The efficacy and safety of percutaneous CT-guided iodine-125 brachytherapy combined with standard chemotherapy and brachytherapy alone for lung malignant nodule: a retrospective comparative cohort study

Background

Lung metastasis nodules and advanced-stage tumors are often considered inoperable conditions for thoracic surgery and remain major challenges to clinical decision-making. Brachytherapy has its advantages in treating localized solid tumors, which can be used in combination with other treatments to achieve good safety and efficacy. In this study, we aimed to determine the outcomes of patients who received a combination of standard chemotherapy and computed tomography (CT)-guided percutaneous brachytherapy treatment for advanced-stage lung malignant lesions.

Methods

We retrospectively collected data on patients with advanced lung cancer or lung metastasis nodules who underwent percutaneous CT-guided iodine-125 (125I) brachytherapy treatment. Patients were divided into two groups: Group A (brachytherapy with chemotherapy) and Group B (brachytherapy-only). Patients were reevaluated 1 month after the operation and then followed up every 3 months. The primary endpoint of this study was overall survival.

Results

Our results showed that the mean age in Group B was higher (62.32±8.79 years) than that of Group A (68.59±11.46 years; P=0.018). Patients receiving a combination of chemotherapy and brachytherapy had a median survival time of 20.5 months [95% confidence interval (CI), 16.5-24.5], while those receiving brachytherapy alone had a median survival time of 16.4 months (95% CI, 11.7-21.1) (P=0.026). Patients who received additional thermal ablation treatment and those who did not have median survival times of 16.4 (95% CI, 10.2-22.7) and 17.0 months (95% CI, 13.3-20.8) (P=0.607). The median survival time for patients with oligo lesions was 19.8 months (95% CI, 15.7-23.9), while it was 10.5 months (95% CI, 7.5-13.4) for those who had multiple lesions.

Conclusions

The combination of percutaneous CT-guided 125I brachytherapy and standard chemotherapy was superior to brachytherapy alone in terms of overall survival for patients with inoperable pulmonary lesions. Our results showed no benefit from additional adjuvant thermal ablation treatment. Patients with a single oligo nodule seem to have a better prognosis than those with multiple lesions.

Dosimetric differences between cesium-131 and iodine-125 brachytherapy for the treatment of resected brain metastases

Purpose

To compare treatment plans and evaluate dosimetric characteristics of permanent cesium-131 (¹³¹Cs) vs. iodine-125 (¹²⁵I) implants used in brain brachytherapy.

Material and methods

Twenty-four patients with ¹³¹Cs implants from a prospective phase I/II trial were re-planned with ¹²⁵I implants. In order to evaluate the volume of brain tissue exposed to radiation therapy (RT), the dose volume histogram was generated for both radioisotopes. To evaluate the dosimetric differences of the two radioisotopes we compared homogeneity (HI) and conformity indices (CI), and dose covering 100% (D₁₀₀), 90% (D₉₀), 80% (D₈₀), and 50% (D₅₀) of the clinical target volume (CTV).

Results

At the 100%, 90%, 80%, and 50% isodose lines, the ¹³¹Cs plans exposed less mean volume of brain tissue than the ¹²⁵I plans (p < 0.001). The D₁₀₀, D₉₀, D₈₀, and D₅₀ were smaller for ¹³¹Cs (p < 0.001). The HI and CI for ¹³¹Cs vs. ¹²⁵I were 19.71 vs. 29.04 and 1.31 vs. 1.92, respectively (p < 0.001).

Conclusions

Compared to ¹²⁵I, ¹³¹Cs exposed smaller volumes of brain tissue to equivalent doses of radiation and delivered lower radiation doses to equivalent volumes of the CTV. ¹³¹Cs exhibited a higher HI, indicating increased uniformity of doses within the CTV. Lastly, ¹³¹Cs presented a CI closer to 1, indicating that the total volume receiving the prescription dose was closer to the desired CTV volume. These results suggest that ¹³¹Cs is dosimetrically superior to ¹²⁵I and may explain the reason for the 0% incidence of radiation necrosis (RN) in our previously published prospective study using ¹³¹Cs.