[Analysis of the incidence and symptomatology of low anterior resection syndrome after laparoscopic anterior resection for rectal cancer]

Objective: This study aims to explore the temporal trend of Low Anterior Resection Syndrome (LARS) and its symptoms after laparoscopic anterior resection for rectal cancer. Methods: A retrospective cohort study design was employed. The study included primary rectal (adenocarcinoma) cancer patients who underwent laparoscopic anterior resection at Tongji Hospital, Huazhong University of Science and Technology, between January 1, 2010, and December 31, 2020. Complete medical records and follow-up data at 3, 6, 9, 12, and 18 months postoperatively were available for all patients. A total of 1454 patients were included, of whom 1094 (75.2%) were aged ≤65 years, and 597 (41.1%) were females. Among them, 1040 cases (71.5%) had an anastomosis-to-anus distance of 0-5cm, and 86 cases (5.9%) received neoadjuvant treatment. All patients completed the Chinese version of the LARS questionnaire and their LARS occurrence and specific symptom information were recorded at 3, 6, 9, 12, and 18 months postoperatively. Considering past literature and clinical experience, further subgroup analyses were performed to explore the potential impact factors on severe LARS, including anastomosis level, preoperative neoadjuvant therapy, postoperative adjuvant therapy, and the presence of preventive stoma. Results: The occurrence rates of LARS at 3, 6, 9, 12, and 18 months postoperatively were 78.5% (1142/1454), 71.4% (1038/1454), 55.0% (799/1454), 45.7% (664/1454), and 45.7% (664/1454), respectively (χ2=546.180, P<0.001). No statistically significant difference was observed between the 12-month and 18-month time points (P>0.05). When compared with the symptoms at 3 months, the occurrence rates of gas incontinence [1.7% (24/1454) vs. 33.9% (493/1454)], liquid stool incontinence [3.9% (56/1454) vs. 41.9% (609/1454)], increased stool frequency [79.6% (1158/1454) vs. 95.9% (1395/1454)], stool clustering [74.3% (1081/1454) vs. 92.9% (1351/1454)], and stool urgency [46.5% (676/1454) vs. 78.7% (1144/1454)] in the LARS symptom spectrum were significantly alleviated at 12 months (all P<0.05) and remained stable beyond 12 months (all P>0.05). With the extension of postoperative time, the incidence rates of severe LARS exhibited a decreasing trend in different subgroups, of anastomosis level, preoperative neoadjuvant therapy, postoperative adjuvant therapy, and the presence of preventive stoma, and reached stability at 12 months postoperatively (all P>0.05). Conclusion: LARS and its specific symptom profile showed a trend of gradual improvement over time up to 1 year postoperatively, and stabilized after more than 1 year. Increased stool frequency and stool clustering are the most common features of abnormal bowel dys function, which improve slowly after surgery.

Machine learning model for prediction of low anterior resection syndrome following laparoscopic anterior resection of rectal cancer: A multicenter study

BACKGROUND

Low anterior resection syndrome (LARS) severely impairs patient postoperative quality of life, especially major LARS. However, there are few tools that can accurately predict major LARS in clinical practice.

AIM

To develop a machine learning model using preoperative and intraoperative factors for predicting major LARS following laparoscopic surgery of rectal cancer in Chinese populations.

METHODS

Clinical data and follow-up information of patients who received laparoscopic anterior resection for rectal cancer from two medical centers (one discovery cohort and one external validation cohort) were included in this retrospective study. For the discovery cohort, the machine learning prediction algorithms were developed and internally validated. In the external validation cohort, we evaluated the trained model using various performance metrics. Further, the clinical utility of the model was tested by decision curve analysis.

RESULTS

Overall, 1651 patients were included in the present study. Anastomotic height, neoadjuvant therapy, diverting stoma, body mass index, clinical stage, specimen length, tumor size, and age were the risk factors associated with major LARS. They were used to construct the machine learning model to predict major LARS. The trained random forest (RF) model performed with an area under the curve of 0.852 and a sensitivity of 0.795 (95%CI: 0.681-0.877), a specificity of 0.758 (95%CI: 0.671-0.828), and Brier score of 0.166 in the external validation set. Compared to the previous preoperative LARS score model, the current model exhibited superior predictive performance in predicting major LARS in our cohort (accuracy of 0.772 for the RF model vs 0.355 for the preoperative LARS score model).

CONCLUSION

We developed and validated a robust tool for predicting major LARS. This model could potentially be used in the clinic to identify patients with a high risk of developing major LARS and then improve the quality of life.

Comprehensive abdominal composition evaluation of rectal cancer patients with anastomotic leakage compared with body mass index-matched controls

BACKGROUND

Anastomotic leakage (AL) is a fatal complication in patients with rectal cancer after undergoing anterior resection. However, the role of abdominal composition in the development of AL has not been studied.

AIM

To investigate the relationship between abdominal composition and AL in rectal cancer patients after undergoing anterior resection.

METHODS

A retrospective case-matched cohort study was conducted. Complete data for 78 patients with AL were acquired and this cohort was defined as the AL group. The controls were matched for the same sex and body mass index (± 1 kg/m²). Parameters related to abdominal composition including visceral fat area (VFA), subcutaneous fat area (SFA), subcutaneous fat thickness (SFT), skeletal muscle area (SMA), skeletal muscle index (SMI), abdominal circumference (AC), anterior to posterior diameter of abdominal cavity (APD), and transverse diameter of abdominal cavity (TD) were evaluated based on computed tomography (CT) images using the following Hounsfield Unit (HU) thresholds: SFA: -190 to -30, SMA: -29 to 150, and VFA: -150 to -20. The significance of abdominal composition-related parameters was quantified using feature importance analysis; an artificial intelligence method was used to evaluate the contribution of each included variable.

