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).

Machine-Learning Algorithms Using Systemic Inflammatory Markers to Predict the Oncologic Outcomes of Colorectal Cancer After Surgery.

BACKGROUND: This study aimed to investigate the clinical significance of machine-learning (ML) algorithms based on serum inflammatory markers to predict survival outcomes for patients with colorectal cancer (CRC). METHODS: The study included 941 patients with stages I to III CRC. Based on random forest algorithms using 15 compositions of inflammatory markers, four different prediction scores (DFS score-1, DFS score-2, DFS score-3, and DFS score-4) were developed for the Yonsei cohort (training set, n = 803) and tested in the Ulsan cohort (test set, n = 138). The Cox proportional hazards model was used to determine correlation between prediction scores and disease-free survival (DFS). Harrell's concordance index (C-index) was used to compare the predictive ability of prediction scores for each composition. RESULTS: The multivariable analysis showed the DFS score-4 to be an independent prognostic factor after adjustment for clinicopathologic factors in both the training and test sets (hazard ratio [HR], 8.98; 95% confidence interval [CI] 6.7-12.04; P < 0.001 for the training set and HR, 2.55; 95% CI 1.1-5.89; P = 0.028 for the test set]. With regard to DFS, the highest C-index among single compositions was observed in the lymphocyte-to-C-reactive protein ratio (LCR) (0.659; 95% CI 0.656-0.662), and the C-index of DFS score-4 (0.727; 95% CI 0.724-0.729) was significantly higher than that of LCR in the test set. The C-index of DFS score-3 (0.725; 95% CI 0.723-0.728) was similar to that of DFS score-4, but higher than that of DFS score-2 (0.680; 95% CI 0.676-0.683). CONCLUSIONS: The ML-based approaches showed prognostic utility in predicting DFS. They could enhance clinical use of inflammatory markers in patients with CRC.

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.

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.

Postchemoradiation magnetic resonance imaging circumferential resection margin predicts treatment failure after multidisciplinary directed sphincter preservation in low rectal cancer.

BACKGROUND: This study aimed to review the magnetic resonance imaging (MRI) features of patients with low rectal cancer (LRC) undergoing preoperative chemoradiotherapy (CRT) and investigate the risk factors for treatment failure after sphincter preserving surgery following preoperative CRT based on multidisciplinary approach. OBJECTIVES: Patients who underwent standard CRT and sphincter preserving radical surgery for LRC between January 2000 and December 2011 were retrospectively reviewed. Sphincter preservation failure (SPF) was defined as any one of the following: positive pathologic circumferential resection margin, local recurrence, failure to repair ileostomy, or permanent stoma formation due to anastomotic complications. RESULTS: Among the 191 patients, there were no overall significant differences between sphincter preservation success (n = 161) and SPF (n = 30) groups. SPF group showed a higher MRI circumferential resection margins (mrCRM) positive rate before and after CRT (before CRT: 33.3% vs. 16.1%, p = 0.027; after CRT: 23.3% vs. 6.2%, p = 0.002). Multivariate analysis showed that only mrCRM after CRT was associated with SPF (hazard ratio = 4.596, p = 0.005). SPF group showed worse 5-year cancer-specific survival (51% vs. 92.7%, p < 0.001). CONCLUSIONS: MRI-based assessment of the tumor after CRT plays a crucial role in predicting the success and feasibility of sphincter preservation as well as oncological outcomes in patients with LRC.

Association of Albumin-Bilirubin Grade and Myosteatosis with its Prognostic Significance for Patients with Colorectal Cancer.

