Background: The maximum standardized uptake value (SUV(max)) on (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG PET) within the primary tumor may predict outcome in patients with surgically resected non-small cell lung cancer (NSCLC). However, it remains uncertain whether the SUV(max) of the primary tumor predicts outcome after chemotherapy in advanced NSCLC. Thus, we evaluated the ratio of SUV(max) of the metastatic tumor to the primary tumor (M/P ratio) to determine whether it could be a useful marker in predicting response and outcome after chemotherapy in advanced NSCLC.
Methods: Chemo-naïve patients with advanced NSCLC who had locoregional lymph nodes and/or distant metastases other than brain, were eligible for inclusion in this study. Response and survival were analyzed according to the SUV(max) of primary tumor, the ratio of the SUV(max) of the tumor to the mean SUV of the mediastinum (T/M ratio) and M/P ratio.
Results: One hundred and four consecutive patients were included in the retrospective study. Patients with high M/P ratio exhibited significantly lower response rates. The value of SUV(max) and T/M ratio were not associated with the response to initial chemotherapy. In the univariate analysis, T/M ratio and SUV(max) were significantly associated with poor outcome. However, the outcome of non-adenocarcinoma was unaffected by T/M ratio and SUV(max). Multivariate analysis confirmed that high M/P ratio was a significant independent factor predicting a poor outcome.
Conclusion: High M/P ratio was associated with a poor response to initial chemotherapy and was a significant independent factor in predicting poor outcome in advanced NSCLC patients with metastatic tumors other than in brain.