Metastasis to the Sigmoid or Sigmoid Mesenteric Lymph Nodes From Rectal Cancer

Abstract

We analyzed metastases to the sigmoid and sigmoid mesenteric lymph nodes from rectal cancer. It has been reported that rectal cancer spreads upward and lateral. However, metastasis to the sigmoid mesenteric or sigmoid nodes from rectal cancer has been rarely reported. We enrolled 347 patients who underwent curative resection for rectal cancer with proven lymph node metastases and dissection of the sigmoid and sigmoid mesenteric lymph nodes. Lymph node classification was performed by the colorectal surgeon and the lymph nodes were sent to pathology. Two hundred ninety sigmoid mesenteric and 248 sigmoid lymph node dissections were confirmed by pathologic examination. There were 185 and 162 patients with extraperitoneal and intraperitoneal rectal cancers, respectively. The T categories were T1 in 4 patients (1.2%), T2 in 25 patients (7.2%), T3 in 252 patients (72.6%), and T4 in 66 patients (18.8%). The N categories were N1 in 216 patients (62.2%) and N2 in 131 patients (37.8%). Metastases to the sigmoid and sigmoid mesenteric lymph nodes occurred in 60 (20.7%) and 28 patients (11.3%), respectively. Metastases to the sigmoid or sigmoid mesenteric lymph nodes, without metastases to the superior rectal and inferior mesenteric lymph nodes, developed in 18 patients (5.2%). Compared with patients without sigmoid mesenteric lymph node metastases, N2 category disease, and poor differentiation, overall recurrence was more common in patients with sigmoid mesenteric lymph node metastases. Patients with sigmoid lymph node metastases were common in the N2 category of disease. However, the number of retrieved lymph nodes, and the overall and local recurrence rates were not significantly different. Seventeen of 18 patients with only sigmoid mesenteric or sigmoid lymph node metastases had N1 category disease; 8 and 10 patients had extraperitoenal and intraperitoneal rectal cancers, respectively. For patients with N1 category disease, there was no difference in the overall and local disease recurrence rates among the patients. Sigmoid mesenteric or sigmoid lymph node metastases developed in 23.2% of patients in the present study. But, there were no differences in the cancer-specific survival, overall and local disease recurrence rates in the patients with sigmoid mesenteric or sigmoid lymph node metastases.