Effectiveness of personalized treatment stage-adjusted digital therapeutics in colorectal cancer: a randomized controlled trial.

BACKGROUND: Colorectal cancer survivors often experience decline in physical performance and poor quality of life after surgery and during adjuvant therapies. In these patients, preserving skeletal muscle mass and high-quality nourishment are essential to reduce postoperative complications and improve quality of life and cancer-specific survival. Digital therapeutics have emerged as an encouraging tool for cancer survivors. However, to the best of our knowledge, randomized clinical trials applying personalized mobile application and smart bands as a supportive tool to several colorectal patients remain to be conducted, intervening immediately after the surgical treatment. METHODS: This study is a prospective, multi-center, single-blinded, two-armed, randomized controlled trial. The study aims to recruit 324 patients from three hospitals. Patients will be randomly allocated to two groups for one year of rehabilitation, starting immediately after the operation: a digital healthcare system rehabilitation (intervention) group and a conventional education-based rehabilitation (control) group. The primary objective of this protocol is to clarify the effect of digital healthcare system rehabilitation on skeletal muscle mass increment in patients with colorectal cancer. The secondary outcomes would be the improvement in quality of life measured by EORTC QLQ C30 and CR29, enhanced physical fitness level measured by grip strength test, 30-sec chair stand test and 2-min walk test, increased physical activity measured by IPAQ-SF, alleviated pain intensity, decreased severity of the LARS, weight, and fat mass. These measurements will be held on enrollment and at 1, 3, 6 and 12 months thereafter. DISCUSSION: This study will compare the effect of personalized treatment stage-adjusted digital health interventions on immediate postoperative rehabilitation with that of conventional education-based rehabilitation in patients with colorectal cancer. This will be the first randomized clinical trial performing immediate postoperative rehabilitation in a large number of patients with colorectal cancer with a tailored digital health intervention, modified according to the treatment phase and patient condition. The study will add foundations for the application of comprehensive digital healthcare programs focusing on individuality in postoperative rehabilitation of patients with cancer. TRIAL REGISTRATION: NCT05046756. Registered on 11 May 2021.

FDG metabolic parameter-based models for predicting recurrence after upfront surgery in synchronous colorectal cancer liver metastasis.

OBJECTIVE: This study aimed to develop and validate post- and preoperative models for predicting recurrence after curative-intent surgery using an FDG PET-CT metabolic parameter to improve the prognosis of patients with synchronous colorectal cancer liver metastasis (SCLM). METHODS: In this retrospective multicenter study, consecutive patients with resectable SCLM underwent upfront surgery between 2006 and 2015 (development cohort) and between 2006 and 2017 (validation cohort). In the development cohort, we developed and internally validated the post- and preoperative models using multivariable Cox regression with an FDG metabolic parameter (metastasis-to-primary-tumor uptake ratio [M/P ratio]) and clinicopathological variables as predictors. In the validation cohort, the models were externally validated for discrimination, calibration, and clinical usefulness. Model performance was compared with that of Fong's clinical risk score (FCRS). RESULTS: A total of 374 patients (59.1 ± 10.5 years, 254 men) belonged in the development cohort and 151 (60.3 ± 12.0 years, 94 men) in the validation cohort. The M/P ratio and nine clinicopathological predictors were included in the models. Both postoperative and preoperative models showed significantly higher discrimination than FCRS (p < .05) in the external validation (time-dependent AUC = 0.76 [95% CI 0.68-0.84] and 0.76 [0.68-0.84] vs. 0.65 [0.57-0.74], respectively). Calibration plots and decision curve analysis demonstrated that both models were well calibrated and clinically useful. The developed models are presented as a web-based calculator ( https://cpmodel.shinyapps.io/SCLM/ ) and nomograms. CONCLUSIONS: FDG metabolic parameter-based prognostic models are well-calibrated recurrence prediction models with good discriminative power. They can be used for accurate risk stratification in patients with SCLM. KEY POINTS: • In this multicenter study, we developed and validated prediction models for recurrence in patients with resectable synchronous colorectal cancer liver metastasis using a metabolic parameter from FDG PET-CT. • The developed models showed good predictive performance on external validation, significantly exceeding that of a pre-existing model. • The models may be utilized for accurate patient risk stratification, thereby aiding in therapeutic decision-making.

