High SUVmax on FDG-PET Indicates Pleomorphic Subtype in Epithelioid Malignant Pleural Mesothelioma

ArticleinJournal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 7(7):1192-7 · May 2012with11 Reads
Impact Factor: 5.28 · DOI: 10.1097/JTO.0b013e3182519d96 · Source: PubMed

    Abstract

    We have recently proposed to reclassify the pleomorphic subtype of epithelioid malignant pleural mesothelioma (MPM) as nonepithelioid (biphasic/sarcomatoid) histology because of its similarly poor prognosis. We sought to investigate whether preoperative maximum standardized uptake value (SUVmax) on F-fluorodeoxyglucose (FDG) positron emission tomography (PET) correlates with histologic subtype in MPM.
    Clinical data were collected for 78 patients with MPM who underwent preoperative FDG-PET. We retrospectively classified the epithelioid tumors into five subtypes: trabecular, tubulopapillary, micropapillary, solid, and pleomorphic. Tumors were categorized by SUVmax into two groups: low (<10.0) and high (≥10.0).
    The median overall survival of epithelioid tumors with high SUVmax (n = 12) was significantly shorter (7.1 months) than that of epithelioid tumors with low SUVmax (n = 54, 18.9 months, p < 0.001) and comparable to nonepithelioid tumors (n = 12, 7.2 months). Epithelioid tumors with pleomorphic subtype (n = 9) had marginally higher SUVmax (mean ± SD: 10.6 ± 5.9) than epithelioid nonpleomorphic subtype (n = 57, 6.5 ± 3.2, p = 0.050), and were comparable to that of nonepithelioid tumors (n = 12, 9.1 ± 4.8). Among the epithelioid tumors with high SUVmax (n = 12), 50% (n = 6) showed pleomorphic subtype. In contrast, among epithelioid tumors with low SUVmax (n = 54), 6% (n = 3) showed epithelioid pleomorphic subtypes (p = 0.001). A positive correlation between mitotic count and SUVmax was observed (r = 0.30, p = 0.010).
    Pleomorphic subtype of epithelioid MPM showed higher SUVmax than the epithelioid nonpleomorphic subtype and was similar to nonepithelioid histology. Preoperative SUVmax on FDG-PET in epithelioid MPM can indicate patients with pleomorphic subtype with poor prognosis, supporting their reclassification as nonepithelioid.