Tailoring rectal cancer surgery: Surgical approaches and anatomical insights during deep pelvic dissection for optimal outcomes in low-lying rectal cancer.

This review article explores advanced surgical approaches and anatomical insights for tailoring rectal cancer surgery, particularly focusing on low-lying rectal cancer. With the evolution of imaging technologies, precise preoperative planning has become possible, enhancing the visualization of anatomy surrounding the rectum and enabling more accurate assessments of circumferential resection margin (CRM) involvement. The article emphasizes the dynamic nature of rectal cancer treatment, advocating for individualized surgical planning based on comprehensive preoperative imaging and intraoperative assessment. This approach aims to optimize patient care by integrating recent advancements and anatomical insights into clinical practice for the management of low-lying rectal cancer. Particularly, the article discusses the importance of customizing the excision of Denonvilliers' fascia (DVF) based on tumor characteristics for optimal oncologic and functional outcomes, especially for anteriorly located tumors. It highlights the need for precise dissection techniques to ensure a negative CRM while preserving critical anatomical structures. Additionally, the review addresses the surgical management of tumors at the anorectal ring and introduces the Gate Approach for deep anterolateral pelvic dissection. Special attention is given to tumors impacting the membranous and prostate urethra, emphasizing tailored surgical approaches to balance complete tumor resection with the preservation of urogenital functions.

Essential knowledge and technical tips for total mesorectal excision and related procedures for rectal cancer.

Total mesorectal excision (TME) has greatly improved rectal cancer surgery outcomes by reducing local recurrence and enhancing patient survival. This review outlines essential knowledge and techniques for performing TME. TME emphasizes the complete resection of the mesorectum along embryologic planes to minimize recurrence. Key anatomical insights include understanding the rectal proper fascia, Denonvilliers fascia, rectosacral fascia, and the pelvic autonomic nerves. Technical tips cover a step-by-step approach to pelvic dissection, the Gate approach, and tailored excision of Denonvilliers fascia, focusing on preserving pelvic autonomic nerves and ensuring negative circumferential resection margins. In Korea, TME has led to significant improvements in local recurrence rates and survival with well-adopted multidisciplinary approaches. Surgical techniques of TME have been optimized and standardized over several decades in Korea, and minimally invasive surgery for TME has been rapidly and successfully adopted. The review emphasizes the need for continuous research on tumor biology and precise surgical techniques to further improve rectal cancer management. The ultimate goal of TME is to achieve curative resection and function preservation, thereby enhancing the patient's quality of life. Accurate TME, multidisciplinary-based neoadjuvant therapy, refined sphincter-preserving techniques, and ongoing tumor research are essential for optimal treatment outcomes.

Mapping the spatial distribution of primary and secondary PM2.5 in a multi-industrial city by combining monitoring and modeling results.

Industrial cities are strongly influenced by primary emissions of PM2.5 from local industries. In addition, gaseous precursors, such as sulfur oxides (SOX), nitrogen oxides (NOX), and volatile organic compounds (VOCs), emitted from industrial sources, undergo conversion into secondary inorganic and organic aerosols (SIAs and SOAs). In this study, the spatial distributions of primary and secondary PM2.5 in Ulsan, the largest industrial city in South Korea, were visualized. PM2.5 components (ions, carbons, and metals) and PM2.5 precursors (SO2, NO2, NH3, and VOCs) were measured to estimate the concentrations of secondary inorganic ions (SO42-, NO3-, and NH4+) and secondary organic aerosol formation potential (SOAFP). The spatial distributions of SIAs and SOAs were then plotted by combining atmospheric dispersion modeling, receptor modeling, and monitoring data. Spatial distribution maps of primary and secondary PM2.5 provide fundamental insights for formulating management policies in different districts of Ulsan. For instance, among the five districts in Ulsan, Nam-gu exhibited the highest levels of primary PM2.5 and secondary nitrate. Consequently, controlling both PM2.5 and NO2 emissions becomes essential in this district. The methodology developed in this study successfully identified areas with dominant contributions from both primary emissions and secondary formation. This approach can be further applied to prioritize control measures during periods of elevated PM levels in other industrial cities.

A qualitative exploration of exercise motivation among colorectal cancer survivors: an application of the theory of planned behavior.

