Extracapsular lymph node involvement differs between squamous cell and adenocarcinoma of the esophagus

There is increasing evidence regarding extracapsular lymph node involvement (LNI) as a prognostic factor for recurrence and poor prognosis in gastrointestinal malignancies. The aim of this study was to assess the prevalence and prognostic impact of LNI in patients with resected esophageal cancer, comparing adenocarcinoma (AC) and squamous cell carcinoma (SCC). Between 1997 and 2006, 243 consecutive patients with resected esophageal cancer without neoadjuvant therapy (103 SCC, 140 AC) were studied. A total of 738 lymph node metastases were reexamined. Survival was analyzed according to intra- and extracapsular LNI. Median survival in patients with extracapsular LNI was 13 months [range 11-14 months, 95% confidence interval (CI)] compared with 28 months (21-34 months, 95% CI) for those with intracapsular LNI alone (p = 0.017). Node-positive patients with AC showed a prevalence of 66% extracapsular LNI compared with 35% in patients with SCC (p < 0.001). The number of resected lymph nodes and the frequency of pN1 cases were comparable between AC and SCC. However the number of infiltrated LN was significantly (p = 0.005) higher in patients with pN1 AC (median = 5) compared with pN1 SCC (median = 3). We conclude that extracapsular LNI is an independent negative prognostic factor which occurs more frequently in esophageal AC than SCC.