathy, while the mechanisms were not very clear at present. This article will focus on the influences of periodontitis on the occurrence and development of various oculopathy such as diabetic retinopathy and senile macular degeneration, and discuss the possible mechanisms of the influence by periodontitis. This will provide a theoretical basis for the new ideas on prevention and treatment of oculopathy.

POS0947 LONG-TERM GOLIMUMAB PERSISTENCE: 5-YEAR TREATMENT RETENTION DATA POOLED FROM FIVE PHASE III CLINICAL TRIALS IN PATIENTS WITH RHEUMATOID ARTHRITIS, PSORIATIC ARTHRITIS, AND ANKYLOSING SPONDYLITIS

Background

Tumor necrosis factor-alpha inhibitors (TNFi), such as golimumab (GLM), are widely prescribed for treatment of chronic immune-mediated rheumatic diseases, such as rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Long-term persistence of GLM response in these diseases has previously been described from individual randomized controlled trials.1-5 While treatment retention is considered an important factor for disease progression, health care utilization, and overall quality of life, and has previously been described, the probability of retention on GLM treatment in these trials has not been evaluated.

Objectives

To evaluate probability of GLM treatment retention over a 5-year period in adult patients with immune-mediated rheumatic diseases, by indication and line of therapy, using pooled data from five Phase III randomized controlled clinical trials.

Methods

Using data prospectively collected from five Phase III studies, this post-hoc analysis evaluated subcutaneous (SC) GLM (50 mg or 100 mg every 4 weeks) for up to 5 years in participants with RA (GO-BEFORE,1,6 GO-AFTER2,7 and GO-FORWARD3,8), PsA (GO-REVEAL4,9), and AS (GO-RAISE5,10). Four of the five studies (GO-BEFORE, GO-FORWARD, GO-REVEAL and GO-RAISE) were pooled to examine 1st-line GLM therapy, while the remaining study (GO-AFTER) was used to examine 2nd-line (i.e., ≥ 1 line) GLM therapy in participants who had previously received and discontinued at least one other TNFi (etanercept, adalimumab, or infliximab) for any reason. Log-rank tests were performed to estimate retention rates by indication and line of therapy. Similarly, Kaplan-Meier analysis was used to estimate the probability of GLM retention over time.

Results

Among the 2228 participants enrolled in the 5 trials, 1797 participants had received GLM as1st-line treatment (RA = 1050; PsA = 394; AS = 353) and 431 participants had received GLM as 2nd-line treatment. Compared to the pooled 1st-line GLM analysis cohort, more participants receiving 2nd-line GLM were female (78.7% vs 62.2%), were > 50 years (61.5% vs 41.2%), and had a longer disease duration (median of 9.2 years vs 3.7 years). In the pooled 1st-line studies, GLM treatment retention remained high over five years, with an overall probability of retention of 87.8% (95% confidence interval [CI], 86.2–89.2) at Year 1 (Week 52), 80.9% (79.0–82.6) at Year 2 (Week 104), 77.3% (75.3–79.2) at Year 3 (Week 156), 73.5% (71.4–75.5) at Year 4 (Week 208) and 69.8% (67.6–71.9) at Year 5 (Week 252). GLM retention rates were similar across the four 1st-line GLM studies with no notable differences observed by indication over time (Figure 1, panel A). Treatment retention was better in participants using GLM as a 1st-line therapy compared to 2nd-line therapy (Figure 1, panel B), with a probability of retention at 5 years (Week 252) with 2nd-line therapy of 41.6% (95% CI: 36.8-46.3).

Figure 1.

Conclusion

In this post-hoc analysis of prospectively collected clinical trial data, the probability of 1st-line GLM treatment retention at 5-years was consistently high across all rheumatic indications (RA, PsA and AS). Probability of long-term GLM treatment retention with 2nd-line therapy, while lower than 1st-line therapy, also remained favorable. Collectively, these data support the value of GLM as a 1st- or 2nd-line therapy in these chronic immune-mediated rheumatic diseases.

References

[1]Emery P, et al. Arthritis Rheum 2009;60:2272-83.