RESULTS

Two thousand two hundred and thirty-eight rectal cancer patients who underwent anterior resection from 2010 to 2020 in a large academic hospital were investigated. Finally, 156 cases were enrolled in the study. Patients in the AL group showed longer operative time (225.03 ± 55.29 vs 207.17 ± 40.80, P = 0.023), lower levels of preoperative hemoglobin (123.32 ± 21.17 vs 132.60 ±1 6.31, P = 0.003) and albumin (38.34 ± 4.01 vs 40.52 ± 3.97, P = 0.001), larger tumor size (4.07 ± 1.36 vs 2.76 ± 1.28, P < 0.001), and later cancer stage (P < 0.001) compared to the controls. Patients who developed AL exhibited a larger VFA (125.68 ± 73.59 vs 97.03 ± 57.66, P = 0.008) and a smaller APD (77.30 ± 23.23 vs 92.09 ± 26.40, P < 0.001) and TD (22.90 ± 2.23 vs 24.21 ± 2.90, P = 0.002) compared to their matched controls. Feature importance analysis revealed that TD, APD, and VFA were the three most important abdominal composition-related features.

CONCLUSION

AL patients have a higher visceral fat content and a narrower abdominal structure compared to matched controls.

[Causal analysis and management strategies of 30-day unplanned revision surgery following single-stage posterior vertebral column resection for severe spinal deformity]

Objective: To investigate the causes of 30-day unplanned revision surgery following one-stage posterior vertebral column resection (PVCR) for severe spinal deformity and the methods of prevention and management. Methods: A total of 112 severe deformity patients underwent one-stage PVCR for surgical treatment in the 306(th) Hospital of People's Liberation Army from May 2010 to December 2015 were retrospectively reviewed. Six patients required reoperation within 30 days after PVCR, including 2 males and 4 females with average age of 21 years (ranging from 12 to 38 years). Four cases were congenital kyphoscoliosis, 1 was post-laminectomy kyphoscoliosis and 1 was post-tuberculous angular kyphosis. Three cases associated with preoperative neurologic deficit (Frankel C in 1 patient and D in 2 patients). The causes, management and outcomes of unplanned revision surgery within 30 days after PVCR were recorded. Results: The total incidence of unplanned revision surgery within 30 days following PVCR was 5.4% (6/112). There was 1 case due to cerebrospinal fluid leak, 5 cases with varying degrees of new neurologic deficits, the causes were as followed: dural buckling in 1 case, residual bone compression in 1 case, epidural hematoma compression in 2 cases, spinal subdural hematoma in 1 case. All the 6 cases underwent surgical exploration again, including further dural repair, decompression and hematoma clearance. After unplanned reoperation, 6 cases recovered completely. The average follow-up time after surgery was 30.8 months (ranging from 10 to 60 months). The major curve at coronal plane was improved from preoperative 87.7° to 34.2°, with a mean correction of 61.0% at final follow-up; the sagittal kyphosis curve was improved from preoperative 119.5° to 45.5°, with a mean correction of 61.9% at final follow-up. Two patients' neurological status improved from Frankel D to Frankel E, one patient's neurological status improved from Frankel C to Frankel E. Conclusions: One-stage PVCR could be an effective method for treatment of severe spinal deformity. The causes of 30-day unplanned reoperation after PVCR are as followed: cerebrospinal fluid leak, dural buckling, residual bone compression and hematoma compression. Timely surgical exploration can gain good clinical outcomes.

Molecular cloning and activity analysis of a seed-specific FAD2-1B gene promoter from Glycine max

Microsomal omega-6 fatty acid desaturase (FAD2-1B) is an enzyme that regulates the polyunsaturated fatty acid content in soybeans (Glycine max). In this study, the FAD2-1B gene was determined to be highly expressed in soybean seeds using quantitative real-time PCR(qRT-PCR). To investigate the expression pattern and activity of the FAD2-1B promoter, a 1929 bp 5'-upstream genomic DNA fragment, named PF, was isolated according to the soybean genomic sequence. Sequence analysis revealed the presence of many motifs related to seed-specific promoters in the PF fragment, such as E-box, SEF4, Skn-1 motif, AACACA, AATAAA and so on. Tobacco transgenics carrying the gus reporter gene driven by the PF and/or 35S promoters were confirmed by PCR and RT-PCR. qRT-PCR and histochemical GUS assays showed that the PF promoter could regulate gus gene accumulation in seeds and the expression level was higher than in other organs. In the meantime, it exhibited similar activity to the 35S promoter in seeds, which could be associated with seed-related cis-elements found in the 1-248 bp, 451-932 bp, and 1627-1803 bp regions of the promoter.

[Influences of 3,4,5-trihydroxystibene-3-beta-mono-D-glucoside on rabbits' platelet aggregation and thromboxane B2 production in vitro]

Platelet aggregation and thromboxane B2 (TXB2) production induced by arachidonic acid (AA) or Adenosine diphosphate (ADP) were studied by turbidimetry and radioimmunoassay in rabbits. 3,4,5-tri-hydroxystibene-3-beta-mono-D-glucoside (PD) 6.7-107.2 mumol/L inhibited platelet aggregation and the production of TXB2 as well. The inhibitions by PD were dose-dependent: 48-90% (AA-induced) and 43-69% (ADP-induced) for platelet aggregation; 50-87% (AA-induced) and 43-68% (ADP-induced) for TXB2. There were positive correlations between the inhibition of platelet aggregation and production of TXB2.