BACKGROUND: The albumin-bilirubin (ALBI) grade is a useful prognostic and predictive marker for patients with liver disease. Its clinical significance has been limited to patients with colorectal cancer (CRC). Furthermore, the association between the ALBI grade and skeletal muscle-related indices is unclear. METHODS: This study enrolled 1015 patients who underwent computed tomography (CT) scans within 31 days before surgery. The prognostic value of the ALBI grade in predicting overall survival (OS) was assessed using the Cox proportional hazards model. The correlation between the ALBI grade and the skeletal muscle index or radiodensity (myosteatosis) was evaluated. The predictive accuracy of ALBI alone and in combination with myosteatosis was compared using Harrell's concordance index (C-index). RESULTS: The significant prognostic factors for OS identified in the multivariable analysis were the ALBI group (low vs high: hazard ratio [HR], 1.566; 95 % confidence interval [CI], 1.174-2.089; p = 0.002) and myosteatosis (low vs. high: HR, 0.648; 95 % CI, 0.486-0.865; p = 0.003). The rate of low-grade myosteatosis increased as the ALBI grade increased. The C-index of combined ALBI and myosteatosis (0.650; 95 % CI, 0.618-0.683) was superior to that of ALBI alone (0.603; 95 % CI, 0.575-0.631; bootstrap incremental area under the curve [iAUC] mean difference, 0.047; 95 % CI, 0.012-0.070) and myosteatosis alone (0.608; 95 % CI, 0.577-0.640; bootstrap iAUC mean difference, 0.042; 95 % CI, 0.023-0.064). CONCLUSION: The ALBI grade is significantly associated with myosteatosis. The ALBI grade is a significant prognostic factor, and the combination of ALBI and myosteatosis show an additive value in discriminating survival of patients with CRC.

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.

Impact of laparoscopic surgical experience on the learning curve of robotic rectal cancer surgery.

BACKGROUND: Robotic surgery has advantages in terms of the ergonomic design and expectations of shortening the learning curve, which may reduce the number of patients with adverse outcomes during a surgeon's learning period. We investigated the differences in the learning curves of robotic surgery and clinical outcomes for rectal cancer among surgeons with differences in their experiences of laparoscopic rectal cancer surgery. METHODS: Patients who underwent robotic surgery for colorectal cancer were reviewed retrospectively. Patients were divided into five groups by surgeons, and their clinical outcomes were analyzed. The learning curve of each surgeon with different volumes of laparoscopic experience was analyzed using the cumulative sum technique (CUSUM) for operation times, surgical failure (open conversion or anastomosis-related complications), and local failure (positive resection margins or local recurrence within 1 year). RESULTS: A total of 662 patients who underwent robotic low anterior resection (LAR) for rectal cancer were included in the analysis. Number of laparoscopic LAR cases performed by surgeon A, B, C, D, and E prior to their first case of robotic surgery were 403, 40, 15, 5, and 0 cases, respectively. Based on CUSUM for operation time, surgeon A, B, C, D, and E's learning curve periods were 110, 39, 114, 55, and 23 cases, respectively. There were no significant differences in the surgical and oncological outcomes after robotic LAR among the surgeons. CONCLUSIONS: This study demonstrated the limited impact of laparoscopic surgical experience on the learning curve of robotic rectal cancer surgery, which was greater than previously reported curves.

Can better surgical outcomes be obtained in the learning process of robotic rectal cancer surgery? A propensity score-matched comparison between learning phases.

BACKGROUND: Although studies of robotic rectal cancer surgery have demonstrated the effects of learning on operation time, comparisons have failed to demonstrate differences in clinicopathological outcomes between unadjusted learning phases. This study aimed to investigate the learning curve of robotic rectal cancer surgery for clinicopathological outcomes and compare surgical outcomes between adjusted learning phases. Study design We enrolled 506 consecutive patients with rectal adenocarcinoma who underwent robotic resection by a single surgeon between 2007 and 2018. Risk-adjusted cumulative sum (RA-CUSUM) for surgical failure was used to analyze the learning curve. Surgical failure was defined as the occurrence of any of the following: conversion to open surgery, severe complications (Clavien-Dindo grade ≥ 3a), insufficient number of harvested lymph nodes (LNs), or R1 resection. Comparisons between learning phases analyzed by RA-CUSUM were performed before and after propensity score matching. RESULTS: In RA-CUSUM analysis, the learning curve was divided into two learning phases: phase 1 (1st-177th cases, n = 177) and phase 2 (178th-506th cases, n = 329). Before matching, patients in phase 2 had deeper tumor invasion and higher rates of positive LNs on pretreatment images and preoperative chemoradiotherapy. After matching, phase 1 (n = 150) and phase 2 (n = 150) patients exhibited similar clinical characteristics. Phase 2 patients had lower rates of surgical failure overall and these components: conversion to open surgery, severe complications, and insufficient harvested LNs. CONCLUSIONS: For robotic rectal cancer surgery, surgical outcomes improved after the 177th case. Further studies by other robotic surgeons are required to validate our results.