PURPOSE: The purpose of this qualitative study was to use semi-structured interviews and thematic analysis to elicit key influencing factors (i.e., behavioral, normative, and control beliefs) related to physical activity and exercise in colorectal cancer survivors. METHODS: Colorectal cancer survivors (N = 17) were recruited from exercise programs designed for colorectal cancer survivors at the Yonsei Cancer Center, Seoul, South Korea. A purposive sampling method was used. Interview questions were informed by the theory of planned behavior (TPB). Semi-structured face-to-face interviews were conducted, and open-ended questions addressed the research question. Interviews were transcribed verbatim and analyzed using thematic analysis. RESULTS: Participants were on average 2.2 years post-treatment. The mean age of the sample was 55.9 years. Key behavioral, normative, and control beliefs emerged in the data. For behavioral beliefs, colorectal cancer survivors believed that exercise would result in physical and psychological improvements, and improve their bowel problems. For normative beliefs, most colorectal cancer survivors wanted their oncologists' approval for participation of exercise. Family members, more specifically the spouse, were also influencing factors for colorectal cancer survivors adopting physical activity. The most frequently mentioned control belief was that supervised exercise with an exercise specialist made exercise participation easier. CONCLUSIONS AND IMPLICATIONS: Beliefs identified in this study can inform TPB-based physical activity interventions tailored for colorectal cancer survivors. While information alone may not lead to behavior change, integrating these beliefs with other influential factors can potentially enhance intervention efficacy and promote physical activity in this population.

Long-term bowel functional outcomes following anal sphincter-preserving surgery for upper and middle rectal cancer: a single-center longitudinal study.

PURPOSE: Despite advances in neoadjuvant chemoradiotherapy and anal sphincter-preserving surgery for rectal cancer, bowel dysfunction is still unavoidable and negatively affects patients' quality of life. In this longitudinal study, we aimed to investigate the changes in bowel function with follow-up time and the effect of neoadjuvant chemoradiotherapy on bowel function following low anterior resection for rectal cancer. METHODS: In this study, 171 patients with upper or middle rectal cancer who underwent low anterior resection between 2012 and 2018 were included. Bowel function was assessed longitudinally with Memorial Sloan Kettering Cancer Center Bowel Function Instrument and Wexner scores every 6 months after restoration of bowel continuity. Patients with at least 2 follow-up visits were included. RESULTS: Overall, 100 patients received neoadjuvant chemoradiotherapy. Urgency, soilage, and fecal incontinence were noted within 24 months in the patients treated with neoadjuvant chemoradiotherapy. After 2 years of follow-up, significant bowel dysfunction and fecal incontinence were observed in the neoadjuvant chemoradiotherapy group. Low tumor level and neoadjuvant chemoradiotherapy were associated with delayed bowel dysfunction. CONCLUSION: Neoadjuvant chemoradiotherapy in combination with low tumor level was significantly associated with delayed bowel dysfunction even after 2 years of follow-up. Therefore, careful selection and discussion with patients are paramount.

Pretreatment MRI-detected extramural venous invasion as a prognostic and predictive biomarker for neoadjuvant chemoradiotherapy in non-metastatic rectal cancer: a propensity score matched analysis.

OBJECTIVES: This study evaluated pretreatment magnetic resonance imaging (MRI)-detected extramural venous invasion (pmrEMVI) as a predictor of survival after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC). MATERIALS AND METHODS: Medical records of 1184 patients with rectal adenocarcinoma who underwent TME between January 2011 and December 2016 were reviewed. MRI data were collected from a computerized radiologic database. Cox proportional hazards analysis was used to assess local, systemic recurrence, and disease-free survival risk based on pretreatment MRI-assessed tumor characteristics. After propensity score matching (PSM) for pretreatment MRI features, nCRT therapeutic outcomes according to pmrEMVI status were evaluated. Cox proportional hazards analysis was used to identify risk factors for early recurrence in patients receiving nCRT. RESULTS: Median follow-up was 62.8 months. Among all patients, the presence of pmrEMVI was significantly associated with worse disease-free survival (DFS; HR 1.827, 95% CI 1.285-2.597, p = 0.001) and systemic recurrence (HR 2.080, 95% CI 1.400-3.090, p < 0.001) but not local recurrence. Among patients with pmrEMVI, nCRT provided no benefit for oncological outcomes before or after PSM. Furthermore, pmrEMVI( +) was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT. CONCLUSIONS: pmrEMVI is a poor prognostic factor for DFS and SR in patients with non-metastatic rectal cancer and also serves as a predictive biomarker of poor DFS and SR following nCRT in LARC. Therefore, for patients who are positive for pmrEMVI, consideration of alternative treatment strategies may be warranted. CLINICAL RELEVANCE STATEMENT: This study demonstrated the usefulness of pmrEMVI as a predictive biomarker for nCRT, which may assist in initial treatment decision-making in patients with non-metastatic rectal cancer. KEY POINTS: • Pretreatment MRI-detected extramural venous invasion (pmrEMVI) was significantly associated with worse disease-free survival and systemic recurrence in patients with non-metastatic rectal cancer. • pmrEMVI is a predictive biomarker of poor DFS following nCRT in patients with LARC. • The presence of pmrEMVI was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

