Proposal for a post-operative surveillance strategy for stage I colorectal cancer patients based on a novel recurrence risk stratification: a multicenter retrospective study.

BACKGROUND: The recurrent risk of stage I colorectal cancer (CRC) is not clear, and the data regarding appropriate post-operative surveillance schedules in stage I CRC are scarce. OBJECTIVES: We aimed to stratify stage I CRC based on the recurrence risk and evaluate optimal post-operative surveillance durations based on this stratification. METHODS: We retrospectively analyzed the cases of 6607 stage I CRC patients from 24 institutions. To assess the patients' clinicopathological factors that impact recurrence-free survival (RFS), we performed univariate and multivariate analyses using Cox proportional hazards models. We divided the patients into classes based on their numbers of factors that were associated with poor RFI in the multivariate analysis. RESULTS: Recurrence occurred in 3.9% patients. The multivariate analysis revealed the independent factors for poor RFS: rectal cancer, T2 depth, presence of lymphatic invasion, high level of pre-operative carcinoembryonic antigen, and absence of D2-3 lymphadenectomy. We also divided the patients into three classes based on their numbers of these risk factors; the 3-year and 5-year RFS rates were 99.3% and 99.1% in the no-risk patients, 97.4% and 96.5% in the patients with 1-2 risks, and 92.1% and 90.0% in the patients with 3-5 risks, respectively. In the patients with no risk and in the patients with 1-2 risks after 3 years post-surgery, ≤ 1% recurrence occurred. Thus, post-operative surveillance may be omitted in these populations. CONCLUSIONS: Our new classification properly stratified the recurrence risks of stage I CRC patients, and may help reduce unnecessary post-operative surveillance.

Adsorptive Granulocyte and Monocyte Apheresis Is Effective in Ulcerative Colitis Patients Both with and without Concomitant Prednisolone.

BACKGROUND: The number of ulcerative colitis (UC) patients is increasing in Japan and other countries. Selective depletion of myeloid lineage leucocytes by adsorptive granulocyte and monocyte apheresis (GMA) with an Adacolumn (JIMRO, Takasaki, Japan) was introduced as a nonpharmacologic treatment strategy in UC patients in 2000. GMA has been reported to be effective in clinical trials; however, the effect of concomitant prednisolone (PSL) on GMA needs to be clarified. METHODS: Thirty-nine patients with active UC were treated with GMA at our institute between June 2009 and September 2018. All patients received GMA therapy once or twice a week with the Adacolumn. Conventional medication was to be continued during the whole GMA treatment course. The clinical response was retrospectively evaluated. RESULTS: According to the partial Mayo score, remission was 33.3%, significant efficacy 25.6%, effective 25.6%, and no response 15.4%. The average partial Mayo score was 6.2 ± 1.4 at entry and significantly declined to 1.8 ± 1.8 after GMA sessions (p < 0.0001). The average number of bowel movements was 9.5 ± 5.6 at entry and significantly declined to 3.0 ± 2.8 after GMA sessions (p < 0.0001). In a comparison between the group treated with concomitant PSL and the group without PSL, the change in partial Mayo score or the number of bowel movements from entry to after GMA sessions was not significantly different. Among 24 patients treated by GMA with concomitant PSL, 75% (18/24) became steroid free. CONCLUSIONS: The effect of GMA with concomitant PSL and that of GMA without PSL were not different, and GMA was effective irrespective of PSL administration. The present study showed that GMA had efficacy and led many UC patients treated by PSL to be steroid free with no safety concern in the real world, although there is the possibility of recruitment bias due to the retrospective nature of the study.

Successful surgical management of mesenteric inflammatory veno-occlusive disease.

