Prospective observational study comparing the perioperative outcomes of laparoscopic colectomy with or without epidural anesthesia: the Kanagawa Yokohama Colorectal Cancer Study Group (KYCC) 1806.

PURPOSE: There have been no adequate comparisons of the efficacy, safety, and efficiency of analgesia after laparoscopic colorectal resection (LAC), with and without epidural anesthesia (EDA). METHODS: This was a multicenter prospective observational study of patients undergoing LAC. The primary end point was the mean visual analog scale (VAS) score on postoperative days (PODs) 1-7. The secondary end points were the highest VAS, complication rate, days to first ambulation and fatigue, length of hospital stay, and time to commencement of surgery. RESULTS: We compared an EDA group (Group E, n = 48) and a no-EDA group (Group O, n = 48) after matching. The mean VAS was not significantly different between the groups (28.7 vs. 30.1, p = 0.288). On assessing the secondary end points, the highest VAS was not significantly different between the groups. In fact, the VAS was lower in Group E only on POD 2. There was no difference in the incidence of complications, the time to first postoperative evacuation was shorter in Group E, and postoperative hospitalization was similar. The time to surgery was shorter in Group O. CONCLUSION: These results suggest that LAC without EDA is a feasible option, but with the early and regular use of adjunctive measures to provide more stable analgesia.

Short- and long-term outcomes of transanal decompression tube and self-expandable metallic stent for obstructive colorectal cancer based on a multicenter database (KYCC2110).

AIM: There are well-known methods for decompressing the colorectal tract before surgery, including transanal decompression tubes (TDT) and self-expanding metallic stents (SEMS). This study aimed to compare the short and long-term results in patients with malignant large bowel obstruction in whom TDT or SEMS were placed before surgery. METHODS: This retrospective observational study enrolled 225 patients with malignant large bowel obstruction in whom TDT or SEMS were placed preoperatively and underwent R0 resection between 2008 and 2020. One-to-two propensity score matching was performed according to patient characteristics. Short- and long-term outcomes were compared. The primary endpoint was relapse-free survival (RFS). The secondary endpoints were the overall survival (OS) and postoperative complication rate. RESULTS: Fifty-seven patients in the TDT group and 114 in the SEMS group were matched. The 3-year RFS rates were 66.7% in the TDT group and 69.9% in the SEMS group (p = 0.54), and the 3-year OS rates were 90.5% in the TDT group and 87.1% in the SEMS group (p = 0.52). No significant differences in the long-term results were observed between the two groups. Regarding short-term results, the SEMS group had significantly fewer stoma construction (p = 0.007) and shorter postoperative hospitalization (p < 0.001). The incidence of postoperative complications (grade ≥ 2) was significantly lower in the SEMS group (p = 0.04). CONCLUSION: No significant differences in the long-term results were observed between the TDT and SEMS group. The SEMS showed significant usefulness in terms of improving short-term outcomes.

Chemotherapy-induced Reversion of Mutant RAS to Wild-type RAS in Metastatic Colorectal Cancer.

BACKGROUND/AIM: Secondary mutation of mutated RAS, induced by chemotherapy, is thought to be rare. However, introduction of liquid biopsy (LB) has made it possible to monitor RAS status in patients' plasma throughout the course of chemotherapy for metastatic colorectal cancer (mCRC), and disappearance of the RAS mutation (RAS-mt), i.e., the NeoRAS-wt phenomenon, has been reported and is receiving attention, especially with respect to treatment implications. PATIENTS AND METHODS: A prospective study of 129 patients undergoing chemotherapy for mCRC (RAS-wt, n=65; RAS-mt, n=64) was carried out. Plasma RAS status was monitored in these patients by LB. Relations between secondary genetic change, chemotherapy, and 6-month disease outcomes were analyzed. The effect of anti-EGFR mAb therapy on NeoRAS-wt mCRC was also examined. RESULTS: NeoRAS-wt was detected in 27 (43.5%) RAS-mt patients overall and in all patients with a G12S or Q61H mutation. First-line treatment was more effective among NeoRAS-wt patients than non-NeoRAS-wt patients (70.9% vs. 48.6% overall response rate, p=0.087), and the time from treatment to LB was shorter in this group. Six-month outcomes were significantly better in the NeoRAS-wt group (p<0.001), and conversion to NeoRAS-wt was found to be predictive of a good outcome (OR=7.886, 95% CI=2.458-25.30; p<0.001). Anti-EGFR mAb therapy was found to restrict disease progression in NeoRAS-wt patients. CONCLUSION: Conversion to NeoRAS-wt is relatively frequent, and it may predict good responses to treatment. Anti-EGFR mAb therapy was effective for our NeoRAS-wt patients. Detection of NeoRAS-wt by LB may significantly change the indication for anti-EGFR mAb therapy and the mCRC treatment strategy.

