High performance of F-fluorodeoxyglucose positron emission tomography and contrast-enhanced CT in a rapid outpatient diagnostic program for patients with suspected lung cancer

Our plain-English summary of High performance of F-fluorodeoxyglucose positron emission tomography and contrast-enhanced CT in a rapid outpatient diagnostic program for patients with suspected lung cancer, by P. Brocken, H.F. van der Heijden, P.N. Dekhuijzen, et al (Respiration; International Review of Thoracic Diseases, 2014).

The study

• Authors: P. Brocken, H.F. van der Heijden, P.N. Dekhuijzen, L. Peters-Bax, L.F. de Geus-Oei
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2014;87(1):32-7
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: The diagnostic evaluation of patients presenting with possible lung cancer is often complex and time consuming. A rapid outpatient diagnostic program (RODP) including (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and contrast-enhanced computed tomography (CT) as a routine diagnostic tool may improve timeliness, however the diagnostic performance of such a combined approach of RODP remains unclear.

Objectives: We evaluated timeliness of care and diagnostic performance of FDG-PET and contrast-enhanced CT (FDG-PET/CT) in an RODP for all patients referred with a chest X-ray suspicious of lung cancer.

Methods: Charts of patients referred to the 2-day RODP of our tertiary care university clinic after an abnormal chest X-ray between 1999 and 2009 were reviewed. Between 1999 and 2005 co-registered FDG-PET and CT imaging took place; from September 2005 onwards, a hybrid system was used. We analyzed timeliness of care and diagnostic performance of FDG-PET/CT to differentiate malignant from benign lesions.

Results: In 386 patients available for analysis, 260 were diagnosed with lung cancer and 23 had another type of malignancy; in 78 patients benign disease was confirmed, and in another 45 the diagnosis was not pathologically confirmed but a median 24.5-month follow-up confirmed a benign outcome. Sensitivity, specificity, negative and positive predictive values and accuracy of FDG-PET/CT to differentiate lung cancer from benign disease were 97.7, 60.2, 92.5, 84.0 and 85.8%, respectively. Lung cancer patients had a median referral, diagnostic and therapeutic delay of 7, 2 and 19 days, respectively.

Conclusions: FDG-PET/CT in an RODP setting for suspected lung cancer has high performance in detecting cancer and facilitates timely care.

Copyright © 2013 S. Karger AG, Basel.

