Pulmonary nodules in breast cancer patients: prevalence, diagnostic intervention rate, and pathologic spectrum

Pulmonary nodules are frequently detected during staging or follow-up in breast cancer, yet their prevalence, the use of invasive diagnostic intervention, and the pathologic spectrum remain uncertain. We searched PubMed, Embase, Web of Science, Cochrane Library, and Chinese databases from inception to 16 October 2025 for observational studies of pulmonary nodules in patients with breast cancer. Random-effects meta-analyses estimated nodule prevalence in CT-based cohorts, the proportion undergoing invasive diagnostic intervention among patients with nodules, and the pathological spectrum among pathologically confirmed nodules. Twenty-seven studies were included. Eleven CT-only studies ( n = 13,363) yielded a pooled pulmonary nodule prevalence of 13.1% (95% CI 5.6–27.4%). Prevalence was 9.8% (95% CI 5.0–18.3%) at initial staging and 12.5% (95% CI 0.1–96.2%) during follow-up. Across seven studies involving 3,163 patients with nodules, the pooled invasive diagnostic intervention proportion was 15.3% (95% CI 6.6–31.6%). Among pathologically confirmed nodules (17 studies, n = 1,223), pooled proportions were 17.5% benign (95% CI 13.0–23.1%), 46.3% primary lung cancer (95% CI 34.9–58.1%), and 37.6% metastatic breast cancer (95% CI 29.7–46.2%). Pulmonary nodules were detected in about 13% of patients with breast cancer undergoing CT, and a minority of patients with nodules underwent invasive diagnostic intervention. Among pathologically confirmed nodules, PLC and MBC were both common, with benign disease also contributing substantially. Pulmonary nodules in patients with breast cancer should therefore not be presumed metastatic; clinical assessment should consider alternative diagnoses and whether tissue confirmation would change management. PROSPERO CRD420261328733.