Nomogram prediction model for overall survival of late-stage lung cancer patients undergoing iodine-125 particle implantation brachytherapy.

Abstract

Purpose: The purpose of this study was to explore the overall survival (OS) rate of late-stage lung cancer patients after receiving iodine-125 (¹²⁵I) particle implantation brachytherapy.

Material and methods: 436 late-stage lung cancer patients who underwent ¹²⁵I radioactive particle brachytherapy in the Department of Nuclear Medicine of the General Hospital of Northern Theater Command from December 2013 to June 2019 were retrospectively analyzed. Patients were randomly divided into training set and validation set in a 7 : 3 ratio. Univariate and multivariate Cox proportional hazards models were employed to show independent factors affecting the prognosis of late-stage lung cancer patients. Based on these factors, a nomogram model was constructed to predict OS at 1, 3, and 5 years after ¹²⁵I particle implantation brachytherapy for late-stage lung cancer as well as 1-year progression-free survival (PFS).

Results: The results of univariate and multivariate Cox proportional hazards model analyses of OS time showed that smoking, lung atelectasis, superior vena cava obstruction syndrome, and surgical time were significantly associated with OS of patients, and were independent influencing factors. The results of univariate and multivariate Cox proportional hazards model analyses of PFS demonstrated that planning target volume, maximum dose, average dose, pre-operative D₉₀ and V₁₀₀ at 1 cm around the lesion, and surgical time were significantly associated with PFS of patients, and were independent influencing factors. Based on these independent prognostic factors, nomogram models were constructed to predict the 1-, 3-, and 5-year OS and 1-year PFS of late-stage lung cancer patients.

Conclusions: This study revealed the potential benefits of ¹²⁵I particle implantation brachytherapy for the OS rate of late-stage lung cancer patients.