Effects of a bowel function improvement program for patients with rectal cancer surgery: A randomized controlled trial.

OBJECTIVES: This study aimed to examine the effectiveness of a bowel function improvement program for male patients with rectal cancer who underwent low anterior resection. METHODS: A prospective, unblinded, and randomized controlled trial was conducted. The enrolled 42 patients were assigned to the experimental or control group at a 1:1 ratio. The bowel function improvement program comprised a 4-week intensive program (face-to-face education and telephone coaching) and an 8-week maintenance program (text messages). Self-efficacy, bowel function, health-related quality of life, and healthcare resource utilization were measured. Collected data were analyzed using independent t-tests, chi-square tests, analysis of covariance, and generalized estimation equations to evaluate the effects of the program based on intention-to-treat. RESULTS: The bowel function improvement program was effective in improving bowel function 3 months after discharge. Additionally, the number of unplanned pharmacy visits was lower in the experimental group than in the control group. Health-related quality of life, self-efficacy, and utilization of other healthcare resources were not statistically or clinically significant. CONCLUSION: These findings indicated that the bowel function improvement program for male patients with rectal cancer was effective in improving bowel function and reducing unplanned healthcare resource utilization. The bowel function improvement program can be delivered as a nurse-led program in clinical practice to promote early recovery after low anterior resection. TRIAL REGISTRATION NUMBER: KCT0003505. https://cris.nih.go.kr/cris/search/detailSearch.do/13708.

Neoadjuvant chemotherapy versus upfront surgery as the initial treatment for patients with resectable, synchronous colorectal cancer liver metastases.

BACKGROUND: Although perioperative chemotherapy has been the standard treatment for colorectal cancer with resectable liver metastases (CRLM), studies that have compared neoadjuvant chemotherapy (NAC) and upfront surgery, especially in the setting of synchronous metastases are rare. METHODS: We compared perioperative outcomes, overall survival (OS) and overall survival after recurrence (rOS) in a retrospective study of 281 total and 104 propensity score-matched (PSM) patients who underwent curative resection, with or without NAC, for synchronous CRLM, from 2006 to 2017. A Cox regression model was developed for OS. RESULTS: After PSM, 52 NAC and 52 upfront surgery patients with similar baseline characteristics were compared. Postoperative morbidity, mortality, and 5-year OS rate (NAC: 78.9%, surgery: 64.0%; p = 0.102) were similar between groups; however, the NAC group had better rOS (NAC: 67.3%, surgery: 31.5%; p = 0.049). Initial cancer stage (T4, N1-2), poorly differentiated histology, and >1 hepatic metastases were independent predictors of worse OS. Based on these factors, patients were divided into low-risk (≤1 risk factor, n = 115) and high-risk (≥2 risk factors, n = 166) groups. For high-risk patients, NAC yielded better OS than upfront surgery (NAC: 74.5%, surgery: 53.2%; p = 0.024). CONCLUSIONS: Although NAC and upfront surgery-treated patients had similar perioperative outcomes and OS, better postrecurrence survival was shown in patients with NAC. In addition, NAC may benefit patients with worse prognoses; therefore, physicians should consider patient disease risk before initiating treatment to identify patients who are most likely to benefit from chemotherapy.

Short-Term Outcomes and Cost-Effectiveness between Long-Course Chemoradiation and Short-Course Radiotherapy for Locally Advanced Rectal Cancer.

