Maxillary sinus inflammation assessment using FDG-PET/CT in head and neck cancer patients with photon, proton, and combined radiation therapy.

BACKGROUND

Head and neck cancer (HNC) patients frequently develop post-radiation maxillary sinusitis. This study investigated how different radiation therapy (RT) modalities, photon, proton, and mixed photon/proton RT, affect maxillary sinus inflammation, using 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT).

METHODS

Seventy-seven HNC patients treated with RT (30 with photon, 20 with proton, and 27 with mixed photon/proton RT) underwent FDG-PET/CT imaging before and 3 months after treatment. Demographic information, tumor location, chemotherapy details, radiation dose (cGy), and post-radiation sinusitis ratings (scale 0-2) were collected. The mean standardized uptake value (SUVmean) of the maxillary sinus was measured by a radiologist with two years of experience using manually delineated regions of interest. Parametric paired t-tests were used to compare pre- and post-treatment SUVmeans for each RT modality. Pre-minus-post-treatment changes in SUVmean (ΔSUVmean) between RT modalities were compared using independent t-tests. Correlation between radiation dose and ΔSUVmean and correlation between ΔSUVmean and clinical sinusitis scores were assessed using Pearson correlation analysis.

RESULTS

Photon RT was associated with a statistically significant increase in maxillary sinus SUVmean post-treatment (+14.32%, P = 0.0324), while proton RT and mixed photon/proton RT did not result in significant changes (-3.39%, P = 0.6549 and -5.33%, P = 0.4541, respectively). A significant difference was found between photon and mixed photon/proton RT (P = 0.0444), whereas the difference between photon and proton RT approached significance (P = 0.0790). Clinical inflammation ratings were highest for photon therapy (average 0.97), followed by mixed therapy (0.78), then proton therapy (0.65), though these differences were not statistically significant.

CONCLUSION

Our findings demonstrate that photon RT leads to significant increases in maxillary sinus SUVmean as measured by FDG-PET/CT, while proton and mixed photon/proton RT do not show statistically significant changes. These preliminary results suggest that proton-based radiation modalities may be associated with reduced maxillary sinus inflammatory activity compared to photon RT alone, though larger studies with longer follow-up are needed to establish clinical significance and patient outcomes.