Prognostic value of 18F-FDG standard uptake value by integrated PET/CT in the staging of malignant pleural mesothelioma

Our plain-English summary of Prognostic value of 18F-FDG standard uptake value by integrated PET/CT in the staging of malignant pleural mesothelioma, by G. Genestreti, A. Moretti, S. Piciucchi, et al (Technology in Cancer Research & Treatment, 2012).

The study

• Authors: G. Genestreti, A. Moretti, S. Piciucchi, M. Tiseo, M. Bersanelli, M. Scarlattei, E. Scarpi, A. Dubini, F. Matteucci, S. Sanna
• Journal: Technology in Cancer Research & Treatment
• Published: 2012;11(2):163-7
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor with generally disappointing results in terms of survival, however, there are occasional long-term survivors probably due to the biologic characteristics of the disease. Standard uptake value (SUV) of [(18)F] Fluorodeoxyglucose (FDG) evaluated by photon emission tomography (PET) is now widely accepted as an indicator of biologic behavior in several malignancies. The aim of this study was to verify whether SUV(max) and SUV(mean) are inversely associated with the prognosis of patients with MPM and whether there was a correlation between grading/disease stage and SUV value. Patients with histologically proven MPM underwent integrated PET and computed tomography (CT) scanning. Patients fasted and received 5.18 MBq of FDG per kilogram of body weight. Based on the maximum Chi-Square method, a SUV(max) of 4.21 (range: 2.30-14.74) and a SUV(mean) of 2.78 (range: 1.80-7.00) were used to classify patients as having a good or poor prognosis, respectively. From January 2004 to March 2010, 27 patients were analyzed: median age was 65 years (range: 54-77) and histologic MPM subtypes were epithelioid (23 patients) and biphasic (4 patients). At a median follow-up of 23 months (range: 1-52), there was no difference in median survival for either high or low SUV(max) [26 months (range: 11-not reached) vs.19 months (range: 12-not reached); p=0.811] or for high or low SUV(mean) [26 months (range: 8-not reached) vs.19 months (range: 11-not reached); p=0.831]. High SUV(max) (p=0.018) was statistically correlated with high-stage disease. There was only a trend towards statistical significance between high-grade disease and high SUV(mean) (p=0.083); no such trend was found between advanced stages and SUV(max) (p=0.268). We observed a significant correlation only between high SUV(max) and high-grade disease. No other relationships between SUV(max) and SUV(mean) with biologic and clinical parameters were found. This is probably due to the patient characteristics and to the non-routine use of 18F-FDG PET/CT to stage rare tumors such as MPM.

In plain English

This retrospective Italian study looked at 27 patients with malignant pleural mesothelioma (23 epithelioid, 4 biphasic) diagnosed January 2004 to March 2010. All had a staging FDG PET/CT scan measuring tumor uptake of a radioactive sugar tracer (SUVmax and SUVmean). The article did not study asbestos exposure. Patients were split at the median SUVmax (4.21) and SUVmean (2.78). Median survival was 26 months for high and 19 months for low SUVmax (intervals 11 to not reached and 12 to not reached; p=0.811), and 26 versus 19 months for high versus low SUVmean (8 to not reached and 11 to not reached; p=0.831). The article calls these intervals both 95% CI and ranges. Neither difference was statistically significant. Higher SUVmax was significantly linked with higher stage (median 6.22 in stages 3 and 4 versus 3.8 in stages 1 and 2; p=0.018). SUVmean showed only a non-significant trend with higher grade (p=0.083). The authors concluded their results only partly confirmed earlier reports, calling the roughly 7-month survival difference clinically important though not statistically significant. They cited the small sample and possible talc pleurodesis effects on uptake.

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 observational study of patients staged with FDG PET/CT
• Who was studied: 27 patients (21 male, 6 female; median age 65, range 54-77) with histologically confirmed malignant pleural mesothelioma (23 epithelioid, 4 biphasic; 15 stage I, 4 stage II, 8 stage III), diagnosed January 2004 to March 2010 and referred to Parma Hospital and I.R.S.T., Meldola, Italy
• Exposure: No asbestos exposure was studied or reported. The factor examined was tumor uptake of the tracer 18F-FDG (SUVmax and SUVmean) on a staging PET/CT scan.
• Main results:
  • Patients with SUVmax above the median had a median survival of 26 months (interval 11 to not reached), compared with 19 months (12 to not reached) for those below. The article labels these intervals as 95% CI and as ranges. The difference was not statistically significant (p=0.811).
  • Patients with SUVmean above the median had a median survival of 26 months (interval 8 to not reached), compared with 19 months (11 to not reached) for those below. The difference was not statistically significant (p=0.831).
  • In a Cox model, higher SUVmax and SUVmean corresponded to a hazard ratio for death above 1.00. Neither was statistically significant (the 95% CI included 1.00).
  • Median SUVmax was 3.8 (range 2.3-7.6) in stages 1 and 2 and 6.22 (range 3.99-14.74) in stages 3 and 4. This was a statistically significant correlation (p=0.018).
  • SUVmean was not significantly associated with disease stage (p=0.203).
  • Median SUVmax was 4.21 (range 2.30-8.60) in grades 1 and 2 and 4.78 (range 2.97-14.74) in grades 3 and 4. This correlation was not statistically significant (p=0.268).
  • SUVmean in grades 3 and 4 (range 2.53-4.31), compared with grades 1 and 2, showed only a trend toward statistical significance (p=0.083).
• The authors' conclusion: The authors concluded that their results only partly confirm the literature. Although the results were statistically negative, they considered the roughly 7-month survival difference between high- and low-SUV patients clinically important, and they called for larger prospective trials.
• Limitations the authors state:
  • The SUV cut-off was calculated from the authors' own patient series rather than a recognized threshold.
  • The number of patients was small.
  • Talc pleurodesis may have raised SUV and given false positive results.
  • Analysis stratified by SUV and stage was not done because there were too few patients.

Topics

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

Medical terms in this study, explained in our Lexicon: Staging, Pleural Mesothelioma, Prognosis, Epithelioid, Biphasic Mesothelioma, Median Survival, Statistical Significance.

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