[Assessing the contribution of a standardized method in defining the tumor bed using surgical clips in breast cancer]. / Évaluation de l'apport d'une méthode standardisée dans la définition du lit tumoral à l'aide de clips chirurgicaux dans le cancer du sein.

PURPOSE OF THE STUDY: The objective of this study was to compare prospectively the delineations of tumour bed after breast conserving surgery from two techniques for defining the target volume. PATIENTS AND METHODS: Sixteen patients treated by lumpectomy with development of surgical clips were included. For each patient, four radiation oncologists delineated the clinical target volume (CTV boost) following its own method (technique 1) or using a predefined methodology (technique 2), the diameter to be applied around each clip relative to the risk of local recurrence. Factors taken into account to adjust the volume were tumour size, age, surgical margins and the presence of extensive ductal carcinoma. We then analyzed the factors varying the volume and variation of delineation for each method by calculating the concordance index: Kappa index and overlap. RESULTS: For all 16 patients, the volume delineated was nearly identical: 29.65 cm(3) with technique 1 and 33.54 cm(3) with technique 2 (P=0.6). The correlation was higher with technique 2 over technique 1, with KI from 0.146 to 0.285 (P=0.0001) and an OV of 0.302 to 0.458 (P=0.0002). CONCLUSION: Our study shows that within the same institute, there is a great variability in CTV delineation boost, even in the presence of surgical clips. A standardized approach to adjusting the volume of relapse risk factors has improved the consistency.

[Interest of FDG-PET for lung cancer radiotherapy]. / Intérêt de la TEP au FDG pour la radiothérapie des cancers bronchiques.

The recent advances in medical imaging have profoundly altered the radiotherapy of non-small cell lung cancers (NSCLC). A meta-analysis has confirmed the superiority of FDG PET-CT over CT for initial staging. FDG PET-CT improves the reproducibility of target volume delineation, especially close to the mediastinum or in the presence of atelectasia. Although not formally validated by a randomized trial, the reduction of the mediastinal target volume, by restricting the irradiation to FDG-avid nodes, is widely accepted. The optimal method of delineation still remains to be defined. The role of FDG PET-CT in monitoring tumor response during radiotherapy is under investigation, potentially opening the way to adapting the treatment modalities to tumor radiation sensitivity. Other tracers, such as F-miso (hypoxia), are also under clinical investigation. To avoid excessive delays, the integration of PET-CT in routine practice requires quick access to the imaging equipment, technical support (fusion and image processing) and multidisciplinary delineation of target volumes.