Treatment of localized pulmonary pleomorphic adenocarcinoma: A systematic review and meta-analysis.

e20040 Background: Pulmonary pleomorphic adenocarcinoma (PPADC) is a rare, aggressive subtype of non-small cell lung cancer (NSCLC) classified under pulmonary pleomorphic carcinoma (PPC), defined as NSCLC with ≥10% spindle or giant cell components or entirely sarcomatoid elements. Optimal treatment for localized disease remains undefined, with surgical resection as the mainstay and uncertain benefits from perioperative chemotherapy or radiotherapy. Methods: A systematic search of PubMed, Cochrane, and ClinicalTrials.gov was conducted in accordance with PRISMA guidelines, identifying five studies on localized PPADC treatment. Inter-study heterogeneity was evaluated using the DerSimonian-Laird estimator. Pooled analyses with 95% confidence intervals (CIs) were conducted via the 'meta' package in R (version 4.16-2). Results: Across five retrospective studies (2007-2018), 162 patients with localized PPADC were analyzed. Median age was 64.7 years (range, 35-90); 85% (n=138) were male. Disease distribution: stage I, 40% (n=66); stage II, 40% (n=64); stage III, 20% (n=32). Tumors were predominantly upper-lobe (70%, n=123) and peripheral (31%, n=51), with a median size of 49 mm (range, 11-100). Median follow-up was 32 months (range, 5-120). Neoadjuvant chemotherapy was rare (n=2/162, 1.2%; poor response). All underwent curative-intent resection; adjuvant chemotherapy/radiation was inconsistent. Pooled 5-year overall survival (OS) was 41.7% (95% CI, 32.3-51.4; I²=91%; P<0.01; n=107); disease-free survival (DFS), 46.7% (95% CI, 32.3-61.3; I²=70%; P=0.07; n=47). Pooled 1-year recurrence rate was 40% (95% CI, 30.2-50.1; I²=0%; P=0.40; n=95). Reported adverse events (Ji et al.): atrial fibrillation (7%, n=4/60), prolonged air leak (5%, n=3), infection (3%, n=2), hemothorax requiring reoperation (2%, n=1), hoarseness (2%, n=1). Conclusions: Localized PPADC is associated with poor long-term outcomes despite curative resection. Evidence is constrained by small retrospective series and variable perioperative therapy use. Prospective trials are essential for refining strategies and improving patient selection.