Prognostic significance of metabolic response by positron emission tomography after neoadjuvant chemotherapy for resectable malignant pleural mesothelioma

Our plain-English summary of Prognostic significance of metabolic response by positron emission tomography after neoadjuvant chemotherapy for resectable malignant pleural mesothelioma, by Y. Tsutani, T. Takuwa, Y. Miyata, et al (Annals of Oncology, 2013).

The study

• Authors: Y. Tsutani, T. Takuwa, Y. Miyata, K. Fukuoka, S. Hasegawa, T. Nakano, M. Okada
• Journal: Annals of Oncology
• Published: 2013;24(4):1005-10
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: To select optimal candidates for extrapleural pneumonectomy (EPP), we retrospectively evaluated the usefulness of metabolic response by fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) after neoadjuvant chemotherapy to predict prognosis for patients with resectable malignant pleural mesothelioma (MPM) who underwent EPP in a multicenter study.

Patients And Methods: We carried out high-resolution CT (HRCT) and FDG-PET/CT before and after neoadjuvant platinum-based chemotherapy on 50 patients with clinical T1-3 N0-2 M0 MPM who underwent EPP ± postoperative hemithoracic radiotherapy. A decrease of ≥30% in the tumor maximum standardized uptake value (SUVmax) was defined as a metabolic responder. The radiologic response using the modified RECIST or metabolic response and surgical results were analyzed.

Results: The median overall survival (OS) from diagnosis was 20.5 months. Metabolic responders significantly correlated to OS with median OS for metabolic responders not reached versus 18.7 months for non-responders. No correlation was observed between OS and radiologic response with median OS for radiologic responders and non-responders. Based on the multivariate Cox analyses, decreased SUVmax and epithelioid subtype were significantly independent factors for OS.

Conclusions: The metabolic response after neoadjuvant chemotherapy is an independent prognostic factor for patients with resectable MPM. Patients with metabolic responder or epithelioid subtype may be good candidates for EPP.

In plain English

This retrospective study from two Japanese institutions examined 50 patients with resectable malignant pleural mesothelioma. Between 2004 and 2011 they received cisplatin-based chemotherapy, then extrapleural pneumonectomy. This operation is defined as removing the lung, pleura, pericardium and diaphragm; the latter two were sometimes partly or not removed. The article does not discuss asbestos exposure. Tumors were scanned by CT and FDG-PET/CT before and after chemotherapy. Patients whose tumor's maximum FDG uptake (SUVmax) fell by 30% or more were "metabolic responders"; 14 qualified. Median overall survival from diagnosis was 20.5 months (95% CI 15.0–26.0) for all 50 patients. Metabolic responders' median survival was not reached; their 3-year survival rate was 60.0%. For the 36 non-responders these were 18.7 months (95% CI 13.3–24.2) and 26.5% (P = 0.025 for the comparison). Radiologic response on CT was not significantly associated with survival (P = 0.22). In multivariate analysis, SUVmax decrease and epithelioid subtype were independent factors for survival. The authors concluded that patients with these features may be suitable candidates for this surgery. They noted the small, retrospective design and called for confirmation in a larger cohort.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective multicenter study of patients drawn from a prospective database
• Who was studied: 50 patients with clinical T1–3 N0-2 M0 malignant pleural mesothelioma who underwent extrapleural pneumonectomy at Hyogo College of Medicine and Hiroshima University, Japan, between 1 January 2004 and 31 December 2011. They came from 73 patients scheduled for multimodality therapy. Of those, 11 were excluded because they did not undergo EPP and 12 because PET/CT data were lacking. Of the 50, 45 (90%) were male. Histology was epithelioid in 38 (76%), biphasic in 10 (20%) and sarcomatoid in 2 (4%).
• Exposure: The article does not report asbestos or other occupational exposure. The treatment studied was three to four cycles of neoadjuvant platinum-based chemotherapy, mainly cisplatin plus pemetrexed (47 patients, 94%). This was followed by extrapleural pneumonectomy, with or without postoperative hemithoracic radiotherapy. Response was measured by modified RECIST on CT and by change in SUVmax on FDG-PET/CT.
• Main results:
  • For all 50 patients, median overall survival from diagnosis was 20.5 months (95% CI 15.0–26.0 months), and the 3-year survival rate was 34.2%.
  • By CT (modified RECIST), 20 patients (40%) were radiologic responders. Their median survival was 25.7 months (95% CI 14.5–37.0; 3-year rate 35.8%). The 30 non-responders had a median survival of 17.7 months (95% CI 12.8–22.6; 3-year rate 35.1%). The difference was not significant (P = 0.22).
  • By PET, 14 patients (28%) were metabolic responders: 1 complete and 13 partial responses. Their median survival was not reached (3-year rate 60.0%). The 36 non-responders had a median survival of 18.7 months (95% CI 13.3–24.2; 3-year rate 26.5%). P for the comparison of responders with non-responders was 0.025.
  • Patients with epithelioid subtype (n = 38) had a median survival of 22.4 months and a 3-year rate of 39.4%. Patients with non-epithelioid subtype (n = 12) had a median survival of 14.9 months and a 3-year rate of 0%. P was 0.072.
  • In multivariate analysis (model 2), two factors were independent prognostic factors for overall survival: epithelioid histology (HR 0.36; 95% CI 0.14–0.97; P = 0.04) and SUVmax decrease (HR 0.80; 95% CI 0.67–0.95; P = 0.01).
  • Surgical results for all 50 patients: complete macroscopic resection in 48 (96%), one postoperative death (30-day mortality 2.0%), and major complications in 16 (32%).
• The authors' conclusion: The authors concluded that epithelioid subtype and metabolic response after neoadjuvant chemotherapy are both independent prognostic factors for patients with resectable MPM who underwent EPP. They concluded that such patients may be suitable candidates for EPP after neoadjuvant chemotherapy. They also stated that further confirmation in a large cohort is required.
• Limitations the authors state:
  • Relatively small number of patients, retrospective design, and no comparison with pleurectomy/decortication or nonsurgical patients
  • SUV values vary widely among institutions, which affects a multicenter PET study

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Neoadjuvant Chemotherapy, Pleural Mesothelioma, Extrapleural Pneumonectomy (EPP), Prognosis, High-Resolution CT (HRCT), Chemotherapy, Modified RECIST (mRECIST), Median Overall Survival.

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• Does positron emission tomography offer prognostic information in malignant pleural mesothelioma? — S. Sharif, I. Zahid, et al. (2011)
• Clinical implications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography at delayed phase for diagnosis and prognosis of malignant pleural mesothelioma — Y. Abe, K. Tamura, et al. (2012)
• Positron Emission Tomography/Computed Tomography for the Pleural Staging of Malignant Pleural Mesothelioma: How Accurate Is It? — V. Pinelli, E. Roca, et al. (2015)
• Integrated positron emission tomography-computed tomography does not accurately stage intrathoracic disease of patients undergoing trimodality therapy for malignant pleural mesothelioma — J. Pilling, J.A. Dartnell, et al. (2010)
• 18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours — D.J. De Maeseneer, B. Lambert, et al. (2010)

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