Advanced Low Rectal Cancer Research Articles

Risk factors for local recurrence in patients with clinical stage II/III low rectal cancer: A multicenter retrospective cohort study in Japan

AbstractBackgroundIdentifying risk factors for local recurrence (LR) is pivotal in optimizing rectal cancer treatment. Total mesorectal excision (TME) and lateral lymph node dissection (LLND) are the standard treatment for advanced low rectal cancer in Japan. However, large‐scale studies to evaluate risk factors for LR are limited.MethodsData from 1479 patients with clinical stage II/III low rectal cancer below the peritoneal reflection, surgically treated between January 2010 and December 2011 across 69 hospitals, were analyzed. Fine–Gray multivariable regression modeling was used to identify risk factors associated with LR. Two models were developed: one using preoperative factors only, and the other incorporating operative and postoperative factors.ResultsAcross the entire cohort, the 5‐year cumulative incidence of LR was 12.3% (95% confidence interval, 10.7–14.1). The multivariable analysis associated LR with various preoperative (body mass index, distance from anal verge, cN category, and histological subtype), treatment‐related (neoadjuvant therapy, and LLND), and postoperative (pT, pN, and resection margins) risk factors. For patients without neoadjuvant treatment, LR risk was unacceptably high with two or three preoperative risk factors (body mass index ≥25 kg/m2, distance from anal verge ≤4.0 cm, non‐well/moderately differentiated adenocarcinoma). The 5‐year cumulative incidence of LR was 24.7% in patients treated without LLND and 22.9% in patients treated with LLND.ConclusionThis large multicenter cohort study identified some risk factors for LR in the setting where upfront TME was predominant, offering insights to optimize rectal cancer treatment.

The potential of an artificial intelligence for diagnosing MRI images in rectal cancer: multicenter collaborative trial

BackgroundAn artificial intelligence-based algorithm we developed, mrAI, satisfactorily segmented the rectal tumor, rectum, and mesorectum from MRI data of rectal cancer patients in an initial study. Herein, we aimed to validate mrAI using an independent dataset.MethodsWe utilized MRI images collected in another nationwide research project, "Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer Patients". MRIs from 467 cases with upfront surgery were utilized; six radiologists centralized the MRI evaluations. The diagnostic accuracies of mrAI and the radiologists for tumor depth were compared using pathologic diagnosis as a reference.ResultsFor all cases, centralized diagnosis demonstrated 84.2% sensitivity, 37.7% specificity, and 73.7% accuracy; mrAI exhibited 70.6% sensitivity, 61.3% specificity, and 68.5% accuracy. After limiting MRIs to those acquired by a Philips scanner, with an inter-slice spacing of ≤ 6 mm—both conditions similar to those used in the development of mrAI—the performance of mrAI improved to 76.8% sensitivity, 76.7% specificity, and 76.7% accuracy, while the centralized diagnosis showed 81.8% sensitivity, 36.7% specificity, and 71.3% accuracy. Regarding relapse-free survival, the prognosis for tumors staged ≥ T3 was significantly worse than for tumors staged ≤ T2 (P = 0.0484) in the pathologic diagnosis. While no significant difference was observed between ≥ T3 and ≤ T2 tumors in the centralized diagnosis (P = 0.1510), the prognosis for ≥ T3 was significantly worse in the mrAI diagnosis (P = 0.0318).ConclusionProper imaging conditions for MRI can enhance the accuracy of mrAI, which has the potential to provide feedback to radiologists without overestimating tumor stage.

Early-stage voiding function following uni- versus bilateral inferior vesical vessel resection during therapeutic lateral lymph node dissection with autonomic nerve sparing for advanced low rectal cancer (with video).