Coordination of the leucine-sensing Rag GTPase cycle by leucyl-tRNA synthetase in the mTORC1 signaling pathway.

A protein synthesis enzyme, leucyl-tRNA synthetase (LRS), serves as a leucine sensor for the mechanistic target of rapamycin complex 1 (mTORC1), which is a central effector for protein synthesis, metabolism, autophagy, and cell growth. However, its significance in mTORC1 signaling and cancer growth and its functional relationship with other suggested leucine signal mediators are not well-understood. Here we show the kinetics of the Rag GTPase cycle during leucine signaling and that LRS serves as an initiating "ON" switch via GTP hydrolysis of RagD that drives the entire Rag GTPase cycle, whereas Sestrin2 functions as an "OFF" switch by controlling GTP hydrolysis of RagB in the Rag GTPase-mTORC1 axis. The LRS-RagD axis showed a positive correlation with mTORC1 activity in cancer tissues and cells. The GTP-GDP cycle of the RagD-RagB pair, rather than the RagC-RagA pair, is critical for leucine-induced mTORC1 activation. The active RagD-RagB pair can overcome the absence of the RagC-RagA pair, but the opposite is not the case. This work suggests that the GTPase cycle of RagD-RagB coordinated by LRS and Sestrin2 is critical for controlling mTORC1 activation, and thus will extend the current understanding of the amino acid-sensing mechanism.

Prognosis of Synchronous Colorectal Liver Metastases After Simultaneous Curative-Intent Surgery According to Primary Tumor Location and KRAS Mutational Status.

BACKGROUND: Tumor location and KRAS mutational status have emerged as prognostic factors of colorectal cancer. We aimed to define the prognostic impact of primary tumor location and KRAS mutational status among synchronous colorectal liver metastases (CRLM) patients who underwent simultaneous curative-intent surgery (SCIS). METHODS: We compared the clinicopathologic characteristics and long-term outcomes of 227 patients who underwent SCIS for synchronous CRLM, according to tumor location and KRAS mutational status. We cross-classified tumor location and KRAS mutational status and compared survival outcomes between the four resulting patient groups. RESULTS: Forty-one patients (18.1%) had right-sided (RS) tumors and 186 (81.9%) had left-sided (LS) tumors. One-third of tumors (78/227) harbored KRAS mutations. The KRAS mutant-type (KRAS-mt) was more commonly observed among RS tumors than among LS tumors [21/41 (51.2%) vs. 57/186 (30.6%), p = 0.012]. Median follow-up time was 43.4 months. Patients with RS tumors had shorter survival times than those with LS tumors [median disease-free survival (DFS): RS, 9.9 months vs. LS, 12.1 months, p = 0.003; median overall survival (OS): RS, 49.7 months vs. LS, 88.8 months, p = 0.039]. RS tumors were a negative prognostic factor for DFS [hazard ratio (HR) 1.878, p = 0.001] and OS (HR 1.660, p = 0.060). RS KRAS-mt and LS KRAS wild-type (KRAS-wt) tumors had the worst and best oncological outcomes, respectively. CONCLUSION: Tumor location has a prognostic impact in patients who underwent SCIS for CRLM, and RS KRAS-mt tumors yielded the worst oncological outcome. These results may allow for more tailored multimodality treatments.

Clinical Significance of Preoperative Serum Carcinoembryonic Antigen Within the Normal Range in Colorectal Cancer Patients Undergoing Curative Resection.

