Jean-Pierre Bissonnette1, Alexander Sun2, Inga S Grills3, Muayad F Almahariq3, Geoffrey Geiger4, Wouter Vogel5, Jan-Jakob Sonke6, Sarah Everitt7, Michael Mac Manus8. 1. Department of Medical Physics, Princess Margaret Hospital Cancer Centre, Toronto, Ontario, Canada; Department of Radiation Oncology and Department of Medical Biophysics, University of Toronto, Techna Institute, Toronto, Ontario, Canada; Department of Radiation Oncology, Princess Margaret Hospital Cancer Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Radiation Oncology, Toronto, Ontario, Canada. Electronic address: https://twitter.com/@JeanPierreBiss2. 2. Department of Radiation Oncology, Princess Margaret Hospital Cancer Centre, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Radiation Oncology, Toronto, Ontario, Canada. 3. Department of Radiation Oncology, Beaumont Hospitals, Royal Oak, MI, United States. 4. Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States. 5. Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands; Department of Nuclear Medicine, Netherlands Cancer Institute, Amsterdam, the Netherlands. 6. Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands. 7. Department of Radiation Therapy, Peter MacCallum Cancer Centre, Melbourne, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia. 8. Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia; Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia.
Abstract
INTRODUCTION: Patients with non-small cell lung cancer (NSCLC) can experience rapid disease progression between initial staging FDG-PET scans and commencement of curative-intent radiotherapy (RT). Previous studies that estimated stage migration rates by comparing staging PET/CT and treatment-planning PET/CT images were limited by small sample sizes. METHODS: This multicenter, international study combined prospective data from five institutions for PET-staged patients with NSCLC who were intended to receive curative-intent RT. TNM status was compared for staging and RT planning scans and the probability of TNM status and overall stage migration was analyzed as a function of the interval between PET/CT scans. The impacts of N classification, overall stage, and pathology were also studied. RESULTS: Pooled data from 181 patients were analyzed. The median interval between PET/CT scans was 42 days (range, 2-208). Upstaging occurred in 32 % of patients. The overall rate of stage migration was higher for patients presenting with initial stage IIIB/IIIC disease (p = 0.006) and patients with N2-3 nodal disease (p = 0.019). Upstaging to M1 disease was significantly associated with initial stage IIIB/IIIC disease (HR = 15.2) and adenocarcinoma (HR = 10) histology. CONCLUSION: Longer intervals between imaging and treatment in patients with NSCLC were associated with high rates disease progression with consequent risks of geographic miss in RT planning and futile treatment in patients with M1 disease. Patients with more extensive initial nodal involvement and those with adenocarcinoma had the highest rates of stage migration. Dedicated RT planning PET/CT imaging is recommended, especially if >3 weeks have elapsed after initial staging.
INTRODUCTION:Patients with non-small cell lung cancer (NSCLC) can experience rapid disease progression between initial staging FDG-PET scans and commencement of curative-intent radiotherapy (RT). Previous studies that estimated stage migration rates by comparing staging PET/CT and treatment-planning PET/CT images were limited by small sample sizes. METHODS: This multicenter, international study combined prospective data from five institutions for PET-staged patients with NSCLC who were intended to receive curative-intent RT. TNM status was compared for staging and RT planning scans and the probability of TNM status and overall stage migration was analyzed as a function of the interval between PET/CT scans. The impacts of N classification, overall stage, and pathology were also studied. RESULTS: Pooled data from 181 patients were analyzed. The median interval between PET/CT scans was 42 days (range, 2-208). Upstaging occurred in 32 % of patients. The overall rate of stage migration was higher for patients presenting with initial stage IIIB/IIIC disease (p = 0.006) and patients with N2-3 nodal disease (p = 0.019). Upstaging to M1 disease was significantly associated with initial stage IIIB/IIIC disease (HR = 15.2) and adenocarcinoma (HR = 10) histology. CONCLUSION: Longer intervals between imaging and treatment in patients with NSCLC were associated with high rates disease progression with consequent risks of geographic miss in RT planning and futile treatment in patients with M1 disease. Patients with more extensive initial nodal involvement and those with adenocarcinoma had the highest rates of stage migration. Dedicated RT planning PET/CT imaging is recommended, especially if >3 weeks have elapsed after initial staging.