Is There Any Reason to Still Consider Lateral Lymph Node Dissection in Rectal Cancer? Rationale and Technique

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.

Management of Surgically Accessible Lymph Nodes Beyond Normal Resection Planes

This article discusses the management of isolated metastatic lymph nodes for colon and rectal cancer. There are traditionally significant differences in how certain regions of lymph nodes for colon and rectal cancer are managed in the East and West. This has led to the development of the lateral lymph node dissection for rectal cancer and extended lymphadenectomy techniques for colon cancer. This article will evaluate the literature on these techniques and what the surgical and oncological outcomes are at this time. In addition, colon and rectal cancers can occasionally have isolated distant lymph node metastases. These would traditionally be treated as systemic disease with chemotherapy. There is consideration though that these could be treated as similar to isolated liver or lung metastases which have been shown to be able to be treated surgically with good oncological results. The literature for these isolated distant lymph node metastases will be reviewed and treatment options available will be discussed.

Comparison of laparoscopic lateral lymph node dissection for rectal cancer with and without routine resection of the visceral branches of internal iliac artery

PURPOSE

This study aimed to explore the safety and feasibility of the modified lateral lymph node dissection (LLND) with routine resection of the visceral branches of internal iliac vessels (IIVs) for mid-low-lying rectal cancer.

MATERIALS AND METHOD

Consecutive patients undergoing LLND for rectal cancer were divided into the routine visceral branches of the IIVs resection group (RVR group) and the NRVR group (without routine resection). The main outcomes were postoperative complications and the number of lateral lymph nodes harvested.

RESULTS

From 2012 to 2021, a total of 75 and 57 patients were included in the RVR and NRVR group, respectively. The operative time was reduced in the RVR group (p = 0.020). No significant difference was observed between the two groups for the incidence of total, major, or minor postoperative complications. Pathologically confirmed LLNM were 24 (32%) patients in the RVR group and 12 (21.1%) in the NRVR group (p = 0.162). The number of lateral lymph nodes harvested had no significant difference between two groups (11 vs. 12, p = 0.329).

CONCLUSION

LLND with routine resection of visceral branches of IIVs is safe and feasible, which brings no major complication or long-term urinary disorder.

Evaluation of National Surgical Practice for Lateral Lymph Nodes in Rectal Cancer in an Untrained Setting

BACKGROUND

Involved lateral lymph nodes (LLNs) have been associated with increased local recurrence (LR) and ipsi-lateral LR (LLR) rates. However, consensus regarding the indication and type of surgical treatment for suspicious LLNs is lacking. This study evaluated the surgical treatment of LLNs in an untrained setting at a national level.

METHODS

Patients who underwent additional LLN surgery were selected from a national cross-sectional cohort study regarding patients undergoing rectal cancer surgery in 69 Dutch hospitals in 2016. LLN surgery consisted of either 'node-picking' (the removal of an individual LLN) or 'partial regional node dissection' (PRND; an incomplete resection of the LLN area). For all patients with primarily enlarged (≥7 mm) LLNs, those undergoing rectal surgery with an additional LLN procedure were compared to those  undergoing only rectal resection.

RESULTS

Out of 3057 patients, 64 underwent additional LLN surgery, with 4-year LR and LLR rates of 26% and 15%, respectively. Forty-eight patients (75%) had enlarged LLNs, with corresponding recurrence rates of 26% and 19%, respectively. Node-picking (n = 40) resulted in a 20% 4-year LLR, and a 14% LLR after PRND (n = 8; p = 0.677). Multivariable analysis of 158 patients with enlarged LLNs undergoing additional LLN surgery (n = 48) or rectal resection alone (n = 110) showed no significant association of LLN surgery with 4-year LR or LLR, but suggested higher recurrence risks after LLN surgery (LR: hazard ratio [HR] 1.5, 95% confidence interval [CI] 0.7-3.2, p = 0.264; LLR: HR 1.9, 95% CI 0.2-2.5, p = 0.874).

CONCLUSION

Evaluation of Dutch practice in 2016 revealed that approximately one-third of patients with primarily enlarged LLNs underwent surgical treatment, mostly consisting of node-picking. Recurrence rates were not significantly affected by LLN surgery, but did suggest worse outcomes. Outcomes of LLN surgery after adequate training requires further research.

