The role of 18F-FDG-PET/ceCT in peritoneal mesothelioma

Our plain-English summary of The role of 18F-FDG-PET/ceCT in peritoneal mesothelioma, by J. Dubreuil, F. Giammarile, P. Rousset, et al (Nuclear Medicine Communications, 2017).

The study

• Authors: J. Dubreuil, F. Giammarile, P. Rousset, D. Rubello, N. Bakrin, G. Passot, S. Isaac, O. Glehen, A. Skanjeti
• Journal: Nuclear Medicine Communications
• Published: 2017;38(4):312-318
• Cited by: 28 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose: The aim of this study was to assess glucose metabolism of multicystic peritoneal mesothelioma and epithelioid peritoneal mesothelioma by fluorine-18 fluorodeoxyglucose (F-FDG)-PET/contrast-enhanced computed tomography (ceCT) and to assess its prognostic impact.

Materials And Methods: Twenty-three (14 women) patients, without previous treatment, underwent F-FDG-PET/ceCT before peritoneal mesothelioma cytoreductive surgery and intraperitoneal chemotherapy. F-FDG-PET/ceCT was interpreted prospectively as positive or negative. Maximum standardized uptake value (SUVmax) of each lesion was measured retrospectively on the basis of postsurgery data. At laparotomy, disease extension was estimated with the Peritoneal Cancer Index. The median follow-up was 27 months (95% confidence interval: 12.9-37.8); progression-free survival (PFS) was recorded.

Results: Nine patients were affected by multicystic and 14 were affected by epithelioid peritoneal mesothelioma. PET showed mild focal uptake in one case of multicystic peritoneal mesothelioma, whereas in eight patients, no abnormal uptake was observed. PET was positive in 12/14 patients with epithelioid peritoneal mesothelioma. Sensitivity, specificity and accuracy were respectively 86, 89 and 87%; the qualitative assessment was statistically different (P=0.0020, χ). Multicystic peritoneal mesothelioma histology was significantly associated with lower SUVmaxlesion (P=0.0061), SUVmaxlesion/liver (P=0.0025), Peritoneal Cancer Index, younger age, and it was observed only in women.Recurrence was observed on nine patients affected by epithelioid peritoneal mesothelioma, whereas no recurrences were observed among multicystic peritoneal mesothelioma patients. SUVmaxlesion (P=0.0278) and age (P=0.0241) were significantly associated with PFS in patients with epithelioid peritoneal mesothelioma.

Conclusion: F-FDG-PET/ceCT showed significant differences between multicystic and epithelioid peritoneal mesothelioma, whereas SUVmaxlesion was associated with PFS in the latter. Although multicentre prospective studies are necessary, F-FDG-PET/ceCT appears to be a promising tool in patients affected by peritoneal mesothelioma.

In plain English

This study from Centre Hospitalier Lyon-Sud in France asked whether a PET/CT scan that measures sugar (glucose) uptake could tell apart two kinds of peritoneal mesothelioma, multicystic and epithelioid. It also asked whether the scan predicted how long patients stayed free of disease progression. The authors reviewed 23 untreated patients (14 women) scanned before planned surgery and heated abdominal chemotherapy. Nine had multicystic and 14 had epithelioid disease. Asbestos exposure was not examined. The scan showed uptake in 1 of 9 multicystic cases and in 12 of 14 epithelioid cases, an accuracy of 87% for telling the types apart. All nine recurrences were in patients with malignant disease. Among epithelioid patients, those with a maximum uptake value above 3.63 had a mean progression-free survival of 11.3 months, compared with 29.2 months for those at or below 3.63 (P = 0.0278). The authors concluded that the scan appears promising. They noted the small sample, the after-the-fact uptake measurements and the single specialist centre, and called for larger multicentre studies.

