Lung cancer screening (LCS) is effective in reducing mortality, particularly when patients adhere to follow-up recommendations standardized by the Lung CT Screening Reporting & Data System (Lung-RADS). However, patient adherence to recommended intervals varies, potentially diminishing benefit from screening. We conducted a systematic review and meta-analysis of patient adherence to Lung-RADS recommended screening intervals. METHODS: We systematically searched MEDLINE, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and major radiology and oncology conference archives between Apr 28, 2014 and Dec 17, 2020. Eligible studies mentioned patient adherence to Lung-RADS recommendations. The review protocol was registered with PROSPERO (CRD42020189326). RESULTS: We identified 24 eligible studies for qualitative summary, of which 21 were suitable for meta-analysis. The pooled adherence rate was 57% (95% confidence interval (CI): 46-69%) for defined adherence (e.g., an annual incidence screen was performed within 15 months) among 6689 patients and 65% (95% CI: 55-75%) for anytime adherence among 5085 patients. Large heterogeneity in adherence rates between studies was observed (I(2)=99% for defined adherence, I(2)=98% for anytime adherence). Heterogeneous adherence rates were associated with Lung-RADS scores, with significantly higher adherence rates among Lung-RADS 3-4 than Lung-RADS 1-2 (p<0.05). CONCLUSIONS: Patient adherence to Lung-RADS recommended screening intervals is suboptimal across clinical LCS programs in the US, especially among patients with Lung-RADS category 1-2 results. To improve adherence rates, future research may focus on implementing tailored interventions after identifying barriers to LCS. We also propose a minimum standardized set of data elements for future pooled analyses of LCS adherence based on our findings.