Lymph node ratio: a confounded quotient

Lymph Node Parameters Predict Adjuvant Chemoradiotherapy Efficacy and Disease-Free Survival in Pathologic N2 Non-Small Cell Lung Cancer

Pathologic N2 non-small cell lung cancer (NSCLC) is prominently intrinsically heterogeneous. We aimed to identify homogeneous prognostic subgroups and evaluate the role of different adjuvant treatments. We retrospectively collected patients with resected pathologic T1-3N2M0 NSCLC from the Shanghai Chest Hospital as the primary cohort and randomly allocated them (3:1) to the training set and the validation set 1. We had patients from the Fudan University Shanghai Cancer Center as an external validation cohort (validation set 2) with the same inclusion and exclusion criteria. Variables significantly related to disease-free survival (DFS) were used to build an adaptive Elastic-Net Cox regression model. Nomogram was used to visualize the model. The discriminative and calibration abilities of the model were assessed by time-dependent area under the receiver operating characteristic curves (AUCs) and calibration curves. The primary cohort consisted of 1,312 patients. Tumor size, histology, grade, skip N2, involved N2 stations, lymph node ratio (LNR), and adjuvant treatment pattern were identified as significant variables associated with DFS and integrated into the adaptive Elastic-Net Cox regression model. A nomogram was developed to predict DFS. The model showed good discrimination (the median AUC in the validation set 1: 0.66, range 0.62 to 0.71; validation set 2: 0.66, range 0.61 to 0.73). We developed and validated a nomogram that contains multiple variables describing lymph node status (skip N2, involved N2 stations, and LNR) to predict the DFS of patients with resected pathologic N2 NSCLC. Through this model, we could identify a subtype of NSCLC with a more malignant clinical biological behavior and found that this subtype remained at high risk of disease recurrence after adjuvant chemoradiotherapy.

The prognostic value of lymph node ratio in patients with surgically resected stage I-III small-cell lung cancer: a propensity score matching analysis of the SEER database

OBJECTIVES

Due to the lack of prospective studies, the role of the lymph node ratio (LNR) in small-cell lung cancer (SCLC) remains unknown. This study aimed to assess the prognostic effect of LNR in surgically resected stage I-III SCLC patients.

METHODS

Clinical data of stage I-III (excluding N3 and NX) SCLC patients diagnosed between 1998 and 2016 were extracted from the Surveillance, Epidemiology and End Results database. Patients were divided into low-risk and high-risk subsets based on the LNR cut-off value of 0.15 using X-tile software. Propensity score matching analysis was employed to reduce bias in baseline characteristics. Kaplan-Meier analysis was performed to determine the overall survival (OS) and lung cancer-specific survival (LCSS). Cox regression analysis was performed to evaluate the effects of multiple variables.

RESULTS

A total of 978 patients were identified, of whom 669 (68.40%) had LNR ≤0.15. Patients with LNR ≤0.15 showed better OS (P < 0.001) and LCSS (P < 0.001) both before and after propensity score matching. Multivariable analyses of the matched population confirmed LNR as an independent prognostic factor. Patients with LNR >0.15 showed poorer OS [hazard ratio (HR) 1.55, 95% confidence interval (CI) 1.09-2.19; P = 0.015] and LCSS (HR 1.65, 95% CI 1.13-2.43; P = 0.010). Subgroup analyses revealed that LNR ≤0.15 was associated with favourable OS (P = 0.009 and 0.197, respectively) and LCSS (P = 0.010 and 0.169, respectively) in N1 and N2 patients.

CONCLUSIONS

LNR was determined as an independent predictor for surgically resected stage I-III SCLC, indicating that higher LNR is associated with reduced survival. The predictive value of LNR should to be further validated in prospective studies.

Residual lymph node disease and mortality following neoadjuvant chemoradiation and curative esophagectomy for distal esophageal adenocarcinoma

Objectives

Neoadjuvant chemoradiation has been shown to improve survival in locally advanced esophageal and gastroesophageal junction cancer. The purpose of our study was to examine the effects of posttreatment persistent lymph node (LN) disease on overall survival (OS) and recurrence in patients with esophageal adenocarcinoma after neoadjuvant chemoradiation as well as the effect of LN harvest and the potential benefit of adjuvant chemotherapy.

Methods

The records of patients who underwent esophagectomy in our hospital from January 2005 until December 2016 were analyzed. Our study group consisted of 509 patients.

Results

Patient groups were created based on pathologic staging after esophagectomy (ypT N) as 22.0% of patients were ypT0 N0, 46.2% had incomplete response only at the primary tumor level (ypT + N0), and 31.8% had at least 1 metastatic lymph node (ypTx N+). Median OS was 58.3 months. The ypTx N+ group was divided into ypTx N1 and ypTx N2 or N3 subgroups based on the number of metastatic lymph nodes. The OS between the 2 groups was not significantly different (median OS, 37.6 vs 29.8 months; P = .097). The disease-free survival did show a statistically significant difference (median disease-free survival, 27.6 vs 13.7 months; P = .007). The LN harvest was not found to be significantly associated with OS. However, administration of adjuvant chemotherapy was a significant prognosticator for increased OS (hazard ratio, 0.590; P = .043).

