True significance of the number of retrieved lymph nodes in stage II colon cancer resected by minimally invasive surgery: Influence of tumor sidedness.

BACKGROUND: In patients with stage II colon cancer (CC) undergoing minimally invasive surgery, the association between the clinical significance of lymph node yield and tumor localization remains unknown. We aimed to determine the optimal number of lymph nodes to be retrieved based on tumor localization in patients with stage II CC undergoing minimally invasive surgery. METHODS: This was a multicenter retrospective study. Overall, 263 patients with stage II CC who underwent laparoscopic surgery between January 1, 2008 and December 31 were enrolled. The primary outcome was the optimal number of lymph nodes retrieved based on tumor localization. RESULTS: The median number of retrieved lymph nodes was 30 and 26 in the right-(n = 125) and left-sided (n = 138) CC groups, respectively (p = .0007). Inadequate dissection (<12 nodes) occurred in 4.2% of patients: 1.6% in the right-sided CC group and 6.5% in the left-sided CC group. Multivariate Cox regression analysis showed a decreasing trend in adjusted hazard ratios with increasing nodes, with an optimal cutoff of 15 lymph nodes in the left-sided CC group (adjusted hazard ratio, 5.868; 95% confidence interval, 1.247-27.62; p = .02). Lymph node yield was not independently associated with survival in the right-sided CC group. CONCLUSIONS: For patients with left-sided stage II CC undergoing laparoscopic surgery, aiming for at least 15 retrieved lymph nodes may be optimal for accurate staging and prognostic assessment. The optimal lymph node yield likely varies based on tumor location, requiring further investigation in right-sided CC.

Localized colorectal cancer database integrating 4 randomized controlled trials; (JCOG2310A).

Although phase III randomized controlled trials (RCTs) represent the most robust statistical approach for answering clinical questions, they require massive expenditures in terms of time, labor, and funding. Ancillary and supplementary analyses using RCTs are sometimes conducted as alternative approaches to answering clinical questions, but the available integrated databases of RCTs are limited. In this background, the Colorectal Cancer Study Group (CCSG) of the Japan Clinical Oncology Group (JCOG) established a database of ancillary studies integrating four phase III RCTs (JCOG0212, JCOG0404, JCOG0910 and JCOG1006) conducted by the CCSG to investigate specific clinicopathological factors in pStage II/III colorectal cancer (JCOG2310A). This database will be updated by adding another clinical trial data and accelerating several analyses that are clinically relevant in the management of localized colorectal cancer. This study describes the details of this database and planned and ongoing analyses as an initiative of JCOG cOlorectal Young investigators (JOY).

Robotic surgery after total neoadjuvant therapy for rectal cancer: pitfalls of beyond total mesorectal excision for patients with sidewall invasion.

AIM: Total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC) is rapidly spreading. The robotic surgical techniques to approach lateral invasion, such as that of the pelvic plexus, have not yet been established. In this technical note, we present a video illustrating a surgical technique for lateral invasion using our novel technique and discuss its pitfalls. METHOD: We present the case of a 65-year-old man with LARC. Robotic surgery was performed after TNT using the da Vinci Xi Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA). The surgical procedure was as follows: (1) D3 lymph node dissection around the inferior mesenteric artery using a medial-to-lateral approach; (2) rectal mobilization; (3) dissection of the ureterohypogastric fascia and ureter; and (4) combined resection of the hypogastric nerve and pelvic plexus. The key surgical point for sidewall invasion is the resection extent. Dividing the resection extent into three areas is important: zone A, which contains the pelvic plexus and is closest to the tumour; zone B, which contains the iliac vessels; and zone C, the most lateral zone, which contains the obturator nerves. This allows organ and function preservation by resecting only the smallest organ that truly requires R0 resection. RESULTS: The operating time was 333 min, console time was 232 min, and blood loss was 0 mL. The circumferential resection margin was 10 mm, and an R0 resection was achieved. CONCLUSION: We introduced a novel approach for robotic surgery after TNT for LARC with sidewall invasion. This technique can be performed safely and may help standardize 'beyond total mesorectal excision'.

Clinical significance of the post/preoperative anti-p53 antibody ratio in predicting the prognosis of patients with colorectal cancer after curative surgery and its usefulness in combination with carcinoembryonic antigen.

