The Advantage Of Using Pet Suv To Evaluate Tumor Response By Recist Criteria In Patients With Stage Iiia/B Non-Small Cell Lung Cancer (Nsclc) After Concurrent Chemotherapy And Tarceva With Radiotherapy

To compare computed tomography (CT) with positron emission tomography (PET) standardized uptake value (SUV) for tumor response evaluation using a modified Response Evaluation Criteria in Solid Tumors (RECIST) in patients with NSCLC. From 11/20/07 to 3/31/2010, 33 patients were eligible for data analysis with pre- and post-treatment PET-CT and/or intravenous contrast CT imaging in Tarceva trial. All patients were treated by: paclitaxel (45 mg/m2) and carboplatin (AUC = 2) on day 1; Tarceva (150 mg p.o.) and radiotherapy on days 2-5; and Tarceva alone on days 6 and 7, repeated weekly for 7 weeks, total radiotherapy dose of 63 Gy/35 fx. Tarceva with two more cycles of consolidation chemotherapy (paclitaxel [200mg/m2] and carboplatin [ACU = 6]). PET-CT was repeated one month after completion of chemoradiotherapy. Tumor response evaluation by CT using RECIST (version 1.1) was based on diagnostic contrast CT or the CT portion of the PET-CT scan. Tumor response evaluation by PET SUV was the same as RECIST 1.1 criteria but modified as: complete response (CR): all target lesions SUV disappearance or less than 2.5; partial response (PR): at least a 30% decrease in the sum of SUV of the target lesions; progressive disease (PD): at least a 20% increase in the sum of the SUV of the target lesions; and stable disease (SD): neither a SUV decrease qualifying for PR nor an SUV increase qualifying for PD. Overall response was the best response from the start of treatment until the date of last follow-up or disease progression/recurrence. The chi-square test was used to assess measures of association in frequency. Compare tumor response between CT and PET SUV in this trial, the overall CR, PR, SD, PD, and inevaluable rates were 33.3%, 48.5%, 9.1%,9.1%, and 0%, respectively, with CT vs. 48.5%; 30.3%, 3.0%, 9.1%, and 9.1%, respectively, by PET SUV (p = 0.177). Further analysis in subgroups showed that the CR, PR, SD, and inevaluable rates for primary tumors response were 39.4%, 36.4%, 24.2%, and 0%, respectively, with CT vs. 57.6%, 27.3%, 3.0%, and 12.1%, respectively, with PET SUV (p = 0.034). Lymph node (LN) tumor response was 57.6%, 18.2%, 3.0%, and 21.2%, respectively, with CT vs. 60.6%, 12.1%, 0.0%, and 27.3%, respectively, with PET SUV (p = 0.510). Inevaluable LN tumor response was a result of N0 stage or the primary tumor and LN tumor merging together. The primary tumor CR rate was significantly higher in the SUV group than in the CT group, perhaps owing to treatment-related toxicity. Our study suggests that SUV has benefit in evaluating primary tumor response for patients with NSCLC after concurrent chemoradiotherapy.