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Primary tumour resection showed survival benefits for non-small-cell lung cancers with unexpected malignant pleural dissemination.

OBJECTIVES
Although non-small-cell lung cancer (NSCLC) with malignant pleural nodules is generally contraindicated for surgery, there is no consensus concerning on-site operative decisions for unexpected, intraoperatively encountered malignant pleural disseminations. The rationale underlying the primary tumour removal and other aggressive interventions remains controversial.


METHODS
All surgical NSCLC cases (9576) of Shanghai Pulmonary Hospital between January 2005 and December 2013 were reviewed. Among them, 83 cases (0.9%) met the definition of 'unexpected' macroscopic malignant pleural nodules, despite routine preoperative evaluations for tumour metastasis. No pleural effusion was visualized in 52 cases during operations, and 31 had pleural effusion in minimal volume (<300 ml). Survivals were calculated with the Kaplan-Meier method and risk factors were evaluated by the log-rank test.


RESULTS
The overall 3- and 5-year survival rates were 36.1 and 16.8%, respectively. The median survival time (MST) after surgery was significantly longer in the group without pleural effusion (37 months) compared with the group with pleural effusion (22 months, P = 0.005). Twenty-one cases had only biopsy, whereas 62 cases had primary tumour resection. Primary tumour resection had significantly better outcome compared with biopsy (MST: respectively, 35 vs 17 months, 3-year survival rate 45.8 vs 11.8%, P = 0.001). No baseline differences emerged in characteristics between biopsy and primary tumour resection groups including targeted therapy. Multivariate analysis showed that primary tumour resection (HR: 3.678, P = 0.014), no pleural effusion (HR: 3.409, P = 0.001) and adenocarcinoma (HR: 5.481, P = 0.002) were favourable prognostic factors in patients with malignant pleural nodules.


CONCLUSIONS
Patients with malignant pleural nodules but without pleural effusion had better survival compared with those with effusions. Primary tumour resection had survival benefits for patients with unexpected intraoperatively proven malignant pleural nodules.