The Middle Rectal Artery: Revisited Anatomy and Surgical Implications of a Neglected Blood Vessel

BACKGROUND

Although the middle rectal artery is a relevant anatomical landmark for rectal resection and lateral lymph node dissection, descriptions of this entity are highly divergent.

OBJECTIVE

Dissection, visualization, morphometry, and 3-dimensional reconstruction of the middle rectal artery to facilitate its management in surgery.

DESIGN

Macroscopic dissection, histologic study, morphometric measurements, and virtual modeling.

SETTING

University laboratory of applied surgical anatomy.

PATIENTS

This study includes formalin-fixed hemipelvis specimens (n=37) obtained from body donors (age, 67-97 y).

MAIN OUTCOME MEASURES

The main outcome measures are photo documentation of origin, trajectory, diameter, and branching pattern; immunolabeling of lymphatics; and 3-dimensional reconstruction of the middle rectal artery.

RESULTS

The middle rectal artery was present in 71.4% of body donors (21.4% bilateral, 50% unilateral), originated from the anterior division of the internal iliac artery, and branched either from the internal pudendal artery (45.5%), the inferior gluteal artery (22.7%), the gluteal-pudendal trunk (22.7%), or a trifurcation (9.1%). One to 3 branches of varying diameters (0.5-3.5 mm) entered the mesorectum from the ventrolateral (35.7%), lateral (42.9%), or dorsolateral (21.4%) aspect. The middle rectal artery was accompanied by podoplanin-immunoreactive lymphatic vessels and gave off additional branches (81.8%) to the urogenital pelvic organs. Three-dimensional reconstruction revealed the complex course of the middle rectal artery from the pelvic sidewall through the pelvic nerve plexus and parietal pelvic fascia into the mesorectum.

LIMITATIONS

Findings retrieved from body donors may be prone to age- and fixation-related processes.

CONCLUSIONS

The investigation disclosed the rather high prevalence of the middle rectal artery, its 3-dimensional topographic anatomy, and its proximity to the autonomic pelvic nerves. These features play a role in the surgical management of this blood vessel. The data provide the anatomical rationale for the lateral lymphatic spread of rectal cancer and an anatomical basis for nerve-preserving lateral lymph node dissection.

Reappraisal of the Lymphatic Drainage System of the Distal Rectum: Functional Lymphatic Flow into the Presacral Space and Its Clinical Implication in Rectal Cancer Treatment

Understanding the source and route of pelvic metastasis is essential to developing an optimal strategy for controlling local and systemic diseases of rectal cancer. This study aims to delineate the distribution of lymphatic channels and flow from the distal rectum. In fresh-frozen cadaveric hemipelvis specimens, the ligamentous attachment of the distal rectum to the pelvic floor muscles and the presacral fascia were evaluated. Using indocyanine green (ICG) fluorescence imaging, we simultaneously evaluated the gross anatomy of the lymphatic communication of the distal rectum. We also investigated the lymphatic flow in the pelvic cavity intraoperatively in rectal cancer patients who underwent radical rectal resection with total mesorectal excision (TME). In fresh cadavers, multiple small perforating lymphovascular branches exist in the retrorectal space, posteriorly connecting the mesorectum to the presacral fascia. The lymphatic flow from the distal rectum drains directly into the presacral space through the branches. In patients who underwent TME for rectal cancer, intraoperative ICG fluorescence signals were seen in the pelvic sidewalls and the presacral space. This anatomical study demonstrated that the lymphatic flow from the distal rectum runs directly to the pelvic lateral sidewalls and the presacral space, suggesting a possible route of metastasis in distal rectal cancer.

Current status of transanal total mesorectal excision for rectal cancer and the expanding indications of the transanal approach for extended pelvic surgeries

Transanal total mesorectal excision (taTME) has been rapidly accepted as a promising surgical approach to the distal rectum. The benefits include ease of access to the bottom of the deep pelvis linearly over a short distance in order to easily visualize the important anatomy. Furthermore, the distal resection margins can be secured under direct vision. Additionally, a two-team approach combining taTME with a transabdominal approach could decrease the operative time and conversion rate. Although taTME was expected to become more rapidly popularized worldwide, enthusiasm for it has stalled due to unfamiliar intraoperative complications, a lack of oncologic evidence from randomized trials, and the widespread use of robotic surgery. While international registries have reported favorable short- and medium-term outcomes from taTME, a Norwegian national study reported a high local recurrence rate of 9.5%. The characteristics of the recurrences included rapid, multifocal growth in the pelvis, which was quite different from recurrences following traditional transabdominal TME; thus, the Norwegian Colorectal Cancer Group reached a consensus for a temporary moratorium on the performance of taTME. To ensure acceptable baseline quality and patient safety, taTME should be performed by well-trained colorectal surgeons. Although the appropriate indications for taTME remain controversial, the transanal approach is extremely important as a means of goal setting in difficult TME cases and as an aid to the transabdominal approach in various types of extended pelvic surgeries. The benefits in transanal lateral lymph node dissection and pelvic exenteration are presented herein.

