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

ABSTRACT: OBJECTIVE:The 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). METHODS:In 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. RESULTS:Median 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. CONCLUSION:The 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.

SUBMITTER: Cho LP

PROVIDER: S-EPMC4688880 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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

Cho Linda P LP Kim Chun K CK Viswanathan Akila N AN

Gynecologic oncology reports 20151102

<h4>Objective</h4>The 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).<h4>Methods</h4>In this pilot study, patients treated for cervical (5) or vaginal (1) ca ...[more]

PMID: 26793770

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Project description:Background3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) has been used to evaluate tumor malignancy and cell proliferation in human brain gliomas. However, (18)F-FLT has several limitations in clinical use. Recently, (11)C-labeled thymidine analogue, 4'-[methyl-(11)C]thiothymidine ((11)C-4DST), became available as an in vivo cell proliferation positron emission tomography (PET) tracer. The present study was conducted to evaluate the usefulness of (11)C-4DST PET in the diagnosis of human brain gliomas by comparing with the images of (18)F-FLT PET.MethodsTwenty patients with primary and recurrent brain gliomas underwent (18)F-FLT and (11)C-4DST PET scans. The uptake values in the tumors were evaluated using the maximum standardized uptake value (SUVmax), the tumor-to-normal tissue uptake (T/N) ratio, and the tumor-to-blood uptake (T/B) ratio. These values were compared among different glioma grades. Correlation between the Ki-67 labeling index and the uptake values of (11)C-4DST and (18)F-FLT in the tumor was evaluated using linear regression analysis. The relationship between the individual (18)F-FLT and (11)C-4DST uptake values in the tumors was also examined.Results(11)C-4DST uptake was significantly higher than that of (18)F-FLT in the normal brain. The uptake values of (11)C-4DST in the tumor were similar to those of (18)F-FLT resulting in better visualization with (18)F-FLT. No significant differences in the uptake values of (18)F-FLT and (11)C-4DST were noted among different glioma grades. Linear regression analysis showed a significant correlation between the Ki-67 labeling index and the T/N ratio of (11)C-4DST (r = 0.50, P < 0.05) and (18)F-FLT (r = 0.50, P < 0.05). Significant correlations were also found between the Ki-67 labeling index and the T/B ratio of (11)C-4DST (r = 0.52, P < 0.05) and (18)F-FLT (r = 0.55, P < 0.05). A highly significant correlation was observed between the individual T/N ratio of (11)C-4DST and (18)F-FLT in the tumor (r = 0.79, P = 0.0001).ConclusionsThe present study demonstrates that (11)C-4DST is useful for the imaging of human brain gliomas with PET. A relatively higher background uptake of (11)C-4DST in the normal brain compared to (18)F-FLT limits the detection of low-tracer-uptake tumors. Moreover, no superiority was found in (11)C-4DST over (18)F-FLT in the evaluation of cell proliferation.

Project description:PurposeBeam angle optimization is a critical issue for modern radiotherapy (RT) and is a challenging task, especially for large body sizes and noncoplanar designs. Noncoplanar RT techniques may have dosimetric advantages but increase the risk of mechanical collision. We propose a software solution to accurately predict colliding/noncolliding configurations for coplanar and noncoplanar beams.Materials and methodsIndividualized software models for two different linear accelerators were built to simulate noncolliding gantry orientations for phantom/patient subjects. The sizes and shapes of the accelerators were delineated based on their manuals and on-site measurements. The external surfaces of the subjects were automatically contoured based on computed tomography (CT) simulations. An Alderson Radiation Therapy phantom was used to predict the accuracy of spatial collision prediction by the software. A gantry collision problem encountered by one patient during initial setup was also used to test the validity of the software. Results: In the comparison between the software estimates and on-site measurements, the noncoplanar collision angles were all predicted within a 5-degree difference in gantry position. The confusion matrix was calculated for each of the two empty accelerator models, and the accuracies were 98.7% and 97.3%. The true positive rates were 97.7% and 96.9%, while the true negative rates were 99.8% and 97.9%, respectively. For the phantom study, the collision angles were predicted within a 5-degree difference. The software successfully predicted the collision problem encountered by the breast cancer patient in the initial setup position and generated shifted coordinates that were validated to correspond to a noncolliding geometry.ConclusionThe developed software effectively and accurately predicted collisions for accelerator-only, phantom, and patient setups. This software may help prevent collisions and expand the range of spatially applicable beam angles.

