Impact of difference in the definition of extranodal spread on the outcome of node-positive patients with gastric cancer

Extra-nodal metastasis should be classified separately from lymph node metastasis in gastric cancer

INTRODUCTION

Extra-nodal metastasis (ENM) is defined as a tumor nodule without histological evidence of a lymph node structure. Although ENM has pathological features distinct from those of metastatic lymph nodes, both ENM and metastatic lymph nodes are considered within the same category in the pathological nodal (pN) classification. This study aimed to clarify the clinicopathological characteristics and prognostic relevance of ENM in gastric cancer patients who underwent curative gastrectomy.

MATERIALS AND METHODS

We retrospectively evaluated 1207 Japanese patients who underwent curative gastrectomy at a single center between January 2009 and December 2013. All resected specimens were fixed in 10% formalin, processed, and stained using hematoxylin and eosin, and subsequently reviewed by two pathologists. Survival times were analyzed using the Kaplan-Meier method, and independent prognostic factors were identified using a Cox proportional hazards regression model.

RESULTS

Patients who were ENM-positive had significantly poorer overall survival; multivariable analysis revealed that independent prognostic factors were older age (hazard ratio [HR]: 3.68, 95% confidence interval [CI]: 2.60-5.20), higher pathological tumor classification (HR: 2.28, 95% CI: 1.43-3.62), presence of metastatic lymph nodes (HR: 1.57, 95% CI: 1.0-2.36), and ENM-positive status (HR: 2.33, 95% CI: 1.48-3.66). ENM-positive patients had similar survival outcomes to those of ENM-negative patients with ≥16 metastatic lymph nodes.

CONCLUSIONS

Among Japanese patients with gastric cancer who underwent curative gastrectomy, ENM was an independent prognostic factor with a prognostic significance different from that of lymph node metastasis. These results suggest that ENM and lymph node metastasis should be classified separately.

Tumour deposits are a significant prognostic factor in gastric cancer - a systematic review and meta-analysis

AIMS

Tumour deposits (TDs) are clusters of cancer cells in the soft tissue that are discontinuous from the primary tumour. In this review we are exploring their relevance for prognosis in patients with gastric cancer.

METHODS AND RESULTS

A literature search was performed to identify studies providing data on TDs and prognosis in gastric cancer patients. Eight papers were included in the meta-analysis, which was carried out in terms of risk ratios (RR) and hazard ratios (HR) with 95% confidence interval (95% CI). Of 7445 patients, 1551 had TDs (20.9%). TDs were associated with a decreased overall survival (OS) in univariate (HR = 2.82, 95% CI = 1.9-4.3) and multivariate analyses (HR = 1.65, 95% CI = 1.3-2.1). TDs were also associated with known prognostic factors such as synchronous metastatic disease (RR = 9.5), invasion depth (RR = 1.8), lymph node metastasis (RR = 1.7), lymphatic invasion (RR = 1.7), vascular invasion (RR = 2.6) and poor differentiation (RR = 1.2).

CONCLUSIONS

We found a strong indication that TDs are independent predictors of prognosis in patients with gastric cancer; hence, TDs should be included in the staging of gastric cancers.

Prognostic significance and the role in TNM stage of extranodal metastasis within regional lymph nodes station in gastric carcinoma

The role of extranodal metastasis (ENM) in TNM stage in gastric carcinoma (GC) is controversial. This study was aimed to make a detailed investigation of the prognostic significance and the role in TNM stage of ENM in GC. The patients with primary GC, who underwent gastrectomy with curative intention in West China Hospital from January 2005 to December 2011, were retrospectively enrolled. The prognosis and clinicopathological traits were compared between ENM positive (ENMP) and negative (ENMN) groups in all patients, TNM I-II, III and IV stages, respectively. The significance of the number and the role in TNM stage of ENM were also assessed. In our study, 1457 patients were enrolled, with 1324 (90.9%) in ENMN group and 133 (9.1%) in ENMP group. ENMP group had significantly more advanced GC and worse prognosis (all p<0.05) than ENMN group in all patients, TNM I-II stages and TNM III stage. ENM>2 subgroup had remarkably larger tumor size (p=0.002) and more advanced N stage (p=0.016) than ENM=1-2 subgroup. The number of ENM was an independent prognostic factor in ENMP group (p=0.029). The prognosis of ENM>2 in TNM I-III stages was significantly worse than ENMN patients in TNM III stage. The C-index of TNM stage plus the number of ENM was significantly higher than that of current TNM stage alone (p=0.005). In conclusion, the patients in ENMP subgroup had more advanced GC and worse prognosis than those in ENMN subgroup. It might be more reasonable to categorize ENM>2 into TNM IV stage.