Case report: Indocyanine green fluorescence-guided imaging in laparoscope, a more sensitive detection technique of lateral lymph nodes metastases from rectal neuroendocrine tumors

Background

The diagnosis and surgical strategy of lateral lymph node metastases of rectal neuroendocrine tumors are still controversial. At present, the major diagnostic means rely on imaging examinations, but will be affected by the size of lymph nodes leading to false negativity. We provide a new technique to determine lateral lymph node metastases during surgery.

Clinical case

A 68-year-old man developed abdominal pain, bloating and fever for a month. Colonoscopy revealed the mass is 2.4 cm x 2.0 cm in size, with a wide stratum, poor mobility, and a rough but intact surface mucosa. Therefore, rectal neuroendocrine tumors (R-NET) were diagnosed. Multiple imaging methods, such as CT, octreotide imaging and endoscopic ultrasonography, have not found lateral lymph node metastases from rectal neuroendocrine tumors. But indocyanine green (ICG)-enhanced near-infrared fluorescence-guided imaging during surgery found left lateral lymph nodes metastases, which was proved by postoperative pathological examination.

Conclusions

We believe that applying ICG-enhanced near-infrared fluorescence-guided imaging in laparoscope can improve the detection of positive LLNs in those R-NET patients who did not reveal LNM on imaging examinations.

Effect of lateral lymph nodes without malignant characteristics on the prognosis of patients with rectal cancer

Background: Lateral lymph node (LLN) metastasis is a poor prognostic factor for rectal cancer patients. However, the effect of LLNs without malignant characteristics on the prognosis of rectal cancer patients has been uncertain. Methods: Consecutive patients who underwent laparoscopic-assisted low anterior resection were included. Patients with MRI-detected LLNs, but without malignant characteristics, were compared with patients with no MRI-detected LLNs. Results: The local recurrence rate was higher in the LLN-present group than in the LLN-absent group (9.8% vs 2.5%; p = 0.056). The overall survival of patients with no MRI-detected LLNs was significantly better than that of patients with MRI-detected LLNs (p = 0.021). Conclusion: The presence of LLNs, even without malignant features, may lead to worse local control and overall survival.

Systematic review and meta-analysis of long-term oncological outcomes of lateral lymph node dissection for metastatic nodes after neoadjuvant chemoradiotherapy in rectal cancer

BACKGROUND

Standard Western management of rectal cancers with pre-treatment metastatic lateral lymph nodes (LLNs) is neoadjuvant (chemo)radiotherapy (nCRT) followed by total mesorectal excision (TME). In recent years, there is growing interest in performing an additional lateral lymph node dissection (LLND). The aim of this systematic review and meta-analysis was to investigate long-term oncological outcomes of nCRT followed by TME with or without LLND in patients with pre-treatment metastatic LLNs.

METHODS

PubMed, Ovid MEDLINE, Embase, Cochrane Library and Clinicaltrials.gov were searched to identify comparative studies reporting long-term oncological outcomes in pre-treatment metastatic LLNs of nCRT followed by TME and LLND (LLND+) vs. nCRT followed by TME only (LLND-). Newcastle-Ottawa risk-of-bias scale was used. Outcomes of interest included local recurrence (LR), disease-free survival (DFS), and overall survival (OS). Summary meta-analysis of aggregate outcomes was performed.

RESULTS

Seven studies, including 946 patients, were analysed. One (1/7) study was of good-quality after risk-of-bias analysis. Five-year LR rates after LLND+ were reduced (range 3-15%) compared to LLND- (11-27%; RR = 0.40, 95%CI [0.25-0.62], p < 0.0001). Five-year DFS was not significantly different after LLND+ (range 61-78% vs. 46-79% for LLND-; RR = 0.72, 95%CI [0.51-1.02], p = 0.143), and neither was five-year OS (range 69-91% vs. 72-80%; RR = 0.72, 95%CI [0.45-1.14], p = 0.163).

