Evaluation of radioactive (125)I seed implantation for the treatment of refractory malignant tumours based on a CT-guided 3D template-assisted technique: efficacy and safety

BACKGROUND: To observe the medium- and long-term clinical efficacy and safety of radioactive (125)I seed implantation for refractory malignant tumours based on CT-guided 3D template-assisted technique. METHODS: Twenty-five patients with refractory malignant tumours who underwent radioactive (125)I seed implantation based on CT-guided 3D template-assisted technique were selected. The post-operative adverse reactions were recorded. The number of puncture needles and particles used in the operation, dosimetric parameters, post-operative physical strength scores, and tumour response were statistically analysed. The overall survival time and survival rate were calculated, and the effect and prognosis were assessed. RESULTS: (125)I seed implantation was successful in all patients without serious complications. The average number of implanted puncture needles was 17 (19.12 ± 13.00), and the median number of particles was 52 (55.12 ± 32.97). D(90) in the post-operative clinical target volume (CTV) (93.24 ± 15.70 Gy) was slightly lower than that in the pre-operative CTV (93.92 ± 17.60 Gy; P > 0.05). The D(90) in the post-operative planning target volume (PTV) (142.16 ± 22.25 Gy) was lower than the pre-operative PTV (145.32 ± 23.48 Gy; P > 0.05). The tumour responses at 6 months post-operatively: complete remission (CR), 20% (5/25); partial remission (PR), 48% (12/25); stable disease (SD), 24% (6/25); progressive disease (PD), 8% (2/25); CR + PR, 68% (17/25); and local control rate, 92% (23/25). The 6-, 12-, and 24-month survival rates were 100, 88, and 52%, respectively. The post-operative physical strength score (Karnofsky performance score, KPS) exhibited a gradual trend towards recovery, which rose to the highest value 12 months after implantation and then decreased slightly, but the average score was still > 90 points. There was one intra-operative pneumothorax, and two patients with superficial malignant tumours developed skin ulcerations. Multivariate analysis of prognosis showed that tumour sites and types were independent risk factors affecting survival. The number of needles and particles and template types were not the factors. CONCLUSIONS: 3D template combined with CT-guided radioactive (125)I seed implantation can improve the rational distribution of radiation dose in the tumour target area because accurate radioactive (125)I particle implantation was achieved. This technique has fewer complications and can further extend the overall survival and improve the quality of life. TRIAL REGISTRATION: Registration number: ChiCTR2000034566 2020/7/10 0:00:00 Retrospectively registered.