Value of combined interpretation of computed tomography response and positron emission tomography response for prediction of prognosis after neoadjuvant chemotherapy in non-small cell lung cancer

INTRODUCTION:: The purpose of this study was to assess the value of tumor response evaluation using combined interpretation of [18F] fluorodeoxyglucose positron emission tomography (PET) and computed tomography (CT) for the prediction of clinical outcome and pathologic response in patients with stage III non-small cell lung cancer who underwent neoadjuvant chemotherapy followed by surgery. METHODS:: This study was approved by the Institutional Review Board with a waiver of informed consent. Forty-four consecutive patients (M:F = 32:12; mean age, 60.7 years) with locally advanced non-small cell lung cancer received neoadjuvant chemotherapy followed by curative surgery. Time to recurrence (TTR) was stratified by radiologic, metabolic, and radiologic-metabolic response using the Kaplan-Meier method. The accuracy of radiologic, metabolic, and radiologic-metabolic response criteria for the prediction of pathologic response was evaluated. RESULTS:: Radiologic-metabolic responders had a longer TTR than nonresponders (mean TTR, 58.7 months versus 22.3 months, p = 0.001 with criteria of ≥ reduction of size and ≥50% reduction of [maximum standardized uptake value] SUVmax and mean TTR, 49.4 months versus 23.5 months, p = 0.022 with criteria of ≥30% reduction of size and ≥25% reduction of SUVmax, respectively). The TTR of radiologic responders (criteria of ≥30% reduction of size) and metabolic responders (criteria of ≥25% reduction of SUVmax) was not different from the TTR of nonresponders (p > 0.05). The accuracy for the prediction of pathologic response was 70% in radiologic responders, 52 to 75% in metabolic responders, and 73 to 82% in radiologic-metabolic responders. CONCLUSIONS:: Tumor response evaluation using combined interpretation of [18F] fluorodeoxyglucose-PET and CT was more effective than single interpretation of CT response or PET response alone for the prediction of tumor recurrence and pathologic response.