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 single-centre diagnostic and prognostic imaging study. Scans were read as positive or negative at the time; uptake values were measured afterwards using pathology reports.
• Who was studied: 23 untreated patients (14 women, 9 men; mean age 54, range 21 to 74) scheduled for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for benign or malignant peritoneal mesothelioma at Centre Hospitalier Lyon-Sud, France, from September 2009 to March 2014. 9 had multicystic and 14 had epithelioid peritoneal mesothelioma. In two patients complete cytoreduction was not possible and no heated intraperitoneal chemotherapy was given.
• Exposure: No asbestos or other exposure was studied. The study assessed 18F-FDG-PET/contrast-enhanced CT scanning (glucose uptake imaging) done before surgery.
• Main results:
  • Among 9 patients with multicystic peritoneal mesothelioma, PET showed mild focal uptake in only one (maximum uptake value 3.3, left ovary). PET was positive in all but two of the 14 epithelioid cases.
  • For distinguishing the two subtypes, the scan's sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 86, 89, 92, 80 and 87% (P = 0.0020).
  • Compared with multicystic disease, epithelioid (malignant) disease was associated with higher maximum uptake values (P = 0.0061), a higher uptake-to-liver ratio (P = 0.0025), older age (P = 0.0013) and higher total Peritoneal Cancer Index (P = 0.0001). Multicystic disease was seen only in women (P = 0.0082). Maximum Peritoneal Cancer Index per site and the Gilly index were not associated with subtype.
  • Nine patients had recurrence, with a median time of 8.2 months (95% CI: 3 to 38.2), and three died from recurrence. All recurrences were in patients with malignant peritoneal mesothelioma; none were in the multicystic group.
  • In epithelioid peritoneal mesothelioma, patients with a maximum uptake value of 3.63 or below (8 patients) had a mean progression-free survival of 29.2 months. Those above 3.63 (6 patients) had a mean of 11.3 months (P = 0.0278; hazard ratio 3.9657, 95% CI: 1.1932 to 21.4839).
  • In epithelioid patients, the uptake-to-liver ratio (cut-off 1.31) showed only a trend toward association with progression-free survival (P less than 0.0504; hazard ratio 4.0332, 95% CI: 0.9975 to 15.1574).
  • In epithelioid patients, age dichotomized at 61 years was associated with progression-free survival in Kaplan–Meier analysis (P = 0.0241; hazard ratio 0.1628, 95% CI: 0.0380 to 0.7947).
  • In Cox analysis, only the maximum uptake value dichotomized at 3.63 was significantly associated with progression-free survival (P = 0.0432). The uptake-to-liver ratio at 1.31 was not (P = 0.0727). Without cut-offs, both uptake measures were each significantly associated with progression-free survival.
• The authors' conclusion: The authors concluded that the scan showed good accuracy in distinguishing multicystic from epithelioid peritoneal mesothelioma. Although the sample was limited, they found it appears to be a promising tool to predict progression-free survival in epithelioid peritoneal mesothelioma. They said its role in predicting surgery results remains to be assessed.
• Limitations the authors state:
  • The uptake values were measured retrospectively, so the results are not free from bias.
  • The sample of patients was small.
  • The surgical department belongs to a specialist network, so results may be hard to replicate in other tertiary hospitals.
  • Using 'optimal' cut-offs for Kaplan–Meier analysis carries a known risk of false-positive findings. The authors ran Cox analyses with and without cut-offs to try to correct for this.
  • Too few patients died to analyse overall survival reliably.
  • Two epithelioid cases were missed by PET. The authors attributed this to very small (under one centimetre) disease and the scanner's spatial resolution.

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Epithelioid, Cytoreductive Surgery, Chemotherapy, Laparotomy, Peritoneal Cancer Index (PCI), confidence interval, Progression-Free Survival.

Related studies

• 18F-FDG-PET/CT of peritoneal tumors: a pictorial essay — J. Dubreuil, F. Giammarile, et al. (2017)
• 18F-FDG Uptake of Localized Malignant Peritoneal Mesothelioma — E. Kodama, T. Kodama, et al. (2020)
• Focal Peritoneal Mesothelioma Demonstrated on FDG PET/CT — J. Xiao, H. Yin, et al. (2019)
• A Case of Localized Malignant Peritoneal Mesothelioma With Lung Cancer Detected by 18F-FDG PET/CT — S. Kobayashi Shimizu, T. Okamura, et al. (2020)
• Prognostic value of pretreatment volume-based quantitative 18F-FDG PET/CT parameters in patients with malignant pleural mesothelioma — K. Kitajima, H. Doi, et al. (2017)
• FDG PET-derived parameters as prognostic tool in progressive malignant pleural mesothelioma treated patients — E. Incerti, S. Broggi, et al. (2018)

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