18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours

Our plain-English summary of 18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours, by D.J. De Maeseneer, B. Lambert, V. Surmont, et al (Acta Clinica Belgica, 2010).

The study

• Authors: D.J. De Maeseneer, B. Lambert, V. Surmont, K. Geboes, S.W. Rottey
• Journal: Acta Clinica Belgica
• Published: 2010;65(5):291-9
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines.We give an overview of data on response prediction in solid tumours by the application of PET.

In plain English

This article was a review of published studies on whether FDG-PET scanning can predict how solid tumours respond to cancer treatment. FDG-PET is an imaging method that tracks the uptake of FDG, a radioactively labelled substance similar to glucose, by metabolically active cells. The article did not study asbestos exposure. The authors covered breast cancer, lung cancer (small cell and non-small cell), mesothelioma, colorectal, rectal, oesophageal, germ cell, and head and neck cancers. For mesothelioma they described two other studies. One reported that in non-sarcomatoid malignant pleural mesothelioma, volume-based PET measures predicted survival better than tumour-node-metastasis staging. In the other, CT response after three cycles of chemotherapy was related to overall survival (p=0.001), two standard PET uptake measures were not (p=0.61 and p=0.68), and decreases in total lesion glycolysis and PET volume were predictive. The authors concluded that PET is a very interesting non-invasive technique for response prediction, especially with treatment given before surgery. They named the wide variety in methods and the difficulty of defining response thresholds as main problems, and said large prospective trials are needed.

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: Narrative literature review
• Who was studied: Published studies (not new patients) on breast cancer, small cell and non-small cell lung cancer, mesothelioma, metastatic colorectal cancer, locally advanced rectal cancer, oesophageal cancer, germ cell tumours, and head and neck cancer
• Exposure: Not an asbestos exposure study; no fibers, products or jobs are discussed. The subject is FDG-PET imaging used to assess response to anti-cancer treatment. FDG is a radiolabelled glucose analogue taken up by metabolically active cells.
• Main results:
  • Reviewed mesothelioma literature: the authors stated that sarcomatoid histology remains the strongest prognostic factor in mesothelioma
  • Reviewed mesothelioma study (another study, reference 33): in patients with non-sarcomatoid disease, volumetric FDG-PET parameters were more predictive of survival than tumour-node-metastasis staging in malignant pleural mesothelioma
  • Reviewed mesothelioma study (another study, reference 34): after three cycles of therapy, CT classified 10 patients as responders, 30 as stable disease and 1 as progressive disease
  • Same mesothelioma study: PET evaluation identified 14 responders, 23 patients with stable disease and 4 patients with progressive disease
  • Same mesothelioma study: CT response after 3 cycles was significantly related to overall survival (p=0.001). Neither SUVmax-response (p=0.61) nor SUVmean-response (p=0.68) was related to survival. A decrease of total lesion glycolysis (p=0.01) and PET volume (p=0.002) was predictive.
  • For non-small cell lung cancer, the authors summarised that the vast majority of studies support the hypothesis that a reduction in FDG uptake is strongly correlated with histopathological findings and survival
  • For breast cancer given chemotherapy before surgery, the authors stated that available data suggest 90% of patients could be accurately defined as responders or non-responders as early as 2 to 3 weeks after starting treatment
  • For metastatic colorectal cancer, the authors judged that sensitivity and specificity are too low to support routine use of PET
  • For oesophageal cancer, a systematic review (another study, reference 64) found sensitivity ranging from 27,3 to 93,3% (printed with decimal commas) across eight qualifying studies
• The authors' conclusion: The authors concluded that PET for response prediction in solid tumours is a very interesting, non-invasive technique. In their view, especially with neo-adjuvant (pre-surgery) treatment, it can reduce the use of ineffective therapy, limiting patient toxicity and cost.
• Limitations the authors state:
  • The authors stated that the main drawback is the wide variety in methodology: how scans are performed and read, and which quantitative tools are used
  • The authors stated that a main problem is clearly defining thresholds of change in FDG uptake to decide whether there is a response
  • The authors stated that large prospective clinical trials are needed, for example to establish the role of FDG-PET in lung cancer management and prognosis

Topics

Medical terms in this study, explained in our Lexicon: Esophageal Cancer.

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