18F-FDG PET/CT in the evaluation of cancer cervix: Where do we stand today?

Prediction of Patient Outcomes in Locally Advanced Cervical Carcinoma Following Chemoradiotherapy-Comparative Effectiveness of Magnetic Resonance Imaging and 2-Deoxy-2-[18F]fluoro-D-glucose Imaging

PURPOSE

To evaluate the utility and comparative effectiveness of three five-point qualitative scoring systems for assessing response on PET-CT and MRI imaging individually and in combination, following curative-intent chemoradiotherapy (CRT) in locally advanced cervical cancer (LACC). Their performance in the prediction of subsequent patient outcomes was also assessed; Methods: Ninety-seven patients with histologically confirmed LACC treated with CRT using standard institutional protocols at a single centre who underwent PET-CT and MRI at staging and post treatment were identified retrospectively from an institutional database. The post-CRT imaging studies were independently reviewed, and response assessed using five-point scoring tools for T2WI, DWI, and FDG PET-CT. Patient characteristics, staging, treatment, and follow-up details including progression-free survival (PFS) and overall survival (OS) outcomes were collected. To compare diagnostic performance metrics, a two-proportion z-test was employed. A Kaplan-Meier analysis (Mantel-Cox log-rank) was performed.

RESULTS

The T2WI (p < 0.00001, p < 0.00001) and DWI response scores (p < 0.00001, p = 0.0002) had higher specificity and accuracy than the PET-CT. The T2WI score had the highest positive predictive value (PPV), while the negative predictive value (NPV) was consistent across modalities. The combined MR scores maintained high NPV, PPV, specificity, and sensitivity, and the PET/MR consensus scores showed superior diagnostic accuracy and specificity compared to the PET-CT score alone (p = 0.02926, p = 0.0083). The Kaplan-Meier analysis revealed significant differences in the PFS based on the T2WI (p < 0.001), DWI (p < 0.001), combined MR (p = 0.003), and PET-CT/MR consensus scores (p < 0.001) and in the OS for the T2WI (p < 0.001), DWI (p < 0.001), and combined MR scores (p = 0.031) between responders and non-responders.

CONCLUSION

Post-CRT response assessment using qualitative MR scoring and/or consensus PET-CT and MRI scoring was a better predictor of outcome compared to PET-CT assessment alone. This requires validation in a larger prospective study but offers the potential to help stratify patient follow-up in the future.

Volumetric PET parameters are predictive for the prognosis of locally advanced cervical cancer

BACKGROUND

The present study evaluates the relationship between PET/CT findings and survival in patients with locally advanced cervical cancer (LACC) with a squamous cell histology.

METHODS

The study included 70 patients with LACC (FIGO stage IB2-IVA). The relationship between pretreatment PET/CT parameters, age, stage, lymph node metastasis and survival was evaluated using the univariate and multivariate Cox proportional hazards model.

RESULTS

The mean age of the 70 patients was 57.4 years and the mean duration of follow-up was 33.6 months. Disease progression occurred in 36 patients and 32 patients died during the follow-up period. In the univariate analysis, MTV-P and TLG-P were found to be related to progression-free survival (PFS), and stage, MTV-P, TLG-P and SUV<inf>max</inf>-Ps were found to be related to overall survival (OS). However, only MTV-P and TLG-P were found to be independent prognostic factors for both PFS and OS.

CONCLUSIONS

The present findings suggest that volumetric PET parameters (MTV-P, TLG-P) predict the progression and survival of the patients with LACC.

FDG PET-CT as an important diagnostic tool and prognostic marker in suspected recurrent cervical carcinoma after radiotherapy: comparison with MRI

BACKGROUND

Recurrent disease in post-irradiation patients with cervical cancer is often difficult to delineate on magnetic resonance imaging (MRI), because posttreatment changes can have a similar appearance, and further evaluation is often required. The aims of the study were to evaluate positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (FDG PET-CT) diagnostic role in suspected recurrent cervical cancer after radiotherapy, compare it to MRI, and assess their prognostic impact in these patients.

PATIENTS AND METHODS

This cohort retrospective study included patients previously treated with radiotherapy for carcinoma of uterine cervix with suspected recurrence, who had undergone MRI of abdomen and pelvis, and were subsequently evaluated on FDG PET-CT, with minimum follow-up period of 12 months.

