Low Frequency of Lymph Node Metastases in Patients in the United States With Early-stage Gastric Cancers That Fulfill Japanese Endoscopic Resection Criteria

BACKGROUND & AIMS

In the West, early gastric cancer is increasingly managed with endoscopic resection (ER). This is, however, based on the assumption that the low prevalence and risk of lymph node metastases observed in Asian patients is applicable to patients in the United States. We sought to evaluate the frequency of and factors associated with metastasis of early gastric cancers to lymph nodes, and whether the Japanese ER criteria are applicable to patients in the US.

METHODS

We performed a retrospective study of 176 patients (mean age 68.5 years; 59.1% male; 58.5% white) who underwent surgical resection with lymph node dissection of T1 and Tis gastric adenocarcinomas, staged by pathologists, at 7 tertiary care centers in the US from January 1, 1999, through December 31, 2016. The frequency of lymph node metastases and associated risk factors were determined.

RESULTS

The mean size of gastric adenocarcinomas was 23.0 ± 16.6 mm-most were located in the lower-third of the stomach (67.0%), invading the submucosa (55.1%), and moderately differentiated (31.3%). Lymphovascular invasion was observed in 18.2% of lesions. Overall, 20.5% of patients had lymph node metastases. Submucosal invasion (odds ratio, 3.9; 95% CI, 1.4-10.7) and lymphovascular invasion (odds ratio, 4.6; 95% CI, 1.8-12.0) were independently associated with increased risk of metastasis to lymph nodes. The frequency of lymph node metastases among patients fulfilling standard and expanded Japanese criteria for ER were 0 and 7.5%, respectively.

CONCLUSIONS

The frequency of lymph node metastases among patients with early gastric cancer in a US population is higher than that of published Asian series. However, early gastric cancer lesions that meet the Japanese standard criteria for ER are associated with negligible risk of metastasis to lymph nodes, so ER can be recommended for definitive therapy. Expanded criteria cancers appear to have a higher risk of metastasis to lymph nodes, so ER may be considered for select cases.

A Model Based on Pathologic Features of Superficial Esophageal Adenocarcinoma Complements Clinical Node Staging in Determining Risk of Metastasis to Lymph Nodes

BACKGROUND & AIMS

It is important to identify superficial (T1) gastroesophageal adenocarcinomas (EAC) that are most or least likely to metastasize to lymph nodes, to select appropriate therapy. We aimed to develop a risk stratification model for metastasis of superficial EAC to lymph nodes using pathologic features of the primary tumor.

METHODS

We collected pathology data from 210 patients with T1 EAC who underwent esophagectomy from 1996 through 2012 on factors associated with metastasis to lymph nodes (tumor size, grade, angiolymphatic invasion, and submucosal invasion). Using these variables, we developed a multivariable logistic model to generate 4 categories for estimated risk of metastasis (<5% risk, 5%-10% risk, 15%-20% risk, or >20% risk). The model was validated in a separate cohort of 39 patients who underwent endoscopic resection of superficial EAC and subsequent esophagectomy, with node stage analysis.

RESULTS

We developed a model based on 4 pathologic factors that determined risk of metastasis to range from 2.9% to 60% for patients in the first cohort. In the endoscopic resection validation cohort, higher risk scores were associated with increased detection of lymph node metastases at esophagectomy (P = .021). Among patients in the first cohort who did not have lymph node metastases detected before surgery (cN0), those with high risk scores (>20% risk) had 11-fold greater odds for having lymph node metastases at esophagectomy compared with patients with low risk scores (95% confidence interval, 2.3-52 fold). Increasing risk scores were associated with reduced patient survival time (P < .001) and shorter time to tumor recurrence (P < .001). Patients without lymph node metastases (pT1N0) but high risk scores had reduced times of survival (P < .001) and time to tumor recurrence (P = .001) after esophagectomy than patients with pT1N0 tumors and lower risk scores.

CONCLUSIONS

Pathologic features of primary superficial EACs can be used, along with the conventional node staging system, to identify patients at low risk for metastasis, who can undergo endoscopic resection, or at high risk, who may benefit from induction or adjuvant therapy.