Long-term oncologic outcome of D3 lymph node dissection for clinical stage 2/3 right-sided colon cancer.

PURPOSE: To investigate oncologic outcomes including overall survival and disease-free survival depending on the extent of lymphadenectomy (D3 versus D2) by comparing D3 and D2 lymphadenectomy in patients with clinical stage 2/3 right colon cancer. METHODS: Consecutive series of patients who underwent radical resection for right colon cancer at our three hospitals between January 2015 and June 2018 were retrospectively analyzed. Study cohorts were divided into two groups: D3 group and D2 group. Oncologic, pathologic, and perioperative outcomes of the two groups were compared. RESULTS: A total of 295 patients (167 in the D2 group and 128 in the D3 group) were included in this study. Patients' characteristics showed no significant difference between the two groups. The median number of harvested lymph nodes was significantly higher in the D3 group than in the D2 group. The rate of complications was not significantly different between the two groups except for chyle leakage, which was more frequent in the D3 group. Five-year disease-free survival was 90.2% (95% CI: 84.8-95.9%) in the D3 group, which was significantly (p = 0.028) higher than that (80.5%, 95% CI: 74-87.5%) in the D2 group. There was no significant difference in overall survival between the two groups. CONCLUSION: Our results indicate that D3 lymphadenectomy is associated with more favorable 5-year disease-free survival than D2 lymphadenectomy for patients with stage 2/3 right-sided colon cancer. D3 lymphadenectomy might improve oncologic outcomes in consideration of the recurrence rate.

Laparoscopic D3 oncological resection in splenic flexure cancer: Technical details and its impact on long-term survival.

AIM: The applicability of laparoscopic D3 oncological resection for splenic flexure cancer (SFC) surgery has not been fully explored due to technical difficulties and variations in surgical procedure. The aim of this work is to describe the feasibility of performing laparoscopic D3 resection in SFC and its impact on long-term survival. METHOD: A retrospective study on 47 out of 52 consecutive patients who underwent elective laparoscopic colectomy for SFC from December 2006 until December 2019 at Korea University Anam Hospital was performed. Data on patients' demographic and clinical features, surgical procedures, intraoperative and postoperative complications, pathological features and follow-up were collected. Categorical data are expressed as frequencies (n) and percentages (%). Continuous data are expressed as mean ± standard deviation and median (range). The Kaplan-Meier test was used to determine the overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS). RESULTS: The median age of patients was 67.0 years (range 27-87 years) and 72.3% were men. Ten (21.3%) patients presented with an obstructing tumour and underwent an elective laparoscopic colectomy, while 68.1% of patients presented with Stage II and III disease. The conversion rate was 4.3% and the morbidity rate was 31.9%. There was one postoperative death secondary to splenic infarction and anastomotic leak leading to multi-organ failure. Four deaths occurred due to disease progression during a median follow-up of 63.8 months. The rate of recurrence was 20%, the 5-year OS was 89.6% and the 5-year PFS was 72.9%. After R0 resection, the 5-year OS was 91.5% and the 5-year DFS was 74.5%. CONCLUSION: Laparoscopic D3 colectomy for SFC is feasible, with an acceptable morbidity and long-term oncological outcome when performed by highly skilled laparoscopic colorectal surgeons with knowledge of the complex anatomy around the splenic flexure. Further randomized trials should be performed to determine the advantage of laparoscopic D3 colectomy over conventional colectomy for SFC.

Laparoscopic Extraperitoneal Approach for Lateral Pelvic Node Dissection in Rectal Cancer: Techniques and Short-Term Outcomes.

