Metastatic lymph node ratio as a prognostic factor after laparoscopic total mesorectal excision for extraperitoneal rectal cancer

The effect of lymph node ratio on the surgical outcomes in patients with colorectal cancer

The current study aimed to evaluate the effect of lymph node ratio (LNR) on the short-term and long-term outcomes of colorectal cancer (CRC) patients who underwent radical CRC surgery. We retrospectively collected CRC patients who underwent radical surgery from Jan 2011 to Jan 2020 in a single-center hospital. The patients were divided into the high LNR group and the low group according to the median. The baseline information and the short-term outcomes were compared between the high group and the low group. Univariate and multivariate logistic regression was performed to analyze the independent predictors for overall survival (OS) and disease-free survival (DFS). A 1:1 proportional propensity score matching (PSM) was used to reduce the selection bias between the two groups. Kaplan-Meier method was used to estimate the OS and DFS between the two groups in different T stages. A total of 1434 CRC patients undergoing radical surgery were enrolled in this study, and there were 730 (50.9%) patients in the low LNR group and 704 (49.1%) patients in the high LNR group. After the PSM, there were 618 patients in both groups, the baseline characteristics between the two groups had no significant difference (p > 0.05). After comparing the Surgery-related information and The Short-term outcomes, the high LNR group had a longer hospital stay (after PSM, p < 0.01). In univariate and multivariate logistic regression analyses, age (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor location (univariate analysis, p = 0.020; multivariate analysis, p = 0.024), lymph-vascular space invasion (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), cancer nodules (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor size (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), LNR (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), and overall complications (univariate analysis, p < 0.01; multivariate analysis, p < 0.01) were independent risk factors for OS, and age (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), tumor location (univariate analysis, p = 0.032; multivariate analysis, p = 0.031), T stage (univariate analysis, p < 0.01; multivariate analysis, p = 0.014), lymph-vascular space invasion (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), cancer nodules (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), LNR (univariate analysis, p < 0.01; multivariate analysis, p < 0.01), and overall complications (univariate analysis, p < 0.01; multivariate analysis, p < 0.01) were identified as independent risk factors for DFS. The high LNR group had a worse OS in T3 (p < 0.01) and T4 (p < 0.01) as well as a worse DFS in T3 (p < 0.01) and T4 (p < 0.01). No association was found between LNR and postoperative complications, but the high LNR group had a longer hospital stay. LNR was identified as an independent predictor for OS and DFS. Furthermore, high LNR had a worse OS and DFS under T3 and T4 stages. Therefore, LNR was more prognostically significant for CRC patients under T3 and T4 stages.

Lymph Node Ratio as a Prognostic Marker in Rectal Cancer Survival: A Systematic Review and Meta-Analysis

Introduction 

The lymph node ratio (LNR) is defined as the ratio of the number of positive lymph nodes to the total number of nodes retrieved. LNR has recently emerged as a prognostic factor in rectal cancer. The objective of our study was to pool eligible studies to elucidate the prognostic role of LNR on overall survival (OS) and disease-free survival (DFS) in rectal cancer patients using a meta-analysis.

Methods

A systematic database search was performed in MEDLINE and Embase for relevant studies that reported LNR in rectal cancer. Two authors independently screened the relevant articles for selection and data extraction. As a result, a list of such studies and references, published in English up to December 2019, was obtained, and a total of 4,486 node-positive patients in 18 studies were included in this meta-analysis. RevMan software 5.3 (Cochrane Collaboration, the Nordic Cochrane Centre, Copenhagen) was used for conducting all statistical analyses.

Results

A higher LNR was significantly correlated with worse OS [hazard ratio (HR): 2.60; 95% confidence interval (CI): 2.21-3.06; p≤.00001] and DFS (HR: 2.43; 95% CI: 2.11-2.80; p≤.00001) in node-positive rectal cancer patients. Besides, LNR is an independent predictive and prognostic marker of OS and DFS (HR: 2.52; 95% CI: 2.17-2.94; p≤.00001 with I²=0%; p=.32 and HR: 2.63; 95% CI: 2.17-3.18; p≤.00001 with I²=0%; p=.63 respectively, irrespective of lymph nodal harvest).

