The role of lateral lymph node dissection in the management of lower rectal cancer

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

BACKGROUND

An innovative instrument for laparoscopy using indocyanine green (ICG) allows easy detection of sentinel lymph nodes (SLNs) in lateral pelvic lymph nodes (LPLNs). Here, we investigated the safety and efficacy of lateral pelvic SLN biopsy (SLNB) using ICG fluorescence navigation in advanced lower rectal cancer and evaluated the sensitivity and specificity of this technique to predict the status of LPLN.

METHODS

From April 1, 2017 to December 1, 2020, we conducted lateral pelvic SLNB using ICG fluorescence navigation during laparoscopic total mesorectal excision and lateral pelvic lymph node dissection (LLND) in 23 patients with advanced low rectal cancer who presented with LPLN but without LPLN enlargement. Data regarding clinical characteristics, surgical and pathological outcomes, lymph node findings, and postoperative complications were collected and analyzed.

RESULTS

We successfully performed the surgery using fluorescence navigation. One patient underwent bilateral LLND and 22 patients underwent unilateral LLND. The lateral pelvic SLN were clearly fluorescent before dissection in 21 patients. Lateral pelvic SLN metastasis was diagnosed in 3 patients and negative in 18 patients by frozen pathological examination. Among the 21 patients in whom lateral pelvic SLN was detected, the dissected lateral pelvic non-SLNs were all negative. All dissected LPLNs were negative in two patients without fluorescent lateral pelvic SLN.

CONCLUSION

This study indicated that lateral pelvic SLNB using ICG fluorescence navigation shows promise as a safe and feasible procedure for advanced lower rectal cancer with good accuracy, and no false-negative cases were found. No metastasis in SLNB seemed to reflect all negative LPLN metastases, and this technique can replace preventive LLND for advanced lower rectal cancer.

Lateral pelvic lymph nodes for rectal cancer: A review of diagnosis and management

The current status and future prospects for diagnosis and treatment of lateral pelvic lymph node (LPLN) metastasis of rectal cancer are described in this review. Magnetic resonance imaging (MRI) is recommended for the diagnosis of LPLN metastasis. A LPLN-positive status on MRI is a strong risk factor for metastasis, and evaluation by MRI is important for deciding treatment strategy. LPLN dissection (LPLD) has an advantage of reducing recurrence in the lateral pelvis but also has a disadvantage of complications; therefore, LPLD may not be appropriate for cases that are less likely to have LPLN metastasis. Radiation therapy (RT) and chemoradiation therapy (CRT) have limited effects in cases with suspected LPLN metastasis, but a combination of preoperative CRT and LPLD may improve the treatment outcome. Thus, RT and CRT plus selective LPLD may be a rational strategy to omit unnecessary LPLD and produce a favorable treatment outcome.

Brazilian society of surgical oncology: Guidelines for the surgical treatment of mid-low rectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in North America, Western Europe, and Brazil, and represents an important public health problem. It is estimated that approximately 30% of all the CRC cases correspond to tumors located in the rectum, requiring complex multidisciplinary treatment. In an effort to provide surgeons who treat rectal cancer with the most current information based on the best evidence in the literature, the Brazilian Society of Surgical Oncology (SBCO) has produced the present guidelines for rectal cancer treatment that is focused on the main topics related to daily clinical practice.

OBJECTIVES

The SBCO developed the present guidelines to provide recommendations on the main topics related to the treatment of mid-low rectal cancer based on current scientific evidence.

METHODS

Between May and June 2021, 11 experts in CRC surgery met to develop the guidelines for the treatment of mid-low rectal cancer. A total of 22 relevant topics were disseminated among the participants. The methodological quality of a final list with 221 sources was evaluated, all the evidence was examined and revised, and the treatment guideline was formulated by the 11-expert committee. To reach a final consensus, all the topics were reviewed via a videoconference meeting that was attended by all 11 of the experts.

RESULTS

The prepared guidelines contained 22 topics considered to be highly relevant in the treatment of mid-low rectal cancer, covering subjects related to the tests required for staging, surgical technique-related aspects, recommended measures to reduce surgical complications, neoadjuvant strategies, and nonoperative treatments. In addition, a checklist was proposed to summarize the important information and offer an updated tool to assist surgeons who treat rectal cancer provide the best care to their patients.