Prediction of lateral lymph node metastasis using OSNA method for mesorectal lymph nodes in low rectal cancer: A prospective study by the Kanagawa Yokohama Colorectal Cancer Study Group (KYCC1801).

BACKGROUND AND OBJECTIVES: Contrary to the Japanese guidelines recommendations regarding lateral lymph node dissection (LatLND) for rectal cancer, its omission is common in clinical practice without reliable omission criteria. Negative pathological mesorectal lymph node metastasis (MesLNM) is reportedly highly correlated with negative pathological lateral lymph node metastasis (p-LatLNM); however, this cannot be used as a criterion because pathological features are revealed postoperatively. Herein, we prospectively evaluated the negative predictive value (NPV) of MesLNM diagnosed via the one-step nucleic acid amplification (OSNA) method for p-LatLNM. METHODS: This prospective study was conducted at a single academic study group in Japan. The key eligibility criterion was mid-to-low rectal cancer planned to be treated using mesorectal excision with LatLND. According to the study protocol, the OSNA method was considered useful if the point estimate of the NPV exceeded 95%. RESULTS: Preoperative case registration was conducted between 2018 and 2020; 34 patients were registered. Among these, 16 were negative for OSNA-MesLNM, and negative p-LatLNM was confirmed in all cases. The point estimate of the NPV was 100%, with the 95% confidence interval ranging from 79.4% to 100.0%. CONCLUSIONS: The OSNA method is useful in selecting patients in whom LatLND can be omitted in real-world clinical practice.

Prospective analysis of tumor spread to the small bowel mesentery in cases of right-sided colon cancer.

PURPOSE: Guidelines advocate minimal ileal resection when right hemicolectomy is performed for right-sided colon cancer. The practice, thought to prevent malabsorption syndrome, does not appear to foster local recurrence. Little evidence based on rigorous study exists, however. To understand the pattern of lymphatic spread of right-sided colon cancer toward the small bowel and thus determine the appropriate margin size, we prospectively investigated anatomical distribution of lymph nodes (LNs) in the small bowel mesentery and of metastasis to these nodes in patients with right-sided colon cancer treated by such surgery. METHODS: In each case, the mesenteric specimen, which had been dissected along the ileocolic vessels and included intermediate LNs, was divided into 2 areas: that 0-3 cm from the vessel pedicle (area 1) and that 3-5 cm from the pedicle (area 2). The peri-intestinal mesentery was cut into 9 segments. RESULTS: Ninety-one patients were included in the study. Overall, 3366 LNs were dissected. Four hundred fifty-three of these LNs were located in area 1 (90 cases), and 15 (3.3%) were metastatic. Only 63 LNs were located in area 2 (34 cases; average of 0.69 per patient); none was metastatic. Overall, 269 LNs were found in the small bowel mesentery (in 56 of the 91 patients). Only 4 were positive (3 cases), and all were within 5 cm of the ileocecal valve. CONCLUSION: Our data indicate that a surgical margin 3 cm from the ileocecal pedicle and a short (5 cm) ileal margin are oncologically reasonable for effective right hemicolectomy.

Laparoscopic vs. Open Surgery for Stage II/III Colon Cancer Patients With Body Mass Index >25 kg/m2.

AIM: To compare long- and short-term outcomes of laparoscopic surgery with those of open surgery for patients with colorectal cancer and body mass index over 25 kg/m2 Patients and Methods: This multicentre, retrospective study analysed clinical records and identified 178 patients with body mass index over 25 kg/m2 who underwent surgery for colon and rectosigmoid cancer between 2000 and 2016. After applying propensity score matching, 96 patients were finally included. The primary outcome was the 3-year recurrence-free survival rate, and the secondary outcomes were short-term results during and after surgery. RESULTS: The 3-year recurrence-free survival rates were similar for the laparoscopic and open surgery groups. The laparoscopic surgery group had longer operative times but less blood loss and shorter periods of hospital stay. There were no differences in incidence of postoperative complications. CONCLUSION: Laparoscopic and open surgeries had similar long-term outcomes for obese patients. Laparoscopic surgery is an effective option for this population.