Conclusions

Our present study demonstrates that LNR is an independent predictor of survival in rectal cancer. LNR should be considered as a parameter in future oncological staging systems. Further well-designed randomized control trials to prospectively assess LNR as an independent predictor of rectal cancer survival are necessary before its application in daily practice.

10-Year Oncologic Outcomes After Laparoscopic or Open Total Mesorectal Excision for Rectal Cancer

BACKGROUND

Only few studies have compared laparoscopic total mesorectal excision (LTME) and open total mesorectal excision (OTME) for rectal cancer with follow-up longer than 5 years. The aim of this study was to compare 10-year oncologic outcomes after LTME and OTME for nonmetastatic rectal cancer.

METHODS

We conducted a retrospective analysis of a prospective database of rectal cancer patients undergoing LTME or OTME. Statistical analyses were performed on an ''intention-to-treat'' basis and by actual treatment. Overall survival (OS) and disease-free survival (DFS) were compared by using the Kaplan-Meier method. A multivariable analysis was performed to identify predictors of poor survival.

RESULTS

Between April 1994 and August 2005, a total of 153 LTME patients and 154 OTME patients were included. Similarly, 10-year OS and DFS after LTME and OTME were observed: 76.8 versus 70.6 % (P = 0.138) and 69.1 versus 67.6 % (P = 0.508), respectively. Conversion to OTME did not adversely affect OS and DFS. Stage-by-stage comparison showed no significant differences between LTME and OTME. No significant differences were observed in local recurrence rates after LTME and OTME (6.5 vs. 7.8 %, P = 0.837). Median time until local recurrence was 24.5 (range, 12-56) months after LTME and 22 (6-64) months after OTME (P = 0.777). Poor tumor differentiation, lymphovascular invasion, and a lymph node ratio of 0.25 or more were the independent predictors of poorer OS and DFS.

CONCLUSION

This retrospective study with long follow-up did not show significant differences between the two groups in OS and DFS.

The lymph node ratio does not provide additional prognostic information compared with the N1/N2 classification in Stage III colon cancer

AIM

The ratio of positive nodes to total nodes, the lymph node ratio (LNR), is a proposed alternative to the current N1/N2 classification of nodal disease. The true clinical benefit of adopting the LNR, however, has not been definitively demonstrated. This study compared the LNR with the current N1/N2 classification of Stage III colon cancer.

METHOD

Patients with Stage III colon cancer were identified from a prospectively maintained database (1996-2012). The specificity and sensitivity of the N1/N2 classification in the prediction of overall survival were determined using R. A cut-off point for the LNR was determined by setting the specificity the same as for the N1/N2 classification. The sensitivity of the two methods was then compared, and bootstrapping 1000-fold was performed. This was then repeated for disease-specific survival.

RESULTS

The specificity and sensitivity of the N1/N2 classification in predicting 3-year overall survival in this cohort (n = 402) was 62.2% and 52.1%, respectively. The cut-off point for the LNR was determined to be 0.27 for these data. On comparing LNR with the N1/N2 classification showed that for a given specificity, the LNR did not provide a statistically significant improvement in sensitivity (52.8% vs 52.1%, P = 0.31). For disease-specific death at 3 years, the specificity and sensitivity were 60.8% and 54.6%, respectively. The LNR did not provide a statistically significant improvement (55.4% vs 54.6%, P = 0.44).

CONCLUSION

Both the N1/N2 system and the LNR predict survival in colon cancer, but both have low specificity and sensitivity. The LNR does not provide additional prognostic value to current staging for overall or disease-specific survival for a given cut-off point.

Prognostic value of lymph node ratio in patients with pathological N1 non-small cell lung cancer: a systematic review with meta-analysis

BACKGROUND

Non-small cell lung cancer (NSCLC) patients with N1 disease have variable outcomes, and additional prognostic factors are needed. The number of positive lymph nodes (LNs) has been proposed as a prognostic indicator. However, the number of positive LNs depends on the number of LNs examined from the resection specimen. The lymph node ratio (LNR) can circumvent this limitation. The purpose of this study is to evaluate LNR as a predictor of survival and recurrence in patients with pathologic N1 NSCLC.

