Can neoadjuvant chemoradiotherapy before lateral pelvic lymph node dissection improve local control and prognosis in rectal cancer patients with clinically suspected lateral lymph node metastasis? A multicenter lateral node study in China.

AIMS: Selective lateral pelvic lymph node (LPN) dissection (LPND) following neoadjuvant chemoradiotherapy (nCRT) for rectal cancer is widely recognized. This study aimed to determine the effects of nCRT before LPND on local control and prognosis of rectal cancer patients. MATERIALS AND METHODS: Data were retrieved from a prospective database for rectal cancer patients with clinical LPN metastasis receiving total mesorectal excision and LPND at three institutions between January 2012 and December 2019. Selection bias was minimized using propensity score matching (PSM) and short-term and clinical outcomes were compared. RESULTS: Patients (n = 213) were enrolled and grouped as either nCRT (n = 97) or non-nCRT (n = 116). PSM was used to identify 83 matched pairs. In the matched cohort, nCRT patients had a longer operation duration (310.6 vs. 265.0 min, P = 0.001), lower pathological LPN metastasis rate (32.5% vs. 48.2%, P = 0.040), and fewer harvested lymph nodes (22 vs. 25, P = 0.018) compared to the non-nCRT group. However, after PSM, the two groups had similar estimated overall 3-year survival (79.5% vs. 80.7%, P = 0.922), 3-year disease-free survival (66.1% vs. 65.5, P = 0.820), and 3-year local recurrence-free survival (88.6% vs. 89.7%, P = 0.927). Distant metastasis was the predominant recurrence pattern in the overall (45/58, 77.6%) and matched (33/44, 75.0%) cohorts. CONCLUSIONS: LPND without nCRT is effective and sufficient in preventing local recurrence in patients with LPN metastases. Future prospective randomized controlled studies are warranted to confirm these findings. Since systemic metastasis is the predominant recurrence pattern in patients with LPN metastasis post-LPND, improved perioperative systemic chemotherapy is needed to prevent micrometastasis.

Risk factors for and prognostic impact of lateral pelvic lymph node metastasis in patients with rectal neuroendocrine tumors: a single-center retrospective analysis of 214 cases with radical resection.

PURPOSE: Lateral pelvic lymph node (LPLN) metastasis of rectal neuroendocrine tumors (NETs) is rare, with unknown oncological features. We investigated the oncological impact of LPLN metastasis in patients with rectal NETs. METHODS: This study included 214 patients with rectal NETs who underwent curative surgery. We evaluated their clinicopathological characteristics and short- and long-term outcomes. RESULTS: LPLN dissection was performed in 15 patients with LPLN swelling ≥ 7 mm (preoperative imaging); 12 patients had LPLN metastases, 6 of whom had LPLN metastases without mesorectal lymph node metastases (skip metastasis). The short-term outcomes were similar between the groups with and without LPLN dissection. The median follow-up period was 59.4 months, and patients with LPLN metastasis showed significantly shorter disease-free and overall survival rates than those without metastasis. Among 199 patients who did not undergo LPLN dissection, only 1 had LPLN recurrence. In a univariate analysis, tumor depth, tumor grade, and LPLN metastasis were associated with the overall survival. In the multivariate analysis, only LPLN metastasis was an independent predictor of the overall survival. CONCLUSIONS: LPLN metastasis is a poor prognostic factor for patients with rectal NETs. LPLN enlargement can be considered an indication for dissection, owing to its high rate of metastasis and associated poor prognosis.

Comparison between preoperative chemoradiotherapy and lateral pelvic lymph node dissection in clinical T3 low rectal cancer without enlarged lateral lymph nodes.

