Significance of lymphocyte recovery from treatment-related lymphopenia in locally advanced pancreatic cancer.

• Lymphopenia was associated with poor OS and poor PFS in pancreatic cancer. • Lymphocyte recovery compensates for poor prognosis of locally advanced pancreatic cancer. • Large PTV and low baseline lymphocyte count were associated with both occurrence and recovery of lymphopenia. Radiation-induced lymphopenia is associated with poor prognosis in resected pancreatic cancer and locally advanced pancreatic cancer. However, whether lymphocyte recovery contributes to pancreatic cancer prognosis has not been well-investigated. We evaluated 497 locally advanced pancreatic cancer patients who underwent concurrent chemoradiotherapy (CCRT). Complete blood counts of patients were obtained before, during, and after CCRT until the 12-month follow-up visit. Patients were categorized into 3 groups according to the development of and recovery from acutte severe lymphopenia (ASL): no ASL (group A, n = 198), recovery from ASL (group B, n = 141), and no recovery from ASL (group C, n = 89). Prognostic factors of overall survival (OS) and progression-free survival (PFS) were determined using Cox regression analyses. In groups A, B, and C, the 2-year OS rates were 40.4%, 31.9%, and 14.6%, respectively, and the 2-year PFS rates were 23.7%, 18.4%, and 10.1%, respectively. OS and PFS were comparable between Groups A and B, while group C had poor OS and PFS (p < 0.001). Recovery from ASL was associated with superior OS (HR 0.42, 95% CI: 0.32–0.55, p < 0.001) and PFS (HR 0.53, 95% CI: 0.41–0.70, p < 0.001). The baseline lymphocyte counts and target volume independently predicted development and recovery from ASL. Recovery from ASL was associated with both superior OS and PFS in patients who received CCRT for locally advanced pancreatic cancer. Baseline lymphocyte counts and target volume were associated with both the development of and recovery from treatment-related ASL. [ABSTRACT FROM AUTHOR]