Who can get the beneficial effect from lateral lymph node dissection for Dukes C rectal carcinoma below the peritoneal reflection?

Effective dissecting range and prognostic significance of lateral pelvic lymph node dissection for middle-low rectal cancer patients with lateral pelvic lymph node metastasis: Results of a large multicenter lateral node collaborative group in China

Background

Lateral pelvic lymph node (LPN) metastasis causes increased lateral local recurrence and poor prognosis. We aimed to investigate the prognostic significance and effective range of dissection for the LPN dissection (LPND) in rectal cancer patients with LPN metastasis.

Materials and methods

Through this large, multicenter retrospective cohort study, we evaluated the therapeutic effect of LPND. From January 2012 to December 2019, 387 rectal cancer patients with clinical evidence of LPN metastasis who underwent total mesorectal excision with LPND were included in the study. According to pathological findings, they were divided into negative (n = 296) and positive (n = 91) LPN groups. Primary endpoints were 3-year overall survival (OS), recurrence-free survival (RFS), and local recurrence-free survival (LRFS).

Results

The OS, RFS, and LRFS in the positive group were significantly worse than those in the negative group; However, LPN metastases were not independent prognostic risk factors for LRFS (hazard ratio [HR]: 2.42; 95% confidence interval [CI], 0.77–7.64; P=0.132). Among patients with pathological LPN metastases, LPN metastases to the common and external iliac arteries were independent prognostic risk factors both for OS (HR: 4.74; 95% CI, 1.74–12.90; P=0.002) and RFS (HR: 2.70; 95% CI, 1.16–6.29; P=0.021). No significant difference was observed in the 3-year OS (72.3% vs. 70.2%, P=0.775) and RFS rates (60.9% vs. 52.6%, P=0.408) between patients with metastases to the obturator or internal iliac arteries and patients at N2b stage.

Conclusions

LPND may be effective in controlling local recurrence in patients with LPN metastasis but not systemic metastases. Patients with LPN metastasis limited to the internal iliac and obturator regions achieve a long-term survival benefit from LPND, and their prognoses may be comparable to those at the N2b stage. Further metastasis to the external iliac or common iliac region should be considered systemic disease, and LPND should be avoided.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT04850027.

Magnetic resonance imaging-based artificial intelligence model in rectal cancer

Rectal magnetic resonance imaging (MRI) is the preferred method for the diagnosis of rectal cancer as recommended by the guidelines. Rectal MRI can accurately evaluate the tumor location, tumor stage, invasion depth, extramural vascular invasion, and circumferential resection margin. We summarize the progress of research on the use of artificial intelligence (AI) in rectal cancer in recent years. AI, represented by machine learning, is being increasingly used in the medical field. The application of AI models based on high-resolution MRI in rectal cancer has been increasingly reported. In addition to staging the diagnosis and localizing radiotherapy, an increasing number of studies have reported that AI models based on high-resolution MRI can be used to predict the response to chemotherapy and prognosis of patients.

Lateral lymph node dissection reduces local recurrence of locally advanced lower rectal cancer in the absence of preoperative neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

Background

The impact of lateral lymph node dissection (LLND) in locally advanced lower rectal cancer remains controversial. This study is to compare total mesorectal excision (TME) with or without LLND in lower rectal cancer cases of stage II/III.

Methods

The electronic databases were systematically searched that compared TME with or without LLND among patients with lower rectal cancer in clinical stage II/III. Subgroup analysis was performed considering neoadjuvant chemoradiotherapy (nCRT). The hazard ratios (HR), relative risk (RR), and weighted mean difference (WMD) were pooled.

Results

Twelve studies of 4458 patients of this meta-analysis demonstrate, LLND alone significantly reduced the local recurrence rate of patients who did not receive nCRT (RR 0.71, P = 0.004), while the difference was not significant when combined with nCRT (RR 0.70, P = 0.36). The analysis shows TME with LLND was associated with significantly longer operation time (WMD 90.73 min, P < 0.001), more intraoperative blood loss (WMD 303.20 mL, P < 0.001), and postoperative complications (RR = 1.35, P =0.02). Whereas urinary dysfunction (RR 1.44, P = 0.38), sexual dysfunction (RR 1.41, P = 0.17), and postoperative mortality (RR = 1.52, P = 0.70), were similar between these two groups. Statistically, no significant differences were observed in OS (HR 0.93, P = 0.62), DFS (HR 0.99, P = 0.96), total recurrence (RR 0.98, P = 0.83), lateral recurrence (RR 0.49, P = 0.14), or distal recurrence (RR 0.95, P = 0.78) between these two groups regardless of whether nCRT was performed or not.