PURPOSE: Long-course chemoradiotherapy (LCRT) has been widely recommended in a majority of rectal cancer patients. Recently, encouraging data on short-course radiotherapy (SCRT) for rectal cancer has emerged. In this study, we aimed to compare these two methods in terms of short-term outcomes and cost analysis under the Korean medical insurance system. MATERIALS AND METHODS: Sixty-two patients with high-risk rectal cancer, who underwent either SCRT or LCRT followed by total mesorectal excision (TME), were classified into two groups. Twenty-seven patients received 5 Gy×5 with two cycles of XELOX (capecitabine 1000 mg/m² and oxaliplatin 130 mg/m² every 3 weeks) followed by TME (SCRT group). Thirty-five patients received capecitabine-based LCRT followed by TME (LCRT group). Short-term outcomes and cost estimation were assessed between the two groups. RESULTS: Pathological complete response was achieved in 18.5% and 5.7% of patients in the SCRT and LCRT groups, respectively (p=0.223). The 2-year recurrence-free survival rate did not show significant difference between the two groups (SCRT vs. LCRT: 91.9% vs. 76.2%, p=0.394). The average total cost per patient for SCRT was 18% lower for inpatient treatment (SCRT vs. LCRT: $18787 vs. $22203, p<0.001) and 40% lower for outpatient treatment (SCRT vs. LCRT: $11955 vs. $19641, p<0.001) compared to LCRT. SCRT was shown to be the dominant treatment option with fewer recurrences and fewer complications at a lower cost. CONCLUSION: SCRT was well-tolerated and achieved favorable short-term outcomes. In addition, SCRT showed significant reduction in the total cost of care and distinguished cost-effectiveness compared to LCRT.

Postoperative inpatient exercise facilitates recovery after laparoscopic surgery in colorectal cancer patients: a randomized controlled trial.

BACKGROUND: Early mobilization is an integral part of an enhanced recovery program after colorectal cancer surgery. The safety and efficacy of postoperative inpatient exercise are not well known. The primary objective was to determine the efficacy of a postoperative exercise program on postsurgical recovery of stage I-III colorectal cancer patients. METHODS: We randomly allocated participants to postoperative exercise or usual care (1:1 ratio). The postoperative exercise intervention consisted of 15 min of supervised exercise two times per day for the duration of their hospital stay. The primary outcome was the length of stay (LOS) at the tertiary care center. Secondary outcomes included patient-perceived readiness for hospital discharge, anthropometrics (e.g., muscle mass), and physical function (e.g., balance, strength). RESULTS: A total of 52 (83%) participants (mean [SD] age, 56.6 [8.9] years; 23 [44%] male) completed the trial. The median LOS was 6.0 days (interquartile range; IQR 5-7 days) in the exercise group and 6.5 days (IQR 6-7 days) in the usual-care group (P = 0.021). The exercise group met the targeted LOS 64% of the time, while 36% of the usual care group met the targeted LOS (colon cancer, 5 days; rectal cancer, 7 days). Participants in the exercise group felt greater readiness for discharge from the hospital than those in the usual care group (Adjusted group difference = 14.4; 95% CI, 6.2 to 22.6; P < 0.01). We observed a small but statistically significant increase in muscle mass in the exercise group compared to usual care (Adjusted group difference = 0.63 kg; 95% CI, 0.16 to 1.1; P = 0.03). CONCLUSION: Postsurgical inpatient exercise may promote faster recovery and discharge after curative-intent colorectal cancer surgery. TRIAL REGISTRATION: The study was registered at WHO International Clinical Trials Registry Platform (ICTRP; URL http://apps.who.int/trialsearch ); Trial number: KCT0003920 .

Customized Denonvilliers' Fascia Excision: An Advanced Total Mesorectal Excision Technique for Anteriorly Located Rectal Cancer.