BACKGROUND: Serum carcinoembryonic antigen (CEA) is a widely used tumor marker in colorectal cancer (CRC), but within normal range of preoperative CEA levels the clinical significance of CEA is unknown. OBJECTIVE: The aim of this study was to evaluate the usefulness of CEA within the normal range as a prognosticator of non-metastatic CRC. METHODS: This retrospective cohort study included 2021 CRC patients with normal preoperative CEA who underwent elective curative surgery (discovery group). We determined the optimal cut-off value for disease-free survival (DFS) discrimination using the Contal and O'Quigley method. We also assessed the prognostic significance of the cut-off value in a prospective cohort of 171 stage III colon cancer patients treated with oxaliplatin-based adjuvant chemotherapy (validation group). RESULTS: The optimal cut-off CEA value was 2.1 ng/mL in the discovery group. The DFS rates were significantly poorer in patients with high-normal preoperative CEA levels (2.1-5.0 ng/mL) than in those with low-normal CEA levels (< 2.1 ng/mL) in both groups. A high-normal CEA level was an independent risk factor for DFS in both groups, and was associated with inferior DFS in patients with stage II and III disease and in never or former smokers. The correlation between DFS and CEA levels was more distinct in left-sided colon and rectal cancer. CONCLUSIONS: A high-normal preoperative CEA level (≥ 2.1 ng/mL), even within the normal range, was an independent prognosticator for poor DFS in CRC. The usefulness of CEA was influenced by smoking status and tumor location in addition to tumor stage.

Significance of Radial Margin in Patients Undergoing Complete Mesocolic Excision for Colon Cancer.

BACKGROUND: Comparable to circumferential resection margin in rectal cancer, radial margin is a potential prognostic factor in colon cancer that has just begun to be studied. No previous studies have investigated the influence of radial margin in the context of complete mesocolic excision. OBJECTIVE: This study aimed to examine the impact of radial margin on oncologic outcomes after complete mesocolic excision for colon cancer. DESIGN: We retrospectively reviewed patients with stage I to III colon cancer who underwent curative resection from October 2010 to March 2013. SETTINGS: This study was conducted using the prospective colorectal cancer registry of Severance hospital. PATIENTS: A total of 834 consecutive patients who underwent complete mesocolic excision for colon adenocarcinoma were included. INTERVENTIONS: We assigned patients into 3 groups according to radial margin distance: group A, radial margin ≥2.0 mm; group B, 1.0 ≤ radial margin < 2.0 mm; group C, radial margin <1 mm. MAIN OUTCOMES AND MEASURES: Overall survival and disease-free survival were estimated. RESULTS: On adjusted Cox regression analysis, only group C was predictive of reduced overall survival (HR, 1.90; 95% CI, 1.11-3.25; p = 0.018) and disease-free survival (HR, 1.93; 95% CI, 1.28-2.89; p = 0.001). We thereby defined radial margin threatening as radial margin <1 mm. Postoperative 5-fluorouracil (HR, 0.86; 95% CI, 0.35-2.10; p = 0.743) and FOLFOX (HR, 1.23; 95% CI, 0.57-2.64; p = 0.581) chemotherapy did not affect disease-free survival in patients with radial margin threatening. LIMITATIONS: This study has the limitations inherent in all retrospective, single-institution studies. CONCLUSIONS: Even with complete mesocolic excision, radial margin <1 mm was an independent predictor of survival and recurrence. This finding suggests that special efforts for obtaining a clear radial margin may be necessary in locally advanced colon cancer. See Video Abstract at http://links.lww.com/DCR/B125. IMPORTANCIA DEL MARGEN RADIAL EN PACIENTES SOMETIDOS A ESCISIÓN MESOCÓLICA COMPLETA PARA CÁNCER DEL COLON: Comparable al margen de resección circunferencial en cáncer rectal, el margen radial en cáncer de colon, es un factor pronóstico potencial, que recientemente comienza a estudiarse. Ningún estudio previo ha investigado la influencia del margen radial, en el contexto de la escisión mesocólica completa.Examinar en cáncer de colon, el impacto del margen radial en los resultados oncológicos, después de la escisión mesocólica completa.Revisión retrospectiva de pacientes con cáncer de colon en estadio I-III, sometidos a resección curativa de octubre 2010 a marzo 2013.Este estudio se realizó utilizando un registro prospectivo de cáncer colorrectal del hospital Severance.Se incluyeron un total de 834 pacientes consecutivos con adenocarcinoma de colon, sometidos a escisión mesocólica completa. Dividimos a los pacientes en 3 grupos según la distancia del margen radial: grupo A, margen radial ≥ 2.0 mm; grupo B, 1.0 ≤ margen radial <2.0 mm; grupo C, margen radial <1 mm.Se estimó la supervivencia general y la supervivencia libre de enfermedad.En el análisis de regresión de Cox ajustado, solo el grupo C fue predictivo de supervivencia global reducida (HR, 1.90; IC 95%, 1.11-3.25; p = 0.018) y supervivencia libre de enfermedad (HR, 1.93; IC 95%, 1.28-2.89; p = 0.001). Definimos como margen radial amenazante, un margen radial <1 mm. La quimioterapia posoperatoria con 5-FU (HR, 0,86; IC 95%, 0,35-2,10; p = 0.743) y FOLFOX (HR, 1,23; IC 95%, 0,57-2,64; p = 0,581), no afectó la supervivencia libre de enfermedad en pacientes con riesgo de margen radial.Este estudio tiene limitaciones inherentes a todos los estudios retrospectivos de una sola institución.Aun con la escisión mesocólica completa, el margen radial <1 mm fue un predictor independiente de supervivencia y recurrencia. Este hallazgo sugiere que pueden ser necesarios esfuerzos especiales para obtener un claro margen radial, en cáncer de colon localmente avanzado. Consulte Video Resumen en http://links.lww.com/DCR/B125.