Conclusions

The study shows LLND alone decreases the local recurrence without using nCRT irrespective of the survival advantage in locally advanced lower rectal cancer. The benefit of controlling local recurrence by LLND alone makes us reconsider the usage of nCRT with LLND.

Trial registration

The protocol for this meta-analysis was registered prospectively with PROSPERO (CRD42020135575) on 16 May 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-020-02078-1.

Prognostic impact of the number of lateral pelvic lymph node metastases on rectal cancer

BACKGROUND

This study aimed to clarify the number of lateral pelvic lymph node metastases of colorectal cancer for which prognosis could be improved by dissection.

METHODS

We analysed the data of 30 patients with lateral pelvic lymph node metastases of rectal cancer that underwent a total mesorectal excision with lateral pelvic lymph node dissection at our institute from 1986 to 2016. We performed survival analysis on the number of lateral pelvic lymph node metastases in each of these patients and identified an optimal cut-off point of the number of lateral pelvic lymph node metastases that would predict recurrence-free survival using the receiver operating characteristic curves and an Akaike information criterion value.

RESULTS

The 5-year recurrence-free survival and overall survival of patients with one or two lateral pelvic lymph node metastases were significantly better than that of those with three or more (5-year recurrence-free survival, 63.3 vs. 0.0%, respectively; hazard ratio, 0.23; 95% CI, 0.07-0.72; P = 0.0124) (5-year overall survival, 68.2 vs. 15.6%, respectively; hazard ratio, 0.29; 95% CI, 0.09-0.92; P = 0.0300). All of the metastatic lateral pelvic lymph nodes in the group with one or two lateral pelvic lymph node metastases were restricted to the internal iliac artery or obturator nerve regions.

CONCLUSIONS

The cut-off number of lateral pelvic lymph node metastases in the internal iliac artery or obturator nerve regions of colorectal cancer cases in whom prognosis was improved by lateral pelvic lymph node dissection was 2; patients who had <3 lateral pelvic lymph node metastases had better prognoses than those with ≥3 lateral pelvic lymph node metastases.

Oncological Impact of Lateral Lymph Node Dissection After Preoperative Chemoradiotherapy in Patients with Rectal Cancer

PURPOSE

To evaluate the efficacy of selective lateral lymph node dissection (LLND) and the effect of preoperative chemoradiotherapy (PCRT) in patients with LLN ≥ 5 mm.

METHODS

Patients who underwent PCRT for rectal cancer were classified: (A) total mesorectal excision (TME)-only with LLN < 5 mm (2001-2009, n = 474), (B) TME-only with LLN < 5 mm (2011-2016, n = 273), (C) TME-only with LLN ≥ 5 mm (2001-2009, n = 102), and (D) TME-LLND with LLN ≥ 5 mm (2011-2016, n = 69). Subgroup analysis was performed in patients with LLN ≥ 5 mm based on the reduction in LLN size to < 5 mm or not on restaging MRI after PCRT.

RESULTS

Oncological outcomes did not differ between groups A and B. Group D had lower 3-year local recurrence (LR) (20.13% vs 5.39%, P = 0.0013) and higher relapse-free survival (RFS) (65.83% vs 77.11%, P = 0.0436) than group C, while the 3-year overall survival (OS) was not significantly different between the two groups (87.64% vs 93.53%, P = 0.0670). In patients with reduction of LLN size from ≥ 5 mm to < 5 mm, LLND significantly reduced LR than did TME alone, but there were no significant differences in survival outcomes. In patients without reduction of LLN size to < 5 mm, LLND reduced LR and improved RFS compared with TME alone.

