Indication and benefit of pelvic sidewall dissection for rectal cancer

Short- and long-term outcomes of robot-assisted versus laparoscopic lateral lymph node dissection for rectal cancer

PURPOSE

The lateral pelvic cavity is an anatomically tricky site to access using a linear approach; therefore, robot-assisted lateral lymph node dissection (LLND) may be superior over existing laparoscopic procedures. In this study, we aimed to compare the short- and long-term outcomes of robot-assisted LLND (R-LLND) versus laparoscopic LLND (L-LLND) for locally advanced low rectal cancer and explore the potential advantages of robot-assisted surgery.

METHODS

This single-center, retrospective cohort study included patients aged ≥ 18 years who underwent minimally invasive total mesorectal excision (TME) plus LLND for low rectal adenocarcinoma. Patients were divided into L-LLND and R-LLND groups. The short- and long-term outcomes of the procedures were compared.

RESULTS

There were 41 patients in the L-LLND group and 21 in the R-LLND group. The incidence of postoperative complications was significantly lower in the R-LLND group (49% vs. 19%, p = 0.029), especially urinary retention (29% vs. 5%, p = 0.046). The median postoperative hospital stay was significantly shorter in the R-LLND group (22 vs. 15 days, p < 0.001). The 3-year relapse-free survival rates in the L-LLND and R-LLND groups were 75.3% (95% confidence interval [CI]: 58.9-85.9) and 65.7% (95% CI: 30.7-86.1), respectively. No significant differences were observed in long-term survival outcomes.

CONCLUSION

Patients with locally advanced rectal cancer who underwent TME plus R-LLND had a significantly lower incidence of postoperative complications and a significantly shorter postoperative hospital stay compared to those who underwent TME plus L-LLND. The long-term outcomes were comparable, and no oncological concerns associated with R-LLND were observed.

Transition to lateral lymph node dissection in rectal cancer: Forty-five years of outcomes data

PURPOSE

To determine how outcomes of lateral lymph node dissection for rectal cancer have changed over time.

METHODS

This retrospective study included patients with rectal cancer without distant metastasis who underwent total mesorectal excision and lateral lymph node dissection at our institution between 1975 and 2020. We examined the association of surgical time period with relapse-free and overall survival. Multivariable analyses were performed using Cox proportional hazards regression models.

RESULTS

Among a total of 992 patients, 386 underwent surgery in 1975-2000, 296 in 2001-2010, and 310 in 2011-2020. Overall, 924 patients (93%) underwent surgery without preoperative therapy. The respective 5-year relapse-free survival rates were 64.2%, 64.2%, and 68.2% (P = .314), and the 5-year overall survival rates were 72.3%, 84.0%, and 89.3% (P < .001). Overall survival could be stratified by surgical time period, especially stage III (P < .001). In patients with lateral lymph node metastasis, the 5-year overall survival rate was 43.5% in 1975-2000, 61.1% in 2001-2010, and 71.1% in 2011-2020 (P = .003). Multivariable analysis revealed significant differences in overall survival between 2011-2020 and 1975-2000 (hazard ratio, 2.81; P < .001) and between 2011-2020 and 2001-2010 (hazard ratio, 1.59; P = .040), but not in relapse-free survival.

CONCLUSION

The impact of lateral lymph node dissection on rectal cancer treatment may not have changed in 45 years, given the lack of difference in relapse-free survival. Treatment outcomes after recurrence may have improved. The prognosis remains poor for lateral lymph node metastasis, highlighting the need for further development of multimodality treatments.

Lateral Pelvic Recurrence in Rectal Cancer Is Not Local Recurrence but Lymphatic Metastasis

Objectives

Complete resection of advanced rectal cancer is challenging, with local recurrence rates ranging from 4% to 12%. Local recurrence is often categorized as central, anastomotic, or lateral, with lateral lymph node (LLN) metastasis being the primary driver of lateral recurrence. Although preoperative radiotherapy effectively manages nonlateral recurrences, it is less effective for lateral recurrences, and LLN dissection significantly reduces lateral recurrence rates. This study aimed to clarify the clinicopathological characteristics associated with lateral and nonlateral recurrences.

Methods

We retrospectively analyzed 232 patients (156 males and 76 females; median age, 64 years) who underwent preoperative radiotherapy followed by curative-intent surgery for clinical T3/4 rectal adenocarcinoma located below the peritoneal reflection between April 2010 and December 2017. In total, 40% of the patients underwent LLN dissection. Univariate and multivariate analyses of clinicopathological data were performed to identify the independent risk factors for lateral and nonlateral recurrences.

Results

Local recurrence occurred in 19 (8%) patients: 7 had lateral recurrence, 13 had nonlateral recurrence, and 1 had both. Multivariate analysis identified mesorectal lymph node metastasis as a significant risk factor for lateral recurrence, whereas positive circumferential resection margin was a significant risk factor for nonlateral recurrence.

Conclusions

The identification of different risk factors for lateral and nonlateral recurrence suggests that lateral recurrence is more strongly associated with lymphatic permeation than nonlateral recurrence. These findings highlight the importance of LLN dissection in minimizing the risk of lateral recurrence.

Short-term Outcomes of Robotic Lateral Pelvic Lymph Node Dissection for Lower Rectal Cancer

INTRODUCTION

Rectal cancer is among the main causes of cancer-related mortalities worldwide, necessitating more effective treatment strategies.　It is considered that lateral pelvic lymph node dissection (LPND) for rectal cancer patients can contribute to local tumor control and that robotic LPND (Rob-LPND) may be more suitable for LPND, due to technical advantages of precise manipulation in a narrow pelvic space.

METHODS

In this retrospective study, we evaluated the short-term outcomes of laparoscopic-LPND (Lap-LPND) versus Rob-LPND in patients undergoing radical surgery for rectal cancer.　Operative time, blood loss, urethral catheter reinsertion, duration of pelvic drainage tube placement, drainage volume, and postoperative hospital stay were compared between Lap-LPND and Rob-LPND.

RESULTS

Our findings revealed that Rob-LPND was associated with longer total operation time, but there was no significant difference in operation time between the two LPND techniques.　Urinary catheter re-insertion rates were lower in Rob-LPND; also, significant reductions in drainage tube duration, total drainage volume, and postoperative hospital stay were observed.

CONCLUSION

Rob-LPND may reduce postoperative total drainage volume and shorten postoperative hospital stays.　These improvement in short-term outcomes suggest potential clinical advantages of Rob-LPND.

[Evidence for the extent and oncological benefits of lymphadenectomy in colon and rectal cancer : A narrative review based on meta-analyses]

BACKGROUND

Lymphadenectomy for rectal cancer is clearly defined by total mesorectal excision (TME). The analogous surgical strategy for the colon, the complete mesocolic excision (CME), follows the same principles of dissection in embryologically predefined planes.

METHOD

This narrative review initially identified key issues related to lymphadenectomy of rectal and colon cancer. The subsequent search was based on PubMed and focused on meta-analyses. The endpoints for rectal cancer were the benefit of high tie versus low tie and the indications for lateral pelvic lymphadenectomy. For colon cancer the evidence for CME, for the longitudinal extent of resection, for the dissection of infrapyloric and gastroepiploic lymph nodes, for the number of lymph nodes and for the sentinel lymph node technique were used as endpoints.

RESULTS

An oncological benefit of the high tie cannot be derived from the current data. Lateral pelvic lymphadenectomy should only be selectively performed after chemoradiotherapy (CRT) in cases of remaining lymph nodes with suspected metastases. In most studies CME proved to be oncologically superior, especially in stage III. The longitudinal extent of resection should be at least 10 cm in both directions if the principles of CME are observed. Infrapyloric and gastroepiploic lymph node involvement is to be expected in 0.7-22% of cases, depending on patient selection, which justifies dissection, particularly in carcinomas of both flexure and the transverse colon. The minimum number of lymph nodes to be removed cannot be clearly derived from the available studies. Precisely performed CME and an optimal pathological work-up are important. The sentinel lymph node technique cannot currently be used as a criterion for limiting the extent of resection.

CONCLUSION

Both TME and CME are reliable standards for the lymphadenectomy in colorectal carcinomas. A lymphadenectomy that goes beyond this is reserved for selected cases and is partly the subject of currently ongoing studies.