AIM: The standard strategy for clinical T3 rectal cancer without enlarged lateral lymph nodes is preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) in Western countries and TME with bilateral lateral pelvic lymph node dissection (LPLND) in Japan. This study compared surgical, pathological and oncological results of these two strategies. METHOD: Patients who underwent preoperative CRT followed by TME in France (CRT + TME group) and those who underwent TME with LPLND in Japan (TME + LPLND group) for clinical T3 rectal adenocarcinoma without enlarged lateral lymph nodes from 2010 to 2016 were retrospectively analysed. RESULTS: In total, 439 patients were included in this study. The estimated local recurrence rate (LRR), disease-free survival and overall survival at 5 years post-surgery was 4.9%, 71% and 82% in the CRT + TME group, and 8.6%, 75% and 90% in the TME + LPLND group, respectively. Lateral LRR versus non-lateral LRR was 0.5% versus 4.2% in the CRT + TME group and 1.8% versus 6.2% in the TME + LPLND group. Obturator nerve injury and isolated pelvic abscess were shown only in the TME + LPLND group. Urinary complications were more frequent in the TME + LPLND group than in the CRT + TME group. CONCLUSION: Disease-free survival was not significantly different after TME with LPLND and after CRT followed by TME. LRR was not significantly different after both strategies; however, there was a trend for higher LRR after TME with LPLND than after CRT followed by TME. Obturator nerve injury, isolated lateral pelvic abscess and urinary complications should be noted when TME with LPLND is applied.

Lateral pelvic sentinel lymph node biopsy using indocyanine green fluorescence navigation: can it be a powerful supplement tool for predicting the status of lateral pelvic lymph nodes in advanced lower rectal cancer.

BACKGROUND: An innovative instrument for laparoscopy using indocyanine green (ICG) allows easy detection of sentinel lymph nodes (SLNs) in lateral pelvic lymph nodes (LPLNs). Here, we investigated the safety and efficacy of lateral pelvic SLN biopsy (SLNB) using ICG fluorescence navigation in advanced lower rectal cancer and evaluated the sensitivity and specificity of this technique to predict the status of LPLN. METHODS: From April 1, 2017 to December 1, 2020, we conducted lateral pelvic SLNB using ICG fluorescence navigation during laparoscopic total mesorectal excision and lateral pelvic lymph node dissection (LLND) in 23 patients with advanced low rectal cancer who presented with LPLN but without LPLN enlargement. Data regarding clinical characteristics, surgical and pathological outcomes, lymph node findings, and postoperative complications were collected and analyzed. RESULTS: We successfully performed the surgery using fluorescence navigation. One patient underwent bilateral LLND and 22 patients underwent unilateral LLND. The lateral pelvic SLN were clearly fluorescent before dissection in 21 patients. Lateral pelvic SLN metastasis was diagnosed in 3 patients and negative in 18 patients by frozen pathological examination. Among the 21 patients in whom lateral pelvic SLN was detected, the dissected lateral pelvic non-SLNs were all negative. All dissected LPLNs were negative in two patients without fluorescent lateral pelvic SLN. CONCLUSION: This study indicated that lateral pelvic SLNB using ICG fluorescence navigation shows promise as a safe and feasible procedure for advanced lower rectal cancer with good accuracy, and no false-negative cases were found. No metastasis in SLNB seemed to reflect all negative LPLN metastases, and this technique can replace preventive LLND for advanced lower rectal cancer.

Clinical significance of metastatic tumor deposit foci in rectal cancer in the lateral pelvic lymph node area.

BACKGROUND: Although previous studies have demonstrated that tumor deposits (TDs) are associated with worse prognosis in colon cancer, their clinical significance in rectal cancer has not been fully elucidated, especially in the lateral pelvic lymph node (LPLN) area. This study aimed to clarify the clinical significance of TDs, focusing on the number of metastatic foci, including lymph node metastases (LNMs) and TDs, in the LPLN area. METHODS: This retrospective study involved 226 consecutive patients with cStage II/III low rectal cancer who underwent LPLN dissection. Metastatic foci, including LNM and TD, in the LPLN area were defined as lateral pelvic metastases (LP-M) and were evaluated according to LP-M status: presence (absence vs. presence), histopathological classification (LNM vs. TD), and number (one to three vs. four or more). We evaluated the relapse-free survival of each model and compared them using the Akaike information criterion (AIC) and Harrell's concordance index (c-index). RESULTS: Forty-nine of 226 patients (22%) had LP-M, and 15 patients (7%) had TDs. The median number of LP-M per patient was one (range, 1-9). The best risk stratification power was observed for number (AIC, 758; c-index, 0.668) compared with presence (AIC, 759; c-index, 0.665) and histopathological classification (AIC, 761; c-index, 0.664). The number of LP-M was an independent prognostic factor for both relapse-free and overall survival, and was significantly associated with cumulative local recurrence. CONCLUSION: The number of metastatic foci, including LNMs and TDs, in the LPLN area is useful for risk stratification of patients with low rectal cancer.

