Clinical features and outcome of primary pancreatic lymphoma.

Introduction: Primary pancreatic lymphoma (PPL) is a rare tumor that is often misdiagnosed. Clinicopathologic features, optimal therapy, and outcomes are not well defined. We reviewed our institutional experience with PPL.

Methods: Search of our institutional database identified that between 1987-2012, 21,760 patients with lymphoma and 11,286 patients with a primary pancreatic tumor were evaluated. There were 44 patients with pathologically confirmed PPL. Clinical data were obtained by chart review and survival distributions were estimated using the Kaplan-Meier method and compared using the log-rank test.

Results: At baseline, LDH was elevated in 55 % of the patients, CA 19-9 in 25 %, and CEA in 20 %. Imaging characteristics included large, unresectable tumors (67 %), and lymphadenopathy inferior to the renal vein (50 %). Twenty-three patients underwent surgery for resection (5), diagnosis (13), or palliation (5). Chemotherapy alone achieved a 75 % complete response rate. Eight patients experienced relapse, 88 % of which occurred at distant sites. Median overall survival was 6.1 years and 10-year disease-specific survival (DSS) was 69 %. Patients with a low risk International Prognostic Index (IPI) and those with a follicular histologic subtype demonstrated 5-year DSS of 100 %.

Conclusions: Chemotherapy for PPL results in a high complete response rate and long DSS, which is similar to nodal non-Hodgkin's lymphoma (NHL). A favorable outcome is expected for IPI low risk patients and follicular histologic subtype. Systemic therapy should generally be the initial therapy when the diagnosis is known. Prolonged follow up is recommended to detect relapses. Surgery alone should be reserved for non-curative intent (i.e. diagnostic or palliative).