Iodine-125 Brachytherapy in Non-Small Cell Lung Cancer

Iodine-125 brachytherapy involves the implantation of sealed radioactive seeds directly into non-small cell lung cancer (NSCLC) lesions, delivering a continuous low-dose-rate irradiation to tumour tissue while minimising exposure to surrounding healthy structures. This modality exploits the physical properties of I-125, whose gamma emissions penetrate only short distances, permitting highly conformal dose distributions. Clinically, seeds are positioned under imaging guidance—most often computed tomography—enabling precise placement even in central or recurrent tumours. Indications include locally advanced, recurrent or oligometastatic NSCLC, particularly in patients unsuitable for further surgery or high-dose external beam radiotherapy. Key advantages comprise enhanced local control, relief of tumour-related symptoms and a favourable toxicity profile, with most adverse events confined to mild pneumonitis or chest wall discomfort. Treatment planning systems calculate parameters such as D90 to ensure adequate tumour dosing and organ-at-risk constraints. Recent improvements in seed delivery platforms, three-dimensional treatment planning and combination regimens with systemic chemotherapy or targeted agents have further expanded its therapeutic potential. Preclinical studies have elucidated mechanisms of tumour cell apoptosis mediated by caspase activation and DNA damage pathways, while clinical series report marked gains in progression-free and overall survival with limited acute toxicity. As a minimally invasive option, I-125 brachytherapy offers a valuable adjunct to multidisciplinary care for NSCLC, with global applicability in centres equipped for image-guided interventional radiotherapy.

Research from Nature Portfolio

A retrospective analysis of thoracic seed implantation evaluated radiation-related adverse effects in patients with recurrent or metastatic disease. Using common terminology for adverse events and dose–volume parameters, it identified an overall low incidence of grade ≥2 toxicity. Skin reactions correlated with D0.1cc > 600 Gy, D2cc > 500 Gy and mean dose > 90 Gy, while other organ-at-risk toxicities remained below clinically significant thresholds. The study established upper confidence-interval limits for critical dosimetric parameters and confirmed that carefully planned I-125 brachytherapy can achieve effective tumour control without unacceptable morbidity.

Iodine-125 Brachytherapy in Non-Small Cell Lung Cancer publication trend

The graph below shows the total number of articles in iodine-125 brachytherapy in non-small cell lung cancer across all publications each year (not limited to Nature Index journals).

Technical terms

Brachytherapy: Internal radiotherapy in which radioactive sources are placed within or next to a tumour.

Computed tomography-guided implantation: Use of CT imaging to precisely place radioactive seeds in tumour tissue.

Oligorecurrence: Recurrence of cancer characterised by a limited number of metastatic or local lesions amenable to focal treatment.

Progression-free survival (PFS): Interval during which a patient’s disease does not worsen following treatment.

D90: Dose of radiation that covers 90 percent of the target volume, ensuring adequate tumour irradiation.

References

1. Radiation-related Adverse Effects of CT-guided Implantation of 125I Seeds for Thoracic Recurrent and/or Metastatic Malignancy. Scientific Reports (2019).
2. I-125 seeds with chemotherapy for progressive non-small-cell lung cancer after first-line treatment: a meta-analysis. Journal of Cardiothoracic Surgery (2022).
3. Oligorecurrence Non–small Cell Lung Cancer After Failure of First-Line Chemotherapy: Computed Tomography–Guided 125I Seed Implantation vs. Second-Line Chemotherapy. Frontiers in Oncology (2020).
4. 125I seeds irradiation inhibits tumor growth and induces apoptosis by Ki-67, P21, survivin, livin and caspase-9 expression in lung carcinoma xenografts. Radiation Oncology (2020).