BACKGROUND: Lateral pelvic lymph node dissection has been performed selectively in rectal cancer cases; however, it involves highly skilled techniques because of the complex adjacent anatomical structures. MATERIALS AND METHODS: Laparoscopic EP-LPND was performed in Korea University Anam Hospital from June 2018, and short-term surgical outcomes were analyzed from June to December 2018. Among the patients with histologically diagnosed rectal adenocarcinoma, patients who were suspected Lateral pelvic lymph node metastasis at magnetic resonance imaging were selected for this procedure. RESULTS: Seven patients underwent laparoscopic extraperitoneal approach for lateral pelvic lymph node dissection in the study period. The mean number of retrieved lymph node was 4.57, and metastatic lymph nodes were identified in 3 patients (42.8%). All of the lymph nodes with suspected metastasis preoperatively were removed in postoperative images. There was no immediate postoperative complication beyond the moderate grade associated with lateral pelvic lymph node dissection. The median follow-up was 9 months, and there were no local recurrence nor complications related to sexual and voiding functions. CONCLUSIONS: The laparoscopic extraperitoneal approach might be an efficient way to perform lateral pelvic lymph node dissection using the same principles as the conventional method without violation of the peritoneum.

Robotic approach may be associated with a lower risk of lung metastases compared to laparoscopic approach for mid-low rectal cancer after neoadjuvant chemoradiotherapy: a multivariate analysis on long-term recurrence patterns.

PURPOSE: Describe differences on recurrence patterns of mid-low rectal cancers treated with neoadjuvant chemoradiotherapy and low anterior resection between laparoscopic and robotic approach. METHODS: Patients were identified from a prospectively maintained institutional database between 2006 and 2019. Demographics, clinicopathological features, recurrence, and survival were investigated. Cox regression analysis was performed for risk factor analysis. RESULTS: A total of 160 patients (36 laparoscopic and 124 robotic) were included. Systemic recurrence rate was higher in laparoscopic group (27.8 vs 12.1%, p = 0.023). Liver recurrence was similar (11.1 vs 4.0%). Lung recurrence was higher after laparoscopy (19.4 vs 6.5%, p = 0.019). Time to lung recurrence was shorter after laparoscopy (13.0 months, IQR 4.0-20.0) compared to robotic (23.5 months, IQR 17.0-42.7) with no statistical significance. Time to liver recurrence was similar between laparoscopy (19.5 months, IQR 4.7-37.5) and robotic (19.0 months, IQR 10.5-33.0). Median overall survival after lung recurrence was different (p = 0.021) between laparoscopy (19.0 months, IQR 16.0-67.0) and robotic (74.0 months, IQR 50.2-112.2). OS after liver recurrence was similar between groups. Overall survival and lung disease-free survival were different between the two groups (p = 0.032 and p = 0.020), while liver disease-free survival and local recurrence-free survival were not. Laparoscopy (p = 0.030; HR 3.074, 95% CI: 1.112-8.496) was a risk factor for lung disease-free survival on multivariate analysis. CONCLUSION: Lung recurrences were less frequent and with better overall survival in the robotic group. Liver recurrences were not influenced by choice of approach. Trials are needed to investigate why the robotic approach affects distant metastasis control.

Midline incision vs. transverse incision for specimen extraction is not a significant risk factor for developing incisional hernia after minimally invasive colorectal surgery: multivariable analysis of a large cohort from a single tertiary center in Korea.

BACKGROUND: Incisional hernia (IH) is a commonly encountered problem even in the era of minimally invasive surgery (MIS). Numerous studies on IH are available in English literature, but there are lack of data from the Eastern part of the world. This study aimed to evaluate the risk factors as well as incidence of IH by analyzing a large cohort collected from a single tertiary center in Korea. METHODS: Among a total number of 4276 colorectal cancer patients who underwent a surgical resection from 2006 to 2019 in Korea University Anam Hospital, 2704 patients (2200 laparoscopic and 504 robotic) who met the inclusion criteria were analyzed. IH was confirmed by each patient's diagnosis code registered in the hospital databank based on physical examination and/or computed tomography findings. Clinical data including specimen extraction incision (transverse or vertical midline) were compared between IH group and no IH group. Risk factors of developing IH were assessed by utilizing univariable and multivariable analyses. RESULTS: During the median follow-up of 41 months, 73 patients (2.7%) developed IH. Midline incision group (n = 1472) had a higher incidence of IH than that of transverse incision group (n = 1232) (3.5% vs. 1.7%, p = 0.003). The univariable analysis revealed that the risk factors of developing IH were old age, female gender, obesity, co-morbid cardiovascular disease, transverse incision for specimen extraction, and perioperative bleeding requiring transfusion. However, on multivariable analysis, specimen extraction site was not significant in developing IH and transfusion requirement was the strongest risk factor. CONCLUSIONS: IH development after MIS is uncommon in Korean patients. Multivariable analysis suggests that specimen extraction site can be flexibly chosen between midline and transverse incisions, with little concern about risk of developing IH. Careful efforts are required to minimize operative bleeding because blood transfusion is a strong risk factor for developing IH.

