title: High SUVmax on FDG-PET indicates pleomorphic subtype in epithelioid malignant pleural mesothelioma: supportive evidence to reclassify pleomorphic as nonepithelioid histology.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Thoracic Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Kyuichi
authors.initials: K
authors.lastname: Kadota
authors.forename: Stefan S
authors.initials: SS
authors.lastname: Kachala
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Nitadori
authors.forename: Kei
authors.initials: K
authors.lastname: Suzuki
authors.forename: Mark P S
authors.initials: MP
authors.lastname: Dunphy
authors.forename: Camelia S
authors.initials: CS
authors.lastname: Sima
authors.forename: William D
authors.initials: WD
authors.lastname: Travis
authors.forename: Valerie W
authors.initials: VW
authors.lastname: Rusch
authors.forename: Prasad S
authors.initials: PS
authors.lastname: Adusumilli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002296:Carcinosarcoma / Q000145:classification / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008654:Mesothelioma / Q000145:classification / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D008875:Middle Aged; D009367:Neoplasm Staging; D009375:Neoplasms, Glandular and Epithelial / Q000145:classification / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D010997:Pleural Neoplasms / Q000145:classification / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D015996:Survival Rate