Objective To evaluate the reporting quality and influencing factors of patient-reported outcome (PRO) data in lung cancer randomized controlled trials (RCTs) from 2010 to 2024. Methods RCTs of lung cancer with PRO as either primary or secondary endpoints were searched from PubMed, EMbase, Medline, CNKI (China National Knowledge Infrastructure), Wanfang Data Knowledge Service Platform, and VIP Chinese Journal Service Platform between January 1, 2010 and April 20, 2024. Reporting quality of included RCT were assessed based on the CONSORT-PRO extension. Descriptive statistics and bivariate regression analysis were used to describe the reporting quality and analyze the factors influencing the reporting quality. Results A total of 740 articles were retrieved. After screening, 53 eligible lung cancer RCTs with 22 780 patients were included. The patients mainly were non-small cell lung cancer (84.91%), with the median sample size was 364 (160.50, 599.50) patients. The primary PRO tool used was the EORTC QLQ-C30 (60.38%). There were 52 studies (98.11%) whose PRO measured the domain of "symptom management of cough, dyspnea, fatigue, pain, etc.", and 45 studies (84.91%) measured "health-related quality of life." Multicenter studies accounted for 84.91%, and randomized non-blind trials accounted for 62.26%. PRO was used as the primary endpoint in 33.96% of the studies and as secondary endpoints in 66.04%. The reliability and validity of the PRO tools were explicitly mentioned in 11.32% and 7.55% of the studies, respectively. The average completeness of reporting according to the CONSORT-PRO guidelines was 60.00%, ranging from 25% to 93%. The main factors affecting the completeness of CONSORT-PRO reporting included sample size and publication year. For each additional sample size, the completeness of reporting increased by 27.5% (SE=0.000, t=2.04, P=0.046). Additionally, studies published after 2019 had a 67.2% higher completeness of reporting compared to those published in or before 2019 (SE=0.178, t=–3.273, P=0.006). Conclusion The study reveals that the overall reporting quality of PRO in lung cancer RCTs is poor. Particularly, the reporting of patient reported outcome measures reliability and validity, PRO assumptions, applicability, and handling of missing data needs further improvement. Future research should emphasize comprehensive adherence to the CONSORT-PRO guidelines.