CONCLUSION

In rectal cancers with pre-treatment metastatic LLNs, nCRT followed by an additional LLND during TME reduces local recurrence risk, but does not impact disease-free or overall survival. Due to the low quality of current data, large prospective studies will be required to further determine the value of LLND.

From "East vs West" towards international multidisciplinary collaboration: An appraisal of lateral lymph nodes in rectal cancer

Western and Eastern practices have traditionally differed in their approach to treating lateral lymph nodes in rectal cancer. While Western clinicians have primarily favored neoadjuvant (chemo)radiotherapy to sterilize lateral compartments, Eastern physicians have often opted for the surgical removed of lymphatic tissue with a lateral lymph node dissection without neoadjuvant treatment. The literature suggests similar oncological outcomes for these two separate techniques, while tangible differences exist. The combination of these paradigms may be beneficial in reducing overall morbidity while sustaining low recurrence rates. This article considers traditional Eastern and Western perspectives, discusses nodal features important for predicting malignancy and attempts to stimulate international, multidisciplinary consensus and collaboration.

Malignant Features in Pretreatment Metastatic Lateral Lymph Nodes in Locally Advanced Low Rectal Cancer Predict Distant Metastases

INTRODUCTION

Pretreatment enlarged lateral lymph nodes (LLN) in patients with locally advanced low rectal cancer are predictive for local recurrences after neoadjuvant (chemo)radiotherapy (n(C)RT) followed by total mesorectal excision (TME). Not much is known of the impact on oncological outcomes when in addition malignant features are present in enlarged LLN.

PATIENTS AND METHODS

A multicenter retrospective cohort study was conducted at five tertiary referral centers in the Netherlands and Australia. All patients were diagnosed with locally advanced low rectal cancer with LLN on pretreatment magnetic resonance imaging (MRI) and underwent n(C)RT followed by TME. LLN were considered enlarged with a short axis of ≥ 5 mm. Malignant features were defined as nodes with internal heterogeneity and/or border irregularity. Outcomes of interest were local recurrence-free survival (LRFS), distant metastatic-free survival (DMFS), and overall survival (OS).

RESULTS

Out of 115 patients, the majority was male (75%) and the median age was 64 years (range 26-85 years). Median pretreatment LLN short axis was 7 mm (range 5-28 mm), and 60 patients (52%) had malignant features. After a median follow-up of 47 months, patients with larger LLN (7 + mm) had a worse LRFS (p = 0.01) but no difference in DMFS (p = 0.37) and OS (p = 0.54) compared with patients with smaller LLN (5-6 mm). LLN patients with malignant features had no difference in LRFS (p = 0.20) but worse DMFS (p = 0.004) and OS (p = 0.006) compared with patients without malignant features in the LLN. Cox regression analysis identified LLN short axis as an independent factor for LR. Malignant features in LLN were an independent factor for DMFS.

CONCLUSION

The current study suggests that pretreatment enlarged LLN that also harbor malignant features are predictive of a worse DMFS. More studies will be required to further explore the role of malignant features in LLN.

Metachronous common iliac lymph node metastasis after rectosigmoid colon cancer resection: A case report

Introduction and importance

Metastases to common iliac lymph nodes from cancer of the rectosigmoid are extremely rare. We report a patient with a right common iliac lymph node metastasis after rectosigmoid cancer resection.

Case presentation

The patient is a 57-year-old woman diagnosed with rectosigmoid cancer (Stage IIIc) who underwent laparoscopic resection followed by 8 courses of adjuvant chemotherapy with capecitabine. Sixteen months after resection, an intra-abdominal mass and a left lung nodule were found on computed tomography scans, which were suspected to be recurrences. Exploratory laparoscopy showed that the abdominal lesion was an enlarged common iliac lymph node, which was completely excised. No other intraabdominal recurrences were found. Subsequently, a left upper lobe lung metastasis was resected thoracoscopically. However, multiple lung metastases developed four months after the lung resection, and systemic therapy was begun.

Clinical discussion

A lower incidence of lateral lymph node metastases from cancer in the rectosigmoid has been reported. Direct lymphatic pathways from the sigmoid colon or rectosigmoid to lateral lymph nodes have been suspected, which may be associated with the poor prognosis in this patient.