Survival outcomes after isolated local recurrence of rectal cancer and risk analysis affecting its resectability.

BACKGROUND AND OBJECTIVES: This study aimed to investigate the clinical course and prognostic factors after isolated local recurrence (iLR) and to identify the predictive factors for R0 resection of locally recurrent rectal cancer (LRRC). METHODS: We retrospectively reviewed the medical records of 76 patients with iLR who had undergone radical surgery for a primary tumor from 2003 to 2015. RESULTS: The iLR rate was 2.5%. From 76 patients, 39 patients underwent R0 resection for iLR. Multivariate analysis revealed that initial open surgery, neoadjuvant chemoradiation, and p/ypT ≥ 3 were poor prognostic factors after iLR as regard to the variables related to the primary tumor; and symptom presence at the time of iLR diagnosis, higher fixity, and no chemotherapy after iLR were associated with shorter overall survival after iLR, and R0 resection of LRRC was the only favorable prognostic factor for progression-free survival after iLR as regard to the variables related to LRRC. Higher tumor level, negative pathologic circumferential margin of the primary tumor, and low fixity of LRRC were favorable factors in achieving R0 resection of LRRC. CONCLUSIONS: Early detection of iLR before symptom development, use of chemotherapy after iLR and R0 resection of LRRC should be considered to improve survival outcomes after iLR.

Metachronous metastasis confined to isolated lymph node after curative treatment of colorectal cancer.

BACKGROUND: The incidence of lymph node metastasis (LNM) in colorectal cancer is known to be 2-6%, but little data are available regarding metachronous metastasis confined to isolated LN. The aim of this study is to determine the distribution of isolated LNM and the risk factors for survival of isolated LNM in colorectal cancer. METHODS: We retrospectively reviewed consecutive patients with colorectal adenocarcinoma between January 2008 and December 2015 at a tertiary referral center. A total of 5902 patients with biopsy-proven colorectal adenocarcinoma treated via surgery were included. Multivariate Cox proportional hazards analysis was used to identify prognostic factors for overall survival. RESULTS: Of the 5902 patients, recurrent cases were 1326. Among the relapsed patients, 301 patients had isolated LNM (22.69%). Para-aortic (48.8%), pelvic (29.9%), and Lung hilum (10.0%) were the most common sites of isolated LNM; there were statistically significant differences in the distribution of isolated LNM between the colon and rectal cancer (p = 0.02). Approximately 80% of isolated LNM were diagnosed within 3 years. Multidisciplinary therapy for LNM, diagnosis time to LNM, the T-stage, and histological type of primary cancer were identified as independent prognostic factors for overall survival. CONCLUSION: This study suggests that multidisciplinary management is a potentially effective treatment strategy for isolated LNM. Since time to LNM, the T-stage, and histological type are prognostic factors, an active follow-up program for colorectal cancer is required.

Late anastomotic leakage after anal sphincter saving surgery for rectal cancer: is it different from early anastomotic leakage?