Clinical characteristics and predictive factors of pathological lateral pelvic lymph node metastasis in patients with rectal cancer

In recent years, selective lateral lymph node dissection (LLND) has been performed more frequently. The present study aimed to explore the clinical characteristics and predictive factors of pathological lateral pelvic lymph node metastasis (LPLNM), which may be helpful for pre-treatment decisions. The present study included 64 patients with rectal cancer and clinically suspected LPLNM who underwent total mesorectal excision (TME) and LLND between February 2019 and April 2024. According to pathological outcomes, the patients were divided into the negative LPLN (n=40) and positive LPLN (n=24) groups. The primary endpoints were the overall pathological LPLNM positivity rate and different clinical characteristics between the two groups. The secondary endpoint was the identification of predictive factors of pathological LPLNM before surgery. Among the 64 patients, 24 (37.5%) had pathologically confirmed LPLNM, and pathological LPLNM was related to initial lymph node size. When initial LPLN size was <7 mm, the pathological LPLNM rate was 10.5%, whereas when LPLN size was between 7 and 10 mm, the rate was 34.6%, and when LPLN size was >10 mm, the rate was 68.4%. Initial LPLN size (≥7.1 mm, P=0.003) and cN stage (N1-2, P=0.005) were significantly associated with pathological LPLNM. In multivariate analysis of risk factors, initial LPN size (≥7.1 mm; hazard ratio=4.856, 95% confidence interval 1.158-20.359, P=0.031) was the only independent risk factor for pathological LPLNM. When the cut-off initial LPLN size was 7.1 mm, the sensitivity and specificity were 87.5 and 52.5%, respectively, and the area under the curve was 0.748 (P=0.0009). When both LPLN size ≥7.1 mm and cN1-2 were satisfied, the sensitivity was 66.7%, the specificity increased to 77.5%, and the positive and negative predictive values were 64.0 and 79.5%, respectively. In conclusion, initial LPLN size and cN stage were identified as significant clinical characteristics associated with pathological LPLNM. Patients with an initial LPLN size of ≥7.1 mm and with cN1-2 stage cancer could benefit from TME + LLND surgery.

Near-infrared imaging with indocyanine green fluorescence for intraoperative lymphatic assessment in rectal cancer surgery: a systematic review

INTRODUCTION

At present, harvesting more lymph nodes is considered more conducive to the prognosis of colorectal cancer surgery. The recent development of enhanced surgical visualization has led to the wide employment of indocyanine green (ICG) to assist minimally invasive surgery. This systematic review aims to provide a wide and critical overview of the current state of the art of ICG lymphography during rectal surgery, by focusing on the most relevant literature on this topic.

EVIDENCE ACQUISITION

After validation and registration in the PROSPERO international prospective register of systematic reviews on the 5th May 2024 (ID: CRD42024539426), 8 publications have been considered relevant for the research query and have been divided into two groups: lateral pelvic lymph node dissection (LPLND) and lateral pelvic sentinel lymph node biopsy (LPSLNB). A meta-analysis has not been performed due to the low statistical significance.

EVIDENCE SYNTHESIS

ICG lymphography seems to improve the number of harvested lateral pelvic lymph nodes, to reduce intraoperative blood loss and hospital length of stay during LPLND. In LPSLNB the detection rate of lateral pelvic sentinel lymph nodes ranged from 91.3% to 92%.

CONCLUSIONS

ICG lymphography for fluorescence guidance for LLND is a feasible and safe technique, with promising application in terms of the number of harvested lymph nodes and post-operative outcomes improvement during rectal oncological surgery. As some of these benefits have been already suggested by the current literature, they need to be confirmed in larger and randomized clinical.

Prognostic Impact of the Postoperative Carcinoembryonic Antigen Level after Curative Resection of Locally Advanced Rectal Cancer

Objectives

This study was conducted to investigate whether preoperative or postoperative carcinoembryonic antigen (CEA) with a new cut-off value is more optimal for predicting long-term outcomes in patients with Stage II/III rectal cancer, and to investigate the effectiveness of postoperative adjuvant chemotherapy (POAC) based on the CEA values.

Methods

Serum CEA levels were measured preoperatively (pre-CEA) and postoperatively (post-CEA). The area under the receiver operating curve (AUROC) was used to determine a cut-off for CEA. The cut-off for CEA relative to recurrence-free survival (RFS) was established as that giving the highest AUROC. In comparison of superiority between pre- and post- CEA levels, Akaike's information criterion (AIC) was used in the Cox proportional-hazard regression model.

Results

The subjects were 323 patients who underwent curative surgical treatment for Stage II/III rectal cancer. AIC values indicated that RFS was better stratified by a post-CEA level with a cut-off of 2.3 ng/ml compared with other classifications of pre- or post- CEA. In Stage III or high-risk Stage II cases, there was no effect of POAC on RFS in those with post-CEA <2.3 ng/ml (p=0.39), but in those with post-CEA ≥2.3 ng/ml there was a trend for better RFS in patients who received POAC compared to those without POAC (p=0.06).

Conclusions

Patients with post-CEA ≥2.3 ng/ml had worse long-term outcomes compared with those with post-CEA <2.3 ng/ml. Post-CEA with a cut-off of 2.3 ng/ml may be useful in determining the indication for POAC for in Stage III or high-risk Stage II cases.

Comparison of robotic and laparoscopic approaches in short- and long-term outcomes of lateral pelvic lymph node dissection for advanced rectal cancer: a Japanese multicenter study

BACKGROUND

Lateral pelvic lymph node dissection (LPND) is a challenging surgical technique with complex anatomy and narrow pelvic manipulation. The outcomes of robotic and laparoscopic surgery for LPND are still unclear.

METHODS

We retrospectively reviewed 169 consecutive patients who underwent rectal cancer surgery with LPND between 2016 and 2023. Patients were divided into two groups according to whether LPND was performed by robotic surgery (R group, n = 40) or laparoscopic surgery (L group, n = 129). Clinicopathological feature and outcomes were compared between groups.

RESULTS

Frequency of surgery with combined resection of adjacent structures (5.0% vs. 19.4%, p = 0.023), frequency of patients with distant metastasis (5.0% vs. 19.4%, p = 0.028), and estimated blood loss from bilateral LPND (74 mL vs. 132 mL, p = 0.013) were all lower in the R group than in the L group. Type of surgical approach did not correlate with postoperative complications. Median follow-up was 31.0 months (range, 1.0-69.0 months). No patients in the R group experienced local recurrence, compared to 4.6% in the L group. Multivariate analysis revealed laparoscopic surgery (odds ratio 3.687, 95% confidence interval 1.505-6.033; p = 0.004) as an independent predictor of poor relapse-free survival.

CONCLUSIONS

Robotic surgery for LPND appears to have good prognostic value in some, but not all, oncologic cases. However, large prospective studies are desirable to validate these findings.

Long-term outcomes of S-1 and oxaliplatin neoadjuvant chemotherapy with total mesorectal excision and lateral lymph node dissection for rectal cancer

PURPOSE

Chemoradiotherapy (CRT) for rectal cancer is limited by its harmful side effects and its insufficient benefit on lateral lymph node metastases. The purpose of this study was to evaluate the long-term outcomes of S-1 and oxaliplatin with total mesorectal excision (TME) and lateral lymph node dissection (LLND) without radiation for rectal cancer.

METHODS

The inclusion criteria were patients with stage II or III rectal cancer located within 10 cm from the anal verge. Fifty-two patients who underwent neoadjuvant chemotherapy (NAC) followed by TME and LLND were evaluated. The primary endpoint was the 3-year local recurrence. The secondary endpoints were the 3-year rates of relapse-free survival and overall survival. Expected post-NAC and surgical outcomes were prospectively analyzed.

RESULTS

The overall recurrence rate was 15.4%, with eight patients developing distant recurrences. The local recurrence rate was 7.7% (n = 4). Among the 4 patients with local recurrence, 3 (5.8%) patients had central pelvis recurrence, and 1 (1.9%) patient had lateral pelvic recurrence. The 3-year survival rate was 98.1%, and the 3-year relapse-free survival rate was 84.6%. The risk factors for local recurrence were mucinous carcinoma (p = 0.016) and a positive resection margin (p = 0.009). Pathological mesorectal lymph node metastasis and local recurrence were independent risk factors for poor survival.

CONCLUSIONS

Although preoperative chemotherapy and TME with LLND are sufficient to control local recurrence, some cases will require more aggressive chemotherapy with radiation therapy.

Nomograms Predicting Survival, Recurrence and Beneficiary Identification of Adjuvant Chemotherapy in Treatment-naïve Patients with Rectal Cancer who Underwent Upfront Curative Resection: A multi-institutional study

Objective

To create and validate nomograms predicting overall survival and recurrence in treatment-naïve rectal cancer (RC) patients who underwent upfront surgery.

Background

Although multidisciplinary treatment is standard for locally advanced RC, understanding surgical efficacy is important for determining indications for perioperative adjuvant therapy.

Methods

RC patients who underwent upfront surgery at the Japanese Society for Cancer of the Colon and Rectum institutions were analyzed. A training cohort (n = 1925) of treatment-naïve patients who underwent surgery between 2007 and 2008 was analyzed to construct prognostic models predicting postoperative survival and recurrence. Discrimination and calibration were performed using an external validation cohort (n = 2957; Japanese colorectal cancer registry, procedures in 2005-2006). Effects of adjuvant chemotherapy on survival were evaluated based on nomogram prediction and Surveillance, Epidemiology, and End Results (SEER) data (n = 10,482; upfront surgery for RC in 2010-2015).