Lateral lymph node dissection (LLND) has now been widely accepted as the optimal procedure to minimize lateral local recurrence (LLR) for selected cases with advanced lower rectal cancer in Asian countries. However, there is still controversy over the preservation or resection of the inferior vesical vessels (IVVs) during LLND due to concerns of impaired post-operative urinary function. Moreover, the standardized procedure for autonomic nerve preservation has not yet been established. To evaluate the early-stage postoperative voiding function in patients who underwent LLND with uni- versus bilateral resection of the IVVs and to introduce an autonomic nerve sparing technique with a fascial space priority approach (FSPA). LLND was performed in 106 consecutive patients with advanced low rectal cancer at Tianjin Union Medical Center from May 2017 to October 2022. Prospectively collected clinical data were retrospectively compared between patients who received uni-lateral and bilateral LLND. A video with narration was provided to introduce the stepwise procedure of autonomic nerve preservation during IVV resection. The unilateral lymph node dissection (LND) group and the bilateral LND group included 75 and 31 cases, respectively. All LLNDs were performed with FSPA with IVV resection as a standard procedure. No significant differences were observed in overall catheterization days (p = 0.336) and re-catheterization rate (p = 0.575) between groups. No patients in either group suffered from long-term (≥ 30 days) voiding dysfunction. Autonomic nerve sparing is achievable with resection of IVVs during LLND. Satisfactory early-stage voiding function could be obtained with IVV resection on both sides.

Endosonography Elastography and Magnetic Resonance Imaging in the Restaging and Response Assessment of Rectal Cancer After Neoadjuvant Therapy.

The objective of this academic research is to assess the efficacy of conventional endorectal ultrasound (ERUS), ultrasonic shear wave elastography (SWE), and magnetic resonance imaging (MRI) techniques in evaluating the impact of neoadjuvant therapy (nCRT). Forty-five patients with advanced low rectal cancer (T ≥ 3) were included. Before and after nCRT, ERUS, SWE, and MRI evaluations were conducted. The T staging of ultrasound (uT) and MRI (mT) were evaluated and compared with the pathological T staging (ypT). The accuracy of the 2 diagnostic methods for T staging, and T downstaging was evaluated. The ultrasound elasticity difference and relative elasticity before and after treatment and pathological T downstaging were compared, and its cutoff value and the area under the curve were assessed. In terms of T staging accuracy after chemoradiotherapy, the values for ERUS, ERUS combined with SWE, and MRI were 64.4%, 71.1%, and 62.2%, respectively. No significant difference was observed among these groups ( P > 0.05). The accuracy of uT downstaging was 84.4%, and that of mT downstaging was 88.9%. The receiver operating characteristic curve of uLD and elastic differences and relative elasticity of T downstaging after treatment were 0.754, 0.817, and 0.886, respectively (all P < 0.05). Both ERUS and MRI can evaluate ypT downstaging. The indicators for evaluating T downstaging are uLD, elasticity difference, and relative elasticity, providing more reference for clinical assessment of nCRT efficacy.

Efficacy and safety of neoadjuvant chemoradiotherapy combined with tislelizumab and thymalfasin in the treatment of locally advanced lower rectal cancer.