PURPOSE: Although multiple studies have examined anastomotic leakage (AL) after low anterior resection (LAR), their definitions of AL varied, and few have studied late diagnosed AL after surgery. This study aimed to characterize late AL after anal sphincter saving surgery (SSS) for rectal cancer by examining clinical characteristics, risk factors, and management of patients with late AL compared with early AL. METHODS: Data from January 2005 to December 2014 were collected from a total of 1903 consecutive patients who underwent anal sphincter saving surgery for rectal cancer and were retrospectively reviewed. Late AL was defined as AL diagnosed more than 30 days after surgery. Variables and risk factors associated with early and late diagnosed AL were analyzed by multivariate logistic regression. RESULTS: Overall, early, and late rates of AL were 13.7%, 6.7%, and 7%, respectively. Receiving neoadjuvant chemoradiotherapy (nCRT) was a risk factor for developing late AL, but not early AL (OR, 3.032; 95% CI, 1.947-4.722; p < 0.001). Protective ileostomy did not protect against late AL. Among the 134 patients with late AL, 26 (19.4%) were classified as asymptomatic and 108 patients (80.6%) as symptomatic. The most frequent symptomatic complications related to late AL were fistula (42 cases, 39.7%), chronic sinus (33 cases, 31.1%), and stenosis (31 cases, 29.2%). CONCLUSION: Clinical characteristics, risk factors, and management of patients with late AL after SSS were different from early AL. Close attention should be given to consider late AL as the continuation of early AL.

Clinical outcome for management of colonic diverticulitis: characteristics and surgical factor based on two institution data at South Korea.

PURPOSE: The aim of this study was to analyze clinical outcomes after surgical and/or conservative management of patients with colonic diverticulitis. MATERIAL AND METHODS: Between January 2001 and November 2018, data for 1175 patients (right (Rt.) side: n = 1037, left (Lt.) side: n = 138) who underwent conservative management (n = 987) and surgical management (n = 188) for colonic diverticulitis were retrieved from a retrospective database. The Rt. sided was defined up to the proximal two-thirds of the transverse colon and Lt. sided was defined from the distal one-third of the transverse colon. RESULTS: The overall incidence of colonic diverticulitis is gradually increasing. The mean age of all patients was 43.2 ± 17 and was significantly higher in patients with Lt.-sided (57.0 ± 15.7) than with Rt.-sided (41.4 ± 13.4) diverticulitis (p = 0.001). The most common lesion site was cecum (71.7%, n = 843). First-time attacks were the most common (91.0%, n = 1069). The surgical rate was 12.2% on the right. sided and 44.9% on the left sided (p < 0.005). The mean age, age distribution, BMI, open surgery rate, stoma formation rate, and Hinchey types III and IV rate were significantly higher in Lt. sided than in Rt. sided (p < 0.005). Older age, higher BMI (≥ 25), and Hinchey types III and IV were significantly associated with surgical risk factors of diverticulitis (p < 0.005). CONCLUSION: Base on present study, Lt.-sided colonic diverticulitis tends to be more severe than Rt. sided, and surgery is more often required. In addition, colonic diverticulitis that requires surgery seems to be older and more obese on Lt. sided.

Prediction of transabdominal total mesorectal excision difficulty according to the angle of pelvic floor muscle.

BACKGROUND: Total mesorectal excision (TME) is challenging to perform in a deep, narrow pelvis. While previous studies used pelvimetry to assess bony pelvic structures, there is no consensus on exact definition of deep, narrow pelvis. We hypothesized that the shape of pelvic floor muscle may impact the performance of transabdominal pelvic dissection. We aimed to evaluate which parameters of the shape of pelvic floor muscle impact the difficulty of TME and present a predictive reference value for TME difficulty. METHODS: From January 2015 to December 2015, 85 consecutive patients who had undergone curative resection for middle to lower rectal cancer were retrospectively studied. Pelvimetry was performed using preoperative T2-weighted magnetic resonance imaging. Predictive factor analysis for surgical duration was studied using linear regression. Mann-Whitney U test, comparing surgical duration between two groups classified by predictive factor, was used for the analysis of reference value. RESULTS: Multivariate analysis revealed that body mass index, protective stoma, number of surgeon, and incline angle of pelvic floor muscle (ß) were independent predictors of surgical duration. Test statistics of Mann-Whitney U for the difference in surgical duration between groups above and below a ß of 54° were maximized. CONCLUSIONS: The incline angle of pelvic floor muscle is an independent predictor of surgical duration. In patients with steeper incline of PFM, transabdominal TME is expected to be difficult. This index is novel, but needs to be further validated.