CONCLUSION

These guidelines summarize concisely the recommendations based on the most current scientific evidence on the most relevant aspects of the treatment of mid-low rectal cancer and are a practical guide that can help surgeons who treat rectal cancer make the best therapeutic decision.

Current Surgical Strategies for the Treatment of Rectal Adenocarcinoma and the Risk of Local Recurrence

BACKGROUND

Despite new medical and surgical strategies, 5-year local recurrence of rectal adenocarcinoma was reported in up to 25% of cases. Therefore, we aimed to review surgical strategies for the prevention of local recurrences in rectal cancer.

SUMMARY

After implementation of the total mesorectal excision (TME), surgical resection of rectal adenocarcinoma with anterior resection or abdominoperineal excision (APE) allowed decrease in local recurrence (3% at 5 years). More recently, extralevator APE was described as an alternative to APE, decreasing specimen perforation and recurrence rate. Moreover, technique modifications were developed to optimize rectal resection, such as the laparoscopic or robotic approach, and transanal TME. However, the technical advantages conferred by these techniques did not translate into a decreased recurrence rate. Lateral lymph node dissection is another technique, which aimed at improving the long-term outcomes; nevertheless, there is currently no evidence to recommend its routine use. Strategies to preserve the rectum are also emerging, such as local excision, and may be beneficial for subgroups of patients. Key Messages: Rectal cancer management requires a multidisciplinary approach, and surgical strategy should be tailored to patient factors: general health, previous perineal intervention, anatomy, preference, and tumor characteristics such as stage and localization.

Total mesorectal excision with and without lateral lymph node dissection: a systematic review of the literature

PURPOSE

Treatment of lateral lymph node metastasis in rectal cancer is still under debate. While these nodes are routinely resected by Japanese teams, neoadjuvant radiochemotherapy alone is performed in Western countries. We aimed to systematically report the current literature assessing the overall and disease-free survivals of patients with rectal cancer treated with total mesorectal resection (TME) with or without lateral lymph node dissection (LLND).

METHODS

MEDLINE/Pubmed, Embase, Cochrane, and Web of Science were searched from database implementation until 19 January 2019. Studies reporting overall survival or recurrence-free survival in patients with LLND for rectal cancer were included. We excluded studies including patients with recurrent rectal cancer, multivisceral resection, and/or without control group (patients with rectal surgery without LLND).

RESULTS

Eleven studies were included, accounting for a total of 4159 patients. Overall survival ranged between 55.6 and 92.6% for TME with LLND versus 49.2 and 90.2% for TME alone, with one study reporting statistically significant benefit of LLND. Recurrence-free survival ranged between 58.3 and 74.1% for TME with LLND versus 39.5 and 76.5% for TME alone. Two studies showed statistically significant differences between the two strategies, one randomized controlled trial showed improved recurrence-free survival in TME alone group (74.5% versus 74.1% with LLND at 5 years) and one observational retrospective study reported increased recurrence-free survival with more extensive resection (65.4% versus 39.5% without LLND, at 5 years).

CONCLUSION

Benefits of LLND are not clear and further randomized controlled trials should be performed to determine which strategy would allow improving survival in rectal cancer patients.

TRIAL REGISTRATION

The study protocol was registered in PROSPERO prior to study screening (CRD42019123181) and published in September 2019.

Lateral lymph node dissection for low rectal cancer: Is it necessary?

Rectal cancer constitutes a major public health issue. Total mesorectal excision has remained the gold standard treatment for mid and low rectal tumors since its introduction in the late 1980s. Removal of all lymph nodes located in the mesorectum has indeed improved pathological and oncological outcomes. However, when cancer spreads to the lateral lymph nodes (located along the iliac and obturator arteries) Western and Japanese practices differ. Where the Western guidelines consider this condition as an advanced form of the disease and use neoadjuvant radiochemotherapy liberally, the Japanese guidelines define it as a local disease and proceed to lateral lymph node dissection with or without neoadjuvant treatment. Herein, we review the current literature regarding both therapeutic strategies, with the aim of contributing to potential improvements in treatment and outcome for patients with low and mid rectal cancer.