e15612 Background: Thymalfasin, as an immunomodulator, can enhance the anti-tumor effects of T cells, NK cells, and macrophages. This study explored the efficacy and safety of a new adjuvant treatment regimen for rectal cancer, combining thymalfasin with chemoradiotherapy and the PD-1 inhibitor tislelizumab, and its impact on the immune microenvironment. Methods: This retrospective study enrolled 26 patients with locally advanced rectal cancer from March 2021 to December 2022. Thirteen patients received long-course concurrent chemoradiotherapy combined with concurrent tislelizumab treatment, and thirteen received thymalfasin combined with long-course chemoradiotherapy and concurrent tislelizumab treatment (radiotherapy: 50 Gy/25 f; capecitabine, 1000mg/m2, bid; tislelizumab: 200mg, every 21 days, 3 cycles; Thymalfasin: 1.6mg, biw). The postoperative pathological complete response rate (ypT0N0M0), tumor regression grade (AJCC 8th Version), and adverse event (CTCAE 4.0) incidence were assessed, along with changes in the immune microenvironment before and after treatment using multiplex immunofluorescence staining. Results: The pathological complete response rates observed postoperatively were 61.5% in the treatment group, compared to 38.5% in the control group. The distribution of tumor regression grades 0, 1, 2, and 3 was 69.2%, 15.4%, 15.4%, 0% in the treatment group respectively, and 38.5%, 38.5%, 7.7%, 15.4%, in the control group respectively. The adverse event rates reached 84.6% in the treatment group and 76.9% in the control group, with all events classified as either grade 1 or 2 according to the CTCAE 4.0. Significant reductions in CD4+PD1+ cell density (p &lt; 0.001), CD8+PD1+ cell density (p = 0.024), CD68+ cell density (p = 0.007), the CD4/CD8 ratio (p &lt; 0.001), and the CD68+CD86+/CD68+CD163+ ratio (p = 0.012) were demonstrated through multiplex immunofluorescence following neoadjuvant treatment. The treatment group exhibited significant decreases in CD8+PD1+ cell density (p = 0.025) and CD68+CD163+ cell density (p = 0.021) when compared to the control group. Conclusions: Thymalfasin combined with chemoradiotherapy and tislelizumab as a neoadjuvant treatment regimen for patients with locally advanced lower rectal cancer has shown favorable efficacy and safety. Neoadjuvant chemoradiotherapy combined with immunotherapy restored T cell function and reduced the proportion of tumor-associated macrophages, but macrophages polarized towards an M2-like phenotype. Thymalfasin may play a role by synergizing with the PD-1 inhibitor to restore cytotoxic T cell function and block macrophage polarization towards M2 cells. Clinical trial information: NCT06024356 .

Recurrence of rectal cancer on the pelvic sidewall after lateral lymph node dissection

PurposeAlthough lateral lymph node dissection has been performed to prevent lateral pelvic recurrence in locally advanced lower rectal cancer, the incidence of lateral pelvic recurrence after this procedure has not been investigated. Therefore, this study aimed to investigate the long-term outcomes of patients who underwent lateral pelvic lymph node dissection, with a particular focus on recurrence patterns.MethodsThis was a retrospective study conducted at a single high-volume cancer center in Japan. A total of 493 consecutive patients with stage II-III rectal cancer who underwent lateral lymph node dissection between January 2005 and August 2022 were included. The primary outcome measures included patterns of recurrence, overall survival, and relapse-free survival. Patterns of recurrence were categorized as lateral or central pelvic.ResultsAmong patients who underwent lateral lymph node dissection, 18.1% had pathologically positive lateral lymph node metastasis. Lateral pelvic recurrence occurred in 5.5% of patients after surgery. Multivariate analysis identified age > 75 years, lateral lymph node metastasis, and adjuvant chemotherapy as independent risk factors for lateral pelvic recurrence. Evaluation of the recurrence rate by dissection area revealed approximately 1% of recurrences in each area after dissection.ConclusionWe demonstrated the prognostic outcome and limitations of lateral lymph node dissection for patients with advanced lower rectal cancer, focusing on the incidence of recurrence in the lateral area after the dissection. Our study emphasizes the clinical importance of lateral lymph node dissection, which is an essential technique that surgeons should acquire.

Does Neoadjuvant Chemoradiotherapy Have an Additional Effect to Lateral Pelvic Lymph Node Dissection for Rectal Cancer?