Oncologic Outcomes of Self-Expandable Metallic Stent as a Bridge to Surgery and Safety and Feasibility of Minimally Invasive Surgery for Acute Malignant Colonic Obstruction.

BACKGROUND: Although self-expandable metal stents (SEMS) are widely used as a bridge to surgery (BTS) in patients with malignant colorectal cancer obstruction, there has been some debate about their effect on long-term oncological outcomes. Furthermore, data on the safety and feasibility of minimally invasive surgery (MIS) combined with stent placement are scarce. We aimed to determine the long-term oncological outcomes of SEMS as a BTS, and the short-term outcomes of SEMS used with minimally invasive colorectal surgery. METHODS: Data from patients who were admitted with malignant obstructing colon cancer between January 2006 and December 2015 were retrospectively reviewed; 71 patients underwent direct surgery and 182 patients underwent SEMS placement as a BTS. Long-term and short-term outcomes of the groups were compared. In a subgroup analysis of the BTS group, the short-term outcomes of conventional open surgery and MIS were compared. RESULTS: There were no differences in long-term oncologic outcomes between groups. The primary anastomosis rate was higher in the stent group than in the direct surgery group. In the stent group, postoperative complication rates were lower in the minimally invasive group than in the open surgery group. Time to flatus and time to soft diet resumption were shorter in the minimally invasive group, as was length of hospital stay. CONCLUSIONS: Elective surgery after stent insertion does not adversely affect long-term oncologic outcomes. Furthermore, MIS combined with stent insertion for malignant colonic obstruction is safe and feasible.

Predictive Factors for Bowel Dysfunction After Sphincter-Preserving Surgery for Rectal Cancer: A Single-Center Cross-sectional Study.

BACKGROUND: With increasing rates of sphincter preservation because of advances in preoperative chemoradiation, restoration of bowel continuity has become a main goal of rectal cancer treatment. However, in many patients, postoperative bowel dysfunction negatively affects the quality of life. OBJECTIVE: This study aimed to analyze predictors of bowel dysfunction after sphincter-preserving surgery in patients with rectal cancer. DESIGN: This was a cross-sectional study. SETTINGS: Assessment of bowel dysfunction was conducted between November 2015 and June 2017 at our institution. PATIENTS: A total of 316 patients with rectal cancer who underwent sphincter-preserving surgery between February 2009 and April 2017 and agreed with an interview for assessing bowel dysfunction were included. MAIN OUTCOME MEASURES: Bowel dysfunction was assessed with the Memorial Sloan Kettering Cancer Center Bowel Function Instrument and Wexner score. All the assessments were conducted face-to-face by the same interviewer. RESULTS: The median time interval between the restoration of bowel continuity and assessment was 10 months (interquartile range, 3-37), and the median total Memorial Sloan Kettering Cancer Center and Wexner scores were 65 (interquartile range, 58-73) and 6 (interquartile range, 0-11). The time interval was correlated with the Memorial Sloan Kettering Cancer Center scores (rho, 0.279) and Wexner scores (rho, -0.306). In a multivariate analysis, handsewn anastomosis and short time interval (≤1 year) were independently associated with poor bowel function (Memorial Sloan Kettering Cancer Center score ≤65). A short time interval (≤1 year), preoperative chemoradiation, and ileostomy were independently associated with major fecal incontinence (Wexner ≥8). LIMITATIONS: Selection bias may be inherent. CONCLUSIONS: Bowel function recovers with time after the restoration of bowel continuity. A short time interval, handsewn anastomosis, preoperative chemoradiation, and ileostomy were significantly associated with poor bowel function or major fecal incontinence. Surgeons should discuss postoperative bowel dysfunction and its predictive factors with the patients. See Video Abstract at http://links.lww.com/DCR/A930.