[2]Smolen JS, et al. Lancet 2009;374:210-21.

[3]Keystone EC, et al. J Rheumatol. 2015;43:298-306.

[4]Kavanaugh A, et al. Ann Rheum Dis. 2014;73:1689-94

[5]Inman RD, et al. Arthritis Rheum 2008;58:3402-12.

[6]Emery P, et al. Arthritis Care Res. 2016;68:744-52.

[7]Smolen JS, et al. Arthritis Res Ther. 2015;17:14.

[8]Keystone EC, et al. Ann Rheum Dis 2009;68:789-96.

[9]Kavanaugh A, et al. Arthritis Rheum 2009;60:976-86.

[10]Deodhar A, et al. Ann Rheum Dis. 2015;74:757-61.

Disclosure of Interests

Cindy Weinstein Shareholder of: Merck & Co., Inc., Kenilworth, NJ, USQA, Employee of: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, Marinella Govoni Shareholder of: Merck & Co., Inc., Kenilworth, NJ, USA, Employee of: MSD Italy, a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, Jianxin Lin Shareholder of: Merck & Co., Inc., Kenilworth, NJ, USA, Employee of: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, Alan Meehan Shareholder of: Merck & Co., Inc., Kenilworth, NJ, USA, Employee of: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, Zaina Qureshi Shareholder of: Merck & Co., Inc., Kenilworth, NJ, USA, Employee of: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA

AB0276 COMPARISON OF METABOLIC DYSFUNCTION-ASSOCIATED FATTY LIVER DISEASE WITH NON-ALCOHOLIC FATTY LIVER DISEASE IN IDENTIFYING CARDIOVASCULAR RISK IN CHINESE INDIVIDUALS WITH RHEUMATOID ARTHRITIS

Background

The nomenclature from non-alcoholic fatty liver disease (NAFLD) to metabolic dysfunction-associated fatty liver disease (MAFLD) is considered to identify more cardiovascular disease (CVD) risk in general population, and patients with rheumatoid arthritis (RA) carry an excess risk for CVD.

Objectives

To compare MAFLD with NAFLD in identifying CVD risk in RA patients.

Methods

Clinical data from a Chinese RA cohort were retrospectively analyzed. Hepatic steatosis was defined by abdominal ultrasound examination. CVD risk in RA patients was estimated by the Prediction for Atherosclerotic Cardiovascular Disease Risk in China.

Results

Among 513 included RA patients, 78.4% were female and the mean ± SD age was 51.8 ± 12.6 years. The prevalence of MAFLD and NAFLD was 21.4% and 20.5%, respectively. 10.9% RA patients concomitated with CVD events and 32.4% had a high 10-year CVD risk. Multivariate logistic regression analysis showed that both MAFLD and NAFLD were associated with an increase in CVD events (MAFLD: AOR = 2.303 [95% CI 1.197, 4.429]; NAFLD: AOR = 2.478 [95% CI 1.185, 4.779] and high 10-year CVD risk (MAFLD: AOR = 3.184 [95% CI 1.777, 5.705]; NAFLD: AOR = 2.870 [95% CI 1.597, 5.156]; all p < 0.05). The NRI and IDI was -0.011 (95% CI -0.025, 0.003) and -0.002 (95% CI -0.007, 0.002) for CVD events, and 0.012 (95% CI -0.014, 0.038) and 0.005 (95% CI -0.003, 0.013; all p > 0.05) for high 10-year CVD risk, which indicated no additional CVD events and high 10-years CVD risk were identified when replacing NAFLD with MAFLD in RA patients.

Conclusion

Both MAFLD and NAFLD are associated with an increased CVD risk which implies the importance of early detection and management of MAFLD or NAFLD in RA patients. However, new nomenclature of MAFLD identify no additional CVD risk in RA patients.

Financial support:

National Natural Science Foundation of China (No. 81971527, 82171780 and 82101892), Science and Technology Program of Guangzhou (No. 202102010188 and 201904010088), and Guangdong Basic and Applied Basic Research Foundation (No. 2019A1515011928 and 2020A1515110061).

Figure 1.