BACKGROUND: The role of Denonvilliers' fascia in achieving a negative circumferential resection margin during anterior total mesorectal excision has been controversial. Opinions on whether to dissect in the anterior or posterior surgical plane varies among researchers. IMPACT OF INNOVATION: We performed total mesorectal excision with selective en bloc resection of Denonvilliers' fascia based on preoperative MRI staging, preoperative clinical tumor stage, and tumor level in selected patients with anterior rectal tumors adherent to Denonvilliers' fascia. TECHNOLOGY MATERIALS AND METHODS: Between March and August 2021, 5 patients who underwent robotic (n = 4) and laparoscopic (n = 1) total mesorectal excision for anteriorly located low rectal adenocarcinomas after neoadjuvant chemoradiotherapy were enrolled in this study. Transabdominal total mesorectal excision dissection is performed by changing to a plane anterior to Denonvilliers' fascia, with partial or total excision tailored to the tumor level and depth of invasion as a further step in circumferential resection margin clearing. Customized excision of Denonvilliers' fascia was performed by dissecting through the extramesorectal plane. This anterior plane permits resection of Denonvilliers' fascia, exposing the prostate and seminal vesicles. PRELIMINARY RESULTS: Two tumors were located at the seminal vesicle level and 3 were found at the prostate level. The mean distance from the anal verge to the distal margin of the tumor was 4.8 ± 0.9 cm. Denonvilliers' fascia was preserved in 1 patient and partially excised in 4. Customized Denonvilliers' fascia excision was performed in 3 robotic ultralow anterior resections with coloanal anastomosis, 1 laparoscopic ultralow anterior resection with coloanal anastomosis, and 1 robot-assisted abdominoperineal resection. The circumferential resection margins in all patients were negative. CONCLUSIONS AND FUTURE DIRECTIONS: Anterior dissection in front of Denonvilliers' fascia can be selectively performed during total mesorectal excision based on preoperative planning, tumor location, and clinical tumor stage. Preoperative MRI and magnified operative views in minimally invasive platforms provide access to more precise surgical planes for clear circumferential resection, achieving optimal functional outcomes and oncological safety.

Comparison of Laparoscopic Versus Robot-Assisted Surgery for Rectal Cancers: The COLRAR Randomized Controlled Trial.

OBJECTIVE: To evaluate whether robotic for middle or low rectal cancer produces an improvement in surgical outcomes compared with laparoscopic surgery in a randomized controlled trial (RCT). BACKGROUND: There is a lack of proven clinical benefit of robotic total mesorectal excision (TME) compared with a laparoscopic approach in the setting of multicenter RCTs. METHODS: Between July 2011 and February 2016, patients diagnosed with an adenocarcinoma located <10 cm from the anal verge and clinically rated T1-4aNxM0 were enrolled. The primary outcome was the completeness of TME assessed by a surgeon and a pathologist. RESULTS: The RCT was terminated prematurely because of poor accrual of data. In all, 295 patients were assigned randomly to a robot-assisted TME group (151 in R-TME) or a laparoscopy-assisted TME group (144 in L-TME). The rates of complete TME were not different between groups (80.7% in R-TME, 77.1% in L-TME). Pathologic outcomes including the circumferential resection margin and the numbers of retrieved lymph nodes were not different between groups. In a subanalysis, the positive circumferential resection margin rate was lower in the R-TME group (0% vs 6.1% for L-TME; P =0.031). Among the recovery parameters, the length of opioid use was shorter in the R-TME group ( P =0.028). There was no difference in the postoperative complication rate between the groups (12.0% for R-TME vs 8.3% for L-TME). CONCLUSIONS: In patients with middle or low rectal cancer, robotic-assisted surgery did not significantly improve the TME quality compared with conventional laparoscopic surgery (ClinicalTrial.gov ID: NCT01042743).

Short-term Changes in Thyroid-Stimulating Hormone Level after Body Fat Reduction via Partial Meal Replacement.

BACKGROUND: Serum thyroid-stimulating hormone (TSH) levels change during body weight reduction. However, the changes that occur during short-term body weight control interventions remain controversial. Thus, this study aimed to evaluate the changes in TSH levels according to body fat reduction. METHODS: We performed a 3-month intervention study involving partial meal replacement. Forty-nine participants completed the study. Correlations between changes in TSH levels and other body composition parameters were determined. The subjects were divided into two groups according to their body fat reduction (>1 kg, n=20; <1 kg, n=29). The changes in metabolic parameters, including TSH levels, were compared. For significant values, a multivariate analysis was performed after adjustment to evaluate the relationship between TSH changes and body fat reduction. RESULTS: The 3-month intervention caused favorable changes in body proportions and metabolic parameters. TSH levels changed significantly only after changes in total body fat, showing a partial correlation. Changes in TSH levels were significantly different between groups (P=0.014). Moreover, the change in TSH levels was significantly different after adjustment (P=0.012). CONCLUSION: A body fat reduction, especially >1 kg, can reduce serum TSH concentrations in subjects with metabolic syndrome after short-term body weight intervention.

Serum 25-hydroxyvitamin D3 is associated with homocysteine more than with apolipoprotein B.