Feasibility and safety of lateral pelvic lymph node dissection for elderly patients with middle-low rectal cancer: results of a large multicenter lateral node collaborative group study in China.

BACKGROUND: Lateral pelvic lymph node (LPN) dissection can improve local control in certain rectal cancer patients with LPN metastasis. However, the effects of this technically complex procedure on perioperative safety and long-term survival of elderly patients (≥ 70 years) remain unclear. METHODS: Locally advanced middle-low rectal cancer patients diagnosed with LPN metastasis who underwent total mesorectal excision (TME) with LPN dissection at three institutions from January 2012 to December 2019 were included in this study. Additionally patients who had neoadjuvant chemoradiotherapy (nCRT) and those who did not were compared. RESULTS: In total there were 407 patients, including 49 elderly and 358 non-elderly patients, of which 249 were male, with a median age of 58 years (range:18-85 years). In the whole cohort, operation time (280.7 vs. 292.0 min, p = 0.498) and estimated blood loss (100 vs. 100 ml, p = 0.384) were comparable in the elderly and non-elderly groups. There was no significant difference in the incidences of overall complications (24.5% vs. 19.8%, p = 0.448) and severe (Clavien-Dindo grade 3-5) surgical complications (8.2% vs. 7.5%, p = 0.778) between the two groups. However, the incidence of urinary retention (14.3% vs. 5.6%, p = 0.032) and intensive care unit admission (16.3% vs. 6.1%, p = 0.018) was significantly higher in the elderly group compared with those in the non-elderly group. The 3-year overall survival (88.7% vs. 82.1%, p = 0.516) and disease-free survival (81.2% vs. 70.7%, p = 0.352) were comparable between the two groups. Moreover, results in the nCRT cohort were comparable to those in the overall cohort. CONCLUSIONS: Even with nCRT, TME combined with LPN dissection is safe and feasible for elderly patients, demonstrating low mortality and acceptable morbidity. Elderly and non-elderly patients with LPN metastasis who undergo LPN dissection can achieve comparable 3-year survival outcomes. TRAIL REGISTRATION: ClinicalTrials.gov Identifier: NCT04850027.

Long-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic lateral pelvic lymph node dissection for clinical stage II/III middle-lower rectal cancer: a propensity score-matched cohort study.

BACKGROUND: We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI. METHODS: This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate. RESULTS: A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048). CONCLUSIONS: This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis. TRIALS REGISTRATION: This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).

Robotic versus laparoscopic approach for minimally invasive lateral pelvic lymph node dissection of advanced lower rectal cancer: a retrospective study comparing short-term outcomes.

PURPOSE: The importance of lateral pelvic lymph node dissection (LLND) for advanced low rectal cancer is gradually being recognized in Europe and the USA, where some patients were affected by uncontrolled lateral pelvic lymph node (LLNs) metastasis, even after total mesorectal excision (TME) with neoadjuvant chemoradiotherapy (CRT). The purpose of this study was thus to compare robotic LLND (R-LLND) with laparoscopic (L-LLND) to clarify the safety and advantages of R-LLND. METHODS: Sixty patients were included in this single-institution retrospective study between January 2013 and July 2022. We compared the short-term outcomes of 27 patients who underwent R-LLND and 33 patients who underwent L-LLND. RESULTS: En bloc LLND was performed in significantly more patients in the R-LLND than in the L-LLND group (48.1% vs. 15.2%; p = 0.006). The numbers of LLNs on the distal side of the internal iliac region (LN 263D) harvested were significantly higher in the R-LLND than in the L-LLND group (2 [0-9] vs. 1 [0-6]; p = 0.023). The total operative time was significantly longer in the R-LLND than in the L-LLND group (587 [460-876] vs. 544 [398-859]; p = 0.003); however, the LLND time was not significantly different between groups (p = 0.718). Postoperative complications were not significantly different between the two groups. CONCLUSION: The present study clarified the safety and technical feasibility of R-LLND with respect to L-LLND. Our findings suggest that the robotic approach offers a key advantage, allowing significantly more LLNs to be harvested from the distal side of the internal iliac region (LN 263D). Prospective clinical trials examining the oncological superiority of R-LLND are thus necessary in the near future.

