FDG-PET as a Potential Tool for Selecting Patients with Advanced Non-Small Cell Lung Cancer Who May Be Spared Maintenance Therapy after First-Line Chemotherapy
Clinical Cancer Research
2 Statement of Translational Relevance Although maintenance treatment with pemetrexed and erlotinib following first-line chemotherapy has shown positive results in patients with NSCLC, toxicities associated with maintenance therapy are of concern in the non-curative setting. There may be a subset of patients with relatively less aggressive disease who may be over-treated by an immediate transition to maintenance treatment after first-line chemotherapy. Our findings demonstrate that metabolic
... ponse evaluated by FDG-PET using percent decrease of maximum/peak SUV after completion of first-line chemotherapy may be useful to differentiate patients with longer TTP after first-line chemotherapy from those with early progressive disease. In addition, good metabolic responders showed prolonged overall survival. These results suggest that FDG-PET may be a useful tool in identifying a subgroup of patients with better prognosis who may be spared immediate maintenance therapy until disease progression. Research. on September 12, 3 Abstract Purpose: To investigate whether 18 F-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) may be a potential tool to select a subgroup of patients who might be spared maintenance treatment, if the metabolic response after first-line chemotherapy could predict time-to-progression (TTP). Experimental Design: A total of 43 patients who underwent baseline FDG-PET scan and didn't show disease progression (DP) after four cycles of first-line chemotherapy were enrolled and underwent second FDG-PET 3 weeks after completion of the first-line chemotherapy. The primary endpoint was to compare percent decrease in maximum standard uptake value (SUVmax) between early (TTP after second PET examination <8 weeks) and late (TTP ≥8 weeks) DP subgroups. Secondary end points were to determine whether fractional decrease in SUVmax could predict TTP and overall survival (OS), both calculated from the date of the second FDG-PET. Results: Percent decreases in SUVmax in late DP subgroup were greater than those in early DP subgroup (mean reduction, 54.7% ± 27.2% vs 27.8% ± 46.8%, p=0.021). Receiver operating characteristic curves identified a 50.0% decrease in SUVmax as the optimal threshold to distinguish these subgroups. Using this value as the cutoff resulted in a positive predictive value of 82.6% and negative predictive value of 60.0% in predicting TTP ≥8 weeks. Research. on September 12, Patients with SUVmax decreases ≥50% had significantly longer median TTP (3.0 vs 1.5 months, p=0.001) and OS (not reached vs 14.2 months, p=0.003). Conclusions: Fractional decrease in SUVmax of the main lesion after completion of four cycles of chemotherapy may discriminate patients with TTP ≥8 weeks and predict TTP and OS in patients with advanced NSCLC.