[Introduction] Anti-p53 antibody (p53Ab) is useful for monitoring colorectal cancer (CRC) recurrence. We retrospectively analyzed the clinical impact of p53Ab ratio (p53R) before and after surgery to predict recurrence in patients with CRC. [Methods] In total, 1,223 patients with stage I-III CRC who underwent curative surgery between January 2005 and December 2019 were enrolled in this retrospective study. In patients with elevated p53Ab levels, p53R was calculated by measuring p53Ab levels within one month preoperatively and three months postoperatively. The optimal p53R level was determined, and its relationship with clinicopathological factors and prognosis was examined. We also evaluated the efficacy of the combination of p53R and preoperative carcinoembryonic antigen (CEA) values. [Results] Overall, 341 patients (27.9%) showed elevated p53Ab levels. Preoperative p53Ab levels were significantly associated with tumor location, lymphatic invasion, and venous invasion. The p53R level was significantly higher in patients with recurrent disease. Patients with high p53R levels had significantly shorter relapse-free survival (RFS) than those with low p53R levels (p < 0.001). When p53R was combined with preoperative CEA values, specificity improved to 0.97, with an accuracy of 0.88. [Conclusion] In patients with CRC and elevated preoperative p53Ab levels, p53R expression may be prognostically useful after radical resection. Furthermore, the combination of p53R and preoperative CEA levels may be useful for postoperative follow-ups.

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.

Novel approach toward minimally invasive surgery for mid-transverse colon cancer: 'moving the left colon' technique.

AIM: During surgery for mid-transverse colon cancer (MTC), surgeons often face the dilemma of whether to mobilize the hepatic or splenic flexure. There is no established optimal minimally invasive surgical procedure for MTC. METHODS: We present our novel minimally invasive surgical technique, called the 'moving the left colon' technique for MTC, along with a video demonstration. The procedure involves four main steps: (i) mobilization of the splenic flexure using a medial-to-lateral approach, (ii) dissection of lymph nodes around the middle colic artery from the left side of the superior mesenteric artery approach, (iii) separation of the pancreas and transverse mesocolon and (iv) 'moving the left colon' and performing an intracorporeal anastomosis. By mobilizing the splenic flexure, anatomical landmarks are revealed, which enables safer dissection. Combining this technique with intracorporeal anastomosis allows for a safe and easy anastomosis. RESULTS: Between April 2021 and January 2023, a single-skilled colorectal surgeon performed laparoscopic transverse colectomies using our new approach on three consecutive patients with MTC. The patients had a median age of 75 years (range 46-89 years). The median operative time was 194 min (range 193-228 min) and blood loss was 8 mL (range 0-20 mL). None of the patients experienced any perioperative complications and the median postoperative hospital stay was 6 days. CONCLUSION: We introduced a novel approach for laparoscopic surgery for MTC. This technique can be performed safely and may help standardize minimally invasive surgery for MTC.

Analysis of surgical outcomes of laparoscopic versus open surgery for locally advanced mid-transverse colon cancer.

PURPOSE: This study compared the surgical outcomes between laparoscopic colectomy (LC) and open colectomy (OC) for mid-transverse colon cancer (MTC). METHODS: This multicenter retrospective study compared the short- and long-term surgical outcomes for patients with advanced MTC (T3 and T4 with or without nodal involvement) who underwent LC or OC between January 2008 and December 2019 using a propensity score-matched analysis. RESULTS: A total of 177 patients with advanced MTC were enrolled. After matching, 58 cases for the OC and LC groups were selected. No significant differences in age, sex, tumor progression, or procedure type (extended resection or segmental resection) existed between groups. The LC group had significantly less blood loss (20 mL vs. 50 mL, p=0.048) and a shorter postoperative hospital stay (8 days vs. 12 days, p<0.001) than the OC group. Postoperative complications (Clavien-Dindo grade ≥ 2) occurred in 27.6% and 25.9% of the OC and LC groups respectively (p=1). Three patients (5.2%) and one patient (1.7%) of the OC and LC groups respectively developed anastomotic leakage (p=0.62). Re-operation was required in five patients (8.6%) in the OC group and one patient (1.7%) in the LC group (p=0.21). No surgery-related deaths occurred in either group. The 3-year overall survival rates (stage II: LC 100% vs. OC 92.8%, p=0.15; stage III: 88.9% vs. 84.3%, p=0.88, respectively) were similar between the two groups. CONCLUSION: LC is a minimally invasive technique with lesser blood loss, shorter postoperative hospital stays, and oncologic equivalence to OC. Hence, LC is useful for MTC treatment. TRIAL REGISTRATION: UMIN000042676.

