Nonductal Primary Malignancies of the Pancreas: Metastatic Malignancies

Neoplastic spread of extrapancreatic malignancies to the pancreas is not rare. The majority of patients, however, are diagnosed with either metastases from aggressive primary neoplasms, such as lung cancer, or present with diffuse metastatic disease. Only a minority of patients (i.e., those with single or localized metastases) are referred for surgical consultation. Understanding the natural history and disease progression of metastases to the pancreas is limited by the selection bias inherent to most uncontrolled or inadequately controlled published data. Individualized patient management by a multidisciplinary team is crucial for optimal outcome. Primary pancreatic neoplasms are much more common than metastatic malignancies; however, metastases must be suspected in patients with personal history of a prior malignancy, especially renal cell carcinoma and melanoma. Critical parameters to consider for each patient with suspected metastases to the pancreas are the patient's general health and fitness, tumor biology (measured by such surrogates as disease-free interval or response to systemic therapy), ability to perform a margin-negative resection, and oncologic control of primary tumor site. Despite advances in operative technique, availability of minimally invasive and ablative techniques, and improvements in perioperative management, pancreatic resection continues to carry substantive morbidity; up to 40% of patients require multivisceral resection during operation for metastases to the pancreas. Metastasectomy is most accepted among patients with renal cell carcinoma; other malignancies with more than case-report evidence are colorectal adenocarcinoma, sarcoma, and melanoma. In all cases of metastases to the pancreas, patient selection is paramount. Ultimately, progress in treatment will depend on improvements in understanding of tumor biology and advances in systemic therapy.