Results

In the training cohort, age predicted survival, venous invasion predicted recurrence, and sex, tumor location, histological type, preoperative carcinoembryonic antigen, invasion depth, lymphatic invasion, positive radial margin, and numbers of metastatic nodes and examined nodes predicted both. Internal and external validated Harrell's C-index values were respectively 0.77 and 0.75 for survival and 0.75 and 0.74 for recurrence. RC patients who underwent upfront surgery in the SEER database were stratified into 3 risk levels by nomogram score. Adjuvant chemotherapy did not improve 5-year survival in low-risk patients, but did so for middle-risk (62.4% vs 76.8%) and high-risk (39.4% vs 63.5%) patients.

Conclusion

These nomograms could predict survival and recurrence after upfront curative resection of RC and identify cases expected to benefit more from adjuvant chemotherapy.

Post-hoc analysis of clinicopathological factors affecting lateral lymph node metastasis based on STELLAR study for rectal cancer

PURPOSE

In post-hoc analyses of phaseIII randomized controlled study(STELLAR), to analyzethe prognostic impact oflateral pelvic lymph node (LPLN)metastasis in locally advanced rectal cancer (LARC).

METHODS

LPLN metastasis was defined as a short diameter > 7 mm on magnetic resonance imaging (MRI).The studyincluded 591 patients with LARC.All patients received neoadjuvant (chemo)radiotherapy combined withradical resection.

RESULTS

Among 591 patients, 99 (16.8 %) were diagnosed with LPLN metastasis, mostly with unilateral metastasis (79.8 %), with internal iliac lymph node metastasis being more common (81.8 %).Significant differences were found among with and without LPLN metastasis in rectal segmentation (P=0.001),N disease (P<0.001), mesenteric LN metastasis or not (P=0.030). The median follow-up timewas 34.0 months, three-year disease-free survival (DFS),overall survival (OS), andmetastasis-free survival (MFS)were significantly lower in LPLN metastaticgroup than those in LPLN non-metastaticgroup (51.4 % vs. 68.2 %, P<0.001; 71.8 % vs. 84.2 %, P=0.006; 60.8 % vs. 80.1 %,P<0.001), respectively; while there were no significant differences in locoregional recurrence(11.4 % vs. 8.5 %, P=0.564). Multivariate analysis found that LPLN metastasis was an independent prognostic factor affecting DFS (P=0.005), OS (P=0.036),MFS (P=0.001).No significantly survival benefit was observed for the short-term radiotherapy based total neoadjuvant therapy compared to long-term concurrent chemoradiotherapy.

CONCLUSIONS

LPLN metastasis observed byMRI should be considered in LARC patients, especially in populations with lowrectal cancer, N2 disease, and mesenteric LN metastasis. LPLN metastasis diagnosed by MRI is a significant and independent risk factor and is associated with worse DFS, OS, MFS.

Lateral pelvic lymph nodes dissection of rectal neuroendocrine neoplasms: A prospective case-series and literature review

BACKGROUND

Rectal neuroendocrine neoplasms are relatively rare. Patients with rectal neuroendocrine neoplasms undergoing radical surgery have a higher rate of lymph node metastases. Robust evidence on the status of lateral pelvic lymph node metastases and the role of lateral pelvic lymph node dissection in those patients is lacking. This case-series study aimed to explore and address these issues.

METHODS

This single-center, prospective case series consecutively enrolled patients with biopsy-proven rectal neuroendocrine neoplasms in a tertiary referral hospital between June 2022 and January 2024. All eligible patients underwent laparoscopic total mesorectal excision surgery and bilateral lateral pelvic lymph node dissection under general anesthesia. The clinicopathologic features, surgical outcomes, and postoperative complications were presented. The last follow-up was conducted in March 2024.

RESULTS

A total of 11 patients with rectal neuroendocrine neoplasms-3 female and 8 male-were enrolled. The average age was 60.0 years (range, 53.5-65.5 years), and the median tumor size was 2.0 cm (range, 1.6-2.5 cm). Tumors invaded the muscularis propria in 7 patients. There were 3 cases of neuroendocrine tumor G1, 6 cases of neuroendocrine tumor G2, and 2 cases of neuroendocrine carcinoma. Among these patients, 11 (100.0%) had lymph node metastases, and 6 (54.5%) had lateral pelvic lymph node metastases. In addition, in 2 patients, only lateral pelvic lymph node metastases were observed, without involvement of the mesenteric lymph nodes. Five patients had tumors located on the left wall of the rectum, and only left-sided lateral pelvic lymph node metastases were observed. The other patient had both sides of lateral pelvic lymph node metastases due to circumferential growth of the tumor around the rectum. Anal preservation was achieved in all patients. The median operating time was 235.0 minutes (range, 210.5-335.5 minutes), and the median estimated blood loss was 50.0 mL (range, 45.0-75.0 mL). Two patients experienced postoperative dysuria and recovered spontaneously within 2-4 months after surgery.

CONCLUSION

On the basis of a prospective case series, we demonstrate, for the first time, the lateral pelvic lymph node metastasis status in patients with rectal neuroendocrine neoplasms requiring radical total mesorectal excision surgery. Simultaneous bilateral lateral pelvic lymph node dissection may be a feasible and beneficial procedure for preventing local recurrence in these patients due to the lack of definitive neoadjuvant or adjuvant therapy options.

Short-term outcomes of 47 selective laparoscopic lymph node dissection for rectal cancer: A retrospective study

This study aims to analyze the safety, feasibility, and short-term oncology outcomes of selective laparoscope lateral lymph node dissection (LLND) with total mesorectal excision surgery. Between December 2019 and May 2023, LLND with total mesorectal excision surgery was performed in 47 selected patients with advanced rectal cancer. Surgical complications and 2-year oncology survival outcomes were analyzed in the study. All 47 procedures were technically successful without converting conversion to open surgery. The mean operation time was 200.6 minutes (135-321 minutes), and the mean estimated blood loss was 92.9 mL (range 10-2000 mL). The most common postoperative complications were anastomotic (8.5%, n = 4), ileus (6.4%, n = 3), and chyle leakage (4.3%, n = 2). Lateral pelvic lymph node metastases were found in 19 (40.4%) patients. When divided into lateral pelvic lymph node positive and negative groups, there was no significant impact on overall survival (94.4% vs 100%, Log-rank P = .596) and local recurrence-free survival (LFRS) (76.7% vs 89.6%, Log-rank P = .210), except disease-free survival (DFS) (58.3% vs 90.2%, Log-rank P = .005). Subgroup analysis showed similar short-term survival outcomes between the pN+ group and the internal iliac metastasis group (Log-rank P of overall survival, LFRS, and DFS were all ˃.05). LRFS and DFS in the obturator or external iliac metastasis group were worse than those in the internal iliac metastasis group when the follow-up time was extended (Log-rank P of LFRS and DFS were .05 and .063). Selective laparoscopy LLND for rectal cancer is safety and feasibility, and its complications are manageable. Oncology survival outcomes for lateral pelvic lymph node metastases limited to the internal iliac are similar to the pN+ stage; therefore, it should be treated positively.

Laparoscopic extraperitoneal approach for lateral lymph node dissection for patients with metachronous lateral pelvic lymph node metastases following surgery for rectal cancer: a case series and short-term outcomes

BACKGROUND

There have been few reports of a totally extraperitoneal approach for laparoscopic lateral lymph node dissection (LLND) for patients with metachronous lateral pelvic lymph node metastases following surgery for rectal cancer. Therefore, this study reports the short-term outcomes of LLND via an extraperitoneal approach.

METHODS

A total of 10 patients underwent LLND through a laparoscopic extraperitoneal approach in our hospital since October 2018. Patients with suspected resectable lateral lymph node recurrence after surgery for rectal cancer on computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography CT (PET-CT) were selected for this procedure.

RESULTS

Nine of the 10 cases were completed using this procedure, but one case was converted to an intraperitoneal approach. The median operative time was 231 min, and the median estimated blood loss was 10 ml. There was one case of wound infection, but no other postoperative complications were seen. In one patient, no metastases were found in the retrieved lymph nodes.

CONCLUSION

The short-term outcomes of LLND through a laparoscopic extraperitoneal approach were acceptable. Because this procedure can be performed without violating the peritoneum, it is less invasive than the conventional intraperitoneal approach and is useful for metachronous lateral pelvic lymph node metastases.

Outcomes and failure patterns after chemoradiotherapy for locally advanced rectal cancer with positive lateral pelvic lymph nodes: a propensity score-matched analysis

PURPOSE

This study aimed to use propensity score matching (PSM) to explore the long-term outcomes and failure patterns in locally advanced rectal cancer (LARC) patients with positive versus negative lateral pelvic lymph node (LPLN).

MATERIALS AND METHODS

Patients with LARC were retrospectively divided into LPLN-positive and LPLN-negative groups. Clinical characteristics were compared between the groups using the chi-square test. PSM was applied to balance these differences. Progression-free survival (PFS) and overall survival (OS), and local-regional recurrence (LRR) and distant metastasis (DM) rates were compared between the groups using the Kaplan-Meier method and log-rank tests.