A total mesenteric excision (TME) with lateral pelvic lymph node dissection (LLND) is the standard treatment for advanced low rectal cancer in Japan. Recently, neoadjuvant (chemo)radiotherapy (n(C)RT) has been used with LLND to improve outcomes at multiple Japanese institutes. This study evaluates the benefits of adding nCRT to TME with LLND. Seventy-two consecutive patients who underwent TME and LLND with or without nCRT between 2006-2019 to treat advanced low rectal cancer were retrospectively reviewed. The clinicopathological data were compared and the risk factors for local recurrence were evaluated. Fifty-seven patients (79.1%) underwent TME and LLND with nCRT, and 15 patients (20.9%) without nCRT. There was no significant difference in the clinicopathological characteristics except the clinical T stage. The occurrence of postoperative complications was statistically insignificant. The 5-year local recurrence rate of patients with nCRT was significantly lower than those without (4.0% versus 26.6%, in all patients, p=0.002). Multivariate analysis revealed that the absence of nCRT was an independent risk factor for local recurrences in patients who underwent TME with LLND (hazard ratio: 6.04, p=0.04). The administration of nCRT prevented local recurrences more effectively in patients with advanced low rectal cancer who underwent TME with LLND.

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.

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. 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. The total operation time was significantly shorter in the 2team group than in the transabdominal group (366min vs. 513min, P < 0.001), as was the time taken to perform unilateral LLND (64min vs. 114min, P < 0.001). Furthermore, there was significantly less intraoperative bleeding in the 2team group (30mL vs. 80mL, 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. 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.

The clinical significance of lateral pelvic sentinel lymph node biopsy using indocyanine green fluorescence navigation in laparoscopic lateral pelvic lymph node dissection

Objectives: This study aims to explore the clinical significance of lateral pelvic sentinel lymph node biopsy (SLNB) using indocyanine green (ICG) fluorescence navigation in laparoscopic lateral pelvic lymph node dissection (LLND) and evaluate the accuracy and feasibility of this technique to predict the status of lateral pelvic lymph nodes (LPLNs). Methods: The clinical and pathological characteristics, surgical outcomes, lymph node findings and perioperative complications of 16 rectal cancer patients who underwent SLNB using ICG fluorescence navigation in laparoscopic LLND in the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College during April 2017 and October 2022 were retrospectively collected and analyzed. The patients did not receive preoperative neoadjuvant radiotherapy and presented with LPLNs but without LPLN enlargement (MRI showed the maximum short axes of the LPLNs were ≥5 mm and <10 mm at first visit). Results: All 16 patients were successfully performed SLNB using ICG fluorescence navigation in laparoscopic LLND. Three patients underwent bilateral LLND and 13 patients underwent unilateral LLND. The lateral pelvic sentinel lymph nodes (SLNs) were clearly fluorescent before dissection in 14 patients and the detection rate of SLNs for these patients was 87.5%. Lateral pelvic SLN metastasis was diagnosed in 2 patients and negative results were found in 12 patients by frozen pathological examinations. Among the 14 patients in whom lateral pelvic SLNs were detected, the dissected lateral pelvic non-SLNs were all negative. All dissected LPLNs were negative in two patients without fluorescent lateral pelvic SLNs. The specificity, sensitivity, negative predictive value, and accuracy was 85.7%, 100%, 100%, and 100%, respectively. Conclusions: This study indicates that lateral pelvic SLNB using ICG fluorescence navigation shows promise as a safe and feasible procedure with good accuracy. This technique may replace preventive LLND for locally advanced lower rectal cancer.

Optimization of treatment strategies based on preoperative imaging features and local recurrence areas for locally advanced lower rectal cancer after lateral pelvic lymph node dissection.

