Purpose/Objective(s): To observe and evaluate the changes of immunological parameters after high-dose hypofractionated radiotherapy for pancreatic cancer.

Materials/Methods: Patients with pancreatic cancer were collected in our study prospectively, and were performed hypofractionated radiotherapy with helical tomotherapy. The prescribed dose of 50/60/70Gy was delivered to PTV, CTV and GTV respectively in 15 or 20 fractions. Humoral immunological indicators including IgG, IgA, IgM, C3 and C4 and cellular immunological indicators including CD3, CD4 and CD8 were examined before and after radiotherapy. Paired-t test was used to evaluate the variance of these indicators before and after treatment.

Results: From February 2015 to May 2016, 34 patients were enrolled in our study. The number of patients was 0, 0, 2, 7 and 1 for whom with lower value of IgG, IgA, IgM, C3 and C4 compared to normal values before treatment respectively, while the number was 1, 0, 7, 6 and 0 after treatment. Similarly, the number of patients was 1, 1, and 7 for whom with cellular immunological parameters including CD3, CD4 and CD8 lower than normal values, and the case number changed to 1, 1, and 9 respectively after treatment. Only IgM value decreased by 9.6 ±17.5% on average (P = 0.011) and the other parameters had no significant difference before and after treatment.

Conclusion: Among all immunological parameters listed, only the IgM values decreased for some patients. The other parameters did not change obviously after high-dose and hypofractionated radiotherapy of pancreatic cancer.