Project description:PurposeThis study aimed to assess the biodistribution, detection rate, and uptake of the [18F]FAPI-42 at two distinct time intervals.MethodsThis prospective study enrolled 60 consecutive patients (median age 59; range 35-74) referred to [18F]FAPI-42 PET/CT. [18F]FAPI-42 PET/CT was performed early and late timepoint after tracer injection for staging or restaging. Positive lesions specified for anatomic locations (primary or recurrent tumor, LN metastasis and other metastasis) by visual analysis at both timepoints. Semiquantitative analysis of the tracer activity in lesions as well as normal tissues at both time points were measured and compared. In a subgroup analysis, eleven patients underwent 2-[18F]FDG PET/CT within 1 week, the detection rate and uptake of lesion were compared between early [18F]FAPI-42 and 2-[18F]FDG.ResultsUptake of [18F]FAPI-42 in the late timepoint was significantly lower than the early timepoint in most organs (all p < 0.05), except for bone (SUVmean 0.88 vs. 0.85; p = 0.218). Tracer retention at biliary system showed less frequent at early timepoint than late timepoint. A total of 194 lesions were detected in 60 patients. One lesion was only seen at early timepoint but not at late timepoint. Lesions on early [18F]FAPI-42 PET/CT had higher visual score than that of late image(23 vs. 6). The uptake of lesion decreased significantly from early to late timepoint (all p < 0.05). In subgroup analysis, early [18F]FAPI-42 illustrated higher detection rate, visual score, and uptake of lesion than that of 2-[18F]FDG PET/CT.ConclusionEarly [18F]FAPI-42 PET/CT provided consistent detection rates and lesion uptake, but less tracer retention in the biliary system compared to late images. Therefore, acquisition at early timepoint could be a feasible strategy for improving acquisition protocols of [18F]FAPI-42 PET/CT.Trial registrationChiCTR2200063441. Registered 28 September 2022-Retrospectively registered, https://www.chictr.org.cn/bin/project/edit?pid=149714 .

Project description:Background and purposeApparent diffusion coefficient (ADC) reflects micro-enviromental changes and therefore might be useful in predicting recurrence prior to brachytherapy. The purpose of this study is to evaluate change in ADC of the primary tumour and pathologic lymph nodes during treatment and to correlate this with clinical outcome.Material and methodsTwenty patients were included who received chemoradiation for locally advanced cervical cancer between July 2016 and November 2017. All patients underwent magnetic resonance imaging (MRI) prior to treatment, and three MRIs in weeks 1/2, 3 and 4 of treatment, including T2 and diffusion weighted imaging (b-values 0, 200, 800 s/mm2) for determining an ADC-map. Primary tumour was delineated on T2 and ADC-map and pathologic lymph nodes were delineated only on ADC-map.ResultsAt time of analysis median follow-up was 15 (range 7-22) months. From MRI one to four, primary tumour on ADC-map showed a significant signal increase of 0.94 (range 0.74-1.46) × 10-3 mm2/s to 1.13 (0.98-1.49) × 10-3 mm2/s (p < 0.001). When tumour was delineated on T2, ADC-value signal increase (in tumour according to T2) was similar. All 46 delineated pathologic lymph nodes showed an ADC-value increase on average from 0.79 (range 0.33-1.12) × 10-3 mm2/s to 1.14 (0.59-1.75) × 10-3 mm2/s (p < 0.001). The mean tumour/suspected lymph node volumes decreased respectively 51/40%. Four patients developed relapse (one local and three nodal), without clear relation with ΔADC. However, the median volume decrease of the primary tumour was substantially lower in the failing patients compared to the group without relapse (19 vs. 57%).ConclusionsADC values can be acquired using T2-based tumour delineations unless there are substantial shifts between ADC-mapping and T2 acquisition. It remains plausible that ΔADC is a predictor for response to EBRT. However, the correlation in this study was not statistically significant.