BACKGROUND: The term "mesenteric inflammatory veno-occlusive disease (MIVOD)" is used to describe an ischemic injury resulting from phlebitis or venulitis that affects the bowel or mesentery in the absence of arteritis. MIVOD is difficult to diagnose because of its rarity and frequent confusion with other diseases. The incidence and etiology of MIVOD remain unclear; only a few cases have been reported. We describe a case of the successful surgical management of a patient with MIVOD with characteristic images. CASE PRESENTATION: A 65-year-old Japanese man visited a hospital with the chief complaint of abdominal pain in January 2018. CT showed edema and thickening of the intestinal wall from the descending colon to the rectum. The patient was admitted to the hospital. Suspected diagnoses were enteritis, ulcerative colitis, amyloidosis, vasculitis, malignant lymphoma, and venous thrombus, but no definitive diagnosis was obtained. The patient was transferred to our hospital for the treatment of stenosis (located from the descending colon to the rectum) and bowel obstruction. An emergency transverse colostomy was performed. The sigmoid colon and mesentery were too rigid and edematous to resect. Colonic hemorrhage occurred 2 weeks after the surgery. With radiology intervention, coiling for the arteriovenous fistula in the descending colon was performed, and hemostasis was obtained. A colonoscopy at 6 months post-surgery showed neither ulceration nor stenosis in the rectum, indicating that the rectum could be preserved in the next surgery. However, severe stenosis in the descending and sigmoid colon remained unchanged. Ten months after the transverse colostomy, we performed a subtotal colectomy and ileorectal anastomosis, and an ileostomy was created. The sigmoid colon and mesentery were not so rigid compared to the first surgery's findings, and we were able to resect intestine and mesentery. Histopathology revealed phlebitis and venulitis, fibrinoid necrosis, and normal arteries, meeting the diagnostic criteria for MIVOD. Postoperatively, the patient showed no recurrence for 8 months. CONCLUSION: Clinicians should consider MIVOD when examining a patient with intestinal ischemia. When MIVOD is suspected, the patient is indicated for surgery based on an accurate diagnosis and good prognosis.

Significance of the 7th postoperative day neutrophil-to-lymphocyte ratio in colorectal cancer.

PURPOSE: High neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation and is associated with poor survival in localized or metastatic cancer. Preoperative NLR in colorectal cancer reportedly correlates with recurrence-free survival and is useful as a recurrence prediction factor. No reports have yet investigated recurrence factors using postoperative NLR. This study assessed the predictive value of NLR preoperatively and on the first (NLR1) and seventh day (NLR7) postoperatively in patients with stage II colorectal cancer. METHODS: We performed a retrospective cohort study involving patients undergoing colorectal resection at a single institution between January 2012 and December 2016; we used medical records of 176 consecutive patients with stage II colorectal cancer undergoing curative tumor resection. NLRs as well as clinical, histopathologic, and laboratory data were analyzed. Univariate and multivariate analyses were conducted to identify prognostic factors associated with recurrence-free survival (RFS). RESULTS: Univariate analysis revealed that elevated NLR, NLR7, and lymphatic invasion were significantly associated with decreased RFS (p < 0.05). NLR7 was revealed as significant via multivariate analysis (p = 0.013). The 3-year RFS rate was 87.1% for patients with normal NLR7 and 70.3% for those with elevated NLR7. CONCLUSION: Elevated seventh-day postoperative NLR is a significant independent predictor of reduced RFS for patients with stage II colorectal cancer and may be a potential biomarker for identifying candidates for adjuvant chemotherapy.

Plasma exosomal microRNA-125b as a monitoring biomarker of resistance to mFOLFOX6-based chemotherapy in advanced and recurrent colorectal cancer patients.

Liquid biomarkers for the early detection of resistance to chemotherapy are important for improving prognosis. This study investigated the usefulness of plasma exosomal microRNA-125b (ex-miRNA-125b) for the early detection of resistance to modified fluorouracil, leucovorin and oxaliplatin (mFOLFOX6)-based first-line chemotherapy in patients with advanced or recurrent (advanced/recurrent) colorectal cancer (CRC). First, ex-miRNAs associated with resistance to mFOLFOX6-based chemotherapy were profiled via miRNA microarray analysis. In this analysis, ex-miR-125b exhibited the greatest upregulation in patients with progressive disease (PD) compared with the findings for patients with stable disease (SD) and healthy controls. Next, another 55 patients with advanced/recurrent CRC who received mFOLFOX6-based first-line chemotherapy underwent a validation study of ex-miR-125b. Blood samples were collected before and during treatment until tumor progression. Ex-miRNA levels were measured via TaqMan microRNA assays. Patients with CRC had significantly higher ex-miR-125b levels than healthy controls. In patients with partial responses, ex-miR-125b levels at the Response Evaluation Criteria in Solid Tumors (RECIST) judgment point were significantly lower than those measured before treatment. In patients with SD, ex-miR-125b levels did not differ before and during treatment. In patients with PD, ex-miR-125b levels at the RECIST judgment point were significantly higher than those measured before treatment. These changes in ex-miR-125b levels were significantly different between groups even 1 month after the initiation of chemotherapy. Progression-free survival (PFS) was significantly worse in patients with high baseline ex-miR-125b levels than in those with low levels. In the Cox analysis, baseline ex-miR-125b levels and KRAS mutation were indicated to be independent prognostic factors for PFS. The present results suggest that plasma ex-miR-125b levels may be useful for the early detection of resistance to mFOLFOX6-based first-line chemotherapy. Furthermore, ex-miR-125b before chemotherapy is a predictive biomarker for PFS in patients with advanced/recurrent CRC.

