Prognostic factors and outcomes of CT-guided Iodine-125 seed brachytherapy for retroperitoneal lymph node metastases from a previously irradiated field in cervical carcinoma: a multicenter retrospective study.

OBJECTIVE

This retrospective study aimed to evaluate the efficacy, safety, and prognostic factors of Iodine-125 seed brachytherapy for Retroperitoneal Lymph Node Metastases (RLNM) from a Previously Irradiated Field in Cervical Carcinoma.

METHODS

Between March 2020 and November 2024, 33 patients (40 lesions) with RLNM from Cervical Carcinoma, who were ineligible for or declined further external beam radiotherapy (EBRT), underwent CT-guided iodine-125 seed brachytherapy at three tertiary hospitals. The follow-up deadline was 28/02/2026. The following endpoints were assessed: disease control rate (DCR), local tumor progression-free survival (LTPFS), overall survival (OS), and adverse events.

RESULTS

The median follow-up time was 18.6 months (range, 2.0-38.3 months), and the 3- and 6- month DCR was 90.0% and 77.5%, respectively. The median LTPFS was 9.0 months (IQR, 5.3 - 20.5), and the median OS was 20.0 months (IQR, 8.0 - 25.0). The 6-, 12-, 18- and 24- month survival rates were 81.8%, 60.5%, 50.2%, 28.2%, respectively. Among 8 patients with preoperative pain, the Numerical Rating Scale (NRS) score decreased from 3.50 ± 1.77 to 1.75 ± 1.49 one month postoperatively (t=3.564, P = 0.009), a statistically significant difference. One patient developed a sigmoid colon fistula 4 months postoperatively. Four patients experienced postoperative low back discomfort with NRS scores of 1-2, which was relieved spontaneously or with oral analgesics. Multivariate analysis using the Cox proportional hazards model showed that a dose to 90% of the gross tumor volume (D90) ≥ 108 Gy was a protective factor for LTPFS, and tumor invasion of the intestinal wall was a risk factor for OS.

CONCLUSION

Iodine-125 seed brachytherapy is safe and effective for treating RLNM in Cervical Carcinoma. A D90 ≥ 108 Gy results in better LTPFS. Tumor invasion of the intestinal wall is a risk factor for OS.