Stage migration in planning PET/CT scans in patients due to receive radiotherapy for non-small-cell lung cancer.
BACKGROUND
This study examined rates of tumor progression in treatment-naive patients with non-small-cell lung cancer (NSCLC) as determined by repeat treatment-planning fluorine-18 ((18)F) fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT).


METHODS
This study assessed patients who underwent PET/CT simulation for NSCLC stage II/III, radiation-naive, nonmetastatic NSCLC. It compared planning PET/CT with previous PET/CT images. Patients were analyzed for change in stage, treatment intent, or both. Progression was defined as a change in TNM status leading to upstaging, and standardized uptake value (SUV) velocity was defined as [(SUVscan2 - SUVscan1)/interscan interval in days].


RESULTS
Of 149 consecutive patients examined between April 2009 and April 2011, 47 had prior PET/CT scans and were included. The median age was 68 years. New nodal disease or metastatic disease was identified in 24 (51%) of 47 patients. Fourteen (30%) had evidence of extrathoracic metastatic disease; the remaining 10 (21%) had new nodal disease that required substantial alteration of treatment fields. At a scan interval of 20 days, the rate of upstaging was 17%. SUV velocity was analyzed in the subset of patients who had their studies on the identical PET/CT scanner (n = 14). Nonupstaged patients had a mean SUV velocity of 0.074 units per day, compared with 0.11 units per day in patients that were upstaged by their second PET/CT scan (P = .020).


CONCLUSIONS
Radiation treatment planning with hybrid PET/CT scans repeated within 120 days of an initial staging PET/CT scan identified significant upstaging in more than half of patients. For a subset of patients who underwent both scans on the same instrument, SUV velocity predicts upstaging, and the difference between those upstaged and those not was statistically significant.
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Geoffrey A
GA
Geiger
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Miranda B
MB
Kim
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Eric P
EP
Xanthopoulos
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Daniel A
DA
Pryma
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Surbhi
S
Grover
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
John P
JP
Plastaras
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Corey J
CJ
Langer
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA.
Charles B
CB
Simone
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Perelman Center for Advanced Medicine, Philadelphia, PA. Electronic address: rengan@uw.edu.
Ramesh
R
Rengan
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018287:Carcinoma, Large Cell / Q000473:pathology / Q000532:radiotherapy; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Chemoradiotherapy; Disease progression; Locally advanced; Stage migration; Will Rogers