Angiotensin I-converting enzyme inhibitors/angiotensin II receptor blockers may reduce tumor recurrence in left-sided and early colorectal cancers.

BACKGROUND: Angiotensin signaling is suggested to be involved in tumorigenesis, tumor proliferation, and metastases. In colorectal cancer (CRC), it was demonstrated that angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) may reduce the risk of CRC; however, their impact on tumor recurrence remains unknown. Therefore, in this study, we evaluated the impact of ACEIs/ARBs on tumor recurrence in CRC patients. PATIENTS AND METHODS: We retrospectively investigated the clinicopathological data of 461 stage I-III CRC patients. We divided the patients into those who took an ACEI and/or ARB (the ACEI/ARB+ group) and those who did not (the ACEI/ARB- group), and we compared the two groups' recurrence-free survival (RFS) using a Kaplan-Meier curve analysis and log rank test. We also examined the impact of AGTR1 expression on tumor recurrence, using two public CRC datasets. RESULTS: The Kaplan-Meier curves showed a trend toward improved RFS in the ACEI/ARB+ group versus the ACEI/ARB- group (p = 0.063). Subgroup analyses demonstrated that the RFS was significantly better in the ACEI/ARB+ group versus the ACEI/ARB- group in the patients with left-sided CRC (p = 0.030) and those with stage I CRC (p = 0.009). Consistent with these findings, the AGTR1 expression was higher in the left-sided versus right-sided colon (p = 0.048). High AGTR1 expression levels were associated with poor RFS in the GSE39582 dataset's stage I-III CRC patients (p < 0.001), and this finding was also validated in the GSE17536 dataset (p = 0.023). CONCLUSION: ACEI/ARB treatment may reduce tumor recurrence in left-sided CRC and early-stage CRC.

G12V and G12C mutations in the gene KRAS are associated with a poorer prognosis in primary colorectal cancer.

PURPOSE: The increased incidence of colorectal cancer (CRC) has necessitated the development of novel prognostic and predictive factors from which new diagnostic tests could evolve. Evidence suggests the KRAS gene represents such a factor; its mutations are considered to be early indicators of CRC progression. This study assessed the prognostic impact of specific known KRAS codon 12/13 mutations on survival in patients with CRC. METHODS: Formalin-fixed paraffin-embedded tissue blocks or sections from primary were obtained from patients registered between 2014 and 2016 for genomic DNA extraction. KRAS gene was analyzed by direct sequencing or Luminex assay. The primary endpoint was the frequency of KRAS gene mutations and the secondary endpoints were differences in KRAS mutation rates by various stratification factors. Univariate and multivariate analyses were performed to investigate relationships between KRAS mutation rates and patient background factors. RESULTS: Sequencing of 200 CRC primary tumor samples demonstrated 74 (37.5%) with KRAS mutations in codons 12 (77%; 57/74) and 13 (23%; 17/74), all of which were TNM stages I-III. Tumors with KRAS mutations were more frequently located in the right side of the colon. Multivariate analysis indicated that G12V or G12C mutations were associated with poor prognosis [hazard ratio (HR) = 3.77, 95% confidence interval (CI), 1.54-8.39 and HR = 6.57; 95% CI, 1.90-17.7, respectively] in terms of recurrence-free survival. CONCLUSION: KRAS codon 12G-to-V or G-to-C mutations are independent prognostic factors in patients with stage I-III CRC.

A case of intussusception developed at the site of ileocolic anastomosis after laparoscopic right hemicolectomy.