CONCLUSIONS

Selective LLND reduced LR and improved RFS in patients with LLN ≥ 5 mm. Selective LLND reduced LR in patients with reduction of LLN size from ≥ 5 mm to < 5 mm after PCRT, and improved both LR and RFS in patients without reduction of LLN size to < 5 mm.

Artificial intelligence system of faster region-based convolutional neural network surpassing senior radiologists in evaluation of metastatic lymph nodes of rectal cancer

BACKGROUND

An artificial intelligence system of Faster Region-based Convolutional Neural Network (Faster R-CNN) is newly developed for the diagnosis of metastatic lymph node (LN) in rectal cancer patients. The primary objective of this study was to comprehensively verify its accuracy in clinical use.

METHODS

Four hundred fourteen patients with rectal cancer discharged between January 2013 and March 2015 were collected from 6 clinical centers, and the magnetic resonance imaging data for pelvic metastatic LNs of each patient was identified by Faster R-CNN. Faster R-CNN based diagnoses were compared with radiologist based diagnoses and pathologist based diagnoses for methodological verification, using correlation analyses and consistency check. For clinical verification, the patients were retrospectively followed up by telephone for 36 months, with post-operative recurrence of rectal cancer as a clinical outcome; recurrence-free survivals of the patients were compared among different diagnostic groups, by methods of Kaplan-Meier and Cox hazards regression model.

RESULTS

Significant correlations were observed between any 2 factors among the numbers of metastatic LNs separately diagnosed by radiologists, Faster R-CNN and pathologists, as evidenced by rradiologist-Faster R-CNN of 0.912, rPathologist-radiologist of 0.134, and rPathologist-Faster R-CNN of 0.448 respectively. The value of kappa coefficient in N staging between Faster R-CNN and pathologists was 0.573, and this value between radiologists and pathologists was 0.473. The 3 groups of Faster R-CNN, radiologists and pathologists showed no significant differences in the recurrence-free survival time for stage N0 and N1 patients, but significant differences were found for stage N2 patients.

CONCLUSION

Faster R-CNN surpasses radiologists in the evaluation of pelvic metastatic LNs of rectal cancer, but is not on par with pathologists.

TRIAL REGISTRATION

www.chictr.org.cn (No. ChiCTR-DDD-17013842).

Prediction of lateral pelvic lymph node metastasis in patients with locally advanced rectal cancer with preoperative chemoradiotherapy: Focus on MR imaging findings

PURPOSE

To investigate the predictive factors for lateral pelvic lymph node (LPLN) metastasis in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy (CRT).

MATERIALS AND METHODS

Fifty-seven patients with locally advanced rectal cancer and LPLNs larger than 5 mm underwent LPLN dissection (LPLD) after preoperative CRT. The MRI findings, including the apparent diffusion coefficient value and LPLN size reduction rate before/after CRT; clinical factors; and pathologic results were evaluated to identify the predictive factors associated with LPLN metastasis.

RESULTS

LPLN metastasis was confirmed in 23 patients (40.4%). Metastasis was significantly higher in LPLNs with multiplicity, short-axis diameter ≥8 mm before CRT, short-axis diameter >5 mm after CRT, size reduction rate ≤33.3%, heterogeneous signal intensity, and irregular margin (P<0.05) on MR. Multivariable analysis showed that pre-CRT short-axis diameter of LPLNs ≥8 mm, size reduction rate ≤33.3%, and heterogeneous signal intensity were independently associated with LPLN metastasis.

CONCLUSIONS

The size and signal intensity of LPLN before and after CRT are useful MRI findings to predict LPLN metastasis and are helpful to determine the indications for LPLD.

Impact of Lateral Pelvic Lymph Node Dissection on the Survival of Patients with T3 and T4 Low Rectal Cancer

BACKGROUND

The aim of this study was to clarify the survival benefit of lateral pelvic lymph node dissection (LPLND) for patients with pathological T3 and T4 (pT3/T4) low rectal cancer.