RESULTS

A total of 651 LARC patients were included, 160 (24.6%) of whom had positive LPLN and 491 (75.4%) had negative LPLN. Before PSM, the LPLN-positive group had higher rates of lower location (53.1% vs. 43.0%, P = 0.025), T4 stage (37.5% vs. 23.2%, P = 0.002), mesorectal fascia (MRF)-positive (53.9% vs. 35.4%, P < 0.001) and extramural venous invasion (EMVI)-positive (51.2% vs. 27.2%, P < 0.001) disease than the LPLN-negative group. After PSM, there were 114 patients for each group along with the balanced clinical factors, and both groups had comparable surgery, pathologic complete response (pCR), and ypN stage rates. The median follow-up was 45.9 months, 3-year OS (88.3% vs. 92.1%, P = 0.276) and LRR (5.7% vs. 2.8%, P = 0.172) rates were comparable between LPLN-positive and LPLN-negative groups. Meanwhile, despite no statistical difference, 3-year PFS (78.8% vs. 85.9%, P = 0.065) and DM (20.4% vs. 13.3%, P = 0.061) rates slightly differed between the groups. 45 patients were diagnosed with DM, 11 (39.3%) LPLN-positive and 3 (17.6%) LPLN-negative patients were diagnosed with oligometastases (P = 0.109).

CONCLUSIONS

Our study indicates that for LPLN-positive patients, there is a tendency of worse PFS and DM than LPLN-negative patients, and for this group patients, large samples are needed to further confirm our conclusion.

Impact of surgical proximal and distal margins on the recurrence of resectable colon cancer: a single-center observational cohort study

PURPOSE

Few studies have investigated the impact of the surgical proximal and distal margins on colon cancer recurrence. We conducted this study to investigate the effect of resection margins on the prognosis of resectable colon cancer.

METHODS

We analyzed data on 1458 patients who underwent colorectal resection in our institute between January, 2004 and March, 2020, including 579 patients with resectable colon cancer. The association between the resection margin and recurrence for each oncological status was assessed and the value of the resection length that influenced recurrence was analyzed.

RESULTS

Patients who had pT4 colon cancer with margins of more than 7 cm had a trend of fewer recurrences and longer relapse-free survival (RFS) than those with colon cancer of other stages (P = 0.033; hazard ratio [HR], 0.42; 95% confidence interval [CI], 0.20-0.89). Multivariate analysis identified a margin of < 7 cm as an independent risk factor for RFS in patients with pT4 colon cancer (P = 0.023; HR, 2.65; 95% CI 1.013-6.17). No correlation was found between resection margins and recurrence, depending on the extent of lymph node metastasis and tumor location.

CONCLUSION

A resection margin of at least 7 cm should be maintained for patients with pT4 colon cancer.

Lateral pelvic lymph node positivity (LPLNP) score: predictive clinic-radiological model of lateral pelvic lymph node involvement in rectal cancer patients

PURPOSE

The population in Western countries differs significantly from that in Eastern countries, and the prevalence of lateral pelvic lymph node (LPLN) involvement in Western populations remains largely unknown due to the limited application of LPLN dissection (LPLND). This discrepancy is primarily attributed to the higher body mass index commonly observed in Western populations, which increases the risk of intraoperative complications. Consequently, the aim of this study is to describe a specific Western clinico-radiological selection tool for LPLND, namely, the lateral pelvic lymph node positivity (LPLNP) score.

METHODS

This retrospective single center study was designed to elaborate the LPLNP score, which was further tested on a prospective cohort of patients. Clinical and MRI factors associated with LPLN involvement were identified, and logistic regression was used to establish the LPLNP score.

RESULTS

In the retrospective series, 120 patients underwent lateral pelvic lymph node dissection. After stepwise logistic regression, five parameters were ultimately included in the LPLNP score. When tested on 66 prospectively selected patients, 40 with an LPLNP score > 0.23 (corresponding to the highest sensitivity and specificity) underwent LPLND: 22 patients (55%) had pathologically confirmed positive LPLN. The negative predictive value of the LPLNP score was 96%, with a sensitivity of 95.7% and a specificity of 58.1%.

CONCLUSION

The LPLNP score was developed based on the largest group of Western patients with locally advanced rectal cancer. This scoring system demonstrated high sensitivity and specificity during validation on the prospective series, correctly identifying LPLN involvement in 55% of cases.

Artificial Intelligence Imaging Diagnosis Using Super-Resolution and Three-Dimensional Shape for Lymph Node Metastasis of Low Rectal Cancer: A Pilot Study From a Single Center

BACKGROUND

Although accurate preoperative diagnosis of lymph node metastasis is essential for optimizing treatment strategies for low rectal cancer, the accuracy of present diagnostic modalities has room for improvement.

OBJECTIVE

The study aimed to establish a high-precision diagnostic method for lymph node metastasis of low rectal cancer using artificial intelligence.

DESIGN

A retrospective observational study.

SETTINGS

A single cancer center and a college of engineering in Japan.

PATIENTS

Patients with low rectal adenocarcinoma who underwent proctectomy, bilateral lateral pelvic lymph node dissection, and contrast-enhanced multidetector row CT (slice ≤1 mm) between July 2015 and August 2021 were included in the present study. All pelvic lymph nodes from the aortic bifurcation to the upper edge of the anal canal were extracted, regardless of whether within or beyond the total mesenteric excision area, and pathological diagnoses were annotated for training and validation.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.

RESULTS

A total of 596 pathologically negative nodes and 43 positive nodes from 52 patients were extracted and annotated. Four diagnostic methods, with and without using super-resolution images and with and without using 3-dimensional shape data, were performed and compared. The super-resolution + 3-dimensional shape data method had the best diagnostic ability for the combination of sensitivity, negative predictive value, and accuracy (0.964, 0.966, and 0.968, respectively), whereas the super-resolution only method had the best diagnostic ability for the combination of specificity and positive predictive value (0.994 and 0.993, respectively).

LIMITATIONS

Small number of patients at a single center and the lack of external validation.

CONCLUSIONS

Our results enlightened the potential of artificial intelligence for the method to become another game changer in the diagnosis and treatment of low rectal cancer. See Video Abstract .

DIAGNSTICO POR IMGENES CON INTELIGENCIA ARTIFICIAL MEDIANTE SUPERRESOLUCIN Y FORMA D PARA LA METSTASIS EN LOS GANGLIOS LINFTICOS DEL CNCER DE RECTO BAJO UN ESTUDIO PILOTO DE UN SOLO CENTRO

ANTECEDENTES:Aunque el diagnóstico preoperatorio preciso de metástasis en los ganglios linfáticos es esencial para optimizar las estrategias de tratamiento para el cáncer de recto bajo, la precisión de las modalidades de diagnóstico actuales tiene margen de mejora.OBJETIVO:Establecer un método de diagnóstico de alta precisión para las metástasis en los ganglios linfáticos del cáncer de recto bajo utilizando inteligencia artificial.DISEÑO:Un estudio observacional retrospectivo.AJUSTE:Un único centro oncológico y una facultad de ingeniería en Japón.PACIENTES:En el presente estudio se incluyeron pacientes con adenocarcinoma rectal bajo sometidos a proctectomía, disección bilateral de ganglios linfáticos pélvicos laterales y tomografía computarizada con múltiples detectores con contraste (corte ≤1 mm) entre julio de 2015 y agosto de 2021. Se resecaron todos los ganglios linfáticos pélvicos desde la bifurcación aórtica hasta el borde superior del canal anal, independientemente de si estaban dentro o más allá del área de escisión mesentérica total, y se registraron los diagnósticos patológicos para entrenamiento y validación.PRINCIPALES MEDIDAS DE RESULTADO:Sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo y precisión.RESULTADOS:Se extrajeron y registraron un total de 596 ganglios patológicamente negativos y 43 positivos de 52 pacientes. Se realizaron y compararon cuatro métodos de diagnóstico, con y sin imágenes de súper resolución y sin datos de imagen en 3D. El método de superresolución + datos de imagen en 3D tuvo la mejor capacidad de diagnóstico para la combinación de sensibilidad, valor predictivo negativo y precisión (0,964, 0,966 y 0,968, respectivamente), mientras que el método de súper resolución solo tuvo la mejor capacidad de diagnóstico para la combinación de especificidad y valor predictivo positivo (0,994 y 0,993, respectivamente).LIMITACIONES:Pequeño número de pacientes en un solo centro y falta de validación externa.CONCLUSIONES:Nuestros resultados iluminan el potencial de la inteligencia artificial para que el método se convierta en otro elemento de cambio en el diagnóstico y tratamiento del cáncer de recto bajo. (Traducción ---Dr. Fidel Ruiz Healy ).

Cross-sectional investigation of the distribution characteristics and prognostic significance of lateral lymph nodes in patients with rectal cancer

BACKGROUND

Information about the distribution characteristics and prognostic significance of lateral lymph nodes (LLNs) on primary computed tomography (CT) scan in rectal cancer patients is lacking.