BACKGROUND: Intussusception is a relatively common condition seen in children. In comparison, adult intussusception is rare and usually occurs as a complication in patients with organic diseases. It is responsible for 1% of all bowel obstructions, in most of intussusceptions a malignant tumor is involved. Herein, we present an extremely unusual case of intussusception that occurred as a complication at the site of a functional end-to-end anastomosis. CASE PRESENTATION: A 57-year-old female patient was diagnosed with tumors in the ascending and descending colon and was referred to our department. Laparoscopic hemicolectomy and laparoscopic descending colectomy were performed. The mechanical intestinal obstruction occurred on the 9th day postoperatively, and computed tomography scan revealed intussusception at the site of the ileocolic anastomosis. Endoscopic reduction was attempted, but the procedure was challenging. Surgery was then performed and revealed that the site of ileocolic anastomosis firmly adhered to the side wall and right retroperitoneum. However, the intestine in the oral side of the anastomosis was not fixed. Examination of the anastomotic site revealed that the ileum had passed through the anastomosis and prolapsed into the transverse colon. The ileocolic anastomosis was resected. End-to-end anastomosis was performed, and surgery was then completed. No neoplastic lesions were observed in the resected tissue of the lead point of intussusception. The postoperative clinical course was favorable, and the patient was discharged on the 11th day after the second round of surgery. CONCLUSIONS: There are no reports the anastomosis is involved as part of the intussception, as observed in the present case. Intussusception should thus be considered as one of the causes of postoperative mechanical intestinal obstruction.

Laparoscopic subtotal colectomy for a patient with chronic idiopathic colonic pseudo-obstruction: Report of a case.

A 47-year-old male patient without a documented past medical history was referred to Sanno Hospital because of constipation and abdominal pain, which he had had for more than 5 years. Abdominal X-ray and CT scan showed an enlarged ascending colon from the cecum to the transverse colon, without apparent mechanical obstruction. The patient was diagnosed with chronic idiopathic colonic pseudo-obstruction, and because his symptoms were resistant to medication, surgical treatment was required. Laparoscopic subtotal colectomy was performed without any complications. Constipation was relieved, and the patient began defecating 2-3 times a day without medication. Pathological specimens showed that Meissner's plexus and Auerbach's plexus had decreased and that there were fewer ganglion cells-findings consistent with chronic idiopathic intestinal pseudo-obstruction.

Left atrial low-voltage zone ablation of persistent atrial fibrillation in a patient with myotonic dystrophy: A case report.

We here report a case of a 32-year-old man with genetically diagnosed myotonic dystrophy and persistent atrial fibrillation (AF) who underwent a low-voltage zone (LVZ) ablation. His cardiac function was normal except for a prophylactic pacemaker implantation for a high risk of complete atrioventricular block. An LVZ was found in the anteroseptal left atrium during sinus rhythm and was ablated during induced AF after a pulmonary vein antrum isolation, which terminated the AF and rendered it noninducible by rapid pacing and/or isoproterenol. During 20 months of follow-up, no atrial tachyarrhythmias were observed with pacemaker monitoring of antiarrhythmic drugs.

A rare case of perivascular epithelioid cell tumor (PEComa) of the greater omentum.

BACKGROUND: A tumor composed exclusively or predominantly of human melanin black 45 (HMB45)-positive epithelioid cells is called a perivascular epithelioid cell tumor (PEComa). We report a very rare case of a PEComa of the greater omentum. CASE PRESENTATION: MRI conducted to examine the orthopedic disease of the patients, a 49-year-old Japanese woman, also identified a tumor in her pelvis. A CT scan revealed a tumor mass on the right side of the pelvic floor and clear nutrient vessels originating from the splenic and celiac arteries. An omental primary tumor or accessory spleen was thus suspected, and tumor resection was performed. The tumor was a light brown solid tumor with a smooth margin, measuring 5.2 × 3.8 × 3.5 cm. Histopathologically, the tumor was composed mainly of spindle and epithelioid cells, and large and small blood vessel formation was observed. In the immunohistochemical staining, tumor cells were positive for human melanin black 45 (HMB-45) and Melan-A and partially positive for alpha-smooth muscle actin. The final diagnosis was PEComa of the greater omentum. CONCLUSIONS: Although omental PEComa is very rare, it should be considered as a differential disease of an omental primary tumor.