The prevalence of MAFLD and NAFLD in RA patients with different stratification.

The prevalence in different genders (A) and ages groups (B); The prevalence in different disease activity groups (C) and disease duration (D); remission (CDAI ≤ 2.8); active (CDAI > 2.8).

Disclosure of Interests

None declared

[Technical difficulties and countermeasures of digestive tract reconstruction in robotic radical gastrectomy for gastric cancer]

There still remain some problemsin digestive tract reconstruction after robotic radical gastrectomy for gastric cancer at present, such as great surgical difficulties and high technical requirements. Based on the surgical experience of the Gastric Surgery Department of Union Hospital, Fujian Medical University and the literatures at home and abroad, relevant issues are discussed in terms of robotic radical distal gastrectomy (Billroth I, Billroth II, and Roux-en-Y gastrojejunostomy), proximal gastrectomy (double-channel and double-muscle flap anastomosis), and total gastrectomy (Roux-en-Y anastomosis, functional end-to-end anastomosis, FEEA, π-anastomosis, Overlap anastomosis, and modified Overlap anastomosis with delayed amputation of jejunum, i.e. later-cut Overlap). This article mainly includes (1) The principles of digestive tract reconstruction after robotic radical gastrectomy for gastric cancer. (2) Digestive tract reconstruction after robotic radical distal gastrectomy: Aiming at the weakness of traditional triangular anastomosis, we introduce the improvement of the technical difficulty, namely "modified triangular anastomosis", and point out that because Billroth II anastomosis is a common anastomosis method in China at present, manual suture under robot is more convenient and safe, and can effectively avoid anastomotic stenosis. (3) Digestive tract reconstruction after robotic proximal gastrectomy: It mainly includes double channel anastomosis and double muscle flap anastomosis, but these reconstruction methods are relatively complicated, and robotic surgery has not been widely carried out at present. (4) Digestive tract reconstruction after robotic total gastrectomy: The most classic one is Roux-en-Y anastomosis, mainly using circular stapler for end-to-side esophagojejunal anastomosis and linear stapler for side-to-side esophagojejunal anastomosis, for which we discuss the solutions to the existing technical difficulties. With the continuous innovation of robotic surgical system and anastomosis instruments, and with the gradual improvement of anastomosis technology, it is believed that digestive tract reconstruction after robotic radical gastrectomy for gastric cancer will have a good application prospect in gastric cancer surgery.

OP0163 A MATRIX PREDICTION MODEL FOR THE SIX-MONTH MORTALITY RISK IN PATIENTS WITH ANTI-MELANOMA DIFFERENTIATION-ASSOCIATED PROTEIN-5 POSITIVE DERMATOMYOSITIS

Background

Recently, the autoantibody recognizing melanoma differentiation-associated gene 5 (anti-MDA5) is of the greatest concern as a specific autoantibody of dermatomyositis (DM), since it delineates a unique clinical phenotype of DM with a high risk of life-threatening lung complications. Considering routine clinical characteristics at baseline are still desired candidates for screening potential mortality predictors, in order to as early as possible stratify the mortality risk in anti-MDA5 positive DM patients before making therapeutic strategies.

Objectives

To investigate the baseline independent risk factors for predicting 6-month mortality of anti-MDA5-positive DM patients and develop a matrix prediction model formed by these risk factors.

Methods

This was a real-world prospective observational study. The hospitalized patients with DM were included if they fulfilled the criteria including: aged over 18 years old; diagnosed as having DM according to the criteria proposed by Bohan and Peter or the modified Sontheimer definitions; and positive anti-MDA5 which was determined by both line immunoassay testing and enzyme-linked immunosorbent testing. The primary outcome was all-cause 6-month mortality after enrolment. A matrix prediction model was built with the mortality risk probability.