Lower Incidence of Postoperative Urinary Retention in Robotic Total Mesorectal Excision for Low Rectal Cancer Compared with Laparoscopic Surgery.

INTRODUCTION: The incidence and clinical significance of postoperative urinary retention (POUR) remain high. This study aimed to evaluate the incidence of POUR and related risk factors in patients who underwent total mesorectal excision (TMR) for low rectal cancer. METHODS: This study is a retrospective review of a prospectively collected colorectal database from a single center. Data from patients who underwent surgery for low rectal cancer between September 2006 and May 2017 were analyzed to assess the risk factors of POUR. POUR was considered inability to void after urinary catheter removal requiring catheter reinsertion and difficulty in bladder emptying requiring intermittent catheterization. RESULTS: Of 555 patients with low rectal cancer, 78 (14.1%) developed POUR. Based on multivariate logistic regression analysis, laparoscopic TMR (odds ratio [OR]; 2.114, 95% confidence interval [CI]; 1.212-3.689, p = 0.008) and postoperative ileus (OR; 2.389, 95% CI; 1.282-4.450, p = 0.006) were independent risk factors of POUR. Male gender, advanced age, neoadjuvant chemoradiation, longer operative time, abdominoperineal resection, and lateral pelvic lymph node dissection were not associated with POUR. Advanced age over 65 years also failed to show statistical significance (OR; 1.604, 95% CI; 0.965-2.668, p = 0.068). CONCLUSION: Laparoscopic approach and postoperative ileus are risk factors for POUR after low rectal cancer surgery. We postulate that the benefits of robotic surgical systems compared to a laparoscopic approach may reduce the incidence of POUR.

Mixed reality navigation system for ultrasound-guided percutaneous punctures: a pre-clinical evaluation.

Image-guided surgery is growing in importance with each year. Various imaging technologies are used. The objective of this study was to test whether a new mixed reality navigation system (MRNS) improved percutaneous punctures. This system allowed to clearly visualize the needle tip, needle orientation, US probe and puncture target simultaneously with an interactive 3D computer user inferface. Prospective pre-clinical comparative study. An opaque ballistic gel phantom containing grapes of different sizes was used to simulate puncture targets. The evaluation consisted of ultrasound-guided (US-guided) needle punctures divided into two groups, standard group consisted of punctures using the standard approach (US-guided), and assisted navigation group consisted of punctures using MRNS. Once a puncture was completed, a computed tomography scan was made of the phantom and needle. The distance between the needle tip and the center of the target was measured. The time required to complete the puncture and puncture attempts was also calculated. Total participants was n = 23, between surgeons, medical technicians and radiologist. The participants were divided into novices (without experience, 69.6%) and experienced (with experience > 25 procedures, 30.4%). Each participant performed the puncture of six targets. For puncture completion time, the assisted navigation group was faster (42.1%) compared to the standard group (57.9%) (28.3 s ± 24.7 vs. 39.3 s ± 46.3-p 0.775). The total punctures attempts was lower in the assisted navigation group (35.4%) compared to the standard group (64.6%) (1.0 mm ± 0.2 vs. 1.8 mm ± 1.1-p 0.000). The assisted navigation group was more accurate than the standard group (4.2 ± 2.9 vs. 6.5 ± 4.7-p 0.003), observed in both novices and experienced groups. The use of MRNS improved ultrasound-guided percutaneous punctures parameters compared to the standard approach.

Stereotactic Pelvic Navigation With Augmented Reality for Transanal Total Mesorectal Excision.