Impact of the extent of low-voltage zone on outcomes after voltage-based catheter ablation for persistent atrial fibrillation.

BACKGROUND: Low-voltage zones (LVZs), as measured by electroanatomic mapping, are thought to be associated with fibrosis. We reported the efficacy of atrial fibrillation (AF) ablation aiming to homogenize left atrial (LA) LVZ. The purpose of this study was to evaluate the impact of LVZ extension outcomes after LVZ homogenization in patients with nonparoxysmal AF. METHODS: This prospective observational cohort study included 172 patients with nonparoxysmal AF undergoing their initial ablation. LVZ was defined as an area with bipolar electrograms <0.5mV during sinus rhythm. LVZ extent was calculated as the percentage of LA surface area, and subsequently, LVZ was categorized into stages I (<5%), II (≥5% to <20%), III (≥20% to <30%), and IV (≥30%). Patients with LVZs underwent LVZ ablation aimed at homogenization of ≥80% of LVZs following pulmonary vein isolation. The primary endpoint was atrial tachyarrhythmia recurrence-free survival after a single procedure at 18 months off antiarrhythmic drugs. The association of %LVZ with recurrence-free survival was examined using Cox proportional hazard models. RESULTS: The survival rates were 76%, 74%, 57%, and 28% in patients with stages I, II, III, and IV LVZ, respectively. The difference was significant between stages I and IV (log-rank, p<0.001), while not significant between stages I vs. II and I vs. III (p=0.843, p=0.073, respectively). Cox proportional hazard model revealed that %LVZ was an independent predictor of recurrence-free survival (hazard ratio, 1.025 per 1% increase, p<0.001; unadjusted model). The results were similar after demographic and clinical covariate adjustments and after excluding 12 patients who did not achieve homogenization of ≥80% of LVZ. CONCLUSIONS: The extent of LVZ is an independent predictor for recurrence even after LVZ homogenization.

Not all rotors, effective ablation targets for nonparoxysmal atrial fibrillation, are included in areas suggested by conventional indirect indicators of atrial fibrillation drivers: ExTRa Mapping project.

Background: Effects of nonparoxysmal atrial fibrillation (non-PAF) ablation targeting complex fractionated atrial electrogram (CFAE) areas and/or low voltage areas (LVAs) are still controversial. Methods and Results: A recently developed online real-time phase mapping system (ExTRa Mapping) was used to conduct LVA mapping and simultaneous ExTRa and CFAE mapping in 28 non-PAF patients after pulmonary vein isolation (PVI). Nonpassively activated areas, in the form of meandering rotors and/or multiple wavelets assumed to contain non-PAF drivers, partly overlapped with CFAE/LVAs but not always coincided with them. Conclusion: Real-time rotor imaging, rather than conventional indirect indicators only, might be very useful for detecting non-PAF drivers.

A case of Wolff-Parkinson-White syndrome presenting spontaneous mutual frequent transition between atrioventricular reciprocating tachycardia and atrioventricular nodal re-entrant tachycardia.

Atrioventricular reciprocating tachycardia (AVRT) and atrioventricular nodal re-entrant tachycardia (AVNRT) can coexist and present unidirectional transition (from AVRT to AVNRT, or from AVNRT to AVRT) in a single patient. Actually, such cases have already been reported previously. However, a case with spontaneous bidirectional transition of both tachycardias during supraventricular tachycardia has never been reported. This article describes a case with spontaneous, mutual, and frequent transition between AVRT and AVNRT.

Feasibility of total intravenous anesthesia by cardiologists with the support of anesthesiologists during catheter ablation of atrial fibrillation.