Results

There were 82 DM patients enrolled (mean age of onset 50±11 years and 63% female), with 40 (49%) showing positive anti-MDA5. Gottron sign/papules (OR: 5.135, 95%CI: 1.489~17.708), arthritis (OR: 5.184, 95%CI: 1.455~18.467), interstitial lung disease (ILD, OR: 7.034, 95%CI: 1.157~42.785), and higher level of C4 (OR: 1.010, 95%CI: 1.002~1.017) were independent associators with positive anti-MDA5 in DM patients. Anti-MDA5-positive DM patients had significant higher 6-month all-cause mortality than those with anti-MDA5-negative (30% vs. 0%). Among anti-MDA5-positive DM patients, compared to the survivors, non-survivors had significantly advanced age of onset (59±6 years vs. 46±9 years), higher rates of fever (75% vs. 18%), positive carcinoma embryonic antigen (CEA, 75% vs. 14%), higher level of ferritin (median 2858 ug/L vs. 619 ug/L, all p<0.05). Multivariate COX regression showed ferritin≥1250 μg/L (HR: 10.4, 95%CI: 1.8~59.9), fever (HR: 11.2, 95%CI: 2.5~49.9), and positive CEA (HR: 5.2, 95%CI: 1.0~25.7) were independent risk factors of 6-month mortality.

According to the matrix prediction model, anti-MDA5-positive DM patients could be stratified into three subgroups based on various probabilities of predicted mortality: (i) High-risk: eight patients with two of the above three features (including fever, serum ferritin≥1250 μg/L, and positive CEA) had high predicted mortality probability with 64%~85% (three red grids in Figure 1A), and the actual mortality was 75% (n=6) with 60%, 100%, and 100% respectively in three red grids (Figure 1B). Five patients with all of three features had extremely high predicted mortality probability with 97% (95%CI: 70%~100%, the dark red grid of Figure 1A), and the actual mortality was 100% in Figure 1B; (ii) Moderate-risk: nine patients with one of the above three features had moderate predicted mortality probability with 11%~29% (three yellow grids in Figure 1A), and the actual mortality was 11% (n=1) with 0%, 0%, and 17% respectively in three yellow grids (Figure 1B); (iii) Low-risk: eighteen patients with none of the above three features had low predicted mortality probability with 2% (95%CI: 0.2%~20%, the green grid in Figure 1A), and the actual mortality was 0% in the green grid (Figure 1B).

Conclusion

Baseline characteristics of fever, positive CEA, and ferritin≥1250 μg/L are risk factors for 6-month all-cause mortality in anti-MDA5-positive DM patients. A novel matrix prediction model composed of these three clinical indicators is firstly proposed to provide a chance for exploration of individual treatment strategies in anti-MDA5-positive DM subgroups with various probabilities of mortality risk.

Disclosure of Interests

None declared

Doubly-robust estimator of the difference in restricted mean times lost with competing risks data

In the context of competing risks data, the subdistribution hazard ratio has limited clinical interpretability to measure treatment effects. An alternative is the difference in restricted mean times lost (RMTL), which gives the mean time lost to a specific cause of failure between treatment groups. In non-randomized studies, the average causal effect is conventionally used for decision-making about treatment and public health policies. We show how the difference in RMTL can be estimated by contrasting the integrated cumulative incidence functions from a Fine-Gray model. We also show how the difference in RMTL can be estimated by using inverse probability of treatment weighting and contrasts between weighted non-parametric estimators of the area below the cumulative incidence. We use pseudo-observation approaches to estimate both component models and we integrate them into a doubly-robust estimator. We demonstrate that this estimator is consistent when either component is correctly specified. We conduct simulation studies to assess its finite-sample performance and demonstrate its inherited consistency property from its component models. We also examine the performance of this estimator under varying degrees of covariate overlap and under a model misspecification of nonlinearity. We apply the proposed method to assess biomarker-treatment interaction in subpopulations of the POPLAR and OAK randomized controlled trials of second-line therapy for advanced non-small-cell lung cancer.