INTRODUCTION: Technical difficulty and unfamiliar surgical anatomy are the main challenges in transanal total mesorectal excision. Precise 3-dimensional real-time image guidance may facilitate the safety, accuracy, and efficiency of transanal total mesorectal excision. TECHNIQUE: A preoperative CT was obtained with 10 skin fiducials and further processed to emphasize the border of the anatomical structure by 3-dimensional modeling and pelvic organ segmentation. A forced sacral tilt by placing a 10-degree wedge under the patient's sacrum was induced to minimize pelvic organ movement caused by lithotomy position. An optical navigation system with cranial software was used. Preoperative CT images were loaded into the navigation system, and patient tracker was mounted onto the iliac bone. Once the patient-to-image paired point registration using skin fiducials was completed, the laparoscopic instrument mounted with instrument tracker was calibrated for instrument tracking. After validating the experimental setup and process of registration by navigating laparoscopic anterior resection, stereotactic navigation for transanal total mesorectal excision was performed in the low rectal neuroendocrine tumor. RESULTS: The fiducial registration error was 1.7 mm. The accuracy of target positioning was sufficient at less than 3 mm (1.8 ± 0.9 mm). Qualitative assessment using a Likert scale was well matched between the 2 observers. Of the 20 scores, 19 were judged as 4 (very good) or 5 (excellent). There was no statistical difference between mean Likert scales of the abdominal or transanal landmarks (4.4 ± 0.5 vs 4.3 ± 1.0, p = 0.965). CONCLUSIONS: Application of an existing navigation system to transanal total mesorectal excision for a low rectal tumor is feasible. The acceptable accuracy of target positioning justifies its clinical use. Further research is needed to prove the clinical need for the procedure and its impact on clinical outcomes.

Hybrid endoluminal stapled pyloroplasty: an alternative treatment option for gastric outlet obstruction syndrome.

BACKGROUND: Gastroparesis is a rapidly increasing problem with sometimes devastating consequences. While surgical treatments, particularly laparoscopic pyloroplasty, have recently gained popularity, they require general anesthesia, advanced skills, and can lead to leaks. Peroral pyloromyotomy is a less invasive alternative; however, this technique is technically demanding and not widely available. We describe a hybrid laparo-endoscopic collaborative approach using a novel gastric access device to allow endoluminal stapled pyloroplasty as an alternative treatment option for gastric outlet obstruction. METHODS: Under general anesthesia, six pigs (mean weight 33 kg) underwent endoscopic placement of intragastric ports using a technique similar to percutaneous endoscopic gastrostomy. A 5 mm laparoscope was used for visualization. A functional lumen imagine probe was used to measure the cross-sectional area (CSA) and diameter of the pylorus before, after, and at 1 week after intervention. Pyloroplasty was performed using a 5 mm articulating laparoscopic stapler. Gastrotomies were closed by endoscopic clips, endoscopic suture, or combination. After 6-8 days, a second evaluation was performed. At the end of the protocol, all animals were euthanized. RESULTS: Six pyloroplasties were performed. In all cases, this technique was effective in achieving significant pyloric dilatation. The median pre-pyloroplasty pyloric diameter (D) and cross-sectional area (CSA) were 8 mm (4.9-11.6 mm) and 58.6 mm2 (19-107 mm2), respectively. After the procedure, these values increased to 13.41 mm (9.8-17.6 mm) and 147.7 mm2 (76-244 mm2), respectively (p = 0.0152). No important intraoperative events were observed. Postoperatively, all animals did well, with adequate oral intake and no relevant complications. At follow-up endoscopy, all incisions were healed and the pylorus widely patent. CONCLUSIONS: Hybrid endoluminal stapled pyloroplasty is a feasible, safe, and effective alternative method for the treatment of gastric outlet obstruction syndrome.

Modular laser-based endoluminal ablation of the gastrointestinal tract: in vivo dose-effect evaluation and predictive numerical model.