BACKGROUND: The optimal methodology for sedation and anesthesia during atrial fibrillation (AF) ablation has not been well established. We assessed the feasibility of total intravenous anesthesia (TIVA) by cardiologists with support from anesthesiologists during AF ablation and quality of pulmonary vein isolation (PVI) and single procedure success rate at 12 months. METHODS: TIVA was performed by cardiologists using IV propofol and fentanyl under controlled ventilation via i-gel™ without neuromuscular blocking drugs in 160 consecutive patients (80 nonparoxysmal) with no anticipated difficult airway or other severe diseases. Anesthesiologists were requested to be on standby during the procedure. The incidence of anesthesia-associated complications and ablation-associated complications were assessed. To evaluate the quality of PVI, the prevalence of acute adenosine triphosphate (ATP)-provoked PV reconnections and late PV reconnections among those requiring a redo procedure was analyzed. RESULTS: TIVA was successfully completed in 152 patients (95%). In five (3%), we requested help from anesthesiologists, and in three (2%), TIVA was abandoned. No major anesthesia-associated complications were observed. Ablation-associated complications were observed in seven patients (4%). ATP provocation test was performed in 141 patients, and no acute PV reconnections were observed in 134 (95%). Success rates at 12 months were 85% of patients off antiarrhythmic drugs. Twenty-one of 24 patients with recurrence underwent a redo session, and 18 (86%) had no PV reconnections. CONCLUSIONS: TIVA by cardiologists with support from anesthesiologists during AF ablation may be feasible. The success rate at 12 months was high, and prevalence of acute and late PV reconnection was very low.

Absorptive anti-adhesion barrier for the prevention of bowel obstruction after laparoscopic colorectal cancer surgery.

OBJECTIVES: The protective efficacy of an absorptive adhesion prevention product (SeprafilmⓇ) against bowel obstruction (BO) during open surgery was demonstrated in a large-scale randomized controlled clinical trial in Europe and America. However, the efficacy of Seprafilm against BO in laparoscopic surgery remains uncertain. The objective of this study was to clarify the protective efficacy of Seprafilm against BO after laparoscopic surgery for colorectal cancer. METHODS: From 2009 to 2016, 1328 laparoscopic colorectal resections were performed for colorectal cancer. From 2009, Seprafilm was used for preventing BO in laparoscopic colorectal surgery. The incidence of BO and short-term results were compared between the Seprafilm and non-Seprafilm groups after propensity score matching. RESULTS: Propensity scoring generated 270 matched patients per group for the comparisons between the Seprafilm and non-Seprafilm groups. The two groups showed no significant differences regarding patients' backgrounds. Among all patients, 73.1% (19/26) of BO occurred within 30 days after the surgery. Significantly lower incidences of all grade (2.6% vs. 7.0%; p = 0.016) and grade 2 + 3a (1.5% vs. 5.2%; p = 0.017) BO were observed in the Seprafilm group than in the non-Seprafilm group; no significant difference regarding grade 3b BO (1.1% vs. 1.9%; p = 0.476) was found. A significant difference in BO within 30 days was also noted between the two groups (1.9% vs. 5.2%, p = 0.036). There were no significant differences between the groups regarding anastomotic leakage and deep surgical site infection. CONCLUSIONS: Seprafilm was useful for preventing BO, requiring decompression therapy of the bowel, after laparoscopic colorectal surgery without increasing adverse events.

Systematic review of laparoscopic vs open surgery for colorectal cancer in elderly patients.

AIM: To verify the safety and validity of laparoscopic surgery for the treatment of colorectal cancer in elderly patients. METHODS: A meta-analysis was performed of a systematic search of studies on an electronic database. Studies that compared laparoscopic colectomy (LAC) in elderly colorectal cancer patients with open colectomy (OC) were retrieved, and their short and long-term outcomes compared. Elderly people were defined as 65 years old or more. Inclusion criteria were set at: Resection of colorectal cancer, comparison between laparoscopic and OC and no significant difference in backgrounds between groups. RESULTS: Fifteen studies were identified for analysis. LAC was performed on 1436 patients, and OC performed on 1810 patients. In analyses of short-term outcomes, operation time for LAC was longer than for OC (mean difference = 34.4162, 95%CI: 17.8473-50.9851, P < 0.0001). The following clinical parameters were lower in LAC than in OC: Amount of estimated blood loss (mean difference = -93.3738, 95%CI: -132.3437 to -54.4039, P < 0.0001), overall morbidity (OR = 0.5427, 95%CI: 0.4425-0.6655, P < 0.0001), incisional surgical site infection (OR = 0.6262, 95%CI: 0.4310-0.9097, P = 0.0140), bowel obstruction and ileus (OR = 0.6248, 95%CI: 0.4519-0.8638, P = 0.0044) and cardiovascular complications (OR = 0.4767, 95%CI: 0.2805-0.8101, P = 0.0062). In analyses of long-term outcomes (median follow-up period: 36.4 mo in LAC, 34.3 mo in OC), there was no significant difference in overall survival (mean difference = 0.8321, 95%CI: 0.5331-1.2990, P = 0.4187) and disease specific survival (mean difference = 1.0254, 95%CI: 0.6707-1.5675, P = 0.9209). There was also no significant difference in the number of dissected lymph nodes (mean difference = -0.1360, 95%CI: -4.0553-3.7833, P = 0.9458). CONCLUSION: LAC in elderly colorectal cancer patients had benefits in short-term outcomes compared with OC except operation time. The long-term outcomes and oncological clearance of LAC were similar to that of OC. These results support the assertion that LAC is an effective procedure for elderly patients with colorectal cancer.