Functional outcomes after lateral pelvic lymph node dissection for rectal cancer: a systematic review and meta-analysis.

PURPOSE: Lateral pelvic lymph node dissection (LPLND) may improve oncological outcomes for select patients with rectal cancer, though functional outcomes may be adversely impacted. The aim of this study is to assess the functional outcomes associated with LPLND for rectal cancer and compare these outcomes with standard surgical resection. METHODS: A systematic search was undertaken to identify relevant studies reporting on urinary dysfunction (UD), sexual dysfunction (SD), and defecatory dysfunction (DD) for patients who underwent LPLND for rectal cancer. Studies comparing functional outcomes in patients who underwent surgery with and without LPLND were assessed. In addition, a comparison of functional outcomes in patients who underwent LPLND before and after the year 2000 was performed. RESULTS: Twenty-one studies of predominantly non-randomised observational data were included. Ten were comparative studies. Male SD was worse in patients who underwent LPLND compared with those who did not (RR 1.68 (95% CI 1.41-1.99, P < 0.001)). No difference was observed for the rate of UD between treatment groups. The rates of UD and male SD in patients who underwent LPLND after the year 2000 were significantly lower than those who underwent LPLND before the year 2000 ((UD) RR = 4.5, p value = 0.0034; male SD RR = 28.7, p value < 0.001). CONCLUSION: Lateral pelvic lymph node dissection is associated with worse male sexual dysfunction compared to standard surgical resection. However, the rates of urine dysfunction and male sexual dysfunction are better in contemporary cohorts which may reflect improved surgical technique and autonomic nerve preservation.

Risk factors and prognostic significance of postoperative complications following lateral pelvic lymph node dissection for rectal cancer: results of the multicenter lateral node study in China.

OBJECTIVE: Total mesorectal excision (TME) plus lateral pelvic lymph node (LPN) dissection (LPND) is a technically complex and challenging procedure with higher morbidity than TME alone. We aimed to investigate the risk factors for postoperative complications after TME + LPND, and the impact of complications on patient prognosis. METHODS: A total of 387 rectal cancer patients with clinical LPN metastasis (LPNM) who underwent TME + LPND at three institutions affiliated with the Chinese Lateral Node Collaborative Group were included. Logistic regression models were used to identify the risk factors for post-surgical complications, and the log-rank test was used to compare the prognosis. Severe complications were described as grade III-V. RESULTS: The incidence rates of overall complications and severe complications after TME + LPND were 15.2% (59/387) and 7.8% (30/387), respectively. Multivariate analysis showed that a duration of operation ≥260 min was an independent risk factor for both overall (odds ratio [OR] = 3.03, 95% confidence interval [CI] = 1.57-5.85, P = 0.001) and severe postoperative complications (OR = 2.67, 95% CI = 1.06-6.73, P = 0.037). The development of overall postoperative complications (P = 0.114) and severe postoperative complications (P = 0.298) had no significant impact on the overall survival. However, patients with overall complications (P = 0.015) or severe complications (P = 0.031) with a postoperative hospital stay >30 days had significantly an overall worse survival. CONCLUSION: A surgical duration of ≥260 min is a significant risk factor for both overall and severe postoperative complications after TME + LPND for middle-low rectal cancer. Furthermore, the development of overall complications or severe complications that require a postoperative hospital stay >30 days significantly worsens the prognosis.

Short- and long-term outcomes of laparoscopic versus open selective lateral pelvic lymph node dissection for locally advanced middle-low rectal cancer: Results of a multicentre lateral node study in China.

