Utility of (18)F-FDG PET/CT in patients with advanced squamous cell carcinoma of the uterine cervix receiving concurrent chemoradiotherapy: a parallel study of a prospective randomized trial

The use of PET/MRI in radiotherapy

Positron emission tomography/magnetic resonance imaging (PET/MRI) is a hybrid imaging technique that quantitatively combines the metabolic and functional data from positron emission tomography (PET) with anatomical and physiological information from MRI. As PET/MRI technology has advanced, its applications in cancer care have expanded. Recent studies have demonstrated that PET/MRI provides unique advantages in the field of radiotherapy and has become invaluable in guiding precision radiotherapy techniques. This review discusses the rationale and clinical evidence supporting the use of PET/MRI for radiation positioning, target delineation, efficacy evaluation, and patient surveillance.Critical relevance statement This article critically assesses the transformative role of PET/MRI in advancing precision radiotherapy, providing essential insights into improved radiation positioning, target delineation, efficacy evaluation, and patient surveillance in clinical radiology practice.Key points• The emergence of PET/MRI will be a key bridge for precise radiotherapy.• PET/MRI has unique advantages in the whole process of radiotherapy.• New tracers and nanoparticle probes will broaden the use of PET/MRI in radiation.• PET/MRI will be utilized more frequently for radiotherapy.

Clinical factor-based risk stratification for precision therapy in locally advanced squamous cell carcinoma of the uterine cervix

BACKGROUND

Concurrent chemoradiotherapy (CCRT) is the standard of care for locally advanced cervical cancer. In this study, we analyzed the pretreatment clinical and 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) characteristics of patients with locally advanced cervical squamous cell carcinoma (SCC) to develop a scoring prototype for risk stratification.

METHODS

Two cohorts were constructed in this study. Cohort 1 comprised patients with cervical SCC with 2009 FIGO stage III-IVA or stage I-II with positive pelvic or para-aortic lymph node (PALN) on PET/CT from AGOG09-001 trial. Cohort 2 comprised patients with similar characteristics who had received adequate therapy in our hospital between 2016 and 2021. Pretreatment patient characteristics and PET/CT parameters including maximum standardized uptake value (SUVmax ) and metabolic tumor volume (MTV) of primary tumor and nodal SUVmax were assessed for cancer-specific survival (CSS) using multivariate Cox regression.

RESULTS

Analysis of combined data from cohorts 1 (n = 55) and 2 (n = 128) indicated age ≥ 66 years, primary tumor MTV ≥87 mL, and positive PALN on PET/CT to be independently significant adverse predictors for CSS (p < 0.001, p = 0.014, and p = 0.026, respectively) with a median follow-up duration of 51 months. Assigning a score of 1 to each adverse predictor, patients with cumulative risk scores of 0, 1, 2, and 3 were discovered to have a 5-year CSS of 86.9%, 71.0%, 32.2%, and 0%, respectively (p < 0.001).

CONCLUSION

Age, primary tumor MTV, and positive PALN on PET/CT may serve as independent predictors of poor survival in patients with locally advanced cervical SCC. Our findings indicate that patients without any adverse factors can receive standard CCRT, whereas those with at least one adverse factor can consider novel combination therapies or clinical trials.

The prognostic value of FIGO staging defined by combining MRI and [18F]FDG PET/CT in patients with locally advanced cervical cancer