METHODS

We evaluated the impact of LPLND on survival for pT3/T4 low rectal cancer patients. The primary endpoint of the study was overall survival (OS). The large-scale database of the Japanese Society for Cancer of the Colon and Rectum registration system was accessed and the data were analyzed using a propensity score matching method based on the likelihood of receiving LPLND. Using seven covariates, the propensity scores were calculated with multivariate logistic regression. A total of 499 propensity score-matched pairs of patients were selected from the entire cohort of 1,840 patients who had received curative resection for pT3/T4 low rectal cancer between 1995 and 2004.

RESULTS

In the matched cohort, the 5-year OS of the patients who had and had not undergone LPLND were 68.9 and 62.0 %, respectively (p = 0.013; hazard ratio [HR], 0.755; 95 % confidence interval [CI], 0.604-0.944). The 5-year OS of the patients with node-negative disease who had and had not received LPLND differed statistically significantly (5-year OS were 82.1 and 71.4 %, respectively. p = 0.006; HR, 0.579; 95 % CI 0.389-0.862). However, those with node-positive disease did not differ significantly (5-year OS were 55.5 and 53.8 %, respectively. p = 0.415; HR 0.893; 95 % CI 0.681-1.172).

CONCLUSIONS

The impact of LPLND on OS for patients with node-negative pT3/T4 low rectal cancer was suggested in this retrospective cohort study. To determine true benefits and harms of LPLND, further prospective studies may be warranted.

Radiation dose intensification in pre-operative chemo-radiotherapy for locally advanced rectal cancer

BACKGROUND

To assess the role of radiation dose intensification with simultaneous integrated boost guided by 18-FDG-PET/CT in pre-operative chemo-radiotherapy (ChT-RT) for locally advanced rectal cancer.

METHODS

A prospective study was approved by the Internal Review Board. Inclusion criteria were: age >18 years old, World Health Organization performance status of 0-1, locally advanced histologically proven adenocarcinoma of the rectum within 10 cm of the anal verge, signed specific informed consent. High-dose volumes were defined including the hyper-metabolic areas of 18-FDG-PET/CT of primary tumor and the corresponding mesorectum and/or pelvic nodes with at least a standardized uptake values (SUV) of 5. A dose of 60 Gy/30 fractions was delivered. A total dose of 54 Gy/30 fractions was delivered to prophylactic areas. Capecitabine was administered concomitantly with RT for a dose of 825 mg/mq twice daily for 5 days/every week.

RESULTS

Between September 2011 and July 2015 fortypatients were recruited. At the time of the analysis, median follow up was 20 months (range 5-51). The median interval from the end of ChT-RT to surgery was 9 weeks (range 8-12). Thirty-seven patients (92.5 %) were submitted to sphincter preservation. Tumor Regression Grade (Mandard scale) was recorded as follows: grade 1 in 7 (17.5 %), grade 2 in 17 (42.5 %), grade 3 in 15 (37.5 %) and grade 4 in 1 (2.5 %). Post-surgical circumferential resection margin was negative in all patients. A tumor downstaging was reported in 62.5 % (95 % CI: 0.78-0.47). A nodes downstaging was registered in 85 % (95 % CI: 0.55-0.25). 18-FDG-PET/CT was not able to predict pCR. No correlation was found between pre-treatment SUV-max values and pCR. A metabolic tumor volume >127 cc was related to ypT ≥2 (p 0.01). Patients with TRG >2 had higher tumor lesion glycolysis values (p 0.05).

CONCLUSION

Preliminary results did not confirm some advantages in terms of primary tumor downstaging/downsizing compared to conventional schedules reported in historical series. The role of 18-FDG-PET/CT in neoadjuvant rectal cancer management needs to be confirmed in further investigations. Long terms results are necessary.

Lateral pelvic lymph node dissection after neoadjuvant chemo-radiation for preoperative enlarged lateral nodes in advanced low rectal cancer: study protocol for a randomized controlled trial

BACKGROUND

Lateral lymph node (LLN) metastasis is a major cause of local recurrence of advanced rectal cancer. Although there is much controversy between Western and Eastern countries on whether lateral pelvic lymph node dissection (LLND) or neoadjuvant chemo-radiation (nCRT) is preferable for the treatment of LLN metastases, existing retrospective cohorts mainly focus on all middle/low advanced rectal cancer patients, not the specific individuals with suspicion of LLN metastases. The aim of this trial is to assess the efficacy and safety of LLND for rectal cancer patients with suspicion of LLN metastases.