METHODS

Between January 2013 and December 2016, patients with pathologically proved rectal cancer and pretreatment abdominal enhanced CT in our department were screened. We firstly redivided LLNs into seven categories based on their locations. Then, the number and distribution of all measurable LLNs and the characteristics of the largest LLN in each lateral compartment were recorded. Furthermore, we investigated the long-term outcomes in patients with different LLN characteristics and LLN risk scoring.

RESULTS

A total of 572 patients were enrolled in this study. About 80% of patients had measurable LLNs, and most patients developed measurable LLNs in the obturator cranial compartment. Lateral local recurrence (LLR) was observed in 20 patients, which accounted for 83.3% of the local recurrence (LR). Patients with the largest LLN short-axis diameter >10 mm had a poor prognosis, which was similar to that in patients with simultaneous distant metastasis (SDM). Patients with LLN risk scoring ≥2 had a worse prognosis than those with LLN risk scoring <2, while better than those with SDM.

CONCLUSION

This study suggests that LLR is the main locoregional recurrence pattern. Most rectal cancer patients have measurable LLNs on primary CT scan. However, patients with enlarged LLNs <10 mm or LLN risk scoring <2 still have a significantly better prognosis than patients with SDM, which indicated the potential value of locoregional treatment for these LLNs.

The Role of Lateral Pelvic Lymph Node Dissection in Middle and Lower Rectal Cancer (Stage II or III): A Literature Review

Lateral lymph node dissection and its inclusion in the treatment of rectal cancer is a controversial issue, with great differences, especially between Eastern and Western countries. Studies try to highlight the superiority of resection of these lymph nodes compared to simple mesorectal resection in terms of local recurrence of the disease, the overall survival of patients, and additional postoperative complications. In this study, the modern literature was reviewed, with the ultimate goal of clarifying the exact importance of lateral lymph node dissection, in terms of oncological outcome in patients with cancer of the middle and lower rectum, by studying the involvement of this lymph node dispersion in terms of local recurrence and overall survival of patients with rectal cancer. This review was carried out using electronic databases, including PubMed, Embase, and MEDLINE, with studies dating back to the last decade. Of the 31 studies that were eventually included in the final review, there is no statistically clear superiority and real benefit from lymph node resection beyond the lymph nodes of the mid-rectum. European guidelines are set against lateral lymph node dissection, except for lymph nodes that show suspicious features on preoperative imaging. In contrast, in Eastern countries, total mesorectal excision (TME) with extensive simultaneous resection of the lateral pelvic lymph nodes (LPLNs) is the protocol followed. Recent studies focus on the subcategory of patients with non-responsive to adjuvant therapy, lateral lymph nodes, in which the ultimate benefit of extensive lymph node dissection is explored. The decision to join the TME procedure for the removal of the LPLNs is a subject of intense research. There are no data on the criteria for determining these lymph nodes as an increased risk of metastatic outbreaks. Despite the great clinical and research interest worldwide nowadays, the resection of LPLNs remains a controversial issue of debate, with intense disagreements according to geographical area, while the existence of additional studies is necessary to come to final conclusions.

The role of lateral pelvic lymph node dissection in advanced rectal cancer: a review of current evidence and outcomes

Metastatic lateral pelvic lymph nodes (LPNs) in rectal cancer significantly impact the prognosis and treatment strategies. Western practices emphasize neoadjuvant chemoradiotherapy (CRT), whereas Eastern approaches often rely on LPN dissection (LPND). This review examines the evolving role of LPND in the context of modern treatments, including total neoadjuvant therapy (TNT), and the impact of CRT on the management of clinically suspicious LPNs. We comprehensively reviewed the key literature comparing the outcomes of LPND versus preoperative CRT for rectal cancer, focusing on recent advancements and ongoing debates. Key studies, including the JCOG0212 trial and recent multicenter trials, were analyzed to assess the efficacy of LPND, particularly in conjunction with preoperative CRT or TNT. Current evidence indicates that LPND can reduce local recurrence rates compared to total mesorectal excision alone in patients not receiving radiation therapy. However, the benefit of LPND in the context of neoadjuvant CRT is influenced by the size and pretreatment characteristics of LPNs. While CRT can effectively control smaller metastatic LPNs, larger or clinically suspicious LPNs may require LPND for optimal outcomes. Advances in surgical techniques, such as robotic-assisted LPND, offer potential benefits but also present challenges and complications. The role of TNT in controlling metastatic LPNs and improving patient outcomes is emerging but remains underexplored. The decision to perform LPND should be individualized based on patient-specific factors, including LPN size, response to neoadjuvant treatment, and surgeon expertise. Future research should focus on optimizing treatment protocols and further evaluating the role of TNT in managing metastatic LPNs.

Comparison of short-term outcomes of laparoscopic surgery, robot-assisted laparoscopic surgery, and open surgery for lateral lymph-node dissection for rectal cancer: a network meta-analysis

This study attempted to compare short-term outcomes of laparoscopic surgery (LS), robot-assisted laparoscopic surgery (RS), and open surgery (OS) for lateral lymph-node dissection (LLND) in treatment of rectal cancer through network meta-analysis. Embase, Web of Science, PubMed, and The Cochrane Library databases were searched to collect cohort studies on outcomes of LS, RS, and OS for LLND for rectal cancer. Newcastle-Ottawa Scale (NOS) was utilized to evaluate the quality of cohort studies. Primary outcomes should at least include one of the following clinical outcome measures: operative time, blood loss, total lymph-node harvest, positive resection margin rate, postoperative complications, and postoperative hospital stay. A network meta-analysis was conducted using STATA software. Fourteen cohort studies including 8612 patients were eligible for inclusion. The network meta-analysis results showed that, in terms of intraoperative outcomes, the RS group had the longest operative time, while the OS group had the shortest; the LS and RS groups had significantly less blood loss than the OS group. In terms of histological outcomes, there were no significant differences in the total number of lymph nodes harvested and the positive margin rate among the LS, RS, and OS groups (P > 0.05). Regarding postoperative outcomes, the OS group had the highest probability of postoperative complications and the longest hospital stay, followed by the LS group, with the RS group being the lowest. RS was the best method in blood loss, postoperative complication rate, and postoperative hospital stay, followed by LS. OS had the shortest operative time and the highest blood loss.

Successfully Resected Isolated Lateral Lymph Node Recurrence in a Patient with T1 Lower Rectal Cancer: Case Report and Literature Review

Lateral lymph node (LLN) metastasis in T1 rectal cancer has an incidence of less than 1%. However, its clinical features are largely uncharted. We report a case of LLN metastasis in T1 rectal cancer and review the relevant literature. A 56-year-old female underwent rectal resection for lower rectal cancer 2 years previously (pT1bN0M0). During follow-up, an elevated tumor marker CA19-9 was documented. Enhanced CT and MRI showed a round shape nodule 2 cm in size on the left side of pelvic wall. PET-CT showed high accumulation of FDG in the same lesion, leading to a diagnosis of isolated LLN recurrence. Because no other site of recurrence was detected, surgical resection of the LLN was performed. Microscopic findings were consistent with metastatic lymph node originating from the recent rectal cancer. Adjuvant chemotherapy for six months was given, and patient remains free of recurrent disease seven months after LLN resection. Although LLN recurrence after surgery for T1 rectal cancer is rare, post-surgical follow-up should not be omitted. When LLN metastasis is suspected on CT, MRI and/or PET-CT will be recommended. Surgical resection of LLN metastasis in patients with T1 rectal cancer may lead to favorable outcomes, when recurrence in other areas is not observed.

Developments in the Use of Indocyanine Green (ICG) Fluorescence in Colorectal Surgery

Indocyanine Green (ICG) has significantly advanced minimally invasive surgery. It is widely recognized for its ability to visualize blood vessel patency in real-time across various surgical specialties. While its primary use in colorectal surgery is to evaluate anastomoses for leaks, numerous other applications have been documented in the literature. In this review, we aim to explore both established and emerging applications of ICG fluorescence in colorectal surgery, with the goal of improving patient outcomes. This includes preoperative tumor marking and the detection of metastatic disease. Some applications, such as lymphatic mapping, require further research to determine their impact on clinical practices. Conversely, others, like the intraoperative localizations of ureters, necessitate additional procedures and are not yet widely accepted by the surgical community. However, the development of alternative compounds could offer better solutions. Future research should focus on areas like quantitative ICG and protocol standardization in prospective multicenter studies.

Efficacy of lateral lymph node dissection for local control of rectal cancer: A multicenter study

Background

This study aimed to evaluate the efficacy of lateral lymph node dissection (LLND) for rectal cancer by comparing the local control in patients with and without pathological lateral lymph node metastasis (LLNM).

