Follow-up or Surveillance (18)F-FDG PET/CT and Survival Outcome in Lung Cancer Patients.
The value of performing follow-up PET/CT imaging more than 6 mo after the conclusion of therapy-either as a routine practice or because of clinically suspected recurrence-is not well established. The purpose of this study was to evaluate the added value of follow-up PET/CT to the clinical assessment and survival outcome of lung cancer patients.


METHODS
This was a retrospective study of 261 biopsy-proven lung cancer patients at a single tertiary center. In total, 488 follow-up PET/CT scans done 6 or more months after the completion of initial treatment were included in this study. Median follow-up from the completion of primary treatment was 29.3 mo (range, 6.1-295.1 mo). Overall survival (OS) benefit was measured using Kaplan-Meier plots with a Mantel-Cox log-rank test. A multivariate Cox regression model was provided with clinical covariates.


RESULTS
Of the 488 PET/CT scans, 281 were positive and 207 negative for recurrence. Overall median survival from the time of the PET/CT study was 48.5 mo. The median survival of PET-positive and PET-negative groups was 32.9 and 81.6 mo, respectively (P < 0.0001). A subgroup analysis demonstrated a similar difference in OS for 212 scans completed between 6 and 24 mo after treatment (P = 0.0004) and 276 scans completed after 24 mo (P = 0.0006). In the context of clinical assessment, PET/CT identified recurrence in 43.7% (107/245) of scans without prior clinical suspicion and ruled out recurrence in 15.2% (37/243) of scans with prior clinical suspicion. There was a significant difference in OS when grouped by clinical suspicion (P = 0.0112) or routine follow-up (P < 0.0001). In a multivariate Cox regression model, factors associated with OS were age (P < 0.0001) and PET/CT result (P = 0.0003). An age-stratified subgroup analysis demonstrated a significant difference in OS by PET scan result among patients younger than 60 y and between 60 and 70 y but not in those older than 70 y (P < 0.0001, P = 0.0004, and P = 0.8193, respectively).


CONCLUSIONS
(18)F-FDG PET/CT performed for follow-up more than 6 mo after the completion of primary treatment adds value to clinical judgment and is a prognostic marker of OS in lung cancer patients, regardless of the timing of the follow-up scan, and especially in patients younger than 70 y.
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
Alexander J
AJ
Antoniou
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
Charles
C
Marcus
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland.
Abdel K
AK
Tahari
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.
Richard L
RL
Wahl
Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland; and Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland rsubram4@jhmi.edu.
Rathan M
RM
Subramaniam
D000367:Age Factors; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18
PET; and surveillance; lung cancer; survival