Extranodal Extension of Nodal Metastases Is a Poor Prognostic Indicator in Gastric Cancer: a Systematic Review and Meta-analysis

INTRODUCTION

The extranodal extension (ENE) of nodal metastases (the extension of neoplastic cells through the nodal capsule into the perinodal soft tissue) is a histological feature that has been considered a prognostic factor in several cancers, but the role in gastric cancer was not yet investigated. We aimed to investigate the prognostic role of ENE in patients affected by gastric cancer through a systematic review and meta-analysis.

MATERIAL AND METHODS

Two independent authors searched major databases until 09/30/2015 to identify studies providing data on gastric cancer patients' prognostic parameters and comparing patients with ENE (ENE+) vs intra-nodal extension (ENE-). The data were summarized using risk ratios (RRs) for the number of deaths/recurrences and hazard ratios (HRs) with 95 % confidence intervals (CI), adjusted for potential confounders.

RESULTS

Nine studies followed up 3250 patients with gastric cancer (1064 ENE+ and 2186 ENE-). ENE+ was associated with a significantly higher risk of all-cause mortality (RR = 1.70; 95 % CI: 1.43-2.03, I (2) = 66 %; HR = 2.14; 95 % CI: 1.66-2.75, I (2) = 0 %), cancer-specific mortality (RR = 1.59; 95 % CI: 1.42-1.79; HR = 1.52; 95 % CI: 1.19-1.96), and disease recurrence (RR = 3.43, 95 % CI: 1.80-6.54, I (2) = 0 %).

DISCUSSION

Judging from our results, ENE in gastric cancer patients should be considered for prognostic purposes from the gross sample to the pathology report.

Node-extranodal soft tissue stage based on extranodal metastasis is associated with poor prognosis of patients with gastric cancer

BACKGROUND

The purpose of this study was to evaluate the effect of Node-Extranodal soft tissue (pNE) stage based on Extranodal Metastasis (EM) on recurrence and survival in patients with gastric cancer (GC).

MATERIALS AND METHODS

A total of 642 patients were divided into two groups according to statue of EM. Clinicopathologic features were compared among the two groups, the log-rank test was used to assess statistical differences between the groups. Independent prognostic factors were identified by the Cox proportional hazards regression model. According to the number of EMs, EM was incorporated into the pN stage of gastric carcinoma. The 5-y overall survival (OS) and disease free survival (DFS) rates were 48.1% and 17.4%, 44.5% and 14.3% between the two groups. Patients with EM had a deeper tumor invasion and more number of lymph node metastases. Peritoneal dissemination and distant metastasis were more frequent with EM. EM is an independent risk factor for distance recurrence (odds ratio = 1.605), and it is the highest risk factor for peritoneal recurrence (odds ratio = 2.448). Multivariate analysis showed that depth of tumor invasion (P = 0.025), lymph node metastasis (P <0.001), and EM (P = 0.006) were independent factors associated with OS. Furthermore, EM (P = 0.0039) was also an independent prognostic factor for DFS. The differences in prognostic prediction between the seventh edition of the pN classification and the pNE classification were directly compared. We found the pNE classification (hazard ratio = 1.730, P <0.001) was more appropriate for predicting the OS of GC patients after curative surgery, and the -2 loglikehood of the pNE staging (4533.991) is smaller than the value of pN.

CONCLUSIONS

EM was closely associated with cancer aggressiveness and the presence of EM was a significant independent predictor of reduced DFS and OS in GC patients. EM is an independent risk factor for distance recurrence, especially for peritoneal recurrence, the selection of postoperative adjuvant therapy in systemic (intravenous or intra-arterial) and regional (intraperitoneal) based on EM may be a reasonable approach. The lymph node imaging techniques such as injecting nanocarbon during surgery should be applied. As an important prognostic factor, EM should be incorporated into N stage according to its number retrieved in postoperative samples.

Lymph node metastasis of gastric cancer

Despite a decrease in incidence in recent decades, gastric cancer is still one of the most common causes of cancer death worldwide [1]. In areas without screening for gastric cancer, it is diagnosed late and has a high frequency of nodal involvement [1]. Even in early gastric cancer (EGC), the incidence of lymph node (LN) metastasis exceeds 10%; it was reported to be 14.1% overall and was 4.8 to 23.6% depending on cancer depth [2]. It is important to evaluate LN status preoperatively for proper treatment strategy; however, sufficient results are not being obtained using various modalities. Surgery is the only effective intervention for cure or long-term survival. It is possible to cure local disease without distant metastasis by gastrectomy and LN dissection. However, there is no survival benefit from surgery for systemic disease with distant metastasis such as para-aortic lymph node metastasis [3]. Therefore, whether the disease is local or systemic is an important prognostic indicator for gastric cancer, and the debate continues over the importance of extended lymphadenectomy for gastric cancer. The concept of micro-metastasis has been described as a prognostic factor [4-9], and the biological mechanisms of LN metastasis are currently under study [10-12]. In this article, we review the status of LN metastasis including its molecular mechanisms and evaluate LN dissection for the treatment of gastric cancer.