Redo laparoscopic colorectal resection: a retrospective analysis with propensity score matching.

PURPOSE: Reports of redo laparoscopic colorectal resection (Re-LCRR) are scarce. In order to evaluate the safety and short-term outcomes of Re-LCRR, we performed a matched case-control analysis of patients who underwent this procedure for colorectal cancer. METHOD: This was a retrospective, monocentric study that included patients who underwent Re-LCRR for colorectal cancer between January 2011 and December 2019 at our institution. The patients were compared to a 2:1 matched sample. Matching was conducted based on age, sex, BMI, surgical procedure, and clinical stage. RESULT: Twenty-nine patients underwent Re-LCRR (RCRR group) and were compared to 58 patients selected by matching who underwent LCRR as primary resection (PCRR group). The median of age of the 29 patients of RCRR group was 75 (IQR 56-81) years and the RCRR group included 14 males. The median operative time of the RCRR group was 167 (IQR 126-232) minutes, and the median intraoperative blood loss was 5 (IQR 2-35) ml. In the RCRR group, there were no cases that required conversion to laparotomy. The short-term outcomes of the two groups did not differ to a statistical extent with respect to operative time (p = 0.415), intraoperative blood loss (p = 0.971), rate of conversion to laparotomy (p = 0.477), comorbidity (p = 0.215), and postoperative hospital stay (p = 0.809). No patients in either group experienced postoperative anastomotic leakage or required re-operation due to postoperative complications, and there was no procedure-related death. However, in terms of oncological factors, although there was no difference in the number of cases with a positive radical margin between the two groups (p = 1.000), the number of harvested lymph nodes in the RCRR group was significantly lower than that in the PCRR group (p = 0.015) and the RCRR group included 10 cases with less than 12 harvested lymph nodes. CONCLUSION: Re-LCRR is associated with good short-term results and can be safely performed; however, the number of harvested lymph nodes is significantly reduced in comparison to primary resection cases, and further studies are needed to evaluate its long-term prognosis.

The effect of preoperative endoscopic tattooing using India ink on lymph node yield in laparoscopic colectomy for stage I right-sided colon cancer.

PURPOSE: The purpose of this study is to evaluate the effect of preoperative endoscopic tattooing using India ink (ETI) on the number of retrieved lymph nodes (LNs) dissected during laparoscopic surgery for stage I right-sided colon cancer (RCC). METHODS: This single-center, retrospective study included stage I RCC patients who underwent laparoscopic surgery between January 2010 and December 2021. The clinicopathological background and number of LNs retrieved were compared between patients managed with and without ETI. A multiple linear regression analysis was used to examine the effect of independent variables on the LN yield. RESULTS: A total of 169 patients were enrolled. Of these, 89 patients (52.7%) were classified into the ETI group, and 80 (47.3%) were classified into the no-ETI group. There were no significant differences in age, sex, body mass index, or tumor progression between the two groups. A univariate analysis showed that the number of LNs retrieved was significantly higher in female (26 vs. 24, p = 0.026), with tumor localization in the ascending or transverse colon (20 in the cecum, 26 in the ascending colon, 27 in the transverse colon, p < 0.001), and with preoperative ETI (28 vs. 21, p < 0.001). In a multivariate linear regression analysis, female sex (p = 0.0011), D3 lymphadenectomy (p = 0.046), and preoperative ETI (p = 0.012) were independently associated with the LN yield. CONCLUSION: In laparoscopic surgery for stage I RCC, preoperative ETI increased the number of LNs retrieved and allowed for appropriate staging.

The usefulness of indocyanine green fluorescence imaging for intestinal perfusion assessment of intracorporeal anastomosis in laparoscopic colon cancer surgery.