Methods

We included 189 patients with rectal cancer who underwent total mesorectal excision and LLND at 13 institutions between 2017 and 2019. Patients with and without pathological LLNM were defined as the pLLNM (+) and (-) groups, respectively. Propensity score-matching helped to balance the basic characteristics of both groups. The incidences of local recurrence (LR) and lateral lymph node recurrence (LLNR) were compared between the groups.

Results

In the entire cohort, 39 of the 189 patients had pathological LLNM. The 3-year LR and LLNR rates were 18.3% and 4.0% (p = 0.01) and 7.7% and 3.3% (p = 0.22) in the pLLNM (+) and (-) groups, respectively. After propensity score matching, the data from 62 patients were analyzed. No significant differences in LR or LLNR were observed between both groups. The 3-year LR and LLNR rates were 16.4% and 9.8% (p = 0.46) and 9.7% and 9.8% (p = 0.99) in the pLLNM (+) and (-) groups, respectively.

Conclusion

LLND would lead to comparable local control in the pLLNM (+) and (-) groups if the clinicopathological characteristics except for LLNM are similar.

Role of Lateral Pelvic Node Dissection in Rectal Cancer Surgery

The role of lateral pelvic lymph node dissection in the treatment of patients with locally advanced rectal cancer is a matter of controversy. Surgical practices in Korea and Japan have accepted this approach and are widely utilized; however, it is not routinely incorporated in the practice of countries in the Western hemisphere. This review will examine the role of lateral pelvic lymph node dissection.

MRI-based Radiomics Model for Preoperative Prediction of Lateral Pelvic Lymph Node Metastasis in Locally Advanced Rectal Cancer

RATIONALE AND OBJECTIVES

To develop a magnetic resonance imaging (MRI)-based radiomics model for preoperative prediction of lateral pelvic lymph node (LPLN) metastasis (LPLNM) in patients with locally advanced rectal cancer MATERIALS AND METHODS: We retrospectively enrolled 263 patients with rectal cancer who underwent total mesorectal excision and LPLN dissection. Radiomics features from the primary lesion and LPLNs on baseline MRI images were utilized to construct a radiomics model, and their radiomics scores were combined to develop a radiomics scoring system. A clinical prediction model was developed using logistic regression. A hybrid predicting model was created through multivariable logistic regression analysis, integrating the radiomics score with significant clinical risk factors (baseline Carcinoembryonic Antigen (CEA), clinical circumferential resection margin status, and the short axis diameter of LPLN). This hybrid model was presented with a hybrid clinical-radiomics nomogram, and its calibration, discrimination, and clinical usefulness were assessed.

RESULTS

A total of 148 patients were included in the analysis and randomly divided into a training cohort (n = 104) and an independent internal testing cohort (n = 44). The hybrid clinical-radiomics model exhibited the highest discrimination, with an area under the receiver operating characteristic (AUC) of 0.843 [95% confidence interval (CI), 0.706-0.968] in the testing cohort compared to the clinical model [AUC (95% CI) = 0.772 (0.589-0.856)] and radiomics model [AUC (95% CI) = 0.731 (0.613-0.849)]. The hybrid prediction model also demonstrated good calibration, and decision curve analysis confirmed its clinical usefulness.

CONCLUSION

This study developed a hybrid MRI-based radiomics model that incorporates a combination of radiomics score and significant clinical risk factors. The proposed model holds promise for individualized preoperative prediction of LPLNM in patients with locally advanced rectal cancer.

DATA AVAILABILITY STATEMENT

The data presented in this study are available on request from the corresponding author.

The use of indocyanine green for lateral lymph node dissection in rectal cancer-preliminary data from an emerging procedure: a systematic review of the literature

INTRODUCTION

Lateral lymph node dissection (LLND) for rectal cancer is still not a widely established technique owing to the existing controversy between Eastern and Western countries and the lack of well-designed studies. The risk of complications and the paucity of long-term oncological results are significant drawbacks for further applying this technique. The use of indocyanine green (ICG) near-infrared (NIR) fluorescence for LLND appears as a promising technique for enhancing postoperative and oncological outcomes. This review aims to evaluate the emerging role of ICG during LLND and present the benefits of its application.

MATERIALS AND METHODS

Systematic electronic research was conducted in PubMed and Google Scholar using a combination of medical subject headings (MeSH). Studies presenting the use of ICG during LLND, especially in terms of harvested lymph nodes, were included and reviewed. Studies comparing LLND with ICG (LLND + ICG) or without ICG (LLND-alone) were further analyzed for the number of lymph nodes and postoperative outcomes.

RESULTS

In total, 13 studies were found eligible and analyzed for different parameters. LLND + ICG is associated with significantly increased number of harvested lateral lymph nodes (p < 0.05), minor blood loss, decreased operative time, and probably decreased urinary retention postoperatively compared with LLND-alone.

CONCLUSIONS

The use of ICG fluorescence during LLND is a safe and feasible technique for balancing postoperative outcomes and the number of harvested lymph nodes. Well-designed studies with long-term results are required to elucidate the oncological benefits and establish this promising technique.

Comparison of the short-term surgical outcomes of lateral lymph node dissection for low rectal cancer using a robotic-assisted transabdominal approach alone or supported by a transanal approach

BACKGROUND

Lateral lymph node metastases are a major cause of local recurrence after surgery for advanced low rectal cancer. Lateral lymph node dissection (LLND) may reduce the risk of local recurrence in patients with suspected lateral lymph node metastasis. Recent reports have shown that robotic-assisted LLND can help to reduce the postoperative complication rate, such as urinary disturbance. Furthermore, with the advent of transanal total mesorectal excision, a novel LLND procedure that combines a transabdominal approach with a transanal approach has been reported. This study aimed to clarify the safety and feasibility of robotic-assisted LLND supported by a transanal approach for advanced low rectal cancer.

METHODS

Thirty-nine patients diagnosed to have low rectal cancer between June 2019 and May 2023 were retrospectively enrolled and divided according to whether they underwent LLND via a robotic-assisted transabdominal approach alone (transabdominal group, n = 19) or in combination with a transanal approach (2team group, n = 20). The patient characteristics and short-term surgical outcomes were compared between the two groups.

RESULTS

The total operation time was significantly shorter in the 2team group than in the transabdominal group (366 min vs. 513 min, P < 0.001), as was the time taken to perform unilateral LLND (64 min vs. 114 min, P < 0.001). Furthermore, there was significantly less intraoperative bleeding in the 2team group (30 mL vs. 80 mL, P = 0.004). There was no significant between-group difference in postoperative complications. The incidence of postoperative urinary disturbance was satisfactory at 5% in both groups.

CONCLUSIONS

The operation time for LLND performed by a robotic-assisted transabdominal approach was shortened when supported by a transanal approach. The frequency of postoperative urinary disturbance was low in both groups. Therefore, robotic-assisted abdominal LLND supported by a transanal approach can be considered a promising treatment option for advanced low rectal cancer.

Clinical influence of prophylactic lateral lymph node dissection on oncologic outcomes of patients with mid-low rectal cancer undergoing mesorectal excision: a meta-analysis

BACKGROUND

Although several recent meta-analyses have investigated the clinical influence of the addition of lateral lymph node dissection (LLND) on oncologic outcomes in patients with mid-low rectal cancer (RC) undergoing mesorectal excision (ME), most studies included in such meta-analyses were retrospectively designed. Therefore, this study aimed to explore the clinical influence of prophylactic LLND on oncologic outcomes in patients with mid-low RC undergoing ME.

METHODS

A comprehensive electronic search of the literature up to July 2022 was performed to identify studies that compared oncologic outcomes between patients with mid-low RC undergoing ME who underwent LLND and patients with mid-low RC undergoing ME who did not undergo LLND. A meta-analysis was performed using fixed-effects models and the generic inverse variance method to calculate hazard ratios (HRs) and 95% CIs, and heterogeneity was analyzed using I2 statistics.

RESULTS

A total of 6 studies, consisting of 3 randomized and 3 propensity score matching studies, were included in this meta-analysis. The results of the meta-analysis of 2 randomized studies demonstrated no significant effect of prophylactic LLND on improving oncologic outcomes concerning overall survival (OS) (HR, 1.22; 95% CI, 0.89-1.69; I2 = 0%; P = .22) and relapse-free survival (RFS) (HR, 1.03; 95% CI, 0.81-1.31; I2 = 28%; P = .83).

CONCLUSION

The results of this meta-analysis revealed no significant influence of prophylactic LLND on oncologic outcomes-OS and RFS-in patients with mid-low RC who underwent ME.

Learning process analysis of robotic lateral pelvic lymph node dissection for local advanced rectal cancer: the CUSUM curve of 78 consecutive patients

PURPOSE

Robotic lateral lymph node dissection (LLND) has been described as a safe and feasible procedure for local advanced rectal cancer. The aim of this study was to evaluate the learning curve for robotic-assisted LLND.

METHODS

We collected data on 78 consecutive patients who underwent robotic-LLND at our hospital. The learning curve was analyzed using the cumulative sum (CUSUM) method to assess changes in the unilateral LLND operative times across the case sequence.