Conclusions

Our results demonstrate that residual LN disease after neoadjuvant chemoradiation is associated with increased mortality. Adjuvant chemotherapy, but not number of LNs resected, was correlated with increased OS in this subset of patients.

[Correlation between Lymph Node Ratio and Clinicopathological Features and Prognosis of IIIa-N2 Non-small Cell Lung Cancer]

BACKGROUND

IIIa-N2 non-small cell lung cancer was significant different in survival, although N stage of lung cancer based on anatomic location of metastasis lymph node. Lymph node ratio considered of prognostic factor might be the evaluation index for IIIa-N2 non-small cell lung cancer prognosis. Therefore, the aim of the study was to evaluate the correlation between lymph node ratio and clinicopathological features and prognosis of IIIa-N2 non-small cell lung cancer prognosis.

METHODS

A total of 288 cases of pathological IIIa-N2 non-small cell lung cancer were enrolled who received radical resection at the Department of Thoracic Surgery II, Peking University Cancer Hospital from January 2006 to December 2016. The univariate analysis between clinicopathological variables and lymph node ratio used Pearson's chi-squared test. Cox regression was conducted to identify the independent prognosis factors for IIIa-N2 non-small cell lung cancer.

RESULTS

There were 139 cases in the lower lymph node ratio group, another 149 cases in the higher lymph node ratio group. Adenocarcinoma (χ²=5.924, P=0.015), highest mediastinal lymph node metastasis (χ²=46.136, P<0.001), multiple-number N2 metastasis (χ²=59.347, P<0.001), multiple-station N2 metastasis (χ²=77.387, P<0.001) and skip N2 lymph node metastasis (χ²=61.524, P<0.001) significantly impacted lymph node ratio. The total number of lymph node dissection was not correlated with the lymph node ratio (χ²=0.537, P=0.464). Cox regression analysis confirmed that adenocarcinoma (P=0.008), multiple-number N2 metastasis (P=0.025) and lymph node ratio (P=0.001) were the independent prognosis factors of disease free survival. The 5-year disease free survival was 18.1% in the higher lymph node ratio group, and 44.1% in the lower. Lymph node ratio was the independent prognosis factor of overall survival (P<0.001). The 5-year overall survival was 36.7% in the higher lymph node ratio group, and 64.1% in the lower.

CONCLUSIONS

Lymph node ratio was correlative with the pathology, highest mediastinal lymph node metastasis, multiple-number N2 metastasis, multiple-station N2 metastasis and skip N2 lymph node metastasis. Lymph node ratio was the independent prognosis factor for IIIa-N2 non-small cell lung cancer.

Strategies of nodal staging of the TNM system for esophageal cancer

The 8^th edition of UICC/AJCC TNM staging for esophageal cancer will start in use since 2018. The nodal staging in this version of TNM system remains unchanged from the 7^th edition that based on the number of lymph nodes (LN) involved, except the limited revision of the regional LN map. In this review, N staging revision was evaluated from its initially simple definition of negative (N0) and positive (N1) LN(s) to the current positive node number based proposal. Meanwhile the disadvantages of current N staging were discussed. The refined nodal staging system in view of the number of metastatic node stations was introduced; as well as the extent and station of metastatic node could better reflect the disease progression and prognosis. The controversy on N staging of esophagogastric junction cancer was also discussed. Other reported N staging associated elements including LN ratio and lymphatic vessel invasion were reviewed and evaluated.

A nomogram to predict the survival of stage IIIA-N2 non-small cell lung cancer after surgery

OBJECTIVE

Postoperative survival of patients with stage IIIA-N2 non-small cell lung cancer (NSCLC) is highly heterogeneous. Here, we aimed to identify variables associated with postoperative survival and develop a tool for survival prediction.

METHODS

A retrospective review was performed in the Surveillance, Epidemiology, and End Results database from January 2004 to December 2009. Significant variables were selected by use of the backward stepwise method. The nomogram was constructed with multivariable Cox regression. The model's performance was evaluated by concordance index and calibration curve. The model was validated via an independent cohort from the Jiangsu Cancer Hospital Lung Cancer Center.

RESULTS

A total of 1809 patients with stage IIIA-N2 NSCLC who underwent surgery were included in the training cohort. Age, sex, grade, histology, tumor size, visceral pleural invasion, positive lymph nodes, lymph nodes examined, and surgery type (lobectomy vs pneumonectomy) were identified as significant prognostic variables using backward stepwise method. A nomogram was developed from the training cohort and validated using an independent Chinese cohort. The concordance index of the model was 0.673 (95% confidence interval, 0.654-0.692) in training cohort and 0.664 in validation cohort (95% confidence interval, 0.614-0.714). The calibration plot showed optimal consistency between nomogram predicted survival and observed survival. Survival analyses demonstrated significant differences between different subgroups stratified by prognostic scores.