PURPOSE: The purpose of this study was to clarify the usefulness of indocyanine green fluorescence imaging (ICG-FI) in the assessment of intestinal vascular perfusion in patients who receive intracorporeal anastomosis (IA) in colon cancer surgery. METHODS: This was a single-center, retrospective study using propensity score matching. We compared the surgical outcomes of colon cancer patients who underwent laparoscopic colonic resection with IA or external anastomosis (EA) with the intraoperative evaluation of anastomotic perfusion using ICG-FI from January 2019 to July 2021. The detection rate of poor anastomotic perfusion by ICG-FI was examined. RESULTS: A total of 223 patients were enrolled. After matching, 69 patients each were classified into the IA and EA groups. There were no significant differences in age, sex, body mass index, tumor localization, or progression between the two groups. The operation time was similar (172 min vs. 171 min, p = 0.62) and the amount of bleeding was significantly lower (0 ml vs. 2 ml, p = 0.0023) in the IA group. The complication rates (grade ≥ 2) of the two groups were similar (14.5% vs. 11.6%, p = 0.59). ICG-FI identified four patients (5.8%) with poor anastomotic perfusion in the IA group, but none in the EA group (p = 0.046). All four patients with poor perfusion in the IA group underwent additional resection; none of these patients developed postoperative complications. CONCLUSION: Poor anastomotic perfusion was detected in 5.8% of cases who underwent laparoscopic colon cancer surgery with IA. ICG-FI is useful for evaluating anastomotic perfusion in IA in order to prevent AL.

Laparoscopic extended right hemicolectomy versus laparoscopic transverse colectomy for mid-transverse colon cancer: a multicenter retrospective study from Kanagawa Yokohama Colorectal Cancer (KYCC) study group.

PURPOSE: The laparoscopic surgery approach for mid-transverse colon cancer (MTC) varies depending on tumor characteristics and the guidelines implemented by each surgeon; the optimal surgical procedure for MTC has not been established. This study aimed to compare the surgical outcomes of laparoscopic extended right hemicolectomy (Lap-ERHC) and laparoscopic transverse colectomy (Lap-TC) for MTC. METHODS: This was a multicenter, retrospective study. We surveyed eight hospitals, by questionnaire, on MTC surgery policies and retrospectively compared the short- and long-term surgical outcomes for patients with MTC who underwent Lap-ERHC or Lap-TC between January 2008 and December 2019. RESULTS: A total of 129 patients were enrolled, of whom 35 underwent Lap-ERHC and 94 underwent Lap-TC. There were no significant differences in tumor progression between the two groups. Operation time was significantly longer (202 min vs. 185 min, p = 0.026). We observed a higher complication rate (≥ grade 3) in the Lap-ERHC group than in the Lap-TC group (11.4% vs. 3.2%, p = 0.086). Three patients (8.6%) who underwent Lap-ERHC developed anastomotic leakage; none of the patients who underwent Lap-TC had this complication (p = 0.018). The 3-year overall survival rates (stage I: 100% vs. 91.9%, p = 0.64; stage II: 100% vs. 95.5%, p = 0.46; stage III: 100% vs. 88.2%, p = 0.91, respectively) were similar between the two groups. CONCLUSION: Lap-ERHC for MTC has the same long-term outcomes as Lap-TC. However, Lap-ERHC for MTC has a higher complication rate. Therefore, Lap-TC may be recommended for patients with MTC. TRIAL REGISTRATION: UMIN000042674.

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.

Impact of Infectious Complications on Survival and Recurrence of Patients With Stage II/III Colorectal Cancer: A Multicenter Retrospective Study.

BACKGROUND/AIM: Postoperative complications are associated with increased recurrence in colorectal cancer (CRC). We investigated the impact of infectious complications on the recurrence of CRC and overall survival after curative surgery in a single study group. PATIENTS AND METHODS: In total, 1,668 patients who underwent radical resection for CRC in Yokohama City University, Yokohama Minami Kyosai Hospital, and Kanagawa Cancer Center between 2011 and 2019 were reviewed. Patients were classified into those with infectious complications (IC group) and those without infectious complications (Non-IC group). The risk factors for recurrence-free survival (RFS) and overall survival (OS) were analyzed. RESULTS: Postoperative complications were found in 560 of the 1,668 patients (33.5%), and IC, which occurred in 312 patients (18.7%), included pneumonia, anastomotic leakage, and intraperitoneal abscess. The 5-year OS rates in the Non-IC and IC groups were 95.5% and 90.4%, respectively, while the 5-year RFS rates were 74.4% and 68.1%, respectively. The multivariate analysis demonstrated that postoperative IC were significant independent risk factors for OS and RFS. CONCLUSION: The presence of postoperative IC after CRC resection is associated with decreased long-term survival. The surgical procedure, surgical strategy, and perioperative care should be carefully planned in order to avoid causing IC.