Local recurrence (LR) is the main cause of treatment failure in locally advanced lower rectal cancer (LALRC). This study evaluated the preoperative risk factors for LR in patients with LALRC to improve the therapeutic strategies. LALRC patients who underwent total mesorectal excision (TME) with lateral pelvic lymph node (LPN) dissection (LPND) from January 2012 to December 2019 were reviewed. The log-rank test was used to assess local recurrence-free survival (LRFS), and multivariate Cox regression was used to identify the prognostic risk factors for LRFS. Follow-up imaging data were used to classify LR according to the location. Overall, 376 patients were enrolled, and 8.8% (n=33) of these patients developed LR after surgery. Multivariate analysis identified positive clinical circumferential resection margin (cCRM) as an independent prognostic factor for LRFS (HR: 4.94; 95% CI, 1.75-13.94; P=0.003). The most common sites for LR were the pelvic plexus and internal iliac area (PIA) (54.5%), followed by the central pelvic area (CPA) (39.4%) and obturator area (OA) (6.1%). Following a subgroup analysis, LR in the OA was not associated with positive cCRM. Patients treated with upfront surgery (n=35, 14.1%) had a lower cCRM positive rate when compared with patients treated with neoadjuvant chemoradiotherapy (nCRT) (n=12, 23.5%). However, the LR rate in the nCRT group was still lower (n=28, 36.4%) than that in the upfront surgery group (n=35, 14.%). Among patients with positive cCRM, the LR rate in patients with nCRT remained low (n=3, 10.7%). Positive cCRM is an independent risk factor for LR after TME plus LPND in LALRC patients. LPND is effective and adequate for local control within the OA regardless of cCRM status. However, for LALRC patients with positive cCRM, nCRT should be considered before LPND to further reduce LR in the PIA and CPA.

Laparoscopic extralevator abdominoperineal resection for low rectal cancer: The myth of reinventing the wheel.

To review oncological outcomes of laparoscopic extralevator abdominoperineal excision (LAP-ELAPE) for low rectal cancer.In locally advanced low rectal cancer, ELAPE which is en-bloc resection of levator muscles along with the tumor in a prone position has significantly decreased the rate of having either positive circumferential resection margin (CRM) or tumor perforation. The aim of the study was to determine the oncological outcomes of laparoscopic extralevator abdominoperineal excision (LAP-ELAPE) for low rectal cancer. This retrospective study was performed at Shaukat Khanum Cancer Hospital and Research Centre Lahore. Patients who underwent ELAPE for low rectal and anal cancer from January 2014 to December 2019 were selected. Data was collected using an electronic database through a hospital information system. A total of 82 patients were included in the study having a median age of 39 years. Clinically preoperative tumor sizes were T2:2, T3:65, T4:15. Neo-adjuvant chemo radiotherapy was administered to 79 (96.3%) patients. Pathologically tumor sizes were T0:12, T2:15, T3:50, T4:5 with 79.2% (n=65) R0 resections. The mean operative time was 340.36±64.51 minutes and the mean blood loss was 99 milliliters. The mean postoperative hospital stay was 6.58±4.64 days. Seventeen (20.7%) cases had pathological circumferential resection margins positive (pCRM<1mm). However, tumor perforation was found in 8(9.8%) patients. Ninety days mortality was none while 36 patients experienced recurrence (local: 23, distant: 30, local + distant 17). The median survival time was 53.00±2.69 months. For locally advanced low rectal cancer, ELAPE has evolved as a safe oncological procedure with acceptable outcomes.

Transanal local excision versus intersphincteric resection for low rectal cancer with stage ypT0-1ycN0 after neoadjuvant chemoradiotherapy: an inverse probability weighting analysis for oncological and functional outcomes.

This study aimed to compare the efficacy of local excision (LE) and intersphincteric resection (ISR) in patients with locally advanced rectal cancer who achieved a significant or complete pathological response following neoadjuvant chemoradiotherapy. We performed a retrospective analysis of data from patients with stage ypT0-1ycN0 low rectal cancer after neoadjuvant chemoradiotherapy who underwent LE or ISR between June 2016 and June 2021. Baseline characteristics, short-term outcomes, long-term oncological outcomes, and functional outcomes, were compared between the two groups. To reduce the selection bias, inverse probability of treatment weighting (IPTW) was performed. This study included 106 patients (LE group: n = 51, ISR group: n = 55). There were significant differences in baseline characteristics between the two groups (P < 0.05). After IPTW, there were almost no significant differences in baseline data between the two groups. The LE group showed less postoperative complications and better function outcomes compared to the ISR group. The LE group had significantly lower rates of complications (13.7% vs. 36.4%, P = 0.014). There were no significant differences between the two groups in terms of long-term oncological outcomes. For patients with locally advanced low rectal cancer achieving significant or complete pathological response after neoadjuvant therapy, both LE and ISR present comparable oncological outcomes. Yet, LE seems to show more advantages in terms of postoperative complications and functional outcomes. These findings offer important insights for surgical decision-making, emphasizing the necessity to consider both oncological and functional outcomes in selecting the optimal surgical approach.