METHODS

This prospective, multicenter, randomized controlled, single-blinded, phase III trial is designed to enroll 512 eligible patients with advanced rectal cancer and preoperative enlarged lateral lymph nodes. The population will be randomly assigned into the solely total mesorectal excision (TME) group or the TME + LLND group after eligible selection. The primary outcomes are to be 3-year local recurrence rate and 3-year disease-free survival, and the secondary outcomes include 3-year overall survival, 1-year sexual and urinary function, and perioperative outcomes.

DISCUSSION

This is the first randomized trial to investigate the efficacy and safety of LLND for advanced low rectal cancer patients with suspicion of LLN metastases; the result is expected to provide new evidence for the treatment of LLN where there is suspicion of metastases in advanced rectal cancer patients.

TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (identifier NCT02614157 ) Registered on 24 November 2015.

Obturator Canal Lymph Node Metastasis from Rectal Carcinoid Tumors: Total Mesorectal Excision May Be Insufficient

BACKGROUND

Optimal surgical treatment for small early rectal carcinoids is controversial. Large tumors (greater than 2 cm) and those with imaging evidence of lymph node metastasis are generally treated by low anterior resection (LAR) with total mesorectal excision (TME). We first observed and reported that midgut carcinoid with extensive mesenteric lymphadenopathy often develops alternated lymphatic drainage pathways. We hypothesize that rectal carcinoids have the same potential to develop alternated lymphatic pathways outside the mesorectal envelope, which allows tumor deposits to be missed by traditional TME.

METHODS

Twenty-two consecutive rectal carcinoid surgical patient charts were reviewed to determine if alternated lymphatic drainage occurred and resulted in extra-mesorectal metastasis. We attempted to identify any risk factor(s) that may lead to developing such alternated lymphatic drainage pathways.

RESULTS

Thirteen patients underwent initial LAR with TME (13/22, 59 %) and nine underwent a staged debulking for locoregional residual disease or regional/distant metastasis after previous resection (9/22, 41 %). Fourteen (14/22, 64 %) underwent radio-guided surgery in attempt to achieve a higher level of pelvic/distant metastatic disease detection and debulking. Six patients (6/22, 27 %) had obturator canal lymph node metastases confirmed histologically.

CONCLUSIONS

Based on our study, at least 27 % of rectal carcinoid patients may have extra-mesorectal metastasis that would be missed by the traditional TME. Radio-guided surgery can identify and remove such metastasis. The effect of having such extra-mesorectal metastasis and its surgical removal on long-term survival has yet to be determined.

Is lateral pelvic node dissection necessary after preoperative chemoradiotherapy for rectal cancer patients with initially suspected lateral pelvic node?

BACKGROUND

Little is known about the effect of lateral pelvic node dissection after preoperative chemoradiotherapy on rectal cancer patients with initially suspected lateral pelvic nodes. The purpose of this study was to identify a subgroup of patients receiving preoperative chemoradiotherapy who can benefit from lateral pelvic node dissection.

METHODS

The study included 580 patients who underwent preoperative chemoradiotherapy and total mesorectal excision. The lateral pelvic node responses to preoperative chemoradiotherapy were divided: group I (no suspected lateral pelvic node), lateral pelvic node <5 mm pre- and post-chemoradiotherapy; group II (responsive lateral pelvic node), lateral pelvic node ≥5 mm pre-chemoradiotherapy but <5 mm post-chemoradiotherapy; and group III (persistent lateral pelvic node), lateral pelvic node ≥5 mm pre- and post-chemoradiotherapy. Prognostic factors for lateral pelvic node recurrence-free survival, locoregional recurrence-free survival, relapse-free survival, and overall survival were analyzed.