BACKGROUND: Endoscopic submucosal dissection allows for "en bloc" removal of early gastrointestinal neoplasms. However, it is technically demanding and time-consuming. Alternatives could rely on energy-based techniques. We aimed to evaluate a predictive numerical model of thermal damage to preoperatively define optimal laser settings allowing for a controlled ablation down to the submucosa, and the ability of confocal endomicroscopy to provide damage information. MATERIALS AND METHODS: A Nd:YAG laser was applied onto the gastric mucosa of 21 Wistar rats on 10 spots (total 210). Power settings ranging from 0.5 to 2.5W were applied during 1-12 s, with a consequent energy delivery varying from 0.5 to 30 J. Out of the 210 samples, a total of 1050 hematoxilin-eosin stained slides were obtained. To evaluate thermal injury, the ratio between the damage depth (DD) over the mucosa and the submucosa thickness (T) was calculated. Effective and safe ablation was considered for a DD/T ratio ≤ 1 (only mucosal and submucosal damage). Confocal endomicroscopy was performed before and after ablation. A numerical model, using human physical properties, was developed to predict thermal damage. RESULTS: No full-thickness perforations were detected. On histology, the DD/T ratio at 0.5 J was 0.57 ± 0.21, significantly lower when compared to energies ranging from 15 J (a DD/T ratio = 1.2 ± 0.3; p < 0.001) until 30 J (a DD/T ratio = 1.33 ± 0.31; p < 0.001). Safe mucosal and submucosal ablations were achieved applying energy between 4 and 12 J, never impairing the muscularis propria. Confocal endomicroscopy showed a distorted gland architecture. The predicted damage depth demonstrated a significant positive linear correlation with the experimental data (Pearson's r 0.85; 95% CI 0.66-0.94). CONCLUSIONS: Low-power settings achieved effective and safe mucosal and submucosal ablation. The numerical model allowed for an accurate prediction of the ablated layers. Confocal endomicroscopy provided real-time thermal damage visualization. Further studies on larger animal models are required.

Outcomes according to body mass index following laparoscopic surgery in patients with colorectal cancer.

PURPOSE: Body mass index (BMI) may not be appropriate for different populations. Therefore, the World Health Organization (WHO) suggested 25 kg/m2 as a measure of obesity for Asian populations. The purpose of this report was to compare the oncologic outcomes of laparoscopic colorectal resection with BMI classified from the WHO Asia-Pacific perspective. PATIENTS AND METHODS: All patients underwent laparoscopic colorectal resection from September 2006 to March 2015 at a tertiary referral hospital. A total of 2408 patients were included and classified into four groups: underweight (n = 112, BMI <18.5 kg/m2), normal (n = 886, 18.5-22.9 kg/m2), pre-obese (n = 655, 23-24.9 kg/m2) and obese (n = 755, >25 kg/m2). Perioperative parameters and oncologic outcomes were analysed amongst groups. RESULTS: Conversion rate was the highest in the underweight group (2.7%, P < 0.001), whereas the obese group had the fewest harvested lymph nodes (21.7, P < 0.001). Comparing oncologic outcomes except Stage IV, the underweight group was lowest for overall (P = 0.007) and cancer-specific survival (P = 0.002). The underweight group had the lowest proportion of national health insurance but the highest rate of medical care (P = 0.012). CONCLUSION: The obese group had the fewest harvested lymph nodes, whereas the underweight group had the highest estimated blood loss, conversion rate to open approaches and the poorest overall and cancer-specific survivals.

Robotic Resection is a Good Prognostic Factor in Rectal Cancer Compared with Laparoscopic Resection: Long-term Survival Analysis Using Propensity Score Matching.