AIM: Lateral pelvic lymph node dissection (LPND) is a technically challenging procedure, and the safety and feasibility of laparoscopic LPND remains undetermined. Here, we compared the short- and long-term survival outcomes of laparoscopic LPND with those of open LPND. METHODS: From January 2012 to December 2019, locally advanced middle-low rectal cancer patients with clinical evidence of lateral pelvic lymph node metastasis (LPNM) who underwent total mesorectal excision with LPND at three institutions were included. Propensity score matching was used to minimize selection bias. The short-term and oncological outcomes of open and laparoscopic LPND were compared. RESULTS: Overall, 384 patients were enrolled into the study including 277 and 107 patients who underwent laparoscopic and open LPND, respectively. After matching, patients were stratified into laparoscopic (n = 100) and open (n = 100) LPND groups. Patients in the laparoscopic LPND group had a shorter operation time (255 vs. 300 min, p = 0.001), less intraoperative blood loss (50 vs. 300 ml, p < 0.001), lower incidence of postoperative complications (32.0% vs. 15.0%, p = 0.005), shorter postoperative hospital stay (8 vs. 14 days, p < 0.001), and excision of more lateral pelvic lymph nodes (9 vs. 7, p = 0.025) than those in the open LPND group. The 3-year overall survival (p = 0.581) and 3-year disease-free survival (p = 0.745) rates were similar between the groups, and LPNM was an independent predictor of survival. CONCLUSION: Laparoscopic LPND is technically safe and feasible with favourable short-term results and similar oncological outcomes as open surgery in selected patients.

A new technique for robotic lateral pelvic lymph node dissection for advanced low rectal cancer with emphasis on en bloc resection and inferior vesical vessel preservation.

BACKGROUND: Lateral pelvic lymph node (LPLN) dissection is becoming increasingly important in the treatment of advanced low rectal cancer patients. However, the surgery has several disadvantages, including its technical complexity and high risk of urinary dysfunction. Herein, we report a new technique for robotic lateral pelvic lymph node dissection for advanced low rectal cancer with emphasis on en bloc resection and inferior vesical vessel preservation. METHODS: Robotic LPLN dissection was performed in 12 consecutive patients between April 2020 and December 2021. Six surgical ports were placed in the abdomen under general anesthesia. Fascia-oriented LPLN dissection of the internal iliac region and obturator region was performed using the ureterohypogastric nerve fascia, vesicohypogastric fascia, and internal obturator muscles as anatomical landmarks. Lymph nodes were resected en bloc via the caudal side of the inferior vesical vessels. The inferior vesical vessels were spared to prevent urinary dysfunction. RESULTS: The median patient age was 62 years (range, 43-82 years), and eight patients were male. The median operative time was 498 min (range, 424-661 min), the median bleeding volume was 56 ml (range, 13-467 ml), and the median number of harvested LPLN was 16 (range, 1-70). The conversion rate to open surgery was 0%. Clavien-Dindo Grade ≥ II urinary dysfunction rated was not observed. CONCLUSION: A new technique for robotic LPLN dissection for advanced low rectal cancer with emphasis on en bloc resection and inferior vesical vessel preservation can be safely performed, making it a promising surgical procedure.

Long-term effects of laparoscopic lateral pelvic lymph node dissection on urinary retention in rectal cancer.

BACKGROUND: The addition of lateral pelvic lymph node dissection (LPLND) in rectal cancer surgery has been reported to increase the incidence of post-operative urinary retention. Here, we assessed the predictive factors and long-term outcomes of urinary retention following laparoscopic LPLND (L-LPLND) with total mesorectal excision (TME) for advanced lower rectal cancer. METHODS: This retrospective single-institutional study reviewed post-operative urinary retention in 71 patients with lower rectal cancer who underwent L-LPLND with TME. Patients with preoperative urinary dysfunction or who underwent unilateral LPLND were excluded. Detailed information regarding patient clinicopathologic characteristics, post-void residual urine volume, and the presence or absence of urinary retention over time was collected from clinical and histopathologic reports and telephone surveys. Urinary retention was defined as residual urine > 100 mL and the need for further treatment. RESULTS: Post-operative urinary retention was observed in 25/71 patients (35.2%). Multivariate analysis revealed that blood loss ≥ 400 mL [odds ratio (OR) 4.52; 95% confidence interval (CI) 1.24-16.43; p = 0.018] and inferior vesical artery (IVA) resection (OR 8.28; 95% CI 2.46-27.81; p < 0.001) were independently correlated with the incidence of urinary retention. Furthermore, bilateral IVA resection caused urinary retention in more patients than unilateral IVA resection (88.9% vs 47.1%, respectively; p = 0.049). Although urinary retention associated with unilateral IVA resection improved relatively quickly, urinary retention associated with bilateral IVA resection tended to persist over 1 year. CONCLUSION: We identified the predictive factors of urinary retention following L-LPLND with TME, including increased blood loss (≥ 400 mL) and IVA resection. Urinary retention associated with unilateral IVA resection improved relatively quickly. L-LPLND with unilateral IVA resection is a feasible and safe procedure to improve oncological curability. However, if oncological curability is guaranteed, bilateral IVA resection should be avoided to prevent irreversible urinary retention.

