Résultats de la TEP [18F]-FDG dans la stadification préopératoire des tumeurs pulmonaires

[Role of PET/CT in primitive non-small cell bronchopulmonary cancer]

Bronchopulmonary cancer is a real public health problem. Morphological imaging plays a central role in its diagnosis, staging as well as post-therapeutic assessment but it has some limitations. Metabolic imaging is a more recent technique which allows to significantly improve the overall imagery performance. We conducted a retrospective, descriptive and analytical study at the Ibn Sina Hospital and at the Military Hospital of instruction Mohammed V in Rabat over a period of 18 months, between September 2014 and February 2016, in order to evaluate the role of Fluorodeoxyglucose-PET/CT in the staging and restaging of non-small cell bronchopulmonary cancer. Initial staging showed a vast majority of locally advanced and metastatic stages: stage IV (40%), Stage IIIB (36%), Stage IIIA (16%), Stage II (8%). PET-CT allowed to detect new sites which were not initially seen on CT scan in 24 cases: 15 new ganglion sites, 8 new adrenal sites and 6 sites of bone lesions. PET/CT allowed to modify initial tumor stage in 60% of cases: upstaging in 23 patients (46%) and downstaging in 7 patients(14%). The initial stage remained unchanged in 40% of patients. Our study confirms the data from the literature concerning the superiority of PET-CT in comparison with CT scan, but only in the optimization of the non-small cell bronchopulmonary cancer management, in particular in locoregional and distant staging.

[Comparison between PET(-FDG) and computed tomography in the staging of lung cancer. Consequences for operability in 94 patients]

INTRODUCTION

Lung cancer, a major application of FDG/PET-CT, has recently been introduced in daily practice in France. The authors retrospectively studied its impact on the management of this disease.

METHODS

The results of PET-CT and conventional assessment (brain imaging, chest and abdominal CT and possibly bone scintigraphy) were compared in 94 patients, referred for the staging of non-small cell lung cancer, or the assessment of a solitary lung lesion. The impact of thoracic lymph node involvement on the operability of patients was studied in 44 patients.

RESULTS

PET-CT revealed metastases in 20% of the patients without metastases found by conventional imaging and modified the stage of the disease in 28% of the cases. It changed the indication of surgical treatment in 19% of the cases and led to induction chemotherapy in two patients. In addition, two synchronous cancers were discovered. Regarding lymph node involvement, PET-CT remains of diagnostic value regardless of the scanner results.

CONCLUSION

The impact of PET-CT in assessing non-small cell lung cancer was confirmed in the authors' practice. Its interest and the consequences in some patients misclassified with conventional assessment have been demonstrated.

[Imaging and PET/CT of lung cancer]

Lung cancer is one of the most frequently occurring cancer in the world. Imaging plays a critical role for screening, diagnosing, staging, and following patients. Although morphologic imaging such as chest X-ray and CT are still useful for these purpose, major limitations occur in the proper evaluation of diagnosing and staging. Metabolic imaging using PET significantly increases the accuracy of staging. This paper will review the role of imaging in patients suspected or diagnosed with lung cancer.

[PET in primary pulmonary or pleural cancer]

In our hospital as in many others, primary lung cancer is the most frequent indication for FDG PET. Studies have assessed the clinical utility of this imaging modality in characterizing solitary pulmonary nodules or masses, initial staging, defining tumor volume in radiotherapy and searching for recurrence of or restaging non-small cell carcinoma; studies are currently underway to evaluate its use in early assessment of chemotherapy response. Small cell lung cancer has a high FDG uptake and PET/CT can be useful for rapid staging. False negative results may be due to pure bronchioloalveolar carcinomas and endocrine tumors. FDG-PET will certainly play a more important role in the diagnosis and follow-up of pleural cancers in the future. An unexpected positive FDG PET focus should be considered as a warning, but histological proof should precede any irrevocable decisions.