RESULTS

In the total of 84 patients included in analysis, MRI vs. FDG PET-CT showed sensitivity, specificity and accuracy of 80.1%, 52.4% and 66.7%, vs. 97.6%, 61.9% and 79.8%, respectively. Patients with positive findings on MRI (Log Rank, p = 0.003) and PET-CT (Log Rank, p < 0.001) had shorter progression-free survival (PFS) than those with negative results. In univariate Cox regression models, MRI and FDG PET-CT results were found to be related to PFS (p = 0.005 and p < 0.001, respectively). However, multivariate analysis proved only FDG PET-CT to be independent prognostic factor, where patients with positive FDG PET-CT results had almost nine times higher risk of progression (p < 0.001).

CONCLUSION

FDG PET-CT represents useful diagnostic tool in suspected recurrent cervical cancer after radiotherapy, showing high sensitivity in its detection. In addition, it is an independent factor in predicting progression-free survival in these patients.

Metabolo-volumetric parameters of 18F-FDG-PET can predict expression of EGFR and HIF 1alpha in uterine cervical cancer

BACKGROUND

The aim of our study was to investigate possible relationships between 18F-FDG-PET parameters and clinically relevant histopathological findings in patients with cervical cancer (CC).

METHODS

Eighteen female patients (mean age 55.4 years) with histologically confirmed squamous cell CC were involved into the study. In all cases, 18F-FDG-PET CT was performed. Mean and maximum standardized uptake values (SUVmean and SUVmax), total lesion glycolysis (TLG) and metabolic tumor volume (MTV) were determined on PET-images. For every tumor the following specimen stainings were performed: epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), tumor suppressor protein p53, hypoxia-inducible factor (HIF)-1α, and histone 3. All stained specimens were digitalized and analyzed by using the ImageJ software 1.48v. Spearman's correlation coefficient (p) was used to analyze associations between investigated parameters. p-values < 0.05 were taken to indicate statistical significance.

RESULTS

TLG and MTV correlated well with expression of EGFR (p= 0.601, P= 0.008 and p= 0.586, P= 0.011, respectively). SUVmedian correlated inversely with expression of HIF 1alpha (p=-0.509, P= 0.031). SUVmean tended to correlate with expression of EGFR and HIF 1alpha. None of the PET parameters correlated with expression of Histone 3, p53 and VEGF.

CONCLUSION

TLG and MTV can reflect expression of EGFR and SUVmedian correlated significantly with expression of HIF-1α. None of the PET parameters can predict expression of Histone 3, p53 and VEGF.

Combinative evaluation of primary tumor and lymph nodes in predicting pelvic lymphatic metastasis in early-stage cervical cancer: A multiparametric PET-CT study

PURPOSE

The purpose of this study is to investigate the value of combining tumor and pelvic lymph node (PLN) characteristics on PET-CT in predicting PLN metastasis of patients with early-stage cervical cancer, specifically to further reduce the false-negative cases of diagnosis.

METHODS

The [18F] FDG PET-CT imaging data of 394 patients who were newly diagnosed with cervical cancer (FIGO stage, Ia-IIa) were retrospectively studied. We measured size, total lesion glycolysis (TLG) of tumor, metabolic tumor volume (MTV), maximum and mean standardized uptake value (SUVmax, SUVmean) of tumor and lymph node (LN). Diagnostic efficiency was evaluated using receiver operator characteristic (ROC) curve. We also investigated additional CT diagnosis information in PET-negative cases.

RESULTS

Our results indicated both lymph node and tumor parameters were independent risk factors for lymphatic metastasis in early-stage cervical cancer. The diagnosis based on above meaningful parameters, we name it 'combination diagnosis', offered significantly higher predictive value than that based on SUV measurement alone, which the values of AUC were 0.842 and 0.784 respectively (P < 0.05). In PET-negative cases, we also found that tumor TLG, suspicious LN in lymphatic drainage pathway, long/short axis of LN ≤ 2, heterogeneity of LN significantly associated with PLN metastasis. ROC analysis showed combination diagnosis of all these parameters above produced an AUC value of 0.859 (P < 0.05, 95% CI, 0.811-0.899), which was significantly higher than either using tumor TLG alone (AUC = 0.622, Z = 3.919, P < 0.05) or indices derived from CT alone (AUC = 0.727, 0.668, 0.695. Z = 3.620, 5.356, 3.696, P < 0.05).

CONCLUSIONS

We proposed a combination diagnosis method that can better predict PLN metastasis for patients with early-stage cervical cancer. In PET-negative cases, combination diagnosis of TLG of tumor and CT indicators also produced improved prediction by reducing false-negative cases of diagnosis. This combination diagnosis approach has significant implications in cervical cancer patient management and treatment planning.