Abstract 22P
Background
Stereotactic ablative radiation therapy (SABR) is actively used for treatment of patients with oligometastatic tumor process. It is assumed, that in addition to the direct effect on the tumor site, SABR can enhance the formation of an antitumor immune response. In this regard, the aim of our study is investigation of SABR’s influence on indicators of the immune status in patients with metastatic solid tumors.
Methods
We performed a preliminary analysis of the immunological parameters of blood before irradiation (point A), via 3-4 weeks (point B) and via 6-8 weeks (point C) after SBRT in 29 patients with malignant tumors with oligometastases in the liver and lungs. Radiotherapy was performed on the linear accelerator “Novalis Tx” EX = 6 MeV, all peripheral blood samples (87) were analyzed by flow cytometry on a FACS Canto ™ II cytometer. We used Friedman test for multiple comparison and Nemenyi test for between-group comparison. Data processing and statistical analysis was performed using Microsoft Excel 2010 and R (ver. 4.0.2).
Results
We observed statistically significant increase of T-lymphocytes (CD3+CD19-), χ2 = 13,8, p = 0,001, pairwise p(A, B) = 0,002; T-helpers (CD3+CD4+), χ2 = 8,2, p = 0,017, pairwise p(A, B) = 0,019; activated T-helpers (CD3+CD4+HLA-DR+), χ2 = 30,1; p < 0,001; pairwise p(A, B) < 0,001, p(A, C) < 0.001; activated cytotoxic T lymphocytes (CD3+СD8+HLA-DR+), χ2 = 13,3; p = 0,001; pairwise p(A, B) = 0,003, p(A, C) = 0.007; and decrease of B-lymphocytes (CD3-CD19+), χ2 = 31,5; p < 0,001, pairwise p(A, B) < 0,001, p(A, C) = 0.006. Interesting, that 6-8 weeks after SABR, in comparison with valued obtained 3-4 weeks after SABR, we detected statistically significant decrease of T-lymphocytes (pairwise p(B, C) = 0.01) and increase of B-lymphocytes (pairwise p(B, C) = 0.034).
Conclusions
Thus, revealed dynamics of immunological parameters indicates the induction of the T-cell link of antitumor immunity against decreasing of indicators of humoral immunity.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.