Comparison of guidelines for the management of rectal cancer

A comparison between NCCN, ESMO and JSCCR Guidelines is presented, concerning the treatment of rectal cancer, with an analysis and discussion of their discrepancies. Differences indicate areas for research.

Prediction of lateral pelvic lymph node metastasis from lower rectal cancer using magnetic resonance imaging and risk factors for metastasis: Multicenter study of the Lymph Node Committee of the Japanese Society for Cancer of the Colon and Rectum

PURPOSE

The goal of the study was to examine prediction of lateral pelvic lymph node (LPLN) metastasis from lower rectal cancer using a logistic model including risk factors for LPLN metastasis and magnetic resonance imaging (MRI) clinical LPLN (cLPLN) status, compared to prediction based on MRI alone.

METHODS

The subjects were 272 patients with lower rectal cancer who underwent MRI prior to mesorectal excision combined with LPLN dissection (LPLD) at six institutes. No patients received neoadjuvant therapy. Prediction models for right and left pathological LPLN (pLPLN) metastasis were developed using cLPLN status, histopathological grade, and perirectal lymph node (PRLN) status. For evaluation, data for patients with left LPLD were substituted into the right-side equation and vice versa.

RESULTS

Left LPLN metastasis was predicted using the right-side model with accuracy of 86.5%, sensitivity 56.4%, specificity 92.7%, positive predictive value (PPV) 61.1%, and negative predictive value (NPV) 91.2%, while these data using MRI cLPLN status alone were 80.4, 76.9, 81.2, 45.5, and 94.5%, respectively. Similarly, right LPLN metastasis was predicted using the left-side equation with accuracy of 83.8%, sensitivity 57.8%, specificity 90.4%, PPV 60.5%, and NPV 89.4%, and the equivalent data using MRI alone were 78.4, 68.9, 80.8, 47.7, and 91.1%, respectively. The AUCs for the right- and left-side equations were significantly higher than the equivalent AUCs for MRI cLPLN status alone.

CONCLUSIONS

A logistic model including risk factors for LPLN metastasis and MRI findings had significantly better performance for prediction of LPLN metastasis compared with a model based on MRI findings alone.

The important risk factor for lateral pelvic lymph node metastasis of lower rectal cancer is node-positive status on magnetic resonance imaging: study of the Lymph Node Committee of Japanese Society for Cancer of the Colon and Rectum

PURPOSE

This study seeks to evaluate lateral pelvic lymph node (LPLN) and perirectal lymph node (PRLN) status on magnetic resonance imaging (MRI) as potential risk factors for lymph node metastasis.

METHODS

The subjects were 394 patients with lower rectal cancer who underwent MRI prior to mesorectal excision (combined with lateral pelvic lymph node dissection in 272 patients) at 6 institutes. No patients received neoadjuvant therapy. Cases were classified as cN(+) and cN(-) based on the short axis of the largest lymph node ≥5 and <5 mm, respectively. LPLN and PRLN status and other clinicopathologic factors were analyzed by multivariate logistic regression. The importance of identified risk factors for lymph node metastasis was examined using the area under the curve (AUC).

RESULTS

Independent risk factors for right LPLN metastasis included histopathological grade (G3 + G4), pPRLN(+), M1, cLPLN(+) [odds ratio (OR) 10.73, 95 % confidence interval (CI) 4.59-27.1], and those for left LPLN metastasis were age (<64), histopathological grade (G3 + G4), pPRLN(+), and cLPLN(+) (OR 24.53, 95 % CI 9.16-77.7). ORs for cLPLN(+) were highest. The AUCs for right and left cLPLN status of 0.7484 (95 % CI 0.6672-0.8153) and 0.7904 (95 % CI 0.7088-0.8538), respectively, were significantly higher than those for other risk factors. In contrast, the ORs for cPRLN(+) and cPRLN status of 2.46 (95 % CI 1.47-4.18) and 0.6396 (95 % CI 0.5917-0.6848) were not much higher than for other factors.