BACKGROUND: Robotic total mesorectal excision for rectal cancer has rapidly increased and has shown short-term outcomes comparable to conventional laparoscopic total mesorectal excision. However, data for long-term oncologic outcomes are limited. OBJECTIVE: The aim of this study is to evaluate long-term oncologic outcomes of robotic total mesorectal excision compared with laparoscopic total mesorectal excision. DESIGN: This was a retrospective study. SETTINGS: This study was conducted in a tertiary referral hospital. PATIENTS: A total of 732 patients who underwent totally robotic (n = 272) and laparoscopic (n = 460) total mesorectal excision for rectal cancer were included in this study. MAIN OUTCOME MEASURES: We compared clinicopathologic outcomes of patients. In addition, short- and long-term outcomes and prognostic factors for survival were evaluated in the matched robotic and laparoscopic total mesorectal excision groups (224 matched pairs by propensity score). RESULTS: Before case matching, patients in the robotic group were younger, more likely to have undergone preoperative chemoradiation, and had a lower tumor location than those in the laparoscopic group. After case matching most clinicopathologic outcomes were similar between the groups, but operative time was longer and postoperative ileus was more frequent in the robotic group. In the matched patients excluding stage IV, the overall survival, cancer-specific survival, and disease-free survival were better in the robotic group, but did not reach statistical significance. The 5-year survival rates for robotic and laparoscopic total mesorectal excision were 90.5% and 78.0% for overall survival, 90.5% and 79.5% for cancer-specific survival, and 72.6% and 68.0% for disease-free survival. In multivariate analysis, robotic surgery was a significant prognostic factor for overall survival and cancer-specific survival (p = 0.0040, HR = 0.333; p = 0.0161, HR = 0.367). LIMITATIONS: This study has the potential for selection bias and limited generalizability. CONCLUSIONS: Robotic total mesorectal excision for rectal cancer showed long-term survival comparable to laparoscopic total mesorectal excision in this study. Robotic surgery was a good prognostic factor for overall survival and cancer-specific survival, suggesting potential oncologic benefits.

Oncologic outcomes in rectal cancer patients with a ≤1-cm distal resection margin.

PURPOSE: Recently, common application of sphincter-saving resection in rectal cancer has led to acceptance of a 1-cm distal resection margin (DRM). The aim of this study was to evaluate oncologic outcomes of a DRM ≤1 cm in sphincter-saving resection for rectal cancer. The outcomes of a DRM ≤0.5 cm was also evaluated. METHODS: We reviewed prospectively collected data from 415 patients who underwent sphincter-saving resection for mid and low rectal cancer between September 2006 and December 2012 at Korea University Anam Hospital. Patients were divided into two groups according to DRM measured in a formalin fixed specimen: ≤1 cm (n = 132) and >1 cm (n = 283). The DRM ≤1 cm group was divided into two subgroups: ≤0.5 cm (n = 45) and >0.5, ≤1 cm (n = 87). RESULTS: Median follow-up periods were 47.2 months. The 5-year local recurrence rate was 8.8% in the DRM ≤1 cm group and 8.5% in the DRM >1 cm group (p = 0.630). The 5-year disease-free survival rate was 75.1 and 76.3% (p = 0.895), and the 5-year overall survival rate was 82.6 and 85.9% (p = 0.401), respectively. In subanalysis of the DRM ≤1 cm group, there was also no significant difference in the local recurrence and survival. CONCLUSIONS: There was no significant difference in local recurrence and survival based on DRM length. We found that DRM length less than 1 cm was not a prognostic factor for local recurrence or survival.

Clinical benefits and oncologic equivalence of self-expandable metallic stent insertion for right-sided malignant colonic obstruction.

BACKGROUND: The efficacy of stenting for right-sided malignant colonic obstruction is unknown. This study aimed to evaluate the safety, feasibility, and clinical benefits of self-expandable metallic stent insertion for right-sided malignant colonic obstruction. METHODS: Clinical data from patients who underwent right hemicolectomy for right colon cancer from January 2006 to July 2014 at three Korea University hospitals were retrospectively reviewed. A total of 39 patients who developed malignant obstruction in the right-sided colon were identified, and their data were analyzed. RESULTS: Stent insertion was attempted in 16 patients, and initial technical success was achieved in 14 patients (87.5 %). No stent-related immediate complications were reported. Complete relief from obstruction was achieved in all 14 patients. Twenty-five patients, including two patients who failed stenting, underwent emergency surgery. In the stent group, 93 % (13/14) of patients underwent elective laparoscopic surgery, and only one surgery was converted to an open procedure. All patients in the emergency group underwent emergency surgery within 24 h of admission. In the emergency group, only 12 % (3/25) of patients underwent laparoscopic surgery, with one surgery converted to an open procedure. All patients in both groups underwent either laparoscopy-assisted or open right/extended right hemicolectomy with primary anastomoses as the first operation. The operative times, retrieved lymph nodes, and pathologic stage did not differ between the two groups. Postoperative hospital stay (9.4 ± 3.4 days in the stent group vs. 12.4 ± 5.9 in the emergency group, p = 0.089) and time to resume oral food intake (3.2 ± 2.1 days in the stent group vs. 5.7 ± 3.4 in the emergency group, p = 0.019) were shorter in the stent group. And there were no significant differences in disease-free survival and overall survival between the two groups. CONCLUSIONS: Stent insertion appears to be safe and feasible in patients with right-sided colonic malignant obstruction. It facilitates minimally invasive surgery and may result in better short-term surgical outcomes.

