Incidence and risk factors for malignancy in patients with incidental solitary pulmonary nodules: a systematic review and meta-analysis.
Huiyu Zheng, Zhipeng Shao, Wensong Shi et al.
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In 30 seconds
This systematic review and random-effects meta-analysis assessed malignancy rates and associated factors in patients with incidentally detected solitary pulmonary nodules (SPNs). Across 54 studies involving 19,985 patients, the pooled malignancy rate was 56.7% (95% CI: 51.5-62.0). Estimates varied substantially between studies (I² = 98.5%, p < 0.001), and the rate was 54.7% (95%CI: 50.9-58.8) after adjustment for potential publication bias. Several patient and imaging characteristics were associated with higher or lower malignancy risk.
Key findings
- The pooled malignancy rate was 56.7% (95% CI: 51.5-62.0) across 54 studies and 19,985 patients.
- Between-study heterogeneity was substantial (I² = 98.5%, p < 0.001); the publication-bias-adjusted estimate was 54.7% (95%CI: 50.9-58.8).
- Older age, cancer history, smoking, larger diameter, and several suspicious imaging features were associated with increased malignancy risk.
- Male sex, calcification, and clear borders were associated with reduced malignancy risk.
Why it matters
The pooled estimate and associated clinical and imaging features may inform risk stratification and follow-up decisions for incidental SPNs. However, the overall malignancy rate should not be applied uncritically to every setting: the authors note marked heterogeneity and a high proportion of retrospective studies and populations from high-risk regions.
What to keep in mind
The pooled estimate had substantial between-study heterogeneity, and the evidence included a high proportion of retrospective studies and populations from high-risk regions.