CONCLUSIONS

An LPLN-positive status with a short axis ≥5 mm on MRI is an important predictor of LPLN metastasis, but PRLN status is not a strong predictor of PRLN metastasis.

Selection of Lymph Node-Positive Cases Based on Perirectal and Lateral Pelvic Lymph Nodes Using Magnetic Resonance Imaging: Study of the Japanese Society for Cancer of the Colon and Rectum

PURPOSE

To investigate the optimum cutoff for lymph node size to identify cases positive for perirectal lymph node (PRLN) and lateral lymph node (LPLN) metastasis of lower rectal cancer on magnetic resonance imaging (MRI).

METHODS

The subjects were 449 patients who underwent preoperative MRI. Mesorectal excision was performed in all patients (combined with lateral pelvic lymph node [LN] dissection in 324) between 2004 and 2013 at 6 institutes. Cases were classified as cN positive and cN negative on the basis of the short axis of the largest LN being greater than or equal to a cutoff or less than a cutoff, respectively. PRLN and LPLN diagnoses using 5 and 10 mm cutoffs were compared with histologic diagnoses. Of the 449 patients, 55 received preoperative chemoradiotherapy. MRI was only performed after this therapy in all of these patients.

RESULTS

For PRLNs, 5 and 10 mm cutoffs gave area under the curve (AUC) values of 0.6364 and 0.5794, respectively. The 5 mm cutoff gave a significantly higher AUC value (P = 0.0152), with an accuracy of 63.7 %, sensitivity of 72.6 %, and specificity of 54.7 %. For right LPLNs, the respective AUC values were 0.7418 and 0.6326 (P = 0.0034), and the variables (5 mm cutoff) were 77.6, 68.6, and 79.7 %. For left LPLNs, AUC values were 0.7593 and 0.6559, respectively (P = 0.0057), and the variables (5 mm cutoff) were 79.3, 70.8, and 81.0 %.

CONCLUSIONS

Identification of LN-positive cases on the basis of PRLN and LPLN sizes was superior at a short-axis 5 mm cutoff. Size-based diagnosis of LN metastasis is simple and useful, but further investigation is needed to clarify whether it is superior to diagnosis based on morphology, such as shape, border, and signal intensity.

Neoadjuvant chemoradiotherapy affects the indications for lateral pelvic node dissection in mid/low rectal cancer with clinically suspected lateral node involvement: a multicenter retrospective cohort study

BACKGROUND

Although lateral pelvic node dissection (LPND) is recommended for rectal cancer with clinically metastatic lateral pelvic lymph nodes (LPNs), LPNs may respond to neoadjuvant chemoradiotherapy (nCRT). Our aim was to determine the optimal indication for LPND after nCRT for mid/low rectal cancer.

METHODS

Of 2,263 patients with clinical stage II/III mid/low rectal cancer who were managed at three tertiary referral hospitals, 66 patients underwent curative surgery including LPND after nCRT were included in this study. Risk factors for LPN metastasis were retrospectively analyzed and oncologic outcomes determined according to LPN response to nCRT.

RESULTS

Persistent LPNs greater than 5 mm on post-nCRT magnetic resonance imaging were significantly associated with residual tumor metastasis, unlike responsive LPN after nCRT (short-axis diameter ≤ 5 mm) (pathologically, 61.1 % [22 of 36] vs. 0 % [0 of 30], P < 0.001). Multivariable analysis revealed post-nCRT LPN size as a significant and independent risk factor for LPN metastasis (odds ratio 2.390; 95 % confidence interval 1.104-4.069). Over a median follow-up of 39.3 months, the recurrence rate was lower in patients with responsive nodes than in patients with persistent nodes (20 % [6 of 30] vs. 47.2 % [17 of 36], P = 0.012). The 5-year overall survival and 5-year disease-free survival rates were lower in patients with persistent LPN than in patients with responsive LPN (44.6 % vs. 77.1 %, P = 0.034; 33.7 % vs. 72.5 %, P = 0.011, respectively).

CONCLUSIONS

In mid/low rectal cancer with clinically metastatic LPNs, the decision to perform LPND should be based on the LPN response to nCRT.