Conclusion

A metachronous metastasis to a common iliac lymph node from primary rectosigmoid cancer is reported. Common iliac lymph node metastases from rectosigmoid cancer might have more malignant potential, and should be treated in the same manner as peri-aortic lymph node metastases.

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Metastases to common iliac lymph nodes from rectosigmoid cancer are extremely rare.

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Direct spread from the rectosigmoid to a common iliac lymph node is suspected.

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The lymph node metastasis was excised laparoscopically.

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A direct lymphatic pathway may be associated with a poor prognosis.

Local recurrences in western low rectal cancer patients treated with or without lateral lymph node dissection after neoadjuvant (chemo)radiotherapy: An international multi-centre comparative study

BACKGROUND

In the West, low rectal cancer patients with abnormal lateral lymph nodes (LLNs) are commonly treated with neoadjuvant (chemo)radiotherapy (nCRT) followed by total mesorectal excision (TME). Additionally, some perform a lateral lymph node dissection (LLND). To date, no comparative data (nCRT vs. nCRT + LLND) are available in Western patients.

METHODS

An international multi-centre cohort study was conducted at six centres from the Netherlands, US and Australia. Patients with low rectal cancers from the Netherlands and Australia with abnormal LLNs (≥5 mm short-axis in the obturator, internal iliac, external iliac and/or common iliac basin) who underwent nCRT and TME (LLND-group) were compared to similarly staged patients from the US who underwent a LLND in addition to nCRT and TME (LLND + group).

RESULTS

LLND + patients (n = 44) were younger with higher ASA-classifications and ypN-stages compared to LLND-patients (n = 115). LLND + patients had larger median LLNs short-axes and received more adjuvant chemotherapy (100 vs. 30%; p < 0.0001). Between groups, the local recurrence rate (LRR) was 3% for LLND + vs. 11% for LLND- (p = 0.13). Disease-free survival (DFS, p = 0.94) and overall survival (OS, p = 0.42) were similar. On multivariable analysis, LLND was an independent significant factor for local recurrences (p = 0.01). Sub-analysis of patients who underwent long-course nCRT and had adjuvant chemotherapy (LLND-n = 30, LLND + n = 44) demonstrated a lower LRR for LLND + patients (3% vs. 16% for LLND-; p = 0.04). DFS (p = 0.10) and OS (p = 0.11) were similar between groups.

CONCLUSION

A LLND in addition to nCRT may improve loco-regional control in Western patients with low rectal cancer and abnormal LLNs. Larger studies in Western patients are required to evaluate its contribution.

Embryological Development and Topographic Anatomy of Pelvic Compartments-Surgical Relevance for Pelvic Lymphonodectomy

Background: The oncological outcome of surgery for the treatment of pelvic malignancies can be improved by performing pelvic lymphonodectomy. However, the extent and regions of lymph node harvest are debated and require profound knowledge of anatomy in order to avoid collateral damage. Methods: The embryological development and topographic anatomy of pelvic compartments in relation to pelvic lymphonodectomy for rectal, uterine, and prostate cancer are reviewed. Based on pre-dissected anatomical specimens, lymph node regions and drainage routes of the posterior and urogenital pelvic compartments are described in both genders. Anatomical landmarks are highlighted to identify structures at risk of injury during pelvic lymphonodectomy. Results: The ontogenesis of urogenital and anorectal compartments and their lymphatic supply are key factors for adequate lymphonodectomy, and have led to compartment-based surgical resection strategies. However, pelvic lymphonodectomy bears the risk of injury to somatic and autonomic nerves, vessels, and organs, depending on the regions and extent of surgery. Conclusion: Embryologically defined, compartment-based resection of pelvic malignancies and their lymphatic drainage routes are based on clearly delineated anatomical landmarks, which permit template-oriented pelvic lymphonodectomy. Comprehensive knowledge of pelvic anatomy, the exchange of surgical concepts between specialties, and minimally invasive techniques will optimize pelvic lymphonodectomy and reduce complications.

Incidence of and risk factors for lymphocele formation after lateral pelvic lymph node dissection for rectal cancer: a retrospective study

AIM

Pelvic lymphocele is a common complication that develops after pelvic lymph node dissection. The incidence of pelvic lymphocele formation has been reported to be 10.5-51% after gynaecological or urological procedures. However, no evidence has been reported thus far with regard to the development of pelvic lymphocele following lateral pelvic lymph node dissection (LPND) for low rectal cancer. The aim of this study was to investigate the incidence of and risk factors for lymphocele formation after LPND for low rectal cancer and to examine its clinical management.

