Lung cancer with air lucency: a systematic review and clinical management guide

BACKGROUND: Lung cancers with air lucency are poorly understood, often recognized only after substantial progression. METHODS: From a systematic review (PubMed and EMBASE, 2000–2022, terms related to cystic, cavitary, bulla, pseudocavitary, bubble-like, date 10-30-2022) 49 studies were selected using broad inclusion criteria (case series of ≥10 cases up to trials and reviews). There was no source of funding. Primary evidence relevant to clinical management issues was assembled. Because data was available only from heterogeneous retrospective case series, meta-analysis and formal risk-of-bias assessment was omitted. A framework was developed to guide clinical management based on the available data. RESULTS: Demographic, smoking and histologic differences suggest that cystic, cavitary and bullous lung cancers with air lucency may be distinct entities; insufficient data leaves it unclear whether this also applies to pseudocavitary (solid) or bubble-like (ground glass) cancers. Annual observation of irregular thin-walled cysts is warranted; a surgical diagnosis (and resection) is justified once a solid component appears because subsequent progression is often rapid with markedly worse outcomes. Bubble-like ground glass lesions should be managed similarly. Cavitary lesions must be distinguished from infection or vasculitis, but generally require needle or surgical biopsy. Pseudocavitary lesions are less well studied; positron emission tomography may be useful in this setting to differentiate scar from malignancy. Further research is needed because these conclusions are based on interpretation of retrospective case series. CONCLUSIONS: The aggregate of available evidence suggests a framework for management of suspected lung cancers with air lucency. Greater awareness, earlier detection, and aggressive management once a solid component appears are needed. This review and framework should facilitate further research; questions include whether the suggested entities and proposed management are borne out and should involve clearly defined terms and outcomes related to progression and treatment. In summary, a conceptual understanding is emerging from interpretation of available data about a previously poorly understood topic; this should improve patient outcomes.