RESULTS

In a multivariate analysis, lateral pelvic node response was an independent factor associated with lateral pelvic node recurrence-free survival, locoregional recurrence-free survival, relapse-free survival, and overall survival (P < .05). Group III had significantly poorer lateral pelvic node recurrence-free survival, locoregional recurrence-free survival, relapse-free survival, and overall survival than groups II and I (74.1%, 93.4%, and 98.6%; 71.7%, 89.4%, and 97%; 56.9%, 76.6%, and 81.7%; 74.9%, 85.7%, and 89.1%, respectively; P < .05). Group II tended to have poorer lateral pelvic node recurrence-free survival, locoregional recurrence-free survival, relapse-free survival, and overall survival than group I, and the differences in relapse-free survival and overall survival between the 2 groups were not significant (P > .05).

CONCLUSION

Our data suggest that the subgroup with lateral pelvic nodes responsive to preoperative chemoradiotherapy may not benefit from lateral pelvic node dissection, and the subgroup with persistent lateral pelvic node may benefit from lateral pelvic node dissection.

Can chemoradiation allow for omission of lateral pelvic node dissection for locally advanced rectal cancer?

OBJECTIVES

We evaluated the relationship between pretreatment clinical parameters and lateral pelvic node (LPN) recurrence in patients with rectal cancer treated with a combination of curative resection and chemoradiotherapy (CRT) and attempted to identify the patients who might benefit from LPN dissection.

METHODS

This study involved 900 patients between June 2001 and June 2009. Pretreatment clinical parameters including radiological size of LPN were analyzed to identify risk factors associated with long-term outcomes.

RESULTS

Locoregional recurrence developed in 65 patients (7.2%); 42 (64.6%) had LPN recurrence, 20 (47.6%) of which had no distant metastasis. Multivariate analysis showed that LPN short-axis diameter (<5, 5-<10, and ≥10 mm) was significantly associated with LPN recurrence-free survival (5-year survival rate (5YSR), 98.2, 91.7, and 40.1%, respectively, P < 0.05), locoregional recurrence-free survival (5YSR, 95.5, 87.6, and 40.1%, respectively, P < 0.05), relapse-free survival (5YSR, 76.8, 72.5, and 30.3, respectively, P < 0.05), and overall survival (5YSR, 86.3, 83.0, and 57.5%, respectively, P < 0.05).

CONCLUSIONS

Patients with an LPN short-axis diameter ≥10 mm represent a potential subgroup at a high risk of LPN recurrence, even after CRT. Further study is needed to confirm whether LPN dissection is beneficial for these patients.

Prognostic significance of lateral lymph node dissection in node positive low rectal carcinoma

PURPOSE

This study was performed to identify patients who would benefit from lateral lymph node (LLN) dissection for advanced low rectal carcinoma.

METHODS

Clinical outcomes were retrospectively studied in 149 patients with node positive low rectal carcinoma undergoing LLN dissection according to LLN status: patients with (group II) or without positive LLNs (group I), and the number (≤3, >3), side (unilateral, bilateral), and site of positive LLNs.

RESULTS

The overall 5-year survival rate was significantly worse in group II (36.2%) than that in group I (69.8%). The 5-year survival rate was significantly worse in patients with >3 positive LLNs, bilateral positive LLNs, and positive LLNs in both areas B and C (high-risk group) than that in patients with ≤3 positive LLNs, unilateral positive LLNs, and positive LLNs in either area B or C. The 5-year survival rate was significantly better in patients without any high-risk factors (54.2%, low-risk group II) than that in patients who belonged to the high-risk group (12.3%). There was no significant difference in 5-year survival rate between group I and low-risk group II. There were significantly more well and moderately differentiated adenocarcinoma, tumors with less than minimal lymphatic invasion, and tumors with less than six involved LNs in the mesorectum in low-risk group II than in high-risk group II.

CONCLUSIONS

LLN dissection for low rectal carcinoma was effective for patients with fewer than four positive unilateral LLNs in either area B or C.

Rectal cancer surgery and regional lymph nodes

In patients with rectal cancer, the status of regional or mesorectal lymph nodes is central to both tumor staging and predicting local and distant recurrence. The importance of mesorectal lymph nodes in rectal cancer should inform treatment decisions around pre-operative diagnostic imaging, surgical techniques, pathologic assessment, and the use of radiation therapy.