METHOD

We retrospectively analysed the incidence of and risk factors for pelvic lymphocele formation after LPND for rectal cancer in our hospital between January 2012 and December 2017. We also compared the size of the lymphocele between asymptomatic and symptomatic patients by using CT volumetry and examined its clinical management.

RESULTS

A total of 30 out of 98 patients (30.8%) developed pelvic lymphocele after rectal LPND. The number of resected nodes was significantly higher in patients with a pelvic lymphocele (P < 0.01). The median volume was significantly higher in patients with symptomatic pelvic lymphocele (P = 0.011). Among the nine symptomatic patients, two underwent CT-guided drainage, one underwent transurethral ureteral stent placement and one underwent laparoscopic marsupialization.

CONCLUSION

It is essential to keep in mind the possibility of pelvic lymphocele formation during follow-up of patients who undergo LPND, and to consider an appropriate treatment when these patients are symptomatic.

Update on indications for lateral lymph node dissection in the management of lower rectal cancer

The presence of lateral lymph node (LLN) metastasis was associated with higher local recurrence risk in patients with lower rectal cancer. The role of LLN dissection has not been fully determined despite prolonged debate that last for few decades. The practical difference between Japan and the West was the main culprit. Japanese used to rely on surgical removal of LLN as local control while the West believed that LLN dissection could be spared after giving neoadjuvant chemoradiotherapy. As time passed, it is getting more common to combine both treatments. With the quality improvement in magnetic resonance imaging, we can now predict the chance of LLN metastasis and evaluate the treatment response with good accuracy. Few large analyses have been published recently and provided us more insight into this topic. In this review, we summarized and provided an update on the latest evidence. We have proposed a treatment algorithm on the management of LLNs which may help clinical decision and provide idea for further research.

Imaging and Management of Rectal Cancer

High-resolution phased array external magnetic resonance imaging (MRI) is the first investigation of choice in rectal cancer for local staging, both in the primary and restaging situations. Use of MRI helps differentiate between those with good prognosis, which can be offered upfront surgery and the poor prognostic cases where treatment intensification is needed. MRI identified poor prognostic factors are threatened or involved mesorectal fascia, T3 tumors with >5 mm extramural spread, those with extramural vascular invasion, pelvic sidewall nodes and mucinous tumors. At restaging, use of MRI helps evaluate response and an MR tumor regression grading system is being evaluated. Complete response seen on clinical examination and endoscopy, needs confirmation on MRI using both T2-weighted and diffusion-weighted sequences to justify a "watch and wait" approach. In this subset of patients, MRI also plays a role in monitoring and detecting early regrowth. In those with partial response, MRI helps define surgical margins and can be used as a roadmap to decide between sphincter preserving surgeries and radical sphincter sacrificing surgeries; pelvic exenteration and pelvic sidewall lymph node dissection. Poor responders on MRI may benefit from adjuvant chemotherapy. Use of MRI thus helps in individualizing treatment in rectal cancer.

Baseline MRI detected lateral lymph node as a prognostic factor: a cohort study in pN0 low-risk rectal cancer

BACKGROUND

It is highly controversial that how to deal with the lateral lymph-node metastasis in patients with rectal cancer. Although lateral lymph node can be detected by preoperative MRI, the metastasis status cannot be accurately determined following standard total mesorectal excision (TME) in low-risk patients. This study was to assess the correlation between preoperative MRI detected lateral lymph-node (LLN) features and prognosis in patients with non-preradiated low recurrence risk rectal cancers.

MATERIALS AND METHODS

This retrospective study included 593 low-risk rectal cancers underwent TME without neoadjuvant chemo-radiotherapy from January 2013 to December 2015. The features of the largest LLN were retrospectively reviewed on preoperative MRI. The relationship of MR-LLN features with overall survival, metastasis-free survival, and local relapse-free survival was analyzed.

