To determine the inflammatory state of cervical cancer after radiotherapy, we examined serum interleukin 6 levels (sIL-6) and C-reactive protein (CRP) before and after radiation therapy in sixteen patients with cervical cancer. External radiation therapy did not cause changes in sIL-6 and CRP during the examined periods. On the other hand, brachytherapy caused transient elevation of sIL-6 on the day after treatment by 6.39 +/- 1.89 pg/ml to 13.41 +/- 2.34 pg/ml (p < 0.05) while CRP did not show any significant change. Therefore, brachytherapy would induce a small inflammatory reaction. However, we confirmed that radiotherapy is a less invasive treatment than surgery from the point of view of cytokine related inflammation.