The last version of the FIGO classification recommended imaging tools to complete the clinical assessment of patients with cervical cancer. However, the preferable imaging approach is still unclear. We aimed to explore the prognostic power of Magnetic Resonance Imaging (MRI), contrast-enhanced Computed Tomography (ceCT), and [18F]-Fluorodeoxyglucose Positron Emission Tomography ([18F]FDG-PET)/CT in patients staged for locally advanced cervical cancer (LACC, FIGO stages IB3-IVA). Thirty-six LACC patients (mean age 55.47 ± 14.01, range 31-82) were retrospectively enrolled. All of them underwent MRI, ceCT and [18F]FDG-PET/CT before receiving concurrent chemoradiotherapy. A median dose of 45 Gy (range 42-50.4; 25-28 fractions, 5 fractions per week, 1 per day) was delivered through the external-beam radiation therapy (EBRT) on the pelvic area, while a median dose of 57.5 Gy (range 16-61.1; 25-28 fractions, 5 fractions per week, 1 per day) was administered on metastatic nodes. The median doses for brachytherapy treatment were 28 Gy (range 28-30; 4-5 fractions, 1 every other day). Six cycles of cisplatin or carboplatin were administered weekly. The study endpoints were recurrence-free survival (RFS) and overall survival (OS). Metastatic pelvic lymph nodes at MRI independently predicted RFS (HR 13.271, 95% CI 1.730-101.805; P = 0.027), while metastatic paraaortic lymph nodes at [18F]FDG-PET/CT independently predicted both RFS (HR 11.734, 95% CI 3.200-43.026; P = .005) and OS (HR 13.799, 95% CI 3.378-56.361; P < 0.001). MRI and [18F]FDG-PET/CT findings were incorporated with clinical evidences into the FIGO classification. With respect to the combination of clinical, MRI and ceCT data, the use of next-generation imaging (NGI) determined a stage migration in 10/36 (27.7%) of patients. Different NGI-based FIGO classes showed remarkably different median RFS (stage IIB: not reached; stage IIIC1: 44 months; stage IIIC2: 3 months; P < 0.001) and OS (stage IIB: not reached; stage IIIC1: not reached; stage IIIC2: 14 months; P < 0.001). A FIGO classification based on the combination of MRI and [18F]FDG-PET/CT might predict RFS and OS of LACC patients treated with concurrent chemoradiotherapy.

18F-FDG-PET/CT imaging of uterine cervical cancer recurrence in women with and without HIV infection

BACKGROUND

To compare the rate, time and, pattern of recurrence of cervical cancer between patients with and without HIV infection and to determine factors predicting cervical cancer recurrence in patients evaluated by ¹⁸F-FDG-PET/CT.

METHODS

We reviewed the ¹⁸F-FDG-PET/CT images of patients with histologically proven cervical carcinoma who were presenting with suspected recurrence. We extracted epidemiologic data, previous treatment, histologic subtype, HIV status, viral load and CD4 counts from the electronic laboratory database and the referral form for the ¹⁸F-FDG-PET/CT study.

RESULTS

We studied 303 women including 112 HIV-infected patients. FIGO stage III disease was present in 131 patients. Of 198 patients with recurrence, 74 were HIV-infected while 124 were not (P=0.849). HIV infected patients were younger (41.99±9.30 years) compared to HIV-uninfected (50.19±11.09), P<0.001. Local recurrence was present in 125 patients while 100 patients had a distant recurrence. Recurrence occurred at a single site in 88 patients and two or more sites in 110 patients. No significant difference in the recurrent patterns between HIV-infected and uninfected patients. Median time to recurrence was 10.50 months (range: 6.00-156.00) among HIV-infected versus 12.00 months (IQR:7.00-312.00) among the uninfected, P=0.065. FIGO stage III (P=0.042) and the presence of histological sub-types other than SCC (P=0.005) were significant predictors of recurrence. HIV infection by itself was not significant in predicting recurrence (P=0.843).

CONCLUSIONS

HIV infection has no significant impact on the rate, time or pattern of recurrence in women with suspected cervical carcinoma recurrence. Advanced disease and histological variant other than SCC are predictive of recurrence.

A Systematic Review and Meta-Analysis of the Prognostic Impact of Pretreatment Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters in Patients with Locally Advanced Cervical Cancer Treated with Concomitant Chemoradiotherapy