Double inferior vena cava, an uncommon but relevant anatomical anomaly in surgery for lower rectal cancer: a report of two cases

BackgroundDouble inferior vena cava (DIVC) is rare and usually detected incidentally. DIVC may be associated with several anatomical variants of the retroperitoneal and pelvic veins. These variants can pose a clinical problem during colorectal surgery. We present two patients with lower rectal cancer who also had a DIVC.Case presentationCase 1 was a 72-year-old man with advanced lower rectal cancer (T3N0M0) who underwent robot-assisted low anterior resection after neoadjuvant therapy. A DIVC was detected on preoperative computed tomography (CT). During the operation, a presacral vein was injured while mobilizing the rectum and hemostasis could not be achieved. We converted to open surgery and packed the pelvic cavity for hemostasis. Retrospective analysis suggested the injured vein arose from an interiliac vein of the presacral pelvic venous plexus. Case 2 was a 50-year-old woman with lower rectal cancer (T3N0M0), immune thrombocytopenic purpura, and a DIVC. Although preoperative three-dimensional CT angiography showed no obvious pelvic vein abnormalities, a short course of preoperative radiotherapy was delivered to avoid lateral pelvic lymph node dissection. Chemotherapy was deferred owing to her thrombocytopenic disease. Laparoscopic abdominoperineal resection was performed meticulously to minimize bleeding and achieve rapid hemostasis. No intraoperative complications occurred.ConclusionDIVC is often accompanied by venous malformations that may pose a problem when mobilizing the mesorectum from the retroperitoneum. Preoperative assessment of pelvic vessel anatomy using three-dimensional CT is essential in patients with a DIVC who undergo rectal surgery.

Robotic abdominoperineal resection for T4b rectal cancer using the daVinci SP platform.

The aim of the present report wasto describe a novel technique of robotic abdominoperineal resection (APR) for the treatment of T4b low rectal cancer using the da Vinci® Single-Port (SP) system (Intuitive Surgical, Sunnyvale, CA, USA). A 3-cm transverse incision was made in the left lower quadrant of the abdomen, in the area designated for permanent colostomy. A Uniport® (Dalim Medical, Seoul, Korea) was introduced and a 25mm multichannel SP trocar was inserted into the Uniport. A 5-mm laparoscopic assistant port was introduced on the upper midline. A video showing each step of the technique is attached. Two consecutive female patients (70 and 74 years old) underwent SP robotic APR with partial resection of the vagina 8 weeks after preoperative chemoradiotherapy. In both cases, rectal cancer was located 1cm above the anal verge and invaded the vagina (initial stage and ymrT stage T4b). Operative time was 150 and 180 min, respectively. Estimated blood loss was 10 and 25 ml, respectively. No postoperative complications occurred. The length of postoperative hospital stay was 5 days in both cases. The final pathological stage was ypT4bN0 and ypT3N0 respectively. In this first experience, SP robotic APR appears to be a safe and feasible procedure for locally advanced low rectal cancer. In addition, the invasiveness of the procedure is reduced by means of the SP system, which only requires a single incision in the area designated for colostomy. Prospective studies on a larger number of patients are necessary to confirm the outcomes of this technique compared to other minimally invasive approaches.