In plain English

This study reviewed 1999 to 2009 charts from a 2-day rapid outpatient program for suspected lung cancer at Radboud University Nijmegen Medical Center, Netherlands. It did not study asbestos exposure. Of 570 patients referred, 386 sent because of an abnormal chest X-ray were analyzed; each had FDG-PET plus contrast-enhanced CT first. Of these, 236 had lung cancer and 27 had malignant pleural mesothelioma or cancer spread from elsewhere. Benign disease was confirmed by pathology in 78; another 45 had no malignancy reported over a median 24.5-month follow-up. The scans detected 97.7% of malignancies (95% confidence interval 94.9 to 99.1%) but correctly identified 60.2% of benign cases (50.9 to 68.8%). Six malignancies were missed, including a mesothelioma seen only as pleural fluid. The authors said CT alone might have excluded malignancy in 32 patients, including 3 with pleural plaques. Lung cancer patients waited a median 7 days to enter the program, 2 days for diagnosis and 19 more for treatment. The authors concluded the program detected lung cancer well with minimal delay, but could not judge afterward whether PET was always 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: Retrospective chart review of a diagnostic program at one university clinic (diagnostic accuracy and timeliness study)
• Who was studied: 386 patients analyzed, out of 570 consecutive patients referred to the 2-day rapid outpatient diagnostic program at Radboud University Nijmegen Medical Center (Netherlands) between August 1999 and April 2009. Only patients referred because of a chest X-ray suspicious of lung cancer were included. Final diagnoses were 236 lung cancer, 23 pulmonary metastases of other cancers, 4 mesothelioma, 78 pathologically confirmed benign disease, and 45 with no pathological diagnosis but benign at a median 24.5-month follow-up.
• Exposure: No asbestos or other exposure was studied. The article evaluated a diagnostic test: whole-body FDG-PET combined with full-dose contrast-enhanced CT, used as the first-line test for all patients. Imaging was co-registered (separate scanners) until September 2005 and done on a hybrid PET/CT scanner afterwards.
• Main results:
  • For diagnosing malignancy across all 386 patients:
• sensitivity 97.7% (95% confidence interval 94.9 to 99.1%)
• specificity 60.2% (50.9 to 68.8%)
• negative predictive value 92.5% (83.8 to 96.9%)
• positive predictive value 84.0% (79.3 to 87.8%)
• accuracy 85.8% (81.4 to 90.0%)
  • Counts behind these figures:
• Of 263 malignant cases, PET/CT was positive in 257 and negative in 6.
• Of 123 benign cases, PET/CT was positive in 49 and negative in 74.
  • Of the 123 benign cases, 78 had benign disease confirmed by pathology. The other 45 had no definite pathological diagnosis, but no malignancy was reported in their charts during a median follow-up of 24.5 months.
  • There were 6 false-negative cases, each with a different histology. One was a malignant pleural mesothelioma that appeared as pleural fluid only.
  • The tumor types among the 386 evaluable patients included 4 mesothelioma (1.0%). The text describes the combined group of 27 patients (7.0%) as having malignant pleural mesothelioma or pulmonary metastases of a nonpulmonary tumor.
  • Performance did not differ statistically between the separate FDG-PET and CT scanners (used until September 2005) and the hybrid PET/CT scanner (used from then on).
  • FDG-PET found disease outside the area covered by diagnostic CT:
• metastatic disease in 26 patients (6.7%; 10.8% of the lung cancer patients)
• a synchronous tumor of another cancer type in 9 patients (2.3%)
  • The authors said that in 32 of 386 patients (8.3%), malignancy might have been excluded on CT alone. Of these, 13 had no abnormalities on CT and 19 had a clearly benign lesion on CT alone, 3 of which were pleural plaques.
  • Patients diagnosed with lung cancer had these median delays:
• referral delay 7 days (IQR 5 to 9)
• diagnostic delay 2 days (IQR 1 to 17)
• therapeutic delay 19 days (IQR 7 to 28)
  For the total patient group, the median diagnostic delay was 1 day (IQR 1 to 15).
• The authors' conclusion: The authors concluded that, in patients referred with an abnormal chest X-ray, a rapid outpatient program integrating FDG-PET/CT provides excellent diagnostic performance in detecting lung cancer with minimized diagnostic delay.
• Limitations the authors state:
  • In 32 patients (8.3%), malignancy might have been excluded on CT alone. The authors said that whether FDG-PET was overused in these cases cannot be judged retrospectively, because PET and CT images were read together.
  • The authors said their study cannot answer whether detecting unexpected metastases and synchronous tumors outweighs performing FDG-PET on radiologically benign lesions. This would require comparing factors such as cost-effectiveness.
  • The authors attributed the relatively low specificity to including patients on the basis of an abnormal chest X-ray.

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: Lung Cancer, Chest X-Ray.

Related studies

• 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)
• 18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours — D.J. De Maeseneer, B. Lambert, et al. (2010)
• 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography fused imaging in malignant mesothelioma patients: looking from outside is not enough — E. Roca, S. Laroumagne, et al. (2013)
• The role of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiating between benign and malignant adrenal lesions — P. Ozcan Kara, T. Kara, et al. (2011)
• Use of computed tomography and positron emission tomography/computed tomography for staging of local extent in patients with malignant pleural mesothelioma — T. Frauenfelder, P. Kestenholz, et al. (2015)
• Clinical value of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiation of malignant mesothelioma from asbestos-related benign pleural disease: an observational pilot study — H. Yildirim, M. Metintas, et al. (2009)

Browse more research in Respiration; International Review of Thoracic Diseases, or return to medical research.