CONCLUSIONS

This nomogram provided the individual survival prediction for patients with stage IIIA-N2 NSCLC after surgery, which might benefit survival counseling for patients and clinicians, clinical trial design and follow-up, as well as postoperative strategy-making.

Siewert III adenocarcinoma: treatment update

Siewert III cancer, although representing around 40% of EGJ cancers and being the EGJ cancer with worst prognosis, does not have a homogenous treatment, has few dedicated studies, and is often not considered in study protocols. Although staged as an esophageal cancer by the TNM 7th ed., it is considered a gastric cancer by new TNM 8th ed. Our aim was to consolidate the current literature on the indications and treatment options for Siewert III adenocarcinoma. A review of the literature was performed to better delineate treatment indications (according to stage, surgical margins, type of lymphatic spread and lymphadenectomy) and treatment strategy. The treatment approach is strictly dependent on cancer site and nodal diffusion. T1m cancers have insignificant risk of nodal metastases and can be safely treated with endoscopic resections. The risk of nodal metastases increases markedly starting from T1sm cancers and requires surgery with lymphadenectomy. The site of this type of cancer and the nodal diffusion require a total gastrectomy and distal esophagectomy, with 5 cm of clear proximal and distal margins and a D2 abdominal and inferior mediastinal lymphadenectomy. Multimodal treatments are indicated in all locally advanced and node positive cancers. Siewert III cancers are gastric cancers with some peculiarities and require dedicated studies and deserve more consideration in the current literature, especially because their treatment is particularly challenging.

Esophageal Cancer: Associations With (pN+) Lymph Node Metastases

OBJECTIVES

To identify the associations of lymph node metastases (pN+), number of positive nodes, and pN subclassification with cancer, treatment, patient, geographic, and institutional variables, and to recommend extent of lymphadenectomy needed to accurately detect pN+ for esophageal cancer.

SUMMARY BACKGROUND DATA

Limited data and traditional analytic techniques have precluded identifying intricate associations of pN+ with other cancer, treatment, and patient characteristics.

METHODS

Data on 5806 esophagectomy patients from the Worldwide Esophageal Cancer Collaboration were analyzed by Random Forest machine learning techniques.

RESULTS

pN+, number of positive nodes, and pN subclassification were associated with increasing depth of cancer invasion (pT), increasing cancer length, decreasing cancer differentiation (G), and more regional lymph nodes resected. Lymphadenectomy necessary to accurately detect pN+ is 60 for shorter, well-differentiated cancers (<2.5 cm) and 20 for longer, poorly differentiated ones.

CONCLUSIONS

In esophageal cancer, pN+, increasing number of positive nodes, and increasing pN classification are associated with deeper invading, longer, and poorly differentiated cancers. Consequently, if the goal of lymphadenectomy is to accurately define pN+ status of such cancers, few nodes need to be removed. Conversely, superficial, shorter, and well-differentiated cancers require a more extensive lymphadenectomy to accurately define pN+ status.

Lymph Node Ratio Is Less Prognostic in Melanoma When Minimum Node Retrieval Thresholds Are Not Met

BACKGROUND

Lymph node ratio (LNR), positive nodes divided by nodes examined, has been proposed for prognostication in melanoma to mitigate problems with low node counts. However, it is unclear if LNR offers superior prognostication over total counts of positive nodes and nodes examined. Additionally, the prognostic value of LNR may change if a threshold number of nodes are examined. We evaluated whether LNR is more prognostic than positive nodes and nodes examined, and whether the prognostic value of LNR changes with minimum thresholds.

METHODS

Using the National Cancer Data Base Participant User File, we identified 74,692 incident cases with nodal dissection during 2000-2006. We compared LNR versus counts of examined and positive nodes based on Harrell's C, a measure of predictive ability. We then stratified by total nodes examined: greater versus fewer than ten for axillary lymph node dissection (ALND) and greater versus fewer than five for inguinal lymph node dissection (ILND).

RESULTS

Overall, LNR had a Harrell's C of 0.628 (95 % confidence interval [CI] 0.625-0.631). Examined and positive nodes were not significantly different from this, with a Harrell's C of 0.625 (95 % CI 0.621-0.630). In ALND, LNR had a Harrell's C of 0.626 (95 % CI 0.610-0.643) with ≥10 nodes versus 0.554 (95 % CI 0.551-0.558) < 10 nodes. In ILND, LNR had a Harrell's C of 0.679 (95 % CI 0.664-0.694) with ≥5 nodes versus C of 0.601 (95 % CI 0.595-0.606) < 5 nodes.

CONCLUSIONS

LNR provides no prognostic superiority versus counts of examined and positive nodes. Moreover, the prognostic value of LNR diminishes when minimum node retrieval thresholds are not met.