Clinical application and standardized implementation of intersphincteric resection

Intersphincteric resection (ISR) is the ultimate sphincter-preserving surgical technique for low rectal cancer. To promote the standardized implementation of ISR, this review discusses the important issues regarding the clinical application of ISR with reference to the latest Chinese expert consensus on ISR. In terms of ISR-related pelvic anatomy of the rectum/anal canal, hiatal ligament is not identical with the anococcygeal ligament. At the level where the rectourethralis muscle continuously extends to the posteroinferior area of the membranous urethra from the rectum, the neurovascular bundle is identified between the posterior edge of rectourethralis muscle and the anterior edge of the longitudinal muscle of the rectum. This knowledge is crucial to detect the anterior dissection plane during ISR at the levator hiatus level. The indication criteria for ISR included: (1) stage I early low rectal cancer; (2) stage II-III low rectal cancer undergoing neoadjuvant treatment, and supra-anal tumors and juxta-anal tumors of stage ycT3NxM0, or intra-anal tumors of stage ycT2NxM0. However, signet ring cell carcinoma, mucinous adenocarcinoma and undifferentiated carcinoma should be contraindicated to ISR. For locally advanced low rectal cancer (especially anteriorly located tumor), neoadjuvant treatment should be carried out in a standardized manner. However, it should be recognized that neoadjuvant chemoradiotherapy was a risk factor for poor anal function after ISR. For surgical approaches for ISR, including transanal, transabdominal, and transanal transabdominal approaches, the choice should be based on oncological safety and functional consequences. While ensuring the negative margin, maximal preservation of rectal walls and anal canal contributs to better postoperative anorectal function. Careful attention must be paid to complications regarding ISR, with special focus on the anastomotic complications. The incidence of low anterior resection syndrome (LARS) was higher than 40%. However, this issue is often neglected by clinicians. Thus, management and rehabilitation strategies for LARS with longer follow-ups were required.

Oncological Impact of the Level of Inferior Mesenteric Artery Ligation in Low Rectal Cancer Surgery.

This study aimed to evaluate the clinical impact of the level of inferior mesenteric artery (IMA) ligation in patients with advanced low rectal cancer. All enrolled patients (n=350) underwent curative resection of rectal cancer with D3 lymph node dissection, with either IMA (high-tie) or superior rectal artery (SRA) (low-tie) ligation. There were 27 and 65 patients in the high-tie and low-tie groups, respectively. There was no significant difference in the postoperative complication rate. Postoperative anastomotic leakage developed in five patients in the low-tie group and none in the high-tie group. The overall recurrence rates were 37.0% (n=10) and 40.0% (n=26) in the high-tie and low-tie groups, respectively, with no significant difference between the two groups (p=0.748). Local recurrences and lymph node metastases developed in five and no patients in the high-tie group and in 13 and one patient in the low-tie group, respectively. In the multivariate analysis, pathological T4 and pathological N2 and N3 were independent poor prognostic factors for overall survival (OS), whereas left colic artery (LCA) preservation was not significant. No significant difference in oncological outcomes was observed in advanced low rectal cancer surgery with respect to the level of the IMA ligation. Thus, the less complicated high-tie procedure should be adopted as a standard procedure.

Key clinical trials in rectal cancer shaping the current treatment paradigms: reference guide for radiologists.

Total neoadjuvant therapy (TNT), which includes chemotherapy and radiation prior to surgical resection, has been recently accepted as the new standard of care for patients with locally advanced low and mid rectal cancers. Multiple clinical trials have evaluated this approach in the last several decades and demonstrated improvement in, local control and reduced risk of recurrence. In addition, in the course of these investigations, it has been shown that between a third and a half of patients experience a clinical complete response (cCR) after being treated with the TNT approach, leading to the development of new organ preservation protocol, now known as watch-and-wait (W&W). On this protocol, cCR patients are not referred for surgery after total neoadjuvant treatment. Instead, they remain on close surveillance and, thus, avoid potential complications associated with surgical resection. Multiple clinical trials are ongoing, investigating the long-term outcomes of these new approaches and the development of less toxic and more effective TNT regimens for LARC. Improvements in technology and rectal MRI protocols position radiologists as vital members of multidisciplinary rectal cancer management teams. Rectal MRI has become a critical tool for rectal cancer initial staging, treatment response assessment, and surveillance on W&W protocols. In this review, we summarize the findings of the pivotal clinical trials that contributed to establishing the current treatment paradigms in locally advanced rectal cancer (LARC) management, with the intention of helping radiologists play more effective roles in their multidisciplinary teams.