Photoinduced release of odorous volatile organic compounds from aqueous pollutants: The role of reactive oxygen species in increasing risk during cross-media transformation

Photoinduced volatile organic compounds (VOCs) release from fatty alcohols at the air-water interface, has attracted considerable attention. This paper comprehensively explores the release of odorous VOCs from aqueous micropollutants under photoirradiation, especially in terms of the important role of the reactive oxygen species (ROS) in increased risk by cross-media transformation. The formation and distribution of photoinduced VOCs produced by aqueous benzyl alcohol (BzOH), a common ingredient in personal care products, were monitored in situ by online gas chromatography equipped with mass spectrometry and flame ionization detector (GC-MS/FID). The photoreaction of BzOH followed first-order kinetics with a rate constant of 0.0158/min under air. After 180 min of ultraviolet irradiation, the accumulated output of the gas-phase products benzene and benzaldehyde (BA) reached 3.8 μmol and 2.6 μmol respectively, being approximately 10 times that under nitrogen. According to electron paramagnetic resonance measurements, singlet oxygen mainly promoted the oxidation of BzOH to BA, which was an important intermediate producing benzene via photocleavage. Odorous alicyclic hydrocarbons were also generated through photorearrangement under nitrogen. On the other hand, the Henry's law constants of the main products were much lower than those of BzOH, indicating that the photoproducts would volatilize from the aqueous phase into the gas phase. The odor threshold of gas-phase products decreased to varying degrees after photoirradiation. Especially for BA, one of the main products, its odor threshold decreased 130 times compared with BzOH. This study shows that the risk of cross-media pollution could significantly increase due to the transformation of aqueous pollutants into odorous VOCs under photoirradiation and provides new insight into its risk prevention.

[Identification of rare variants in exons of NLRC4 gene in patients with type 1 diabetes and their impact on gene function]

Objective: To identify rare variants in exon and exon-intron boundary of containing NLR family CARD domain protein 4 (NLRC4) in type 1 diabetes (T1DM) patients, and to explore their effects on gene function. Methods: A total of 508 T1DM patients and 527 healthy controls in the Department of Metabolic Endocrinology, Second Xiangya Hospital of Central South University from August 2017 to September 2020 were selected. The case group included 264 males and 244 females, and the age [M (Q₁, Q₃)] was [27 (11, 43)] years. The control group included 290 males and 237 females, and their age［M（Q₁，Q₃）］was [47 (36, 60)] years old. Identification of rare variants in exons of NLRC4 gene in T1DM patients and healthy controls was performed and verified by next-generation sequencing and sanger sequencing. The NLRC4 gene wild-type and mutant plasmids were constructed and transfected into 293T cells. Western blot (WB) was used to detect the expression of NLRC4 protein and cleavage products of pro-cysteinyl aspartate specific proteinase(procaspase-1). Cycloheximide (CHX) was added to 293T cells transfected with wild-type or mutant NLRC4 plasmid to detect the degradation of NLRC4 protein. The localization of NLRC4 protein was detected by immunofluorescence, and the concentration of IL-1β in the cell supernatant was detected by enzyme-linked immunosorbent assay (ELISA). Results: The sequencing results showed that 4 patients and 2 healthy controls had a heterozygous variant c.208C>T in exon 3 of the NLRC4 gene. Two patient had a heterozygous variant c.1564T>C in exon 4, and 1 patients had c.1219G>C in exon 4. These three variants might be pathogenic variants in T1DM. In 293T cells transfected with NLRC4 wild-type and c.208C>T、c.1564T>Cc.1219G>C mutant plasmids, the expression level, degradation rate, localization of NLRC4 protein and the content of cleavage products of procaspase-1 did not change significantly. However, the concentration of IL-1β secreted by 293T cells transfected with c.1219G>C and c.208C>T plasmid [M(Q₁, Q₃)] was 15.25 (12.98, 17.52) and 15.44 (13.81, 17.07) ng/L, respectively, which was lower than 18.70 (16.59, 20.81) ng/L of 293T cells transfected wild-type plasmid (P=0.020, 0.010). Conclusions: NLRC4 gene rare variants c.208C>T, c.1564T>C and c.1219G>C may not change the protein expression, degradation and localization, but c.208C>T and c.1219G>C may inhibit the secretion of IL-1β. This result suggests that NLRC4 rare variants may have an impact on gene function.

