Almost all forms of cancer are reported to cause pleural effusions. In their review, Hausheer and Yarbro summarized six large series of malignant pleural effusions (MPEs). In aggregate, they found over two thirds of all malignant effusions were attributed to carcinomas of the lung (35%) and breast (23%) and to lymphoma (10%). The next most common etiology was adenocarcinoma of unknown primary, accounting for 95 of 811 cases (12%). Given the prevalence of breast and lung carcinoma, it is not surprising that some investigators report up to 50% of patients afflicted with these malignancies will develop MPE at some time during their disease. Such observations are currently 2 to 4 decades old, and have been criticized as being outdated given oncologic advances. This may be valid regarding breast cancer treatment, in which survival has been much improved. Alternatively, longer survival may unmask or allow for more recurrences, including those within the pleura. As for lung cancer, the incidence of this malignancy continues to rise with little improvement in effective therapies for advanced disease. Therefore, little reason exists to doubt the lung cancer MPE data from past decades. canadian health&care mall
Presentation and Diagnosis
Most patients with MPE present with symptoms. Fewer than 25% of patients thus diagnosed have no respirator) complaints. This figure may increase as aggressive oncologic follow-up allows new malignant effusions to be detected before symptoms arise. Dyspnea is the predominant complaint when symptoms are present, although it may be subtle, occurring only with increased activity. Cough and chest pain are the other common presenting complaints. The discomfort varies from sharp and pleuritic in nature to a more dull ache often characterized as heaviness or pressure. Physical examination usually reveals decreased breath sounds dependency with dullness to percussion and decreased fremitus. Tracheal deviation may be seen when effusions become large. A history of malignancy biases the treating clinician to consider MPE high in the differential diagnosis of new-onset dyspnea. In patients without prior cancer diagnoses, MPE is still a relatively common problem. In separate reports of nearly 100 new cancer cases each, Chernow and Sahn and Martini et al found MPE as the presenting process in 46% and 64% of cases, respectively.