High rates of tumor growth and disease progression detected on serial pretreatment fluorodeoxyglucose-positron emission tomography/computed tomography scans in radical radiotherapy candidates with nonsmall cell lung cancer.
BACKGROUND
The authors studied growth and progression of untreated nonsmall cell lung cancer (NSCLC) by comparing diagnostic and radiotherapy (RT) planning fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) scans before proposed radical chemo-RT.


METHODS
Patients enrolled on a prospective clinical trial were eligible for this analysis if they underwent 2 pretreatment whole body FDG-PET/CT scans, >7 days apart. Scan 1 was performed for diagnosis/disease staging and scan 2 for RT planning. Interscan comparisons included disease stage, metabolic characteristics, tumor doubling times, and change in treatment intent.


RESULTS
Eighty-two patients underwent planning PET/CT scans between October 2004 and February 2007. Of these, 28 patients (61% stage III, 18% stage II) had undergone prior staging PET/CT scans. The median interscan period was 24 days (range, 8-176 days). Interscan disease progression (TNM stage) was detected in 11 (39%) patients. The probability of upstaging within 24 days was calculated to be 32% (95% confidence interval [CI], 18%-49%). Treatment intent changed from curative to palliative in 8 (29%) cases, in 7 because of PET. For 17 patients who underwent serial PET/CT scans under standardized conditions, there was a mean relative interscan increase of 19% in tumor maximum standardized uptake value (SUV) (P=.022), 16% in average SUV (P=.004), and 116% in percentage injected dose (P=.002). Estimated doubling time of FDG avid tumor was 66 days (95% CI, 51-95 days).


CONCLUSIONS
Rapid tumor progression was detected in patients with untreated, predominantly stage III, NSCLC on serial FDG-PET/CT imaging, highlighting the need for prompt diagnosis, staging, and initiation of therapy in patients who are candidates for potentially curative therapy.
Everitt
Sarah
S
Department of Radiation Oncology, Radiation Therapy Services, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia. sarah.everitt@petermac.org
Herschtal
Alan
A
Callahan
Jason
J
Plumridge
Nikki
N
Ball
David
D
Kron
Tomas
T
Schneider-Kolsky
Michal
M
Binns
David
D
Hicks
Rodney J
RJ
MacManus
Michael
M
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D002986:Clinical Trials as Topic; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011859:Radiography
D019788:Fluorodeoxyglucose F18