Immune response after systematic lymph node dissection in lung cancer surgery: changes of interleukin-6 level in serum, pleural lavage fluid, and lung supernatant in a dog model

Background: Systematic nodal dissection (SND) is regarded as a core component of lung cancer surgery. However, there has been a concern on the increased morbidity associated with SND. This study was performed to investigate whether or not SND induces significant immune response. Methods: Sixteen dogs were divided into two groups; group 1 (n = 8) underwent thoracotomy only, and group 2 (n = 8) underwent SND after thoracotomy. We compared interleukin-6 (IL-6) levels in serum, pleural lavage fluid and lung supernatant at the time of thoracotomy (T0) and at 2 h(T1) after thoracotomy (group 1) or SND (group 2). Severity of inflammation and IL-6 expression in lung tissue were evaluated in a semi-quantitative manner. Results: The operative results were comparable. IL-6 was not detected in serum in either group. IL-6 in pleural lavage fluid marginally increased from 4.75 +/- 3.74 pg/mL at T0 to 19.75 +/- 8.67 pg/mL at T1 in group 1 (P = 0.112), and from 7.75 +/- 5.35 pg/mL to 17.72 +/- 8.58 pg/mL in group 2 (P = 0.068). IL-6 in lung supernatant increased from 0.36 +/- 0.14 pg/mL/mg to 1.15 +/- 0.17 pg/mL/mg in group 1 (P = 0.003), and from 0.25 +/- 0.08 pg/mL/mg to 0.82 +/- 0.17 pg/mL/mg in group 2 (P = 0.001). However, the degree of increase in IL-6 in pleural lavage fluid and lung supernatant were not different between two groups (P = 0.421 and P = 0.448). There was no difference in severity of inflammation and IL-6 expression between groups. Conclusions: SND did not increase IL-6 in pleural lavage fluid and lung supernatant. This result suggests that SND could be routinely performed in lung cancer surgery without increasing the significant inflammatory response.

via World Journal of Surgical Oncology