[Establishment of artificial neural network model for predicting lymph node metastasis in patients with stage Ⅱ-Ⅲ gastric cancer]

Objective: To establish a neural network model for predicting lymph node metastasis in patients with stage II-III gastric cancer. Methods: Case inclusion criteria: (1) gastric adenocarcinoma diagnosed by pathology as stage II-III (the 8th edition of AJCC staging); (2) no distant metastasis of liver, lung and abdominal cavity in preoperative chest film, abdominal ultrasound and upper abdominal CT; (3) undergoing R0 resection. Case exclusion criteria: (1) receiving preoperative neoadjuvant chemotherapy or radiotherapy; (2) incomplete clinical data; (3) gastric stump cancer.Clinicopathological data of 1231 patients with stage II-III gastric cancer who underwent radical surgery at the Fujian Medical University Union Hospital from January 2010 to August 2014 were retrospectively analyzed. A total of 1035 patients with lymph node metastasis were confirmed after operation, and 196 patients had no lymph node metastasis. According to the postoperative pathologic staging. 416 patients (33.8%) were stage Ⅱ and 815 patients (66.2%) were stage III. Patients were randomly divided into training group (861/1231, 69.9%) and validation group (370/1231, 30.1%) to establish an artificial neural network model (N+-ANN) for the prediction of lymph node metastasis. Firstly, the Logistic univariate analysis method was used to retrospectively analyze the case samples of the training group, screen the variables affecting lymph node metastasis, determine the variable items of the input point of the artificial neural network, and then the multi-layer perceptron (MLP) to train N+-ANN. The input layer of N+-ANN was composed of the variables screened by Logistic univariate analysis. Artificial intelligence analyzed the status of lymph node metastasis according to the input data and compared it with the real value. The accuracy of the model was evaluated by drawing the receiver operating characteristic (ROC) curve and obtaining the area under the curve (AUC). The ability of N+-ANN was evaluated by sensitivity, specificity, positive predictive values, negative predictive values, and AUC values. Results: There were no significant differences in baseline data between the training group and validation group (all P>0.05). Univariate analysis of the training group showed that preoperative platelet to lymphocyte ratio (PLR), preoperative systemic immune inflammation index (SII), tumor size, clinical N (cN) stage were closely related to postoperative lymph node metastasis. The N+-ANN was constructed based on the above variables as the input layer variables. In the training group, the accuracy of N+-ANN for predicting postoperative lymph node metastasis was 88.4% (761/861), the sensitivity was 98.9% (717/725), the specificity was 32.4% (44/136), the positive predictive value was 88.6% (717/809), the negative predictive value was 84.6% (44/52), and the AUC value was 0.748 (95%CI: 0.717-0.776). In the validation group, N+-ANN had a prediction accuracy of 88.4% (327/370) with a sensitivity of 99.7% (309/310), specificity of 30.0% (18/60), positive predictive value of 88.0% (309/351), negative predictive value of 94.7% (18/19), and an AUC of 0.717 (95%CI:0.668-0.763). According to the individualized lymph node metastasis probability output by N+-ANN, the cut-off values of 0-50%, >50%-75%, >75%-90% and >90%-100% were applied and patients were divided into N0 group, N1 group, N2 group and N3 group. The overall prediction accuracy of N+-ANN for pN staging in the training group and the validation group was 53.7% and 54.1% respectively, while the overall prediction accuracy of cN staging for pN staging in the training group and the validation group was 30.1% and 33.2% respectively, indicating that N+-ANN had a better prediction than cN stage. Conclusions: The N+-ANN constructed in this study can accurately predict postoperative lymph node metastasis in patients with stage Ⅱ-Ⅲ gastric cancer. The N+-ANN based on individualized lymph node metastasis probability has better accurate prediction for pN staging as compared to cN staging.

Solitary fibrous tumour of the sacrum: A report of 2 cases with review of the literature

INTRODUCTION

Solitary fibrous tumour (SFT) of the sacrum is a very rare disease. So far, there have been few reports on this disease. Here, we reported 2 such cases and reviewed the other 7 reports in the literature.

