Pre-Treatment FDG-PET Predicts the Site of In-Field Progression Following Concurrent Chemoradiotherapy for Stage III Non-Small Cell Lung Cancer
Menée sur 28 patients atteints d'un cancer du poumon non à petites cellules de stade III traité par chimioradiothérapie concomitante entre 2007 et 2010 (durée médiane de suivi : 39 mois), cette étude montre que la réalisation, avant traitement, d'une tomographie par émission de positrons à base de fluorodésoxyglucose (18F) peut permettre d'identifier les lésions pulmonaires pour lesquelles le traitement risque d'être inefficace
Purpose : Locoregional progression following definitive chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer (NSCLC) is common. In this study, we explore the utility of pre-treatment PET for predicting sites of disease progression following CRT.
Methods : We identified patients treated at our institution with definitive, concurrent CRT for stage III NSCLC in the years 2007-2010 who underwent staging FDG-PET/CT. Using a semiautomatic gradient-based tool, visible thoracic hypermetabolic lesions were contoured on each patient's pre-treatment PET. Post-treatment imaging was reviewed to identify specific locations of disease progression. Patients’ maximum SUV (SUVmax_pat) and metabolic tumor volume (MTV_pat) were evaluated as predictors of clinical outcomes using logrank testing. Competing risks analysis was performed to examine the relationship between lesion (tumor or lymph node) MTV (MTV_les) and the risk of local disease progression. Patient death and progression in other sites were treated as competing risks.
Results : 28 patients with 82 hypermetabolic lesions (27 pulmonary tumors, 55 lymph nodes) met inclusion criteria. Median follow-up was 39.0 months for living patients. Median progression-free survival (PFS) was 12.4 months, and median overall survival (OS) was 31.8 months. Low MTV_pat was associated with improved PFS (median 14.3 months for MTV < 60 cc v. 9.7 months for MTV > 60 cc, p = 0.039). MTV_les was strongly associated with the risk of local disease progression. The 2-year cumulative incidence rate (CIR) for progression in lesions larger than 25 cc was 45%, compared to 5% for lesions under 25 cc (p < 0.001).
Conclusion : Pre-treatment PET can be used to identify specific lesions at high risk for treatment failure following definitive CRT for locally advanced NSCLC. Selective treatment intensification to high-risk lesions should be studied as a strategy to improve clinical outcomes in this patient population.
Lung Cancer , résumé, 2013