Backgrounds: The purpose of this paper is to investigate the prognostic value of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters in patients treated with concurrent chemoradiotherapy (CCRT) for locally advanced cervical cancer (LACC). Methods: Studies that met the following criteria were retrieved from PubMed and Embase: patients treated with CCRT for LACC; FDG PET/CT scans performed before CCRT treatment; and a detected relationship between the parameters of FDG PET/CT and the prognosis of patients. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the overall survival (OS) or event-free survival (EFS). Results: In total, 14 eligible studies with 1313 patients were included in this meta-analysis. Patients with a high maximum standardized uptake value (SUVmax) have a shorter OS than those with a low SUV_max (HR = 2.582, 95% = CI 1.936–3.443, p < 0.001). Primary tumor SUV_max values (HR = 1.938, 95% CI = 1.203–3.054, p = 0.004) were significantly correlated with EFS, with a relatively high heterogeneity (I² = 84% and I² = 69.4%, respectively). Based on the limited data, the combined HR for EFS with the highest primary tumor total lesion glycolysis (TLG) and metabolic tumor volume (MTV) was 1.843 (95% CI = 1.100–3.086, p = 0.02) and 2.06 (95% CI = 1.21–3.51, p = 0.007), respectively. Besides, the combined HR for OS with the highest nodal SUV_max was 2.095 (95% CI = 2.027–2.166, p < 0.001). Conclusion: A high primary SUVmax has a significant correlation with the OS and EFS of patients treated with CCRT for LACC and may therefore serve as a prognostic predictor. Due to the limited data, to explore the correlation between survival and TLG, MTV, and nodal SUVmax, further large-scale prospective studies are needed.

EANM/SNMMI practice guideline for [18F]FDG PET/CT external beam radiotherapy treatment planning in uterine cervical cancer v1.0

PURPOSE

The aim of this EANM / SNMMI Practice Guideline with ESTRO endorsement is to provide general information and specific considerations about [18F]FDG PET/CT in advanced uterine cervical cancer for external beam radiotherapy planning with emphasis on staging and target definition, mostly in FIGO stages IB3-IVA and IVB, treated with curative intention.

METHODS

Guidelines from related fields, relevant literature and leading experts have been consulted during the development of this guideline. As this field is rapidly evolving, this guideline cannot be seen as definitive, nor is it a summary of all existing protocols. Local variations should be taken into consideration when applying this guideline.

CONCLUSION

The background, common clinical indications, qualifications and responsibilities of personnel, procedure / specifications of the examination, documentation / reporting and equipment specifications, quality control and radiation safety in imaging is discussed with an emphasis on the multidisciplinary approach.

Prediction of treatment response in patients with locally advanced cervical cancer using midtreatment PET/MRI during concurrent chemoradiotherapy

PURPOSE

We aimed to find metabolic, functional or morphological characteristics of the tumor predicting failure to achieve complete metabolic remission (CMR) by the midtreatment PET/MRI (positron emission tomography/magnetic resonance imaging) in cervical cancer patients.

METHODS

We evaluated 66 patients treated between August 2015 and November 2019 who underwent pretreatment staging, subsequent midtreatment evaluation, and definitive restaging 3 months after completing the whole treatment, all using PET/MRI. The pretreatment parameters (pre-SUVmax, pre-SUVmean, pre-MTV, pre-MTV‑S, pre-TLG, pre-TLG‑S [SUV: standard uptake value, MTV: metabolic tumor volume, TLG: total lesion glycolysis]), and the midtreatment parameters at week 5 during chemoradiotherapy (mid-SUVmax, mid-SUVmean, mid-MTV, mid-MTV‑S, mid-TLG and mid-TLG-S) were recorded. The value of ADC (apparent diffusion coefficient) was also measured. Furthermore, we recorded absolute and relative changes in all parameters-∆ and ∆%. We divided the whole group of patients into "responders" (CMR) and "non-responders" (non-CMR), and compared them on the basis of the parameters from pre-PET/MRI and mid-PET/MRI.

RESULTS

A statistically significant difference in the evaluated parameters between responders and non-responders was found for the following parameters: mid-MTV, mid-TLG, mid-TLG‑S, mid-MTV‑S, mid-tumor size, and ∆%SUVmax. According to the ROC (receiver operating characteristic) analysis, mid-MTV‑S showed the best albeit moderate discrimination ability for the prediction of non-CMR. Significant mutual correlations of all variables, in particular between mid-MTV‑S and mid-TLG‑S and between mid-MTV and mid-TLG, were found (all p < 0.05).

