| Part 1: Prognostic value of 18F-FDG PET-CT before and during radiotherapy in locally advanced nasopharyngeal carcinomaObjective: To evaluate 18FDG PET-CT for the assessment of therapy response and prediction of patient outcome after concurrent chemoradiotherapy (CCRT) for non-small cell lung cancer (NSCLC).Methods: Forty-six patients with pathologically proven stage III NSCLC had 2 serial FDG PET-CT scans, before and during CCRT. The maximum standardized uptake value (SUVmax) of the primary lung lesion was calculated. The value changes of SUVmax before and during treatment were calculated according to the following equation: SUV = (SUVbefore ?SUVduring)100%/SUVbefore. The relationship between changes of the SUVmax and the therapy response as well as long-term survival was studied in the responsive and non-responsive groups after CCRT.Results: The initial SUVmax in the responsive and non-responsive groups was 7.59±3.14 and 14.72±4.67, respectively. The SUVmax during treatment in the two groups was 2.89±1.39 and 9.82±3.31, respectively. Significant difference (P=0.001; P=0.001) in SUVmax was observed either before or during treatment. Furthermore, the percent change of SUVmax before and during treatment was 61.91±86.69%and 33.56±90.37%, respectively. There was significant difference between these two groups (P=0.007). In addition, the 1-year survival rate in the responsive and non-responsive group was 73% and 69%, respectively. The 2-year survival rate in the two groups was 40% and 37%, respectively. There was significant difference between these two groups (P=0.001).Conclusion: 18FDG PET-CT is an effective method in the prediction of therapy response in patients with stage III NSCLC. The analysis of percent change of SUVmax provides additional value in early prediction of therapy response and patient outcome.Part 2: The correlation between 18FDG PET-CT metabolic tumor volume and prognosis in lung cancerObjective: Our purpose was to assess the prognostic value for disease progression and survival of tumor burden measured by 18FDG-PET imaging.Methods: We identified 56 patients with lung cancer who had staging PET-CT scans before any therapy, and adequate follow-up for 2years. Metabolically active tumor regions were segmented on pretreatment PET scans semi- automatically using custom software. We determined the relationship between over survival (OS) and two PET parameters: total metabolictumor volume (MTV), and standardized uptake value (SUV).Results: The estimated median OS for the cohort were 14.5 months. On Kaplan-Meier analysis for os, MTV had a significant effect on the hazard of death, statistically significant(LR = 5.420, df = 1, P =0.014). We also find a significant relationship between SUVand OS( LR=0.735, df=1, P=0.041). On multivariate Logistic regression analysis, MTV was associated with increased of death, statistically significant(P=0.001)Conclusion: In this study, high tumor burden assessed by PET MTV is an independent poor prognostic feature in stage III NSCLC, MTV is valuable for predicting tumor survival and treatment response. These results will need to be validated in larger cohorts with longer follow-up, and evaluated prospectively. |
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