RESULTS

Among the 78 patients, 52 underwent bilateral LLND and 26 underwent unilateral LLND. A total of 130 consecutive data were recorded. We arranged unilateral robotic-LLND operative times and calculated cumulative sum values, allowing the differentiation of three phases: phase I (learning period, cases 1-51); phase II (proficiency period, cases 52-83); and phase III (mastery period, cases 84-130). As the learning curve accumulated, the operation time and estimated blood loss of unilateral robotic-LLND decreased significantly with each phase (P < 0.05). By 12 months after surgery, the International Prostatic Symptom Score of patients at phase III was significantly lower than at phase I (P < 0.05).

CONCLUSION

The CUSUM curve shows three phases in the learning of robotic-LLND. The estimated learning curve for robotic-assisted rectal-LLND is achieved after 51 cases.

Preoperative lateral lymph node features and impact on local recurrence after neoadjuvant chemoradiotherapy and total mesorectal excision for locally advanced rectal cancer: results from a multicentre international cohort study

AIM

Locally advanced rectal cancer (LARC) is commonly treated with neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME) to reduce local recurrence (LR) and improve survival. However, LR, particularly associated with lateral lymph node (LLN) involvement, remains a concern. The aim of this study was to investigate preoperative factors associated with LLN involvement and their impact on LR rates in LARC patients undergoing nCRT and curative surgery.

METHOD

This multicentre retrospective study, including four academic high-volume institutions, involved 301 consecutive adult LARC patients treated with nCRT and curative surgery between January 2014 and December 2019 who did not undergo lateral lymph node dissection (LLND). Baseline and restaging pelvic MRIs were evaluated for suspicious LLNs based on institutional criteria. Patients were divided into two groups: cLLN+ (positive nodes) and cLLN- (no suspicious nodes). Primary outcome measures were LR and lateral local recurrence (LLR) rates at 3 years.

RESULTS

Among the cohort, 15.9% had suspicious LLNs on baseline MRI, and 9.3% had abnormal LLNs on restaging MRI. At 3 years, LR and LLR rates were 4.0% and 1.0%, respectively. Ten out of 12 (83.3%) patients with LR showed no suspicious LLNs at the baseline MRI. Abnormal LLNs on MRI were not independent risk factors for LR, distant recurrence or disease-free survival.

CONCLUSION

Abnormal LLNs on baseline and restaging MRI assessment did not impact LR and LLR rates in this cohort of patients with LARC submitted to nCRT and curative TME surgery.

Lateral Lymph Node Dissection for Locally Advanced Rectal Carcinoma: A Step-by-Step Description of Surgical Anatomical Planes During Cadaveric Dissection and Minimally Invasive Surgery

PURPOSE

Total mesorectal excision (TME) is accepted as gold standard method in rectal cancer globally. But there is no standard for lateral lymph nodes. Combination of neoadjuvant treatment plus lateral lymph node dissection (LLND) in select patients might be a promising method. Our purpose is to describe the anatomic landmarks of LLND on cadavers and minimally invasive surgery.

MATERIALS AND METHODS

Local advanced rectal cancer and lateral lymph node (LLN) metastasis are accepted as an indication of neoadjuvant treatment. LLND was performed according to preoperative imaging after radiochemotherapy.

RESULTS

Twenty-eight (10.5%) of 267 patients with rectal cancer who had suspected lateral lymph node metastasis (LLNM) with magnetic resonance imaging (MRI) underwent LLND in addition to TME after neoadjuvant chemoradiotherapy. Eight of them had LLNM. Three patients had bilateral LLND and only 1 had LLNM. The median number of harvested lymph nodes was 6. The rates of LLNM increased with the presence of poor prognosis markers. One regional and 1 distant recurrence were detected in patients who had no LLN metastasis compared with2 regional and 4 distant recurrences in the LLN-positive group.

CONCLUSIONS

Local advanced rectal cancer cases may benefit from LLND, but it does not appear to have an effect on overall survival. There is no consensus whether size and/or morphologic criteria in MRI are the ideal guide for LLND.

Late Local Recurrence after Neoadjuvant Therapy and Radical Resection for Locally Advanced Rectal Cancer

Neoadjuvant radiochemotherapy (RCT) and lately total neoadjuvant therapy (TNT) improved local recurrence rates of rectal cancer significantly compared to total mesorectal excision (TME) alone. Yet the occurrence and impact of late local recurrences after many years appears to be a distinct biological problem. We included n = 188 patients with rectal cancer after RCT and radical resection in this study; n = 38 of which had recurrent disease (sites: local (8.0%), liver (6.4%), lung (3.7%)). We found that 68% of all recurrences developed within the first two years. Four patients, however, experience recurrence >8 years after surgery. Here, we report and characterize four cases of late local recurrence (10% of patients with recurrent disease), suggesting that neoadjuvant therapy in principle delays local recurrence.

Risk factors for lateral lymph node metastasis based on the molecular profiling of rectal cancer

AIM

The association between molecular profiles and lateral lymph node metastasis (LLNM) in patients with rectal cancer remains unclear. Therefore, this study aimed to identify the molecular profiles of rectal cancer associated with LLNM.

METHOD

We retrospectively examined patients who underwent rectal cancer surgery with lateral lymph node dissection without preoperative treatment and whose surgically resected specimens were evaluated using multiomics-based analyses from 2014 to 2019. We compared the clinical characteristics and molecular profiles of patients with pathological LLNM (pLLNM+) with those of patients without (pLLNM-) and identified risk factors for LLNM.

RESULTS

We evaluated a total of 123 patients: 18 with and 105 without pLLNM. The accumulation of mutations in genes key for the development of colorectal cancer were similar between the groups, as was the tumour mutation burden. The distribution of consensus molecular subtypes (CMS) was significantly different between the groups (p = 0.0497). The pLLNM+ patients had a higher prevalance of CMS4 than the pLLNM- patients (77.8% vs. 51.4%). According to the multivariate analysis, the independent risk factors for LLNM were a short-axis diameter of the lateral lymph node of ≥6.0 mm and CMS4; furthermore, the presence of either or both had a sensitivity of 100% for the diagnosis of LLNM.

CONCLUSION

Lateral lymph node size and CMS4 are useful predictors of LLNM. The combination of CMS classification and size criteria was remarkably sensitive for the diagnosis of LLNM.

Total Mesorectal Excision with or without Lateral Pelvic Lymph Node Dissection in Rectal Cancer

Results

Incidence of local recurrence was slightly higher in Group A (8.7%) than in Group B (4.3%) but was not statistically significant. There was no statistical significance between both groups regarding distant metastasis (8.7% in Group A and 13% in Group B). Urinary and sexual dysfunctions were higher in Group B (26.1%) compared to those in Group A (21.7%) but were not statistically significant. The incidence of lateral pelvic lymph node metastasis was 30.4%. Also, intraoperative blood loss was higher and operative time was longer in Group B which was statistically significant (P value <0.001).

Conclusion

Our conclusion was that prophylactic addition of LPLD to TME was not associated with a statistically significant decrease in the risk of local recurrence or distant metastasis in patients with rectal cancer, although it was numerically better. LPLD is associated with longer operative time and higher intraoperative blood loss.

Low Rectal Cancers at Initial Staging MRI

Low rectal cancers, which are associated with increased risk of local recurrent disease and poorer prognosis, have unique anatomic considerations and issues for staging and treatment that do not apply to mid and high rectal cancers. Although tumor histology help drive the staging and treatment of all rectal cancers, it is of particular importance in low rectal cancers, which may involve the anal canal, to help establish whether a low rectal mass should be staged and treated as a rectal cancer (ie, adenocarcinoma) or an anal cancer (ie, squamous cell carcinoma). Optimal staging and treatment of rectal cancer are contingent on tumor location and local extent, which help guide management decisions including neoadjuvant therapy and curative surgical treatment strategies. Tumor location in the low rectum and local involvement of the anal canal, sphincter, and pelvic floor help determine whether a patient can undergo sphincter-preserving resection such as a low anterior resection versus abdominoperineal resection to achieve negative surgical margins. Issues exist related to the anatomy and patterns of disease spread that are unique to the low rectum and include how to determine and stage anal sphincter involvement, mesorectal fascia status at the pelvic floor, and nodal status of extramesorectal nodes such as the external iliac and inguinal lymph nodes. For these reasons, it is imperative that radiologists who interpret rectal cancer staging MRI examinations feel comfortable with the unique anatomy of the low rectum and anal canal, nuances of low rectal cancer local disease spread, and treatment paradigms for low rectal cancer. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Gollub in this issue.

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.

Risk factors for lateral pelvic lymph node metastasis in patients with lower rectal cancer: a systematic review and meta-analysis

Background and objective

Lateral pelvic lymph node (LPLN) metastasis is one of the prominent reasons for local recurrence (LR) in patients with rectal cancer (RC). The evaluation criteria of lateral lymph node dissection (LLND) for patients in eastern (mainly in Japan) and western countries have been controversial. The aim of this study was to analyse the risk factors for LPLN metastasis in order to guide surgical methods.