CONCLUSION

Our study confirmed that when using the midtreatment PET/MRI we are able to identify metabolic parameters having the discrimination ability for the prediction of non-CMR. In particular mid-MTV‑S, mid-MTV, mid-tumor size, mid-TLG‑S, mid-TLG and ∆%SUVmax.

Parametric Response Mapping of Coregistered Positron Emission Tomography and Dynamic Contrast Enhanced Computed Tomography to Identify Radioresistant Subvolumes in Locally Advanced Cervical Cancer

PURPOSE

To identify subvolumes that may predict treatment response to definitive concurrent chemoradiation therapy using parametric response mapping (PRM) of coregistered positron emission tomography (PET) and dynamic contrast-enhanced (DCE) computed tomography (CT) in locally advanced cervical carcinoma.

METHODS AND MATERIALS

Pre- and midtreatment (after 23 ± 4 days of concurrent chemoradiation therapy) DCE CT and PET imaging were performed on 21 patients with cervical cancer who were enrolled in a pilot study to evaluate the prognostic value of CT perfusion for primary cervical cancer (NCT01805141). Three-dimensional coregistered maps of PET/CT standardized uptake value (SUV) and DCE CT blood flow (BF) were generated. PRM was performed using voxel-wise joint histogram analysis to classify voxels within the tumor as highly metabolic and perfused (SUV^hiBF^hi), highly metabolic and hypoxic (SUV^hiBF^lo), low metabolic activity and hypoxic (SUV^loBF^lo), or low metabolic activity and perfused (SUV^loBF^hi) tissue based on thresholds determined from population means of pretreatment PET SUV and DCE CT BF. Relationships between baseline pretreatment imaging metrics and relative changes in metabolic tumor volume (ΔMTV), calculated from before treatment and during treatment imaging, were determined using univariable and multivariable linear regression models.

RESULTS

The relative volume of three PRM subvolumes significantly changed during treatment (SUV^hiBF^hi: P = .04; SUV^hiBF^lo: P = .0008; SUV^loBF^hi: P = .02), whereas SUV^loBF^lo did not (P = .9). Pretreatment PET SUV_max (r = -.58, P = .006), PET SUV_mean (ρ = -.59, P = .005), DCE CT BF_mean (r = -.50, P = .02), tumor volume (ρ = -.65, P = .001) and PRM SUV^hiBF^hi (ρ = -.59, P = .004) were negatively correlated with ΔMTV, whereas PRM SUV^loBF^lo was positively related to ΔMTV (r = .77, P < .0001). In a multivariable model that predicted ΔMTV, PRM SUV^loBF^lo, which combines both PET/CT and DCE CT, was the only significant variable (β = 1.825, P = .03), dominating both imaging modalities independently.

CONCLUSIONS

PRM was applied in locally advanced cervical carcinoma treated definitively with chemoradiation, and radioresistant subvolumes were identified that correlated with changes in MTV and predicted treatment response. Identification of these subvolumes may assist in clinical decision making to tailor therapies, such as brachytherapy, in an effort to improve patient outcomes.

Feasibility Study and Preliminary Results of Prognostic Value of Bone SPECT-CT Quantitative Indices for the Response Assessment of Bone Metastatic Prostate Carcinoma to Abiraterone

Objective: We assessed the prognostic value of quantitative indices extracted from bone SPECT-CT to evaluate the response of bone metastatic castrate-resistant prostate cancer (BmCRPC) to abiraterone.

Methods: Consecutive patients with BmCRPC initiating treatment with abiraterone from March 2014 to March 2015 were prospectively included. Three 2-bed SPECT-CT [at baseline [M0], after 3 months [M3], and 6 months [M6] of treatment], were planned (Symbia Intevo^®, Siemens). SPECT data were reconstructed using an Ordered Subset Conjugate Gradient Minimization (OSCGM) algorithm allowing SUV quantification. SUVmax and SUVpeak of the highest uptake lesion were measured in each SPECT-CT. Total Neoplastic Osteoblastic Metabolic Volume (NOMV) was assessed. PSA level was recorded at baseline, M3, and M6 of treatment. Overall survival (OS), progression-free survival (PFS), and disease-specific survival (DSS) were calculated.

Results: Nineteen patients aged 71.1 ± 7.7 years were included. Low M0 SUVmax was significantly predictive of longer OS (p = 0.04). Low NOMV at M0 were significantly predictive of longer PFS (p = 0.02). Patients with increase of at least 12.5% of the SUVpeak of the highest uptake lesion between M0 and M3 (ΔSUVpeakM0M3) had a significantly longer OS (p = 0.03). Patients with increase (or decrease lesser than 25%) of ΔSUVpeakM0M3 had a significantly longer DSS (p = 0.01). Patients with increase of NOMV of at least 45% between M0 and M6 had a significantly shorter PFS (p < 0.001). Variations of NOMV between M0 and M6 were significantly correlated with PSA variations between M0 and M6 (rs = 0.73, p = 0.02).

Conclusions: Quantitative bone SPECT-CT appears to be a promising tool of BmCRPC assessment. Early flare-up phenomenon seems to predict longer OS.

Multiparametric PET/MR (PET and MR-IVIM) for the evaluation of early treatment response and prediction of tumor recurrence in patients with locally advanced cervical cancer

OBJECTIVES

To assess the value of ¹⁸F-FDG PET and MR-IVIM parameters before and during concurrent chemoradiotherapy (CCRT) for evaluating early treatment response and predicting tumor recurrence in patients with locally advanced cervical cancer (LACC) using a hybrid PET/MR scanner.

METHODS

Fifty-one patients with LACC underwent pelvic PET/MR scans with an IVIM sequence at two time-points (pretreatment [pre] and midtreatment [mid]). Pre- and mid-PET parameters (SUV_max, MTV, TLG) and IVIM parameters (D, F, D*) and their percentage changes (Δ%SUV_max, Δ%MTV, Δ%TLG, Δ%D, Δ%F, Δ%D*) were calculated. We selected independent imaging parameters and built a combined prediction model incorporating imaging parameters and clinicopathological risk factors. The performance of the combinative evaluation for tumor early shrinkage rates (TESR) and the prediction model for tumor recurrence was assessed.

RESULTS

Thirty-two patients were classified into the good response (GR) group with TESR ≥ 50%, and 19 patients were categorized into the poor response (PR) group with TESR < 50%. Δ%D (p = 0.013) and Δ%F (p = 0.006) are independently related to TESR with superior combined diagnostic ability (AUC = 0.901). Pre-TLG, Δ%D, and suspicious lymph node metastasis (SLNM) were selected for the construction of the combined prediction model. The model for identifying the patients with high risk of tumor recurrence reached a moderate predictive ability and good stability with c-index of 0.764 (95% CI, 0.672-0.855).

CONCLUSION

The combined prediction model based on pretreatment PET metabolic parameter (pre-TLG), IVIM-D percentage changes, and LNs status provides great potential to identify the LACC patients with high risk of recurrence at early stage of CCRT.

KEY POINTS

• PET/MR plus IVIM offers various complementary information for LACC. • IVIM-D and IVIM-F percentage changes are independently related to tumor early shrinkage rates. • The combined prediction model can help identify the LACC patients with high risk of tumor recurrence.

Quantitative accuracy of positron emission tomography/magnetic resonance and positron emission tomography/computed tomography for cervical cancer

With the spread of positron emission tomography/magnetic resonance (PET/MR), the question of comparability of studies becomes important. We aim to determine whether PET/MR and PET/computed tomography (PET/CT) are comparable for the case of cervical cancer. Fifteen cervical cancer patients identified by either a radiation oncologist or an oncologic surgeon had both PET/MR and PET/CT performed for initial staging within 3 weeks. We then compared the results both quantitatively (measuring standardized uptake values [SUVs] on visible lesions) as well as qualitatively (having radiologists and nuclear medicine physicians interprets the results). While interpretations between PET/MR and PET/CT varied in many cases, SUVs of primary lesions were similar