Project description:In locally advanced cervical cancer, (18)F-fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET/CT) has become important in the initial evaluation of disease extent. It is superior to other imaging modalities for lymph node status and distant metastasis. PET-defined cervical tumor volume predicts progression-free and overall survival. Higher FDG uptake in both primary and regional lymph nodes is strongly predictive of worse outcome. FDG-PET is useful for assessing treatment response 3 months after completing concurrent chemo-radiotherapy (CRT) and predicting long-term survival, and in suspected disease recurrence. In the era of image-guided adaptive radiotherapy, accurately defining disease areas is critical to avoid irradiating normal tissue. Based on additional information provided by FDG-PET, radiation treatment volumes can be modified and higher doses to FDG-positive lymph nodes safely delivered. FDG-PET/CT has been used for image-guided brachytherapy of FDG-avid tumor volume, while respecting low doses to bladder and rectum. Despite survival improvements due to CRT in cervical cancer, disease recurrences continue to be a major problem. Biological rationale exists for combining novel non-cytotoxic agents with CRT, and drugs targeting specific molecular pathways are under clinical development. The integration of these targeted therapies in clinical trials, and the need for accurate predictors of radio-curability is essential. New molecular imaging tracers may help identifying more aggressive tumors. (64)Cu-labeled diacetyl-di(N(4)-methylthiosemicarbazone) is taken up by hypoxic tissues, which may be valuable for prognostication and radiation treatment planning. PET/CT imaging with novel radiopharmaceuticals could further impact cervical cancer treatment as surrogate markers of drug activity at the tumor microenvironment level. The present article reviews the current and emerging role of PET/CT in the management of cervical cancer.

Project description:PurposeTo determine if quantitative features extracted from pretherapy fluorine 18 fluorodeoxyglucose (18F-FDG) PET/CT estimate prognosis in patients with locally advanced cervical cancer treated with chemoradiotherapy.Materials and methodsIn this retrospective study, PET/CT images and outcomes were curated from 154 patients with locally advanced cervical cancer, who underwent chemoradiotherapy from two institutions between March 2008 and June 2016, separated into independent training (n = 78; mean age, 51 years ± 13 [standard deviation]) and testing (n = 76; mean age, 50 years ± 10) cohorts. Radiomic features were extracted from PET, CT, and habitat (subregions with different metabolic characteristics) images that were derived by fusing PET and CT images. Parsimonious sets of these features were identified by the least absolute shrinkage and selection operator analysis and used to generate predictive radiomics signatures for progression-free survival (PFS) and overall survival (OS) estimation. Prognostic validation of the radiomic signatures as independent prognostic markers was performed using multivariable Cox regression, which was expressed as nomograms, together with other clinical risk factors.ResultsThe radiomics nomograms constructed with T stage, lymph node status, and radiomics signatures resulted in significantly better performance for the estimation of PFS (Harrell concordance index [C-index], 0.85 for training and 0.82 for test) and OS (C-index, 0.86 for training and 0.82 for test) compared with International Federation of Gynecology and Obstetrics staging system (C-index for PFS, 0.70 for training [P = .001] and 0.70 for test [P = .002]; C-index for OS, 0.73 for training [P < .001] and 0.70 for test [P < .001]), respectively.ConclusionPrognostic models were generated and validated from quantitative analysis of 18F-FDG PET/CT habitat images and clinical data, and may have the potential to identify the patients who need more aggressive treatment in clinical practice, pending further validation with larger prospective cohorts.Supplemental material is available for this article.© RSNA, 2020.

Dataset Information

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

Publications

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

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