Efficacy of Left Atrial Voltage-Based Catheter Ablation of Persistent Atrial Fibrillation.

BACKGROUND: Low-voltage zones (LVZs) represent fibrotic tissue and are substrates for atrial fibrillation (AF). We hypothesized that LVZ-based substrate modification along with pulmonary vein isolation (PVI) would improve outcomes in persistent AF (PeAF) patients with LVZs, whereas PVI alone would work in patients without LVZs. METHODS AND RESULTS: Voltage mapping of the left atrium (LA) was performed during sinus rhythm in 101 PeAF patients in whom LVZ was defined as an area with bipolar electrograms <0.5 mV. Thirty-nine patients had LVZs and underwent ablation of the entire LVZ area after PVI (LVZabl group). In the remaining 62 patients without LVZs, PVI alone was performed with no further substrate modifications (PVI group). An additional group of 16 consecutive PeAF patients with LVZ did not undergo any substrate modification after PVI and were used as a comparison group (LVZnon-abl group) despite having similar size of LVZs to that in the LVZabl group. After a single session, 28 (72%) patients in the LVZabl group had no recurrence, whereas 49 (79%) patients in the PVI group had no recurrence during 18 ± 7 months of follow-up (log-rank, P = 0.400). In the LVZnon-abl group, only 6 patients (38%) had no recurrence during 32 ± 7 months of follow-up, even after a mean number of sessions of 1.8 (log-rank, P < 0.001, compared with the LVZabl group). CONCLUSIONS: Additional LVZ-based substrate modification after PVI improved the outcome in PeAF patients with LVZs, whereas PVI alone worked in patients without LVZs, even in those with PeAF.

Spatial Relation Between Left Atrial Anatomical Contact Areas and Circular Activation in Persistent Atrial Fibrillation.

INTRODUCTION: Atrial low-voltage zones (LVZs) may be related to maintenance of atrial fibrillation (AF). The influence of left atrial (LA) contact areas (CoAs) on reentrant or rotor-like sources maintaining AF has not been investigated. METHODS AND RESULTS: Forty patients with persistent AF (PsAF) were analyzed. Three representative CoA regions in the LA (ascending aorta: anterior wall; descending aorta: left inferior pulmonary vein; and vertebrae: posterior wall) were visualized by enhanced CT. Using circular catheters, the LVZs (<0.5 mV) were assessed after restoration of SR, and local activation mapping and frequency domain analyses were performed after induction of AF. Circular activation during AF was visually defined as sites with ≥2 rotations by serial electrograms encompassing >80% of the mean AF cycle length. A pivot was defined as the core of the localized circular activation. Anterior (39/40 patients, 98%), left pulmonary vein antrum (27/40, 68%), and posterior (19/40, 48%) CoAs were identified, and 80% (68/85) of those sites were overlapped by or close (<3 mm) to LVZs. Thirty-six (90%) patients demonstrated circular activation (3.1±1.7 sites/patients) along with significantly higher organized dominant frequencies (6.3 ± 0.5 Hz, regularity-index: 0.26 [0.23-0.41]) within the LA, and the average electrogram amplitude of those pivots was 0.30 mV (0.18-0.52). Of those sites, 55% (66/120) were located at or close to CoA regions. Catheter ablation including of LVZs neighboring CoAs terminated AF in 9 (23%) patients. CONCLUSIONS: External anatomical structures contacting the LA may be related to unique conduction properties in diseased myocardium necessary for PsAF maintenance.