Efficacy and dosimetry analysis of image-guided radioactive 125I seed implantation as salvage treatment for pelvic recurrent cervical cancer after external beam radiotherapy

Objective: To investigate the efficacy of image-guided radioactive I-125 seed (IGRIS) implantation for pelvic recurrent cervical cancer (PRCC) after external beam radiotherapy (EBRT), and analyze the influence of clinical and dosimetric factors on efficacy. Methods: From July 2005 to October 2015, 36 patients with PRCC received IGRIS. We evaluated local progression-free survival (LPFS) and overall survival (OS). Results: The median follow up was 11.5 months. The 1- and 2-year LPFS rate was 34.9% and 20%, respectively. The multivariate analysis indicated recurrence site (central or pelvic wall) (hazard ratio [HR]=0.294; 95% confidence interval [CI]=0.121-0.718), lesion volume (HR=2.898; 95% CI=1.139-7.372), D-90 (HR=0.332; 95% CI=0.130-0.850) were the independent factors affecting LPFS. The 1- and 2-year OS rate was 52.0% and 19.6%, respectively. The multivariate analysis suggested pathological type (HR=9.713; 95% CI=2.136-44.176) and recurrence site (HR=0.358; 95% CI=0.136-0.940) were the independent factors affecting OS. The dosimetric parameters of 33 patients mainly included D-90 (128.5 +/- 47.4 Gy), D-100 (50.4 +/- 23.7 Gy) and V-100 (86.7%+/- 12.9%). When D-90 >= 105 Gy or D-100 >= 55 Gy or V-100 >= 91%, LPFS was extended significantly, but no significant difference for OS. The 79.2% of 24 patients with local pain were suffering from pain downgraded after radioactive I-125 seed implantation. Conclusion: IGRIS implantation could be a safe and effective salvage treatment for PRCC after EBRT, which could markedly release the pain. Recurrence site, tumor volume and dose were the main factors affected efficacy. Compared with central recurrence, it was more suitable for patients with pelvic wall recurrent cervical cancer after EBRT.