BACKGROUND/OBJECTIVES: The incidence of cardiovascular diseases (CVDs) has increased worldwide. Although a low serum vitamin D level is known to be associated with the risk of CVD, the mechanism is not well understood yet. The aim of this study was to determine the relationship of serum 25-hydroxyvitamin D3 (25[OH]D) with homocysteine and apolipoprotein B (ApoB). SUBJECTS/METHODS: Of 777 subjects recruited from one health promotion center for routine heath exam from January 2010 to December 2016, 518 subjects were included in this study. Serum 25(OH)D, serum homocysteine, and other metabolic parameters including ApoB were analyzed. Simple and partial correlations were carried out after adjustments. Simple linear regression analysis was used for precise correlation of parameters. Multivariate regression analysis was done to know which factor (serum homocysteine or ApoB) was more related to serum 25(OH)D after adjustments. Finally, logarithms of homocysteine concentrations according to tertiles of serum 25(OH)D were compared. RESULTS: After sex and age adjustments, serum 25(OH)D showed negative correlations with serum homocysteine (r' = -0.114) and ApoB (r' = -0.098). In simple linear regression analysis, serum 25(OH)D showed a significant negative correlation with ApoB (P = 0.035). However, in multivariate regression analysis, serum 25(OH)D was significantly associated with serum homocysteine after adjustments (P = 0.022). In addition, serum homocysteine concentration was significantly high in the lowest 25(OH)D group (P = 0.046). CONCLUSION: Serum 25(OH)D concentration showed a stronger negative association with serum homocysteine than with ApoB.

Impact of neoadjuvant treatment on rectal gastrointestinal stromal tumors.

Although gastrointestinal stromal tumors (GISTs) are rare disease and rectal GISTs is only 5% of total GISTs, they have the worst prognosis. Due to narrow pelvis, tumor rupture or positive resection margin are common in the management of rectal GISTs. The impact of neoadjuvant treatment on the clinical outcomes of rectal gastrointestinal stromal tumors (GISTs) remains unclear. Thus, we conducted a retrospective study to investigate the impact of neoadjuvant imatinib on rectal GIST. The cohort comprised 33 patients; of them, 10 and 23 belonged to the neoadjuvant (i.e., those who underwent neoadjuvant imatinib treatment) and the control group (i.e., those who underwent surgery without prior imatinib treatment), respectively. Neoadjuvant group was associated with more common levator ani muscle displacement (P = 0.002), and showed significantly larger radiologic tumor size (P = 0.036) than the control group. The mean tumor size was significantly decreased after imatinib treatment (6.8 cm to 4.7cm, P = 0.006). There was no significant difference in resection margin involvement (P >0.999), and sphincter preservation rates (P = 0.627) between the two groups. No difference was observed with respect to morbidities, hospital stay, local recurrence and disease-free survival. Neoadjuvant imatinib treated group had similar propensity with control group after treatment. We thought reduced tumor sized could enhance resectability and provide more chance to preserve sphincter for rectal GIST patients. Considering large tumor size and higher rate of sphincter invasion in the neoadjuvant group, imatinib treatment could be helpful as a conversion strategy to make huge and low-lying rectal GIST operable and achieve better surgical outcomes.

Exposure of the Middle Rectal Artery and Lateral Ligament of the Rectum Following the Gate Approach during Total Mesorectal Excision.

Controversial surgical anatomical landmarks in the deep pelvis can be visualized and identified using current technologies. Performing the gate approach technique during deep lateral dissection for total mesorectal excision facilitates visualization of the pelvic neurovascular structures following simple dissection steps to preserve the pelvic autonomic nerves and avoid accidental vascular injuries. Here, we discuss laparoscopic exposure of an infrequent disposition of the middle rectal artery anterior to the lateral ligament of the rectum while performing the gate approach.

Double-layered hand-sewn anastomosis: a valuable resource for the colorectal surgeon.

Hand-sewn anastomosis is an essential and fundamental skill for surgeons dealing with any gastrointestinal anastomosis. Despite the advances in minimally invasive surgery and stapling devices, there are still complex surgical circumstances when the surgeon's surgical know-how are necessary. Therefore, a safe hand-sewn technique for bowel anastomosis is required to establish a tension-free, well-perfused, and sealed anastomosis that allows gastrointestinal continuity with no unexpected complications. We describe a step-by-step procedure for hand-sewn double-layered anastomosis that reflects these principles and is practical for small and large bowel anastomosis.