Methods

We searched relevant databases (Embase (Ovid), Medline (Ovid), PubMed, Cochrane Library, and Web of Science) for articles published between 1 January 2000 and 05 October 2022 to evaluate the risk factors for LPLN metastasis in patients with RC in this meta-analysis.

Results

A total of 24 articles with 5843 patients were included in this study. The overall results showed that female sex, age <60 years, pretherapeutic CEA level >5 ng/ml, clinical T4 stage (cT4), clinical M1 stage (cM1), distance of the tumour from the anal verge (AV) <50 mm, tumour centre located below the peritoneal reflection (Rb), short axis (SA) of LPLN ≥8 mm before nCRT, short axis (SA) of LPLN ≥5 mm after nCRT, border irregularity of LPLN, tumour size ≥50 mm, pathological T3-4 stage (pT3-4), pathological N2 stage (pN2), mesorectal lymph node metastasis (MLNM), lymphatic invasion (LI), venous invasion (VI), CRM (+) and poor differentiation were significant risk factors for LPLN metastasis (P <0.05).

Conclusion

This study summarized almost all potential risk factors of LPLN metastasis and expected to provide effective treatment strategies for patients with LRC. According to the risk factors of lateral lymph node metastasis, we can adopt different comprehensive treatment strategies. High-risk patients can perform lateral lymph node dissection to effectively reduce local recurrence; In low-risk patients, we can avoid overtreatment, reduce complications and trauma caused by lateral lymph node dissection, and maximize patient survival and quality of life.

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 ).

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.

Robot-assisted lateral pelvic lymph node dissection in patients with advanced rectal cancer: a single-center experience of 65 cases

The treatment of lateral pelvic lymph node (LPLN) metastasis of rectal cancer has evolved because of technical difficulties from open surgery to laparoscopy and, recently, robot-assisted surgery. This study aimed to evaluate the technical feasibility and short- and long-term outcomes of robot-assisted LPLN dissection (LPND) following total mesorectal excision (TME) in advanced rectal cancer. Clinical data of 65 patients who underwent robotic-assisted TME with LPND from April 2014 to July 2022 were reviewed. Data regarding operative details, postoperative morbidity (within 90 postoperative days) for short-term outcomes and lateral recurrence as long-term outcomes were analyzed. Among the 65 patients with LPND, preoperative chemoradiotherapy was performed in 49 (75.4%). The mean operative time was 306.8 (range 191-477) min, and the mean time of unilateral LPND was 38.6 (range 16-66) min. LPND was bilaterally performed in 19 (29.2%) patients. The mean number of each side of harvested LPLNs was 6.8. Lymph node metastasis was observed in 15 (23.0%) patients, and 10 (15.4%) patients had postoperative complications. Lymphocele (n = 3) and pelvic abscess (n = 3) were the most common, followed by voiding difficulty, erectile dysfunction, obturator neuropathy, and sciatic neuropathy (all n = 1). During the 25 months of median follow-up, no lateral recurrence of the LPND site was noted. Robot-assisted LPND following TME is safe and feasible and showed acceptable short- and long-term outcomes. Despite some study limitations, we may be able to apply this strategy more widely through subsequent prospective controlled studies.

Management of lateral pelvic lymph nodes in rectal cancer

Lateral pelvic lymph node (LPLN) involvement occurs in 10%-25% of rectal cancer cases. Total mesorectal excision (TME) with routine LPLN dissection (LPLND) is predominantly applied in Japan whereas TME with neoadjuvant treatment are used in the West. LPLND is a morbid procedure and minimally invasive techniques may help reduce its morbidity. Selective lateral pelvic node dissection with TME following neoadjuvant treatment achieves acceptable disease-free and overall survival.

Global Status of Research on Lateral Lymph Nodes in Rectal Cancer from 1994 to 2022: A Bibliometric Analysis

Tremendous progress has been made in the field of lateral lymph nodes (LLNs) in rectal cancer, but no bibliometric analysis in this field has been carried out and published. To reveal the current status and trends in LLNs in rectal cancer, this bibliometric analysis was performed. Cooperation network, co-citation and keyword co-occurrence analyses were conducted. Annual publication, cooperation relationships among authors, institutions and countries, co-cited journal, co-cited author, co-cited reference and keywords were the main outcomes. A total of 345 studies were included in this bibliometric analysis. The number of articles published in this field has been increasing year by year. The authors, institutions and countries worked closely together in this field. Japan has the largest number of published articles, accounting for 51.59% of the total publications. International Journal of Colorectal Disease (30 papers, 8.70%) published the most papers in this field. The JCOG0212 trial was the most cited article. Preoperative chemoradiotherapy, multicenter, lateral lymph node dissection (LLND) and metastasis are recent hot keywords, and LLND had the highest burst strength. In conclusion, this bibliometric analysis found that Japanese institutions and authors dominated the field of LLNs in rectal cancer. The JCOG0212 trial was the most influential article, which had a significant impact on the development of guidelines. LLND is a hotspot in this field with the highest burst strength. Further prospective studies are needed in this field.

Total neoadjuvant treatment to increase the clinical complete response rate for distal locally advanced rectal cancer (TESS): A study protocol of a prospective, open-label, multicenter, single-arm, phase 2 trial

BACKGROUND

Standard treatment of locally advanced rectal cancer (LARC) was neoadjuvant chemoradiotherapy (CRT), followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, attempts to deliver both systemic chemotherapy and neoadjuvant CRT prior to surgery. Patients treated with neoadjuvant chemotherapy were more likely to show higher tumor regression. The objective of this trial was to increase complete clinical rate (cCR) for LARC patients by optimizing tumor response, using TNT regimen as compared to conventional chemoradiotherapy. TESS, a prospective, open-label, multicenter, single-arm, phase 2 study, is underway.

METHODS

Main inclusion criteria include cT3-4aNany or cT1-4aN+ rectal adenocarcinoma aged 18-70y; Eastern Cooperative Oncology Group (ECOG) performance 0-1; location ≤5 cm from anal verge. Ninety-eight patients will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplatin) before, during, and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as Watch and Wait strategy) and adjuvant chemotherapy capecitabine 2 cycles. Primary endpoint is the cCR rate. Secondary endpoints include ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; local recurrence or metastasis; disease-free survival; locoregional recurrence-free survival; acute toxicity; surgical complications; long-term anal function; late toxicity; adverse effect, ECOG standard score, and quality of life. Adverse events are graded per Common Terminology Criteria for Adverse Events V5.0. Acute toxicity will be monitored during antitumor treatment, and late toxicity will be monitored for 3 years from the end of the first course of antitumor treatment.

DISCUSSION

The TESS trial aims to explore a new TNT strategy, which is expected to increase the rate of cCR and sphincter preservation rate. This study will provide new options and evidence for a new sandwich TNT strategy in patients with distal LARC.

Transanal lateral lymph node dissection with intraoperative hologram support in low rectal cancer

BACKGROUND

In Japan, the standard treatment for stage II/III advanced low rectal cancer is total mesorectal excision plus lateral lymph node dissection (LLND). There are also recent reports on the use of transanal LLND. However, the transanal anatomy is difficult to understand, and additional support tools are required to improve the surgical safety. The present study examined the utility of holograms with mixed reality as an intraoperative support tool for assessing the complex pelvic anatomy.

METHODS

Polygon (stereolithography) files of patients' pelvic organs were created and exported from the SYNAPSE VINCENT imaging system and uploaded into the Holoeyes MD virtual reality software. Three-dimensional images were automatically converted into patient-specific holograms. Each hologram was then installed into a head mount display (HoloLens2), and the surgeons and assistants wore the HoloLens2 when they performed transanal LLND. Twelve digestive surgeons with prior practice in hologram manipulation evaluated the utility of the intraoperative hologram support by means of a questionnaire.

RESULTS

Intraoperative hologram support improved the surgical understanding of the lateral lymph node region anatomy. In the questionnaire, 75% of the surgeons answered that the hologram accurately reflected the anatomy, and 92% of the surgeons answered that the anatomy was better understood by simulating the hologram intraoperatively than preoperatively. Moreover, 92% of the surgeons agreed that intraoperative holograms were a useful support tool for improving the surgical safety.

CONCLUSIONS

Intraoperative hologram support improved the surgical understanding of the pelvic anatomy for transanal LLND. Intraoperative holograms may represent a next-generation surgical tool for transanal LLND.

Essential updates 2020/2021: Advancing precision medicine for comprehensive rectal cancer treatment

In the paradigm shift related to rectal cancer treatment, we have to understand a variety of new emerging topics to provide appropriate treatment for individual patients as precision medicine. However, information on surgery, genomic medicine, and pharmacotherapy is highly specialized and subdivided, creating a barrier to achieving thorough knowledge. In this review, we summarize the perspective for rectal cancer treatment and management from the current standard-of-care to the latest findings to help optimize treatment strategy.