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.

Can D3 Lymph Node Dissection for Patients With Colon Cancer With a Poor C-Reactive Protein/Albumin Ratio Improve Survival Outcomes?

AIM: D3 lymph node dissection (LND) for stage II and III colon cancer has been shown to improve prognosis, however, it generally increases surgical stress. Studies have reported that the C-reactive protein/albumin ratio (CAR) may be a useful inflammatory-nutritional biomarker to predict postoperative complications and poor prognosis for with various types of cancer. Our purposes were to assess the short- and long-term outcomes of D3 LND in patients with a high preoperative CAR (≥ 0.04). PATIENTS AND METHODS: This was a retrospective cohort analysis reviewing a prospectively collected database of Yokohama City University and three affiliated hospitals. A total of 449 patients with stage II or III colon cancer with high CAR who underwent primary resection with D2 or D3 LND were identified between 2008 and 2020. The primary and secondary outcomes of interests were the 3-year recurrence-free survival and postoperative complication rates. RESULTS: After propensity matching, 230 patients were evaluated. There was no significant difference between the D3 and D2 groups in the rate of postoperative complications overall (14.8% versus 11.3%, p=0.558), however, the incidence of anastomotic leakage tended to be greater in the D3 group (9.6% versus 2.6%, p=0.050). The long-term findings showed that there was no significant difference between the two groups (3-year recurrence-free survival rate: 77.2% versus 77.2%, p=0.880). CONCLUSION: D3 LND did not improve survival outcomes for patients with colon cancer with a poor CAR in this study. D2 LND may be a treatment option for patients with stage II-III colon cancer with a high preoperative CAR.

Preoperative Pre-albumin Concentration as a Predictor of Short-term Outcomes in Elderly Patients With Colorectal Cancer.

BACKGROUND/AIM: Population aging results in increasing numbers of elderly persons undergoing surgery for colorectal cancer. We sought to identify objective preoperative indicators of outcomes, with a view toward development of safe, effective treatments for such patients. PATIENTS AND METHODS: The study included 99 patients aged 80 years or more, who were treated surgically for stage I- III colorectal cancer. Preoperative nutritional status was compared retrospectively between those who suffered postoperative complications (n=40) and those who did not (n=59). RESULTS: Univariate analysis revealed low prealbumin (PreAlb) concentration (p=0.032) and low platelet-to-lymphocyte ratio (p=0.116) as risk factors for postoperative complications. Multivariate analysis showed preoperative PreAlb concentration to be an independent risk factor (OR=0.884; 95% confidence interval=0.791-0.989; p=0.024) associated with postoperative length of hospital stay (coef.=-0.336, p=0.002). CONCLUSION: PreAlb, a rapid turnover protein, shows promise as a simple predictor of postoperative complications in elderly patients treated for colorectal surgery.

Impact of Intraoperative Blood Loss on the Survival of Patients With Stage II/III Colorectal Cancer: A Multicenter Retrospective Study.

BACKGROUND: Resection of the primary lesion with radical lymph node dissection is the most promising treatment avenue for patients with cancer. On the other hand, these procedures often induce excessive intraoperative blood loss (IBL) and require perioperative blood transfusion. The influence of IBL on the long-term postoperative outcomes of patients with digestive cancer is controversial. We investigated the impact of IBL on survival and recurrence after curative surgery in patients with colorectal cancer (CRC) in a single study group. PATIENTS AND METHODS: In total, 1,597 patients who underwent radical resection for CRC at three group hospitals between 2000 and 2019 were reviewed. Patients were classified into a group with high IBL (≥200 ml) or low IBL (<200 ml). The risk factors for disease-free (DFS) and overall (OS) survival were analyzed. RESULTS: A total of 489 and 1,108 patients were classified into the high and low IBL groups, respectively. The OS and DFS rates at 5 years after surgery were 89.3% and 63.4%, respectively, for the high IBL group and 96.9% and 77.8% for the low IBL group; these differences were statistically significantly (p<0.001). The multivariate analysis demonstrated that IBL was a significant independent risk factor for OS and DFS. CONCLUSION: The amount of IBL was associated with significant differences in the OS and DFS of patients with stage II/III CRC who received curative resection. The surgical procedure, surgical strategy, and perioperative care should be carefully planned to avoid causing IBL.

Potential Benefits of Minimally Invasive Laparoscopy in Reducing Local Recurrence After Surgery for Low Rectal Cancer.

