Comparison of¹⁸F-FLT PET and¹⁸F-FDG PET for detection of cervical lymph node metastases in head and neck cancers

Abstract

The mean (± SD) FLT SUV in visualized metastatic lymph nodes was 4.8 ± 2.9 as compared with 6.9 ± 4.9 for FDG SUV (p < 0.001). Significant correlations were found between the area of metastatic lymph nodes and both FLT SUV (r = 0.8; p < 0.0001) and FDG SUV (r = 0.84; p < 0.0001). The false-positive (over-staged) and false-negative (under-staged) rates for lymph node staging by FLT PET were 4% (1/23) and 17% (4/23), respectively. Those for FDG PET were 9% (2/23) and 13% (3/23). All metastatic lymph nodes measuring more than 9 mm in short-axis diameter were correctly detected by FLT PET. However, both FLT and FDG PET had low sensitivity for detecting the lymph node metastases ≤ 9 mm in short-axis diameter and tumor deposits < 5 mm.

Non-18F-FDG PET/CT in the management of patients affected by HNC

“…A recent paper comparing [ 18 F]FLT and 18 F-FDG reported false-positive (overstaged) and false-negative (understaged) rates for lymph-node staging by [ 18 F]FLT PET of 4 and 17%, respectively; the corresponding values for 18 F-FDG PET were 9 and 13%. As such, no significant differences between the two techniques could be found, although a slightly better tumour-to-background ratio in metastatic lymph nodes was observed with 18 F-FDG [72]. More recently, Schaefferkoetter et al [73] showed, in 11 patients undergoing surgical resection of SCC of the oral/ head and neck region, that the use of pre-operative [ 18 F] FLT PET/CT resulted in better overall performance for detecting lymphadenopathy on a qualitative assessment compared with 18 F-FDG PET/CT.…”

PET Imaging of Proliferation with Pyrimidines

“…In 23 patients examined with 18 F-FLT PET and 18 F-FDG PET, the 18 F-FLT SUV in metastatic lymph nodes was 4.8 6 2.9, compared with 6.9 6 4.9 for 18 F-FDG SUV (P , 0.001). The false-positive and false-negative rates by 18 F-FLT and 18 F-FDG PET were 4% (1/23) and 17% (4/23), respectively (63). All metastatic lymph nodes larger than 9 mm were detectable by 18 F-FLT PET.…”

PET Imaging During Radiotherapy of Head and Neck Cancer

“…The intracellular trapping of 18 F-FLT is a function of the enzymatic activity of thymidine kinase 1, a key enzyme in DNA synthesis with high activity during the proliferative S phase of the cell cycle and low activity in the quiescent G0/G1 phase (9). Untreated head and neck squamous cell cancers are readily detectable with 18 F-FLT PET, with high tumor-to-background ratios, although the SUV with 18 F-FLT tends to be generally lower than with 18 F-FDG (10)(11)(12)(13)(14). Comparison studies of 18 F-FLT and 18 F-FDG by Hoshikawa et al showed similar detectability and false-positive rates in primary tumors and cervical nodal metastases for 18 F-FLT and 18 F-FDG (11,12).…”

“…Untreated head and neck squamous cell cancers are readily detectable with 18 F-FLT PET, with high tumor-to-background ratios, although the SUV with 18 F-FLT tends to be generally lower than with 18 F-FDG (10)(11)(12)(13)(14). Comparison studies of 18 F-FLT and 18 F-FDG by Hoshikawa et al showed similar detectability and false-positive rates in primary tumors and cervical nodal metastases for 18 F-FLT and 18 F-FDG (11,12). The pretherapy staging of head and neck cancer with 18 F-FLT PET appears limited by the nontumoral uptake in reactive cervical nodes due to proliferation of reactive B-lymphocytes (15).…”