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

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. 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. 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. 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.

New Scale Predicting Distant Recurrence in Locally Advanced Lower Rectal Cancer Patients After Neoadjuvant Chemoradiotherapy.

Neoadjuvant chemoradiotherapy (nCRT) for locally advanced lower rectal cancer (LALRC) is effective in preventing locoregional recurrence; however, it is less effective for preventing distant recurrence. This study aimed to evaluate a new scale for predicting distant recurrence before administering nCRT. Sixty-three patients underwent nCRT for LALRC between 2009 and 2016 at the Tokyo Women's Medical University. Of these, 51 consecutive patients who underwent curative surgery were enrolled in this study. Patients with ≥cT3 status or cN-positive LALRC were classified into three groups before nCRT based on the neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR): high-risk, NLR ≥3.2 and LMR <5.0; intermediate-risk, NLR <3.2 and LMR ≥5.0 or NLR ≥3.2 and LMR <5.0; and low-risk, NLR <3.2 and LMR ≥5.0. Independent risk factors associated with distant relapse-free survival were analysed using the Cox proportional hazards model. Relapse-free survival from distant metastasis was evaluated using the log-rank test. Patient characteristics and tumour-associated factors were not significantly different between the groups. Distant recurrence in the high-, intermediate-, and low-risk groups was 61.5%, 42.9%, and 20.8% (p=0.046), respectively. In the multivariate analysis, the new scale was an independent risk factor for distant relapse-free survival (high-risk vs. low-risk groups, p=0.004 and intermediate-risk vs. low-risk groups, p=0.055). The 3-year distant relapse-free survival rate in the high-, intermediate-, and low-risk groups was 38.5%, 56.3%, and 81.7% (p=0.028), respectively. A new scale combining the pre-nCRT NLR and LMR was independently associated with distant relapse-free survival. The new scale for LALRC may aid selection for total neoadjuvant chemotherapy.

Clinical Relevance of Lateral Pelvic Lymph Node Dissection for Enlarged Lateral Nodes in Locally Advanced Low Rectal Cancer without Preoperative Treatment.

The present study aimed to investigate the clinical relevance of lateral pelvic lymph node dissection (LPLND) in low rectal cancer without preoperative treatment, with a focus on the presence of LPLN enlargement in preoperative imaging. Consecutive patients with cT3 to T4 low rectal cancer who underwent mesorectal excision and LPLND without preoperative treatment between 2007 and 2018 at a single dedicated cancer center were included. LPLN short-axis diameter (SAD) measured using preoperative multi-detector row computed tomography (MDCT) was evaluated retrospectively. A total of 195 consecutive patients were analyzed. Overall, 101 (51.8%) and 94 (48.2%) patients had visible and no visible LPLNs in preoperative imaging, including 56 (28.7%), 28 (14.4%), and 17 (8.7%) patients had SADs of <5 mm, 5-7 mm, and ≥7 mm, respectively. Incidence of pathologically confirmed LPLN metastasis were 18.1%, 21.4%, 28.6%, and 52.9%, respectively. Overall, thirteen (6.7%) patients developed local recurrence (LR), including one patient who developed lateral recurrence, yielding a 5-year cumulative risk for LR of 7.4%. Five-year RFS and OS for all patients were 69.7% and 85.7%, respectively. No differences were observed in the cumulative risk for LR and OS between any pairs of groups. No significant difference was observed in the cumulative risk for LR and OS regardless of LPLN SAD, implying the good impact of LPLND on the prevention of lateral recurrence, as well as the difficulty of predicting LPLN metastasis using only LPLN SAD in preoperative imaging.