Establishment and validation of a nomogram for predicting potential lateral pelvic lymph node metastasis in low rectal cancer.

BACKGROUND: Identifying lateral pelvic lymph node (LPN) metastasis in low rectal cancer is crucial before treatment. Several risk factors and prediction models for LPN metastasis have been reported. However, there is no useful tool to accurately predict LPN metastasis. Therefore, we aimed to construct a nomogram for predicting LPN metastasis in rectal cancer. METHODS: We analyzed the risk factors for potential LPN metastasis by logistic regression analysis in 705 patients who underwent primary resection of low rectal cancer. We included patients at 49 institutes of the Japan Society of Laparoscopic Colorectal Surgery between June 2010 and February 2012. Clinicopathological factors and magnetic resonance imaging findings were evaluated. The nomogram performance was assessed using the c-index and calibration plots, and the nomogram was validated using an external cohort. RESULTS: In the univariable logistic regression analysis, age, sex, carcinoembryonic antigen, tumor location, clinical T stage, tumor size, circumferential resection margin (CRM), extramural vascular invasion (EMVI), and the short and long axes of LPN and perirectal lymph node (PRLN) were nominated as risk factors for potential LPN metastasis. We identified a combination of the short axis of LPN, tumor location, EMVI, and short axis of PRLN as optimal for predicting potential LPN metastasis and developed a nomogram using these factors. This model had a c-index of 0.74 and was moderately calibrated and well-validated. CONCLUSIONS: This is the first study to construct a well-validated nomogram for predicting potential LPN metastasis in rectal cancer, and its performance was high.

Mesorectal excision with lateral lymph node dissection for mid-low rectal cancer with lateral lymph node metastasis: efficacy and prognostic analysis.

BACKGROUND: The aim of this study was to evaluate the efficacy of lateral pelvic lymph node (LPN) dissection (LPND) for rectal cancer patients with LPN metastasis (LPNM) and investigate the impact of LPNM on prognosis. METHODS: One hundred twenty-five matched pairs were selected and divided into the total mesorectal excision (TME) group and TME + LPND group for evaluation after propensity matching. RESULTS: No significant difference was observed in the 3-year local recurrence rate between the TME group and the TME + LPND group (10.7% vs 8.8%, P = 0.817); however, the rate of distant metastasis after TME + LPND was significantly higher (15.2% vs 7.2%, P = 0.044). When the mesorectal LN and LPN groups were subdivided, 3-year RFS was not significantly different between the internal LPN and N2 groups (57.1% vs. 55.3%, P = 0.613). There was no significant difference in RFS between the external group and the stage IV group (49.1% vs. 22.5%, P = 0.302), but RFS in the former group was significantly worse than that in the N2 group (49.1% vs. 55.3%, P = 0.044). CONCLUSION: Although patients with suspected LPNM can achieve satisfactory local control after TME + LPND, systemic metastases are more likely to develop after surgery. Patients limited to internal iliac and obturator LN metastasis appear to achieve a survival benefit from LPND and can be regarded as regional LN metastasis. However, patients with LPNM in the external and common iliac LN metastasis have a poor prognosis that is significantly worse than that of N2 and slightly better than that of stage IV, and LPND should be carefully selected.

Stereotactic navigation using registration based on intra-abdominal landmarks in robotic-assisted lateral pelvic lymph node dissection.

