Surgical treatment of pancreatic metastases: a clinicopathologic study of 43 patients

Abstract Purpose It is rare to find surgically-resectable metastatic lesions that are limited to the pancreas, by preoperative imaging. In this retrospective study, we reviewed the histopathologic findings in pancreatic surgical resection specimens to determine the factors that contribute to the prognostic improvement of surgical treatment for pancreatic metastases. Methods From 1979 to 2018, 43 patients underwent pancreatic resection for metastatic tumors in the Department of Hepato-Biliary-Pancreatic Surgery of the Cancer Institute of the Japanese Foundation for Cancer Research. Survival curves were created using the Kaplan–Meier method, and comparisons of survival were performed using the log-rank test.Results Primary tumors comprised renal cell carcinoma (RCC), colorectal carcinoma (CRC), and miscellaneous malignancies (MM) in 23, 9, and 11 cases, respectively. Histopathologically, the patterns of metastases were classified as hematogenous (32), lymphatic (8), and peritoneal (3). Regarding the prognosis after metastasectomy of the pancreas, there were significant differences for disease-free interval (< 5 years versus ≥5 years) and primary tumor (RCC versus CRC/MM). The rate of secondary or accompanying lymph node metastasis around the main metastasis was 5/9 (56%) for CRC, 5/11 (45%) for MM, and 1/23 (4%) for RCC. Conclusion Survival outcomes are more favorable for disease-free intervals ≥ 5 years, pancreatic metastasis from RCC, and with lymphatic metastasis. Lymph node dissection is not strictly necessary for the surgical removal of pancreatic metastasis from RCC, whereas this is highly recommended for patients with metastasis from CRC or MM.