Relating acute esophagitis to radiotherapy dose using FDG-PET in concurrent chemo-radiotherapy for locally advanced non-small cell lung cancer.

Abstract

RESULTS

Eighty-two patients were included (gr < 2 = 25, gr ≥ 2=57). The mathematical left angle bracket SUV(50%) mathematical right angle bracket ≥ was significantly higher for gr ≥ 2AE (2.2 vs. 2.6, p < 0.01). The LKB parameters (95% CI) were n = 0.130 (0.120-0.141), m = 0.25 (0.13-0.85) and TD(50) = 50.4 Gy (37.5-55.4), which resulted in improved predictability of AE compared to other predictors.

MATERIALS AND METHODS

Patients treated with 24 × 2.75 Gy were selected on presence of a post-RT PET (PET(post)) scan acquired within 3 months after cCRT. The value of PET(post) in relation to AE was evaluated by comparing the mean esophageal SUV of the highest 50% (mathematical left angle bracket SUV(50%) mathematical right angle bracket) between gr < 2 and gr ≥ 2AE. The local dose on the esophagus wall was correlated to the SUV and modeled using a power-law fit. The Lyman-Kutcher-Burman (LKB) model was used to predict gr ≥ 2AE. The local dose-response relation was used in the LKB model to calculate the EUD. Resulting prediction accuracy was compared to D(mean), V(35), V(55) and V(60).

PURPOSE

To correlate radiotherapy (RT) dose to acute esophagitis (AE) by means of FDG-PET scans acquired after concurrent chemo-radiotherapy (cCRT) for locally advanced non-small-cell lung cancer (NSCLC).

CONCLUSION

Esophageal uptake of FDG post-cCRT reflects AE severity. Predictability of grade ≥ 2AE was improved by using the local dose-SUV response model, with narrow confidence intervals for the optimized LKB parameters.