BACKGROUND: We carried out robot-assisted lateral pelvic lymph node dissection (LPLND) for rectal cancer with a stereotactic navigation system. The purpose of this study was to evaluate the accuracy and feasibility of the system. METHODS: We constructed a navigation system based on the Polaris Spectra optical tracking device (Northern Digital Inc., Canada) and the open-source software 3D Slicer (version 3.8.1; http://www.slicer.org ). We used the landmark-based registration method for patient-to-image registration. Body surface landmarks and intra-abdominal landmarks were used. We evaluated the time required for registration and target registration error (TRE; the distance between corresponding points after registration) for the root of the superior gluteal artery the root of the obturator or superior vesical artery, and the obturator foramen during minimally invasive LPLND for rectal cancer. Five patients who had LPLND for rectal cancer at the University of Tokyo Hospital between September 2020 and May 2021 were enrolled. RESULTS: The mean time required for registration was 49 s with the body surface landmarks and 88 s with the intra-abdominal landmarks. The mean TRE improved markedly when the registration was performed using intra-abdominal landmarks. The mean TRE of the root of the superior gluteal artery, the root of the obturator or superior vesical artery, and the obturator foramen were 55.8 mm, 53.4 mm, and 55.2 mm with the body surface landmarks and 11.8 mm, 10.0 mm, and 12.6 mm with the intra-abdominal landmarks, respectively. There were no adverse events related to the registration process. CONCLUSIONS: When stereotactic navigation systems are used for minimally invasive LPLND, the use of intra-abdominal landmarks for registration is feasible and may allow simpler and more accurate navigation than the use of body surface landmarks.

Prognostic Value of Lateral Pelvic Lymph Node Dissection for Rectal Cancer: A Meta-Analysis.

BACKGROUND AND AIMS: The benefit of lateral pelvic lymph node dissection (LPLD) for locally advanced rectal cancer remains controversial. This meta-analysis aimed to evaluate the prognostic value of LPLD in patients with locally advanced rectal cancer. METHODS: We performed a systematic search in PubMed, Embase, and the Cochrane Library for publications comparing radical resection plus LPLD (LPLD group) with single radical resection (non-LPLD group) for locally advanced rectal cancer. A total of 15 studies satisfied our inclusion criteria and were assessed. Random-effects and fixed-effects meta-analytical models were used where indicated, and between-study heterogeneity was assessed. RESULTS: LPLD significantly increased grade 3-4 postoperative complications (odds ratio [OR]1.44, 95% CI 1.03-2.02; P = 0.03) compared with non-LPLD. There were no significant differences in 5-y overall survival (hazard ratio = 0.90, 95% CI 0.77-1.05; P = 0.17), 5-y disease-free survival (hazard ratio 1.12, 95% CI 0.60-2.09; P = 0.73), local recurrence (OR 0.89, 95% CI 0.53-1.51; P = 0.68) or distant recurrence (OR 0.85, 95% CI 0.64-1.12; P = 0.24). CONCLUSIONS: We found that LPLD significantly increased grade 3-4 postoperative complications but did not increase 5-y overall survival or 5-y disease-free survival compared with single radical resection for locally advanced rectal cancer. Furthermore, it did not decrease the local recurrence or distant recurrence rates. Thus, more multicenter large-scale randomized controlled trials should be conducted to further explore whether the long-term survival benefits of LPLD truly exist.

Lateral pelvic lymphadenectomy for low rectal cancer: a META-analysis of recurrence rates.

BACKGROUND: Locoregional recurrence (LR) remains a problem for patients with lower rectal cancer despite standardized surgery and improved neoadjuvant treatment regimens. Lateral pelvic lymph node dissection (LPLND) has been routine practice for some time in the Orient/East, but other regions have concerns about morbidity. As perioperative care and surgical approaches are refined, this has been revisited for selected patients. The question as to whether LPLND improves oncological outcomes was explored here. METHODS: A systematic review of patients who underwent TME with or without LPLND from 2000 to 2020 was performed. The primary endpoint was the rate of LR between the two groups. RESULTS: Seven papers met the predefined search criteria in which 2000 patients underwent TME alone, while 1563 patients had TME and LPLND. The rate of LR was marginally higher with TME alone when compared with TME plus LPLND, but this result was not statistically significant (9.8 vs 9.4%, odds ratio 0.75, 95% CI 0.41-1.38, *p = 0.35). In addition, four studies reported on distant recurrence rates, with TME and LPLND showing a slight reduction in overall rates (27.3 vs 29.9%, respectively, OR 0.65, 95% CI 0.45-0.92, *p = 0.02). CONCLUSION: The addition of LPLND to TME is not associated with a significantly lower risk of LR in patients who undergo surgery for lower rectal cancer.

