Procedure-related tumour seeding in lung cancer with malignant pleural effusion: Radiological features and outcomes

Introduction: Pleural procedures are performed to prove the diagnosis of pleural effusion. This study was to assess the incidence and outcome of pleural procedure-related tumour seeding in lung cancer with malignant pleural effusion, and to review the characteristics of the implanted tumours on computed tomography (CT) images. Methods: From January 2008 to December 2010, 165 patients with the diagnosis of lung cancer with malignant pleural effusion, who underwent at least one pleural procedure and had follow-up CT, were included. Two radiologists retrospectively reviewed the presence of implanted tumours and their manifestations on CT images. The incidence of tumour seeding, the time to tumour seeding, and hazard ratios for death associated with the procedures and presence of tumour seeding were evaluated. Multivariable logistic regression analysis was used to identify variables that were independently associated with procedure-related tumour seeding. Results: The incidence of procedure-related tumour seeding was 22.4%. Conventional intercostal drainage (ICD) was the independent predictor of tumour seeding. Patients with a history of ICD rapidly developed implanted tumours (P = 0.0319). The estimated mean time of tumour seeding was 2.9 months. There was an increased risk of death with the presence of tumour seeding (HR: 3.35, 95% CI: 1.87-6.01). The majority of CT features showed ill-defined margins with heterogeneous enhancement. Conclusion: Pleural procedure-related tumour seeding in lung cancer with malignant pleural effusion is common. There was a significantly increased risk of death with the presence of tumour seeding. The majority of the CT features in implanted tumours were ill-defined margins with heterogeneous enhancement.