Pilot study assessing 18F-fluorothymidine PET/CT in cervical and vaginal cancers before and after external beam radiation

Abstract

ObjectiveThe role of F-18-fluorothymidine (FLT) PET-CT imaging in the evaluation of gynecologic cancers has not been established. We sought to evaluate (FLT) PET-CT imaging in gynecologic cancers by comparing standard uptake values (SUVs) of FLT with F-18-fluorodeoxyglucose (FDG) PET in the primary tumor at diagnosis, and assess FLT uptake immediately following concurrent chemoradiotherapy (chemoRT).MethodsIn this pilot study, patients treated for cervical (5) or vaginal (1) cancer underwent FLT-PET and FDG-PET scanning at diagnosis (FLT1 and FDG1). Five patients (4 cervical and 1 vaginal) also underwent FLT-PET within 1–3 weeks after chemoRT before brachytherapy (FLT2). Wilcoxon rank-sum test was used to compare the FLT1 and FDG1 parameters.ResultsMedian age at diagnosis was 61-years (range, 33–72). Cervical cancers were staged as IB2 (n = 1, 20%), IIB (n = 1, 20%), IIIB (n = 1, 20%) and IVA (n = 2, 40%) and the single vaginal cancer was staged IIIB. The most common histology was squamous cell carcinoma (n = 3, 50%) followed by adenocarcinoma (n = 2, 33%) and clear-cell adenosquamous carcinoma (n = 1, 17%). Median tumor SUVmax at diagnosis was 7.8 on FLT1-PET (3.9–14.2) versus 11.6 (5.9–23.2) on FDG1-PET (p = 0.15). Tumor SUVmax of FLT declined 54%–100% after chemoRT.ConclusionThe tumor SUV of FLT at diagnosis was lower than that of FDG-PET. FLT uptake was markedly decreased after chemoRT. Results indicate that there may not be a significant effect of inflammation on FLT uptake in gynecologic cancers. FLT may be a useful tool when assessing the effects of chemoRT on gynecologic malignancies and planning for postchemoRT brachytherapy treatments.

Impact of [18F]FDG-PET and [18F]FLT-PET-Parameters in Patients with Suspected Relapse of Irradiated Lung Cancer

“…Patient characteristics are presented in Table 1. Timing between scans Time from the end of radiotherapy to relapse suspicion; in months (median (IQ)) 7 (5)(6)(7)(8)(9)(10)(11)(12) Time from relapse suspicion to FDG-PET/CT; in days (median (IQ)) 21 (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) Time from relapse suspicion to FLT-PET/CT; in days (median (IQ)) 23 (21)(22)(23)(24)(25)(26)(27)(28)(29) Time between FLT-PET/CT and FDG-PET/CT; in days (median (IQ)) 6 (3-9) Thirty patients were diagnosed with intrapulmonary relapse within 6 months after inclusion. In 16 patients, the relapse was located within the HDV.…”

“…During and after radiotherapy, the FLT-uptake decreased more rapidly and more pronounced than the FDG-uptake in several cancers [ 9 , 10 , 11 , 12 ], including lung cancer [ 13 , 14 , 15 , 16 ]. With a higher specificity and better discrimination between inflammatory lesions and lung cancer [ 17 ], the FLT-uptake may reflect a relapse-status better than FDG-uptake.…”

Comparing radioactive tracers 18F-FDG and 18F-FLT in the staging of diffuse large B-cell lymphoma by PET/CT examination: A single-center prospective study

“…14 Cho et al conducted an study using 18 F-FLT PET and 18 F-FDG PET scans in patients with cervical and vaginal cancer before therapy and after the end of chemo-and radiotherapy. 15 The FLT SUV max value was significantly lower than the FDG SUV max in the first examination. After treatment, the FLT SUV max value was much lower regardless of the presence of the inflammatory response after radiotherapy.…”

Comparison of semiquantitative metabolic parameters of the primary tumor obtained in PET/CT with 18F-FDG and 18F-FLT in patients with cervical cancer

“…This imaging biomarker showed significant accumulation in lung, breast and colorectal cancer, lymphomas and gliomas [6]. The role of 18 F-FLT PET/CT in cervical cancer is still under investigation, however there are some data suggesting that 18 F-FLT PET/CT may be useful in the assessment of response to either chemo-or radiation therapy and for the post-chemotherapy brachytherapy planning [4]. In the same paper authors noticed slightly lower uptake of 18 F-FLT compared to 18 F-FDG in gynecologic cancers before treatment [4].…”