Short-term Outcomes Following Robotic-assisted Laparoscopic Surgery for Technically Demanding Rectal Cancer.

AIM: To clarify the benefits of robotic-assisted laparoscopic surgery (RALS) regarding short-term outcomes in patients with technically demanding rectal cancer (TDRC). PATIENTS AND METHODS: Between April 2015 and September 2019, 88 TDRC cases were identified from our database, and divided into the RALS (n=32) and conventional laparoscopic surgery (CLS) (n=56) groups. TDRC was defined as mid-rectal tumors presenting at least one of the following risk factors: Male sex, high body mass index, T4 stage, bulky tumor, or low rectal tumor. RESULTS: Patient baseline characteristics were similar in both groups. One and 15 patients developed anastomotic leakage in the RALS and CLS groups (3% vs. 27%, p<0.01), respectively. The postoperative complication rate was lower in the RALS group (19% vs. 43%, p=0.03). Multivariate analysis showed the surgical approach to be an independent predictor for anastomotic leakage. CONCLUSION: RALS has potential advantages to prevent anastomotic leakage complications in patients with TDRC.

[A Case of Malignant Peritoneal Mesothelioma Resected Four Times in Five Years].

We report a long-surviving case of malignant peritoneal mesothelioma requiring 4 operations in 5 years. A 63-year-old man was diagnosed with gastrointestinal stromal tumor(GIST)that was excised for the first time in June 2011. The pathological diagnosis was malignant peritoneal mesothelioma. Thereafter, we excised recurrences of the tumor in the hepatic hilum in December 2011. Similar operations were performed in March 2012 and August 2015 because of tumors in the small bowel mesentery and the segment 8 of the liver. The pathological diagnosis was malignant peritoneal mesothelioma. It is an extremely rare variant of malignant peritoneal mesothelioma. There is no record of multiple excision of malignant peritoneal mesothelioma for recurrences. In this case, the cause of long survival was considered to be the excision of recurrent tumors.

[Eight Cases of Primary Carcinoma of the Vermiform Appendix].

Primary carcinoma of the vermiform appendix is a rare neoplasm, and its treatment strategy has not yet been established. We retrospectively analyzed 8 cases of primary carcinoma of the vermiform appendix from 2007 to 2017. Six cases were male and two were female, with a median age of 60.5 years. Ileocecal resection and right hemicolectomy were performed in 7 cases and 1 case, respectively. Regarding pathological staging, 5 cases were of pStage Ⅱ, 2 were of pStage Ⅲa, and 1 was of pStage Ⅳ. Three cases had recurrences after curative resection. The postoperative median overall survival time was 45 months. Three cases with a tumor diameter of 20mm were alive without any recurrence; however, 3 of 5 cases with a tumor diameter of B21mm had recurrences. Although only 1 of 3 cases with adjuvant chemotherapy(pStage Ⅲa case)had recurrence, 2 of 4 cases without adjuvant chemotherapy, including a pStage Ⅱ case, had recurrences. Early diagnosis, surgery, and adjuvant chemotherapy could improve the long-term outcomes of patients with primary carcinoma of the vermiform appendix.

[A re-do case of recurrent constrictive pericarditis 35 years after pericardiectomy; report of a case].

Reports of recurrent constrictive pericarditis are scarce. We report a re-do case of recurrent constrictive pericarditis 35 years after pericardiectomy. The calcified pericardium was thick and severely adhesive. We performed pericardiectomy on pump, using Harmonic Scalpel and rib scissors for a safe and secure operation. The calcified pericardium looked like a crab's shell. The patient was discharged on 14th post-operative day. Long-term follow-up is necessary for this patient.

Left atrium ball thrombus in a patient with hemorrhagic cerebral infarction.

The patient was a 72-year-old man with left hemiparesis. Multiple hemorrhagic cerebral infarctions were recognized on a computed tomographic (CT) scan. A transesophageal echocardiogram showed a huge left atrial mass, which was floating and nearly obstructed the mitral orifice in the diastolic phase. Emergency left atrial mass removal was performed. To reduce the risk of critical brain hemorrhage, the dose of heparin was reduced (100 U/kg) and 1 mg/kg/h of nafamostat mesilate was administered into the venous circuit during extracorporeal circulation. A postoperative brain CT scan showed no evidence of deterioration of cerebral hemorrhage. Pathologic examination showed a ball thrombus.