MRI Radiomics Model Predicts Pathologic Complete Response of Rectal Cancer Following Chemoradiotherapy.

Background Preoperative assessment of pathologic complete response (pCR) in locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT) is increasingly needed for organ preservation, but large-scale validation of an MRI radiomics model remains lacking. Purpose To evaluate radiomics models based on T2-weighted imaging and diffusion-weighted MRI for predicting pCR after nCRT in LARC and compare their performance with visual assessment by radiologists. Materials and Methods This retrospective study included patients with LARC (clinical stage T3 or higher, positive nodal status, or both) who underwent post-nCRT MRI and elective resection between January 2009 and December 2018. Surgical histopathologic analysis was the reference standard for pCR. Radiomic features were extracted from the volume of interest on T2-weighted images and apparent diffusion coefficient (ADC) maps from post-nCRT MRI to generate three models: T2 weighted, ADC, and both T2 weighted and ADC (merged). Radiomics signatures were generated using the least absolute shrinkage and selection operator with tenfold cross-validation. Three experienced radiologists independently rated tumor regression grades at MRI and compared these with the radiomics models' diagnostic outcomes. Areas under the curve (AUCs) of the radiomics models and pooled readers were compared by using the DeLong method. Results Among 898 patients, 189 (21%) achieved pCR. The patients were chronologically divided into training (n = 592; mean age ± standard deviation, 59 years ± 12; 388 men) and test (n = 306; mean age, 59 years ± 12; 190 men) sets. The radiomics signatures of the T2-weighted, ADC, and merged models demonstrated AUCs of 0.82, 0.79, and 0.82, respectively, with no evidence of a difference found between the T2-weighted and merged models (P = .49), while the ADC model performed worse than the merged model (P = .02). The T2-weighted model had higher classification performance (AUC, 0.82 vs 0.74 [P = .009]) and sensitivity (80.0% vs 15.6% [P < .001]), but lower specificity (68.4% vs 98.6% [P < .001]) than the pooled performance of the three radiologists. Conclusion An MRI-based radiomics model showed better classification performance than experienced radiologists for diagnosing pathologic complete response in patients with locally advanced rectal cancer after neoadjuvant chemoradiotherapy. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Taylor in this issue.

Single-incision laparoscopic surgery compared to conventional laparoscopic surgery for appendiceal mucocele: a series of 116 patients.

BACKGROUND: Although the safety and feasibility of conventional laparoscopic surgery (CLS) for appendiceal mucocele (AM) has been reported, studies on single-incision laparoscopic surgery (SILS) for AM have not been reported. Here, we aimed to compare the perioperative and short-term outcomes between SILS and CLS for AM and to evaluate the oncological safety of SILS. METHODS: We retrospectively analyzed the medical records of patients, diagnosed based on computed tomography findings, who underwent laparoscopic surgery for AM between 2010 and 2018 at one institution. We excluded patients strongly suspected of having malignant lesions and those with preoperative appendiceal perforation. Patients were divided into two groups-CLS and SILS. Pathological outcomes and long-term results were investigated. The median follow-up period was 43.7 (range: 12.3-118.5) months. RESULTS: Ultimately, 116 patients (CLS = 68, SILS = 48) were enrolled. Patient demographic characteristics did not differ between the groups. The preoperative mucocele diameter was greater in the CLS than in the SILS group (3.2 ± 2.9 cm vs. 2.3 ± 1.4 cm, P = 0.029). More extensive surgery (right hemicolectomies and ileocecectomies) was performed in the CLS than in the SILS group (P = 0.014). Intraoperative perforation developed in only one patient per group. For appendectomies and cecectomies, the CLS group exhibited a longer operation time than the SILS group (63.3 ± 24.5 min vs. 52.4 ± 17.3 min, P = 0.014); the same was noted for length of postoperative hospital stay (2.9 ± 1.8 days vs. 1.7 ± 0.6 days, P < 0.001). The most common AM etiology was low-grade appendiceal mucinous neoplasm (71/116 [61.2%] patients); none of the patients exhibited mucinous cystadenocarcinoma. Among these 71 patients, there were 8 patients with microscopic appendiceal perforation or positive resection margins. No recurrence was detected. CONCLUSIONS: SILS for AM is feasible and safe perioperatively and in the short-term and yields favorable oncological outcomes. Despite the retrospective nature of the study, SILS may be suitable after careful selection of AM patients.