There are no large prospective studies comparing the optimal technique for obtaining a diagnostic specimen for MPM. Common methods include cytologic analysis and pleural biopsy (Abrams needle, computed tomography (CT)-guided, thoracoscopy, and open biopsy).
Although tissue biopsy is generally preferred, cytologic analysis of the pleural fluid is often an initial consideration, since patients commonly present with a pleural effusion. The sensitivity of cytology alone ranges widely between 32% and 76%.17 This is likely due to sampling rather than interpretation; therefore, an adequate amount of fluid is necessary to ensure sufficient cell concentration. The addition of immunohistochemistry enhances the diagnostic accuracy.
The diagnostic sensitivity of thoracoscopy for MPM is as high as 94%–98% in case series.22–24 This is in contrast to diagnostic rates of 21%–71% with blind pleural biopsy and 83%–88% with CT-guided needle biopsy.23,25–29 Thoracoscopy also has the advantage of allowing additional staging information to be obtained in those patients being considered for surgery.
Patients are staged according to the IMIG TNM staging system, which was approved by the American Joint Committee on Cancer and the International Union for Cancer Control (Table 1).
(To view a larger version of Table 1, click here.)