Solid Pseudopapillary Neoplasms of the Pancreas Across Races Demonstrate Disparities with Comparably Good Prognosis

Background: Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare with low-grade malignancy and unclarified clinicopathological features. This study aimed to examine their characteristics and re-evaluate current treatments. Methods: Databases from three sources were screened for patients with SPNs. We compared the perioperative variables, clinical data, overall survival (OS), and prognostic factors for recurrence among the three corresponding cohorts. Results: We identified 286 patients diagnosed with SPNs between 1988 and 2020. Patients were mostly women (81%; median age: 38 years), and peak incidence was observed in women of 20–29 years of age. SPNs had a peak incidence in Asian men at 50–59 years of age (p = 0.002) and a delayed peak incidence in Asian women at 30–39 years of age (p < 0.001). Treatment strategies differed significantly across the institutions and included variations in the number of harvested lymph nodes and rates of vascular resection. Lymph node positivity was the only predictor of postoperative recurrence (odds ratio, 2.2; 95% confidence interval, 1.38–2.99; p = 0.007). Higher rates of lymphovascular invasion (p = 0.02), perineural invasion (p < 0.001), and R1 margin involvement (p < 0.001), as seen in one institution, did not result in poorer long-term survival in terms of the overall (p = 0.43), SPN-specific (p = 0.69), and recurrence-free survivals (p = 0.067). Conclusions: In contrast to previous findings that SPNs are prevalent in young women, a racial predilection for middle-aged Asian men and a delayed female peak incidence were noted. Parenchyma-preserving pancreatectomy may be an acceptable treatment. Non-radical surgery may be appropriate in patients with multiple comorbidities.