Mechanical Bowel Preparation Does Not Affect Clinical Severity of Anastomotic Leakage in Rectal Cancer Surgery.

BACKGROUND: Previous multicenter randomized trials demonstrated that omitting mechanical bowel preparation (MBP) did not increase anastomotic leakage rates or other infectious complications. However, the most serious concern regarding the omission of MBP is ongoing fecal peritonitis after anastomotic leakage occurs. The aim of this study was to compare the clinical manifestations and severity of anastomotic leakage between patients who underwent MBP and those who did not. METHODS: This study was a single-center retrospective review of a prospectively maintained database. From January 2006 to September 2013, 1369 patients who underwent elective rectal cancer resection with primary anastomosis were identified and analyzed. RESULTS: Anastomotic leakage rates were not significantly different between patients who did not undergo MBP (77/831, 9.27%) and those who did (42/538, 7.81%). However, a significantly lower rate of clinical leakage requiring surgical exploration was observed in the leakage without MBP group (30/77, 39.0%) compared with the leakage with MBP group (30/42, 71.4%) (P = 0.001). There were no significant differences in the clinical severity of anastomotic leakage as assessed by the length of hospital stay, time to resuming a normal diet, length of antibiotic use, ileus rate, transfusion rate, ICU admission rate, and mortality rate between the leakage without MBP and leakage with MBP groups. CONCLUSION: MBP was not found to affect the clinical severity of anastomotic leakage in elective rectal cancer surgery.

Robotic versus laparoscopic intersphincteric resection for low rectal cancer: comparison of the operative, oncological, and functional outcomes.

BACKGROUND: Robotic surgery was developed to overcome the limitations of laparoscopic surgery and is increasingly used to treat low rectal cancer. In this study, we compared the operative, oncological, and functional outcomes of low rectal cancer patients who underwent robotic or laparoscopic intersphincteric resection (ISR). METHODS: Prospectively collected data from low rectal cancer patients who underwent laparoscopic or robotic ISR between September 2006 and August 2011 were retrospectively compared. The functional outcomes of patients followed up for ≥ 12 months after ileostomy closure were evaluated via questionnaire. RESULTS: Forty-four and 26 patients underwent robotic and laparoscopic ISR, respectively. The robotic group patients had a higher body mass index (BMI; 21.42 ± 3.13 vs. 24.13 ± 3.33 kg/m(2); p = 0.001), more advanced clinical N stage (p = 0.029), lower cancer location (3.71 ± 0.89 vs. 3.24 ± 0.78 cm; p = 0.023), more frequent chemoradiotherapy (26.9 vs. 54.5 %; p = 0.025), and longer operation time (286.77 ± 51.46 vs. 316.43 ± 65.11 min; p = 0.038). However, no intergroup differences were observed in the pathological details (except the number of retrieved lymph nodes), postoperative morbidity, 3-year overall survival, recurrence-free survival (RFS), local RFS, and functional outcomes. CONCLUSIONS: Robotic and laparoscopic ISR yielded similar operative, oncological, and functional outcomes in patients with low rectal cancer, despite differences in unfavorable outcome-affecting factors, including BMI, clinical N stage, cancer location, and chemoradiotherapy frequency. A randomized trial will provide more solid methodology for investigating the potential benefits of robotic ISR.