RESULTS

A total of 593 patients including 415 cases of pN0, 86 cases of pN1, and 92 cases of pN2 were enrolled in this study. In pN0 patients, at least one visible LLN was detected in 104 patients on primary MRI. The MR-T staging, postoperative therapy status, the presence of MR-LLN, and short axis (SA) of MR-LLN were significantly correlated with the recurrence in pN0 patients (all p < 0.05). The OS and MFS were significantly lower in patients with MR-LLN SA ≥ 8 mm than SA < 8 mm (p < 0.01, HR = 4.35, 95% CI = 1.48-12.77). The OS and MFS of patients with pN0-LLN(+) and SA ≥ 8 mm were similar to pN2-LLN(-) patients. The location of MR-LLN showed no significant impact on prognosis.

CONCLUSION

For low-risk rectal cancers without neoadjuvant chemo-radiotherapy, the presence of MR-LLN is associated with poor prognosis. The pN0-LLN(+) SA ≥ 8 mm patients might be concerned as pN2 patients and receive more intensive neoadjuvant or adjuvant treatment.

Oncological Outcomes of Patients with Locally Advanced Rectal Cancer and Lateral Pelvic Lymph Node Involvement

INTRODUCTION

The optimal management of patients with radiologically positive lateral pelvic lymph nodes in locally advanced rectal cancer remains unclear. We compared local recurrence rates and oncological outcomes of patients with locally advanced cancer with and without lateral pelvic lymph nodes.

METHODS

Patients who underwent curative surgery for stage III rectal adenocarcinoma between 2009 and 2014 and had a preoperative MRI at our institution as well as preoperative neoadjuvant treatment were included. Patients with positive lateral pelvic lymph nodes (iliac or obturator nodes) on preoperative MRI (LPND +) were compared to patients with no lateral pelvic nodal disease (LPND -). Data were collected from a prospectively maintained institutional database. Differences between the groups were compared in univariate analysis. Log-rank test was used to evaluate overall and disease-free survival between the groups.

RESULTS

A total of 125 patients met inclusion criteria with a mean age of 56.3 ± 12.2 and 75% were male. Median follow-up was 44 months (IQR 32, 106). Positive LPND was present on preoperative MRI in 43/125 (34.4%) patients who were in the LPND (+) group. Seventeen out of 43 patients had a post-neoadjuvant treatment MRI and 15 patients had a decrease in size of nodes or disappearance of LPND. On univariate analysis, LPND (+) and LPND (-) groups were comparable. Local recurrence rates were higher in the LPND (+) group, although this was not statistically significant (16.3% vs. 6%, p = 0.06). Overall and disease-free survival rates were comparable between the LPND (+) and LPND (-) groups (p = 0.97, p = 0.51).

CONCLUSIONS

Management of patients with advanced rectal cancer and radiologically positive lateral pelvic lymph nodes is challenging due to high local recurrence rates. Further studies are needed to develop care pathways for the optimal treatment processes.

Lateral Node Dissection in Rectal Cancer in the Era of Minimally Invasive Surgery: A Step-by-Step Description for the Surgeon Unacquainted with This Complex Procedure with the Use of the Laparoscopic Approach

INTRODUCTION

Lateral node dissection in rectal cancer has been routinely performed in Eastern countries. Technical and anatomical challenges and potential significant postoperative morbidity associated with the procedure have prevented its implementation into clinical practice in Western countries. However, the minimally invasive approach may offer the opportunity of performing this complex procedure with precise anatomical dissection and minimal intraoperative blood loss. In this setting, proper training and standardization of technical steps is highly warranted for surgeons not fully acquainted with the procedure.

TECHNIQUE

Access to the lateral nodes along the obturator and internal iliac vessels is described by using specific anatomical landmarks. Opening of the peritoneum along the ureter provides access to the region of interest. Dissection of the medial limit is performed preserving the neurovascular bundle and ureter. The lateral dissection is performed along the external iliac vein to provide access to the obturator muscle. Identification of the obturator nerve with blunt dissection of the fat is a critical part of the procedure. Once the lymphatic connections between the inguinal and iliac nodes are transected, dissection is performed along the internal iliac vessels, and branches are separated from the lymphadenectomy specimen.

RESULTS

Evidence supports that lateral node dissection performed for highly selected patients with minimally invasive access leads to less intraoperative blood loss and similar oncological outcomes. Technical steps illustrated in the present video may aid surgeons in performing this procedure with precise anatomical landmarks and minimal risk for intraoperative complications.

CONCLUSIONS

Lateral node dissection for rectal cancer is a procedure that may follow standardized technical steps by using precise anatomical landmarks with the use of minimally invasive approach.