CASE SERIES

Case 1, a 48-year-old man presented with lumbosacral pain for 2 months and numbness in the left plantar region for more than 1 month. The report of CT scan indicated that the sacrum was destroyed and the soft tissue mass projected into the pelvis. Histopathology showed that the cells were fusiform or short fusiform, arranged in strips, sheets, and wavy patterns. Case 2, a 40-year-old woman presented with hip joint pain and lower extremity dyskinesia for more than 2 months. The result of the MRI examination demonstrated a mass on the right sacral foramen and anterior sacrum. The characteristics of histopathology are ovoid or spindle-shaped cells with focal nuclear pleomorphism and prominently branched, hemangiopericytoma-like vascular patterns. In addition, immunohistochemical showed that CD34, Bcl-2, CD99, STAT6 and vimentin were positive, while Desmin, MSA, EMA, S100 were negative in both cases.

CONCLUSION

Previous literatures have revealed that SFTs of the sacrum are rare neoplasms. Case 1 and a part of these lesions previously reported seem to be malignant and should be treated with surgery. Radiation or chemotherapy was adopted if necessary. Since SFT of the sacrum is prone to recur and metastasis, long-term follow-up should be considered. To a certain extent, new risk stratification models can predict prognosis more accurately.

Measurement of Lepton-Jet Correlation in Deep-Inelastic Scattering with the H1 Detector Using Machine Learning for Unfolding

The first measurement of lepton-jet momentum imbalance and azimuthal correlation in lepton-proton scattering at high momentum transfer is presented. These data, taken with the H1 detector at HERA, are corrected for detector effects using an unbinned machine learning algorithm (multifold), which considers eight observables simultaneously in this first application. The unfolded cross sections are compared with calculations performed within the context of collinear or transverse-momentum-dependent factorization in quantum chromodynamics as well as Monte Carlo event generators.

[Risk stratification and low-density lipoprotein cholesterol goal attainment rates in patients with very high-risk or extreme high-risk atherosclerotic cardiovascular diseases regarding three guidelines]

Objective: To explore the differences of risk stratification of very high-risk or extreme high-risk atherosclerotic cardiovascular diseases (ASCVD) and the attainment rates of low-density lipoprotein cholesterol (LDL-C) management targets evaluated by three different criteria, and the causal attributions of these differences. Methods: Patients with ASCVD were consecutively enrolled from January 1 to December 31 in 2019, and were evaluated for very high-risk or extreme high-risk and LDL-C goal attainment rates with 2018 American guideline on the management of blood cholesterol (2018AG), 2019 China Cholesterol Education Program (CCEP) Expert Advice for the management of dyslipidemias (2019EA) and 2020 Chinese expert consensus on lipid management of very high-risk ASCVD patients(2020EC), respectively. The causal attributions of the differences in attainment rates were analyzed as well. Results: A total of 1 864 ASCVD patients were included in this study. According to 2018AG, 2019EA and 2020EC, the proportions of the patients with very high-risk or extreme high-risk were 59.4%, 90.7%, and 65.6%, respectively. The absolute LDL-C target attainment rates were 37.2%, 15.7%, and 13.7%, respectively, the differences between each two rates were statistically significant (all P<0.001). As to the differences in attainment rates between 2020EC and 2018AG, 61.5% were due to the different LDL-C goal attainment values and 38.5% were caused by the different risk stratifications, while for the differences between 2020EC and 2019EA attainment rates, different LDL-C goal attainment values were responsible for 13.2%, and different risk stratifications were responsible for 86.8% of the differences. Conclusions: There are significant differences in the proportions and LDL-C attainment rates among the three different criteria for very high-risk or extreme high-risk ASCVD. 2020EC showed a moderate proportion of patients with extreme high-risk, and had the lowest LDL-C attainment rate. The differences between 2020EC and 2018AG are mainly due to the LDL-C target values, and the differences between 2020EC and 2019EA are mainly caused by the risk stratifications.