Meta-analysis of direct-to-surgery lateral pelvic lymph node dissection for rectal cancer.

AIM: Direct-to-surgery rectal resection with lateral pelvic lymph node dissection (LPLND) is a treatment strategy commonly employed in Japan to improve oncological outcomes for rectal cancer. The aim of this study was to assess oncological outcomes in the literature for patients with low rectal cancer who underwent direct-to-surgery resection and LPLND compared with those who underwent total mesorectal excision (TME) alone. METHOD: A literature search of Medline, Embase and PubMed databases was performed to identify relevant studies published between 1989 and 2020. The primary outcomes were 5-year overall survival (OS) and 5-year disease-free survival (DFS). The secondary outcomes were cancer recurrence (local, distant and total) and operative burden (operative time and blood loss). Pooled relative risk (RR) of oncological outcomes was performed using the DerSimonian-Laird method random-effect model. RESULTS: Twenty-one studies fulfilled inclusion criteria, including 19 nonrandomized studies of interventions and two studies from one randomized controlled trial. No differences were observed in 5-year OS or 5-year DFS. Local recurrence in nonrandomized studies was worse in patients who underwent LPLND [RR 1.41 (95% CI 1.21-1.64, p < 0.001)], as was total recurrence [RR 1.44 (95% CI 1.25-1.67, p < 0.001)]. No differences were observed for distant recurrence. CONCLUSION: In the published literature, direct-to-surgery resection with LPLND was associated with worse local and total recurrence. These predominantly nonrandomized data suggest that a nonselective approach to LPLND does not provide optimal management in radiotherapy-naïve patients with low rectal cancer. Further prospective randomized studies with a focus on patient selection are required.

Risk factors and prognostic significance of lateral pelvic lymph node dissection after neoadjuvant chemoradiotherapy for rectal patients with clinically suspected lateral lymph node metastasis.

AIM: It is still controversial whether the addition of lateral pelvic lymph node (LPN) dissection (LPND) to total mesorectal excision (TME) can provide a survival benefit after neoadjuvant chemoradiotherapy (nCRT) in rectal cancer patients with pathological lateral lymph node metastasis (LPNM). METHODS: Patients with clinically suspected LPNM who underwent nCRT followed by TME + LPND were systematically reviewed and divided into the positive LPN group (n = 15) and the negative LPN group (n = 58). Baseline characteristics, clinicopathological data and survival outcomes were collected and analysed. RESULTS: Of the 73 patients undergoing TME + LPND after nCRT, the pathological LPNM rate was 20.5% (15/73). Multivariate analysis showed that a post-nCRT LPN short diameter ≥ 7 mm (OR 49.65; 95% CI 3.98-619.1; P = 0.002) and lymphatic invasion (OR 9.23; 95% CI 1.28-66.35; P = 0.027) were independent risk factors for pathological LPNM. The overall recurrence rate of patients with LPNM was significantly higher than that of patients without LPNM (60.0% vs 27.6%, P = 0.018). Multivariate regression analysis identified that LPNM was an independent risk factor not only for overall survival (OS) (HR 3.82; 95% CI 1.19-12.25; P = 0.024) but also for disease-free survival (DFS) (HR 2.33; 95% CI 1.02-5.14; P = 0.044). Moreover, N1-N2 stage was another independent risk factor for OS (HR 7.41; 95% CI 1.63-33.75; P = 0.010). CONCLUSIONS: Post-nCRT LPN short diameter ≥ 7 mm and lymphatic invasion were risk factors for pathological LPNM after nCRT. Furthermore, patients with pathological LPNM still show an elevated overall recurrence rate and poor prognosis after TME + LPND. Strict patient selection and intensive perioperative chemotherapy are crucial factors to ensure the efficacy of LPND.