Abstract:

Background and purpose: More and more patients with multiple primary early-stage lung cancer are choosing to receive stereotactic body radiation therapy (SBRT), and this study aimed to retrospectively analyze the efficacy and prognostic factors of SBRT. Methods: In this study, patients who underwent SBRT at Shanghai Chest Hospital, Shanghai Jiao Tong University School of Medicine from August 2014 to December 2020 and who met the inclusion criteria were included. Patients with multiple primary early-stage lung cancer were examined for efficacy and prognostic factors. After using propensity score matching (PSM), the difference in efficacy of SBRT between single and multiple primary early-stage lung cancer was observed. Results: This study included 241 early-stage lung cancer patients with SBRT, including 94 patients with multiple primary early-stage lung cancer. The 3- and 5-year local control rate (LC), progression-free survival (PFS) and overall survival (OS) were 87.1% and 71.3%, 84.0% and 66.9%, 93.3% and 79.3% in multiple primary early-stage lung cancer, respectively. Patients with multiple primary early-stage lung cancer did not experience any grade 3 or higher pulmonary toxicity with an overall toxicity incidence of 54.3%, and grade 2 toxicity occurred in 24 patients (25.5%). There was a total of 18 (19.1%) recurrences, and there were 3 (3.2%), 1 (1.1%), 12 (12.7%) and 2 (2.1%) patients with multiple primary early-stage lung cancers who experienced local recurrence, regional recurrence, distant metastasis and uncertain death, respectively. Patients with multiple primary early-stage lung cancer and those with single primary early-stage lung cancer had significant differences in clinical features prior to PSM. After PSM, there were 56 patients with multiple primary early-stage lung cancer and 56 patients with single primary early-stage lung cancer, and there was no statistically significant difference in LC (P = 0.291), PFS (P = 0.954) and OS (P = 0.880). Age≥70 years was an independent risk factor for OS of multiple primary early-stage lung cancer, according to an analysis of the prognostic variables of SBRT in 94 patients with multiple primary early-stage lung cancer. Regarding synchronous (≤180 d) and metachronous (>180 d) multiple primary early-stage lung cancer, there was no discernible difference between the two groups (P = 0.440). There was no significant difference in the total number of treatments for multiple primary early-stage lung cancer (P = 0.232) and no significant difference in the type of treatment for multiple primary early-stage lung cancer (P = 0.225) among 59 patients with synchronous multiple primary early-stage lung cancer within 5 years of the first-to-last treatment interval. Conclusion: SBRT has a strong and comparable efficacy for multiple primary early-stage lung cancer compared with single primary early-stage lung cancer, making it a viable treatment choice. Based on age and tumor biological behavior of the lesion, future strategies and procedures for local intervention of multiple primary early-stage lung cancer need to be investigated.

Key words: Multiple primary early-stage lung cancer, Stereotactic body radiation therapy, Propensity score matching, Prognosis