Clinical characteristics and prognosis of pancreatic metastases: a 10-year retrospective study

Background: Pancreatic metastasis is rare. Its characteristics have primarily been described in autopsy studies and case reports, which may not accurately reflect the actual clinical profiles. Moreover, few studies have addressed the prognostic feature in patients with pancreatic metastasis. Methods: Cases of pancreatic metastases that were diagnosed by the multidisciplinary tumor board from September 2013 to July 2023 at our hospital were collected and analyzed. Results: A total of 77 cases were collected. The most common primary tumor sites were the lung (35.1%) and kidney (23.4%). Clear cell renal carcinoma (CCRC) accounted for 23.4% of cases, making it the most common histological type, followed by small-cell lung cancer (SCLC, 16.9%). Among the cases, 36.4% (28 cases) presented with organ-related symptoms, and 74.0% (57 cases) were solitary metastases. Metachronous metastases accounted for 70.1% (54 cases), with an average interval of 62.7 ± 74.4 months between the diagnosis of the primary tumor and metastasis. The overall survival (OS) of the collected cases was 42 months. OS varied by primary tumor type, with pancreatic metastases secondary to lung, kidney, digestive tract, and gynecological cancers showing OS of 23, 81, 11, and 32 months, respectively. Subgroup analysis indicated that 15 cases secondary to the CRCC were metachronous with an average interval of 132.4 ± 83.9 months from initial diagnosis to metastasis, which had an OS of 80 months. Radical resection was performed in 10 of these cases, increasing the OS to 91 months. Conclusion: Pancreatic metastasis was uncommon and imperceptible. The prognosis of patients depended on the primary tumor type and the timing of metastasis. Pancreatic metastases secondary to CCRC were the most frequent and had the most favorable prognosis. Radical resection of the metachronous metastases prolonged survival. This study described the real-world clinical profiles of pancreatic metastases, providing valuable insights to reduce misdiagnosis and guide treatment decisions.