Texture indices of 4′-[methyl-11C]-thiothymidine uptake predict p16 status in patients with newly diagnosed oropharyngeal squamous cell carcinoma: comparison with 18F-FDG uptake

Background In oropharyngeal squamous cell carcinoma (OPSCC), human papillomavirus (HPV)/p16 status is important as a prognostic biomarker. Purpose We evaluated the relationship between 4′-[methyl- 11 C]-thiothymidine ( 11 C-4DST) and 18 F-FDG PET texture indices and p16 status in patients with newly diagnosed OPSCC. Methods We retrospectively reviewed the collected data of 256 consecutive, previously untreated patients with primary head and neck tumors enrolled between November 2011 and October 2019. Complete data on both 11 C-4DST and 18 F-FDG PET/CT studies before therapy, patients with OPSCC, and p16 status were available for 34 patients. Six of them were excluded because they did not exhibit sufficient 11 C-4DST and/or 18 F-FDG tumor uptake to perform textural analysis. Finally, 28 patients with newly diagnosed OPSCC were investigated. The maximum standardized uptake value (SUVmax) and 6 texture indices (homogeneity, entropy, short-run emphasis, long-run emphasis, low gray-level zone emphasis, and high gray-level zone emphasis) were derived from PET images. The presence of p16 expression in tumor specimens was examined by immunohistochemistry and compared with the PET parameters. Results Using 11 C-4DST, the expression of p16 was associated with a higher homogeneity ( P = 0.012), lower short-run emphasis ( P = 0.005), higher long-run emphasis ( P = 0.009), and lower high-gray-level-zone emphasis ( P = 0.042) values. There was no significant difference between 18 F-FDG PET parameters and p16 status. Conclusion Texture indices of the primary tumor on 11 C-4DST PET, but not 18 F-FDG PET, may be of value in predicting the condition’s p16 status in patients with newly diagnosed OPSCC.