The pattern of lymph node involvement in carcinoma of the head of the pancreas. A histologic study of the surgical findings in patients undergoing extensive nodal dissections.

To clarify the pattern of lymph node metastasis in carcinoma of the pancreas, lymph node involvement was examined in forty-two patients who underwent extensive nodal dissections, including the paraaortic lymph nodes. The correlation between the spread of the tumor and lymph node involvement was evaluated: The most common site of involved lymph nodes was the retropancreatic region. The prevalence of nodal metastases was 78.6%. Metastases to the paraaortic region were present in seven patients, among whom metastases in the paraaortic region were most common in the median region from the celiac artery to the inferior mesenteric artery and in the space between the aorta and the vena cava. The risk of lymph node metastases tended to increase with tumor size, except in the paraaortic region, where the correlation between the frequency of metastasis and tumor size was poor. The probability of lymph node metastases increased with the degree of lymphatic invasion (ly) and the growth pattern of the tumor (INF) and was high in patients with invasion into the retropancreatic tissue and in tumors with scirrhous histology. These results indicate that even in small cancers, lymph nodes of the paraaortic region frequently harbor metastases and should be dissected en block during radical resections of pancreatic cancer.