Prognostic value of lateral lymph node metastasis for advanced low rectal cancer

AIM

To evaluate the risk factors for lateral lymph node metastasis in patients with advanced low rectal cancer, in order to make the effective selection of patients who could benefit from lateral lymph node dissection, as well as the relationship of lateral lymph node metastasis with local recurrence and survival of patients with advanced low rectal cancer.

METHODS

A total of 96 consecutive patients who underwent curative surgery with lateral pelvic lymphadenectomy for advanced lower rectal cancer were retrospectively analyzed. The relation of lateral lymph node metastasis with clinicopathologic characteristics, local recurrence and survival of patients was identified.

RESULTS

Lateral lymph node metastasis was observed in 14.6% (14/96) of patients with advanced low rectal cancer. Lateral lymph node metastasis was detected in 10 (25.0%) of 40 patients with tumor diameter >or= 5 cm and in 4 (7.1%) of 56 patients with tumor diameter < 5 cm. The difference between the two groups was statistically significant (c2 = 5.973, P = 0.015). Lateral lymph node metastasis was more frequent in patients with 4/4 diameter of tumor infiltration (7 of 10 cases, 70.0%), compared with patients with 3/4, 2/4 and 1/4 diameter of tumor infiltration (3 of 25 cases, 12.0%; 3 of 45 cases, 6.7%; 1 of 16 cases, 6.3%) (c2 = 27.944, P = 0.0001). The lateral lymph node metastasis rate was 30.0% (9 of 30 cases), 9.1% (4 of 44 cases) and 4.5% (1 of 22 cases) for poorly, moderately and well-differentiated carcinoma, respectively. The difference between the three groups was statistically significant (c2 = 8.569, P = 0.014). Local recurrence was 18.8% (18 of 96 cases), 64.3% (9 of 14 cases), and 11.0% (9 of 82 cases) in patients with advanced low rectal cancer, in those with and without lateral lymph node metastasis, respectively. The difference between the two groups was statistically significant (c2 = 22.308, P = 0.0001). Kaplan-Meier survival analysis showed significant improvements in median survival (80.9 +/- 2.1 m, 95% CI: 76.7-85.1 m vs 38 +/- 6.7 m, 95% CI: 24.8-51.2 m) of patients without lateral lymph node metastasis compared with those with lateral lymph node metastasis (log-rank, P = 0.0001).

CONCLUSION

Tumor diameter, infiltration and differentiation are significant risk factors for lateral lymph node metastasis. Lateral pelvic lymphadenectomy should be performed following surgery for patients with tumor diameter >or= 5 cm. Lateral lymph node metastasis is an important predictor for local recurrence and survival in patients with advanced low rectal cancer.

The incidence of lateral pelvic side-wall nodal involvement in low rectal cancer may be similar in Japan and the West

BACKGROUND

There is an East-West divide with regard to the frequency, significance and management of lateral pelvic side-wall nodes associated with low rectal cancer. In Japan, removal of nodes is considered essential in curative treatment of selected patients. In the West, involved nodes are generally considered as metastatic disease. There may be international differences in rectal cancer behaviour.

METHODS

A review of relevant studies was undertaken using PubMed, Cochrane Library and personal archives of references; further cross-referencing was conducted. Historical developments, relevant anatomy and reports on lateral pelvic lymphadenectomy (LPLD) were identified. Outcomes following LPLD were assessed.

RESULTS

The low rectum has lateral lymphatic drainage. Enhanced pelvic imaging techniques suggest that some patients with low rectal cancer have lateral pelvic lymph node involvement. However, there is no universal agreement on the definition of either the rectum or low rectal cancer. Selective use of LPLD has led to good outcomes in Japan. An alternative strategy might be neoadjuvant therapy for involved lateral nodes.

CONCLUSION

Pelvic imaging and correlation with pathological findings are crucial in the assessment of lateral pelvic side-wall nodes. East and West should combine their experience of preoperative staging, surgical treatment and pathological assessment of low rectal cancer.

Prognostic value of lateral lymph node metastasis for advanced low rectal cancer

AIM: To evaluate the risk factors for lateral lymph node metastasis in patients with advanced low rectal cancer, in order to make the effective selection of patients who could benefit from lateral lymph node dissection, as well as the relationship of lateral lymph node metastasis with local recurrence and survival of patients with advanced low rectal cancer.