AIM: To compare the mid-term oncological results between patients with low rectal cancer who underwent minimally invasive laparoscopic surgery (MILS) and those who underwent open surgery (OS). PATIENTS AND METHODS: Overall, 262 matched patients who underwent primary resection for low rectal cancer between 2000 and 2019 were divided into MILS (n=131; n=107, conventional laparoscopic surgery; n=24, robotic surgery) and OS (n=131) groups. The short- and mid-term outcomes were compared. RESULTS: Similar baseline characteristics were noted. The operative time was longer and blood loss was lesser in the MILS group; the conversion rate was 3.8%. The incidence of postoperative complications was similar. The 2-year cumulative incidence of local recurrence was noted to be much lower in the MILS group (1.9%) than in the OS group (8.4%). MILS had a significantly low hazard ratio (0.208, p=0.036). CONCLUSION: MILS has potential benefits in reducing local recurrence of low rectal cancer.

Prognostic impact of tumour sidedness in patients with stage II colon cancer: a single-centre retrospective study.

BACKGROUND: The search for high-risk factors in stage II colon cancer (CC) is ongoing and several high-risk factors for stage II CC have been identified; however, the effects of tumour sidedness on prognosis are not clear. This study aims to determine whether tumour sidedness could be identified as another high-risk factor for stage II CC. METHODS: We retrospectively analysed 189 patients with stage II CC and compared clinicopathological findings and long-term outcomes between the patients with right colonic cancer (RCC) and with left colonic cancer (LCC). Prognostic factors for survival were determined using univariate and Cox proportional regression analyses. RESULTS: A total of 72 patients were diagnosed with RCC and 117 patients were diagnosed with LCC. Patients with RCC were significantly older (P < 0.001), and the number of harvested lymph nodes was greater in the RCC group (RCC: 25 versus LCC: 19; P = 0.003). The overall survival (OS) was worse in the RCC group than the OS in the LCC group (5-year survival rate - RCC: 81.3% versus LCC: 90.4%; P = 0.025). Cox proportional regression analysis showed that tumour sidedness was an independent prognostic factor for both OS (hazard ratio (HR) 3.78, 95% confidence interval (CI) 1.61-8.85, P = 0.022) and DFS (HR 2.58, 95% CI 1.33-4.99, P = 0.005). CONCLUSION: Patients with RCC have more negative prognostic factors and worse long-term outcomes than those with LCC in stage II CC. Tumour sidedness is a high-risk factor in stage II CC patients.

Automated non-invasive identification of pelvic autonomic nerves with a handheld Raman spectrometer and potential application to nerve-sparing colorectal surgery: a preliminary study in surgical specimens.

BACKGROUND: Although minimally invasive surgery for colorectal cancer, whether performed as standard laparoscopic or robotic surgery, has been established as an oncologically safe procedure, postoperative urinary dysfunction and sexual dysfunction remain matters of concern, even when so-called nerve-sparing surgery is performed. We have hypothesized that Raman spectroscopy can be used intraoperatively as a non-invasive label-free means of objective identification of the pelvic nerves, and we conducted a preliminary study by applying a newly developed handheld Raman spectrometer to surgical specimens. METHODS: Samples of nervous tissue, colon cancer tissue, and tissues from surrounding pelvic organs were obtained from 25 patients undergoing colectomy. Raman spectra were obtained by irradiation with the Progeny™ Raman spectrometer. We looked for characteristic Raman shifts to distinguish nervous tissue from cancer tissue. To improve discrimination between nervous tissue and other tissues, the spectral data were subjected to principal component analysis. RESULTS: We detected characteristic differences in the spectra at 1,309 cm-1, 1,442 cm-1, and 1,658 cm-1. A significant difference was detected at 1,442 cm-1, and accuracy of the modality for identification of nervous tissue was 75%. The addition of principle component analysis (4 components) yielded 100% sensitivity, 85% specificity, and 90%, notably increasing accuracy from 75% to 90% in discriminating between nervous tissue and cancer tissue. CONCLUSIONS: Raman spectroscopy holds promise for non-invasive intraoperative recognition of nervous tissue. We expect the modality to become a powerful clinical tool, compensating for the lack of tactile feedback intrinsic to minimally invasive colectomy and thus thwarting the risk of postoperative urinary and/or sexual dysfunction.