METHODS

We systematically reviewed studies published before March 17, 2016, on the prognostic value of LNR in patients with pathologic N1 NSCLC. The hazard ratios (HRs) and their 95% confidence intervals (CIs) were used to combine the data. We also evaluated heterogeneity and publication bias.

RESULTS

Five studies published between 2010 and 2014 were eligible for this systematic review with meta-analysis. The total number of patients included was 6,130 ranging from 75 to 4,004 patients per study. The combined HR for all eligible studies evaluating the overall survival (OS) and disease-free survival (DFS) of N1 LNR in patients with pathologic N1 NSCLC was 1.53 (95% CI: 1.22-1.85) and 1.64 (95% CI: 1.19-2.09), respectively. We found no heterogeneity and publication bias between the reports.

CONCLUSIONS

LNR is a worthy predictor of survival and cancer recurrence in patients with pathological N1 NSCLC.

Prognostic value of metastatic N1 lymph node ratio and angiolymphatic invasion in patients with pathologic stage IIA non-small cell lung cancer

With regard to pathologic stage IIA (pIIA) non-small cell lung cancer (NSCLC), there is a paucity of literature evaluating the risk factors for disease-free survival (DFS) and overall survival (OS). The aim of this study was to identify the prognostic factors of DFS and OS in patients with NSCLC pIIA.We performed a retrospective review of 98 stage II patients (7th edition of the American Joint Committee on Cancer) who underwent lung resection from January 2005 to February 2011. Of these, 23 patients were excluded for this study because of loss of follow-up or different substage, and 75 patients with pIIA were included for further univariate and multivariate analysis. Risk factors for DFS and OS were analyzed, including age, gender, smoking history, operation method, histology, differential grade, visceral pleural invasion, angiolymphatic invasion, and metastatic N1 lymph node ratio (LNR).Of the 75 patients with pIIA NSCLC who were examined, 29 were female and 46 were male, with a mean age of 61.8 years (range: 34-83 years). The average tumor size was 3.188 cm (range: 1.10-6.0 cm). Under univariate analysis, angiolymphatic invasion and metastatic N1 LNR were risk factors for DFS (P = 0.011, P = 0.007). Under multivariate analysis, angiolymphatic invasion and metastatic N1 LNR were all independent risk factors for DFS, while adjuvant chemotherapy and higher metastatic N1 LNR were independent prognostic factors for OS.For patients with pIIA, higher metastatic N1 LNR and angiolymphatic invasion were related to poor DFS. In addition to DFS, higher metastatic N1 LNR was also a poor prognostic factor for OS rates and adjuvant therapy effectiveness. Clinical physicians should devise different postsurgical follow-up programs depending on these factors, especially for patients with high risk.

Laparoscopic versus open resection for colon cancer: 10-year outcomes of a prospective clinical trial

BACKGROUND

Laparoscopic resection (LR) and open resection (OR) for colon cancer have similar oncologic outcomes at 5-year follow-up. However, results from studies with longer follow-up are limited. This study aimed to compare 10-year oncologic outcomes of LR and OR for non-metastatic colon cancer.

METHODS

A prospective non-randomized trial comparing patients undergoing LR or OR for non-metastatic colon cancer at a single institution was conducted. Statistical analyses were performed on an ''intention-to-treat'' basis and by actual treatment. Kaplan-Meier curves were compared to analyze overall survival (OS) and disease-free survival (DFS). A multivariate analysis was performed to identify predictors of poor survival.

RESULTS

The study included 304 colon cancer patients: 154 patients underwent LR and 150 underwent OR. Fifteen (9.7 %) had LR converted to OR. During a median follow-up period of 138 (range, 120-220) months, no significant differences were observed between LR and OR patients in 10-year OS and DFS rates: 87.2 % versus 78.7 % (P = 0.182) and 80.9 % versus 76.8 % (P = 0.444), respectively. Conversion to open surgery was associated with a non-significant reduction in OS and DFS. Stage-by-stage comparison showed no significant differences between the two groups. Both OS and DFS were similar between right colon and left-sided colon cancer patients. On multivariate analysis, pT4 cancer and a lymph node ratio of 0.20 or more were the only independent predictors of both OS and DFS.

CONCLUSIONS

The 10-year follow-up results confirm the oncological effectiveness of the laparoscopic approach to non-metastatic colon cancer.