METHODS: A total of 96 consecutive patients who underwent curative surgery with lateral pelvic lymphadenectomy for advanced lower rectal cancer were retrospectively analyzed. The relation of lateral lymph node metastasis with clinicopathologic characteristics, local recurrence and survival of patients was identified.

RESULTS: Lateral lymph node metastasis was observed in 14.6% (14/96) of patients with advanced low rectal cancer. Lateral lymph node metastasis was detected in 10 (25.0%) of 40 patients with tumor diameter ≥ 5 cm and in 4 (7.1%) of 56 patients with tumor diameter < 5 cm. The difference between the two groups was statistically significant (χ² = 5.973, P = 0.015). Lateral lymph node metastasis was more frequent in patients with 4/4 diameter of tumor infiltration (7 of 10 cases, 70.0%), compared with patients with 3/4, 2/4 and 1/4 diameter of tumor infiltration (3 of 25 cases, 12.0%; 3 of 45 cases, 6.7%; 1 of 16 cases, 6.3%) (χ² = 27.944, P = 0.0001). The lateral lymph node metastasis rate was 30.0% (9 of 30 cases), 9.1% (4 of 44 cases) and 4.5% (1 of 22 cases) for poorly, moderately and well-differentiated carcinoma, respectively. The difference between the three groups was statistically significant (χ² = 8.569, P = 0.014). Local recurrence was 18.8% (18 of 96 cases), 64.3% (9 of 14 cases), and 11.0% (9 of 82 cases) in patients with advanced low rectal cancer, in those with and without lateral lymph node metastasis, respectively. The difference between the two groups was statistically significant (χ² = 22.308, P = 0.0001). Kaplan-Meier survival analysis showed significant improvements in median survival (80.9 ± 2.1 m, 95% CI: 76.7-85.1 m vs 38 ± 6.7 m, 95% CI: 24.8-51.2 m) of patients without lateral lymph node metastasis compared with those with lateral lymph node metastasis (log-rank, P = 0.0001).

CONCLUSION: Tumor diameter, infiltration and differentiation are significant risk factors for lateral lymph node metastasis. Lateral pelvic lymphadenectomy should be performed following surgery for patients with tumor diameter ≥ 5 cm. Lateral lymph node metastasis is an important predictor for local recurrence and survival in patients with advanced low rectal cancer.

Lateral lymph node metastasis is a major cause of locoregional recurrence in rectal cancer treated with preoperative chemoradiotherapy and curative resection

BACKGROUND

In rectal cancer patients treated with preoperative chemoradiotherapy (CRT) and curative resection, we evaluated the effect of clinical parameters on lateral pelvic recurrence and made an attempt to identify a risk factor for lateral pelvic recurrence.

METHODS

The study involved 366 patients who underwent preoperative CRT and curative resection between October 2001 and December 2005. Clinical parameters such as gender, age, tumor size, histologic type, cT and cN classification, ypT and ypN classification, circumferential resection margin, tumor regression grade, chemotherapeutic regimen, and lateral lymph node size were analyzed to identify risk factors associated with lateral pelvic recurrence.

RESULTS

Of the 366 patients, 29 patients (7.9%) had locoregional recurrence: 6 (20.7%) with central pelvic recurrence and 24 (82.7%) had lateral pelvic recurrence, of which 1 had simultaneous central and lateral pelvic recurrence. Multivariate analysis showed that ypN classification and lateral lymph node size were significantly associated with lateral pelvic recurrence (P < .001). Of 250 ypN0 patients, lateral pelvic recurrence developed in 1.4%, 2.9%, and 50% of patients with lateral lymph node sizes of < 5, 5-9.9, and > or = 10 mm, respectively (P < .001). Of 116 ypN+ patients, lateral pelvic recurrence developed in 4.3%, 35.7%, and 87.5% of patients with lateral lymph node sizes of < 5, 5-9.9, and > or = 10 mm, respectively (P < .001).

CONCLUSIONS

In our study, lateral pelvic recurrence was a major cause of locoregional recurrence, and ypN+ and lateral lymph node size were risk factors for lateral pelvic recurrence.