Myeloid ecotropic viral integration site-1 inhibition promotes apoptosis, suppresses proliferation of acute myeloid leukemia cells, accentuates the effects of anticancer drugs

To investigate the effects of myeloid ecotropic viral integration site-1 (MEIS1) on the proliferation and apoptosis of acute myeloid leukemia (AML) cells and the anticancer effects of the drug, we screened Kasumi-6, KG-1, and Kasumi-1 cells using quantitative reverse transcription polymerase chain reaction. Kasumi-6 and Kasumi-1 cells were subjected to human antigen R (HuR)-mediated interference (IV). Hexokinase 2 (HK2) expression and phosphorylation of protein kinase B (p-AKT) and mammalian target of rapamycin (p-mTOR) were observed with Western blotting. Cell proliferation was assessed using Cell Counting Kit-8, apoptosis was examined using Hoechst 33,258 staining, and glucose uptake was detected with a colorimetric biochemical assay kit. We found that, among the three cell lines tested, MEIS1 expression was highest in Kasumi-1 cells, which were therefore selected for subsequent experiments. Kasumi-1 cells receiving IV showed significantly decreased proliferation (p < 0.05) and increased apoptosis compared to the control group. Compared with the controls, IV significantly increased the expression of HK2, p-AKT, p-mTOR, multidrug resistance-associated protein 1 and P-glycoprotein (P < 0.05), but decreased glucose uptake. Treatment with adriamycin, daunorubicin and imatinib resulted in a progressive increase in inhibition of cell proliferation, with the IV group showing the highest inhibition rate among the three groups (P < 0.05). Thus, inhibition of MEIS1 activity promoted apoptosis, inhibited the proliferation of Kasumi-1 and Kasumi-6 cells, and increaseed the anticancer effect of the drugs, suggesting that inhibition of MEIS1 may be a potential strategy for the treatment of AML.

Abstract P3-19-26: The impact of post-mastectomy radiotherapy on the survival of breast cancer patients aged 70 years or older: A study based on SEER database

The impact of post-mastectomy radiotherapy on the survival of breast cancer patients aged 70 years or older: a study based on SEER databaseIntroduction: This study aimed to investigate the role of post-mastectomy radiotherapy (PMRT) in the female aged 70 years or older diagnosed with breast cancer, which is still controversial.Methods: This retrospective study extracted data from the Surveillance, Epidemiology, and End Results (SEER) database. Women aged 70 years or more diagnosed with breast cancer between 2004 and 2016 following mastectomy were enrolled. Propensity score matching (PSM) was performed to reduce covariable imbalance. The univariable and multivariable analyses calculated the prognostic factors. Kaplan-Meier survival curves and multivariable Cox regression model were applied to compare breast cancer-specific survival (BCSS) and overall survival (OS) between two arms and among subgroups stratified by various clinicopathological factors. Results: Of the 27,636 female were eligible, 17.2%(n=4,747) received PMRT while 82,8%(n=22,889) not. By multivariable Cox analysis, radiotherapy was still founded to be independent prognostic factors for BCSS and OS. After 1:1 matching, PMRT were associated with significant improvement in BCSS and OS(p &lt;0.001). By contrast, the BCSS and OS benefit from PMRT were not statistically significant in patients with T1 tumor and 1-3 positive lymph nodes(BCSS:HR = 0.716,95%CI 0.406-1.263,p = 0.249;OS:HR = 0.908,95%CI 0.648-1.270,p = 0.572), and the results were consistent in patients with T2 tumor and 1-3 positive lymph nodes(BCSS:HR = 0.866,95%CI 0.664-1.130,p = 0.289;OS:HR = 0.879,95%CI 0.732-1.055,p = 0.166). Stratified by grade, number of positive lymph nodes, and HR status, there were still not survival advantage of PMRT observed for patients with T1-2N1 breast cancer(all p&gt;0.05).Conclusions: This study demonstrates that post-mastectomy radiotherapy has a definite role in improving the survival of females with elderly breast cancer. After a comprehensive assessment of the side effects and the quality of life, the omission of PMRT could be considered in patients with T1-2N1 breast cancer.

Citation Format: Jingyi Lin, Shiping Luo, Jie Zhang, Chuangui Song. The impact of post-mastectomy radiotherapy on the survival of breast cancer patients aged 70 years or older: A study based on SEER database [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-26.