Abstract 425P
Background
Immunotherapy has become the first-line treatment for recurrent head and neck squamous cell carcinoma. However, there is still a lack of precise non-invasive imaging methods to assess its effective reactivity. This study aims to use 18F-FAPI PET/CT to evaluate the efficacy of immunotherapy in HNSCC.
Methods
A single-center prospective study. A total of 15 HNSCC patients treated with anti-PD-1 inhibitors were included, including 6 locally advanced patients and 9 advanced HNSCC patients. Compare 18F-FAPI uptake indicators with traditional treatment efficacy and MR images defined according to RECIST v.1.1. All patients underwent 18F-FAPI PET/CT and traditional imaging MRI before and after immunotherapy. The index of 18F-FACI uptake in HNSCC primary lesions and lymph nodes is represented by the maximum standard uptake value (SUVmax).
Results
Among the 15 patients who received immunotherapy combined with chemotherapy, 2 patients achieved CR, 11 patients achieved PR, and 2 patients achieved PD diagnosed by MRI. In the 18F-FAPI evaluation, imaging results were found to be consistent with MRI in 11 patients. But the FAPI of the other 4 patients indicated poor tumor regression. Still exhibiting local high uptake of 18F-FAPI. This includes 1 patient with CR and 3 patients with PR. The 18F-FAPI PET/CT image of this CR patient showing no reduation in Primary SUVmax after treatment compared to pre-treatment SUVmax(9.8 vs 9.7). The SUVmax of 3 PR patients before treatment was significantly higher than that of other PR patients. The SUVmax in 3 PR patients was significantly higher than that in other PR patients before treatment. (22.4, 34.2, 21.7 vs other PR patients’ average SUVmax14.87) ΔSUVmax(%) after treatment is less than 50%. The average ΔSUVmax(%) of other PR patients was 64%. 1 year follow-up revealed that the 4 patients, 1died and 1progressed, and 1 patient showed high squamous cell carcinoma antigen (SCC). The remaining 11 patients who achieved ORR had no death or recurrence before the statistics were collected.
Conclusions
Compared with traditional imaging evaluation, 18F-FAPI PET/CT shows better evaluation results and provides further guidance for subsequent precise treatment. Larger sample sizes and are needed for further evaluation in the future.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.