Background     Malignant pleural effusions (MPEs) are a common cause of dyspnea, cough, and chest pain in patients with cancer. Most are due to metastases to the pleura by either lung or breast cancer (50-65% of all MPEs), lymphoma (10%), or ovarian or gastric cancer (5%) (1,2).  Mesothelioma is the most common primary pleural tumor and is highly associated with MPEs as well. MPEs are a sign of advanced disease that usually upstage cancer to stage four (3).  When found in a cancer refractory to systemic treatment, prognosis may only be 4-6 months (4).  Survival is worse for patients with a poor functional status and better in those who are naïve and/or sensitive to systemic cancer treatment.

Clinical presentation   Dyspnea and cough are very common, however, 15% of MPEs are asymptomatic (5). On physical examination, a dullness to percussion and reduction in air exchange may be appreciated in the dependent part of the lung.  A large, unilateral effusion is seen on imaging (e.g., chest x-ray, CT scan, ultrasound). Definitive diagnosis comes from cytology of the fluid or a pleural biopsy.

Symptom causality   The cause of dyspnea, even in the presence of a known MPE, is not always evident. The size of the effusion may not correlate with symptom severity either (6). Common confounding problems include congestive heart failure, chronic obstructive pulmonary disease, pulmonary emboli, pericardial effusion, lung metastases, ascites, and radiation lung injury. A ‘diagnostic’ therapeutic thoracentesis may determine if removal of fluid leads to symptom improvement. The decision to proceed with thoracentensis should be made after considering the overall goals of care, functional status, prognosis, and co-morbid conditions. It was once prevailing wisdom that no more than 1.5 L of fluid be removed at any a time to prevent reexpansion edema, but research suggests that large effusions can be drained completely in many cases (7,8).

Management options   While symptom relief from a therapeutic thoracentesis usually comes immediately, reaccumulating fluid occurs in 98% by 30 days (2,5). 

• Repeated thoracentesis is appropriate for patients with a short prognosis (weeks).  Problems associated with this approach include the need for repeated procedures, pneumothorax, infection, and the development of loculation.
• Chest tube drainage alone: the use of a large-bore tube to drain the pleural cavity followed by the tube’s removal, without sclerosis. This prevents re-accumulation in at 30 days in 11-40% (5,9).
• Systemic chemotherapy or hormonal therapy is the best long-term management option for treatment sensitive tumors (see Fast Fact #14 and Fast Fact #99). 
• Chemosclerosis requires chest tube insertion followed by instillation of a sclerosing agent.  In carefully selected patients, it has a 1-month success rate of 70-95% (5,9). Heavy tumor burden, reflected by low pleural pH (<7.2) or glucose concentration (< 3.3 mmol/L), is associated with a lower success rate and shorter survival (10). Talc is inexpensive and has the lowest re-accumulation rates (3-8% after 30 days), compared to doxycycline and bleomycin (3). Talc is rarely associated with ARDS and systemic embolization; more common side effects are pain and fever. Sclerosis requires a large-bore chest tube which often remains in place for 5-7 days – a major consideration in patients with a short prognosis. Adequate pain management is crucial regardless of sclerosis technique.
• Video-assisted thoracoscopic surgery: this is a surgical procedure in which a small tube with a camera (thoracoscope) and other small instruments are inserted in several small incisions.  Surgeons can deflate the lung allowing for better visualization to determine if pleurodesis, decortication, or pleurectomy should be performed. It is reserved for those with good functional status. While it has a high success rate (>90% with 30-day resolution), it is associated with higher cost, clinical complication rate, in-hospital mortality (1-8%), and length of hospital stay (11-13).
• Indwelling tunneled pleural catheters involve a cuff which is tunneled under the skin to prevent infections. Once installed, the fluid can be drained as needed even as an outpatient (typically with the help of a home nurse). In a cost analysis study, tunneled pleural catheters were found to be the most cost-effective management approach when prognosis was 3 months or less (14).  A retrospective study showed symptom improvement in 96% of patients at 2 weeks post insertion; spontaneous pleurodesis was noted in 44% of all patients (15).
• Pleuroperitoneal shunts are occasionally indicated in patients with intractable effusions and trapped lungs.  The shunt drains pleural fluid into the abdomen via a subcutaneous reservoir that the patient must pump ~ 400 times/day. Cost, limited efficacy and frequent malfunctioning all limit usefulness of this procedure. In addition, malignant ascites can occur if the patient lives long enough (3).
• Pleurectomy is only indicated in patients who are expected to have a prolonged survival. There is significant associated morbidity (20%) and mortality (10%) (16).

References 

1. Psallidas I, Kalomenidis I, Porcel JM, Robinson BW, Stathopoulos GT. Malignant pleural effusion: from bench to bedside. Eur Respir Rev. 2018;25(140):189-198.
2. Gayen S.  Malignant pleural effusion: presentation, diagnosis, and management. The American Journal of Medicine 2022; 135(10):1188-1192.
3. Belani CP, Pajeau TS, Bennett CL. Treating malignant pleural effusions cost consciously. Chest. 1998; 113:78S-85S.
4. Putnam JB,Jr. Malignant pleural effusions. Surg Clin North Am. 2002; 82:867-883.
5. American Thoracic Society Management of malignant pleural effusions Am J Respir Crit Care Med. 2001; 162(5):1987-2001.
6. Koegelenberg CFN, Shaw JA, Irusen EM, et al.  Contemporary best practice in the management of malignant pleural effusion. Ther Adv Respir Dis 2018; 1753466618785098.
7. Feller-Kopman D, Berkowitz D, Boiselle P, et al.  Large-volume thoracentesis and the risk of reexpansion pulmonary edema. The Annals of Thoracic Surgery 2007; 84(5):1656-61.
8. Grodzin CJ, Balk RA. Indwelling small pleural catheter needle thoracentesis in the management of large pleural effusions. Chest. 1997; 111:981-988.
9. DeCamp MM,Jr, Mentzer SJ, Swanson SJ, Sugarbaker DJ. Malignant effusive disease of the pleura and pericardium. Chest. 1997; 112:291S-295S.
10. Heffner JE, Nietert PJ, Barbieri C. Pleural fluid pH as a predictor of pleurodesis failure: Analysis of primary data. Chest. 2000; 117:87-95.
11. Shaw P, Agarwal R. Pleurodesis for malignant pleural effusions. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD002916. DOI: 10.1002/14651858.CD002916.pub2.
12. Belani C, Einarson TR, Arikian SR, Doyle J. Cost-effectiveness analysis of pleurodesis in the management of malignant pleural effusion. J Oncology Management. 1995; Jan/Feb:24-34.
13. Cardillo G, Facciolo F, Carbone L, et al.  Long-term follow-up of video assisted talc pleurodesis in malignant recurrent pleural effusions.  Eur J Cardiothorac Surg 2002; 21(2):302-306.
14. Puri V, Pyrdeck TL, et al. Treatment of malignant pleural effusion: a cost-effectiveness analysis. The Annals of Thoracic Surgery 2012; 94:374-380.
15. Tremblay A, Michaud G. Single-center experience with 250 tunnelled pleural catheter insertions for malignant pleural effusion. Chest. 2006; 129:362-368.
16. Rusch VW. Pleurectomy/decortication and adjuvant therapy for malignant mesothelioma. Chest. 1993; 103:382S-384S.

Version History:  This Fast Fact was originally edited by David E Weissman MD and published in June 2006.  Version copy-edited in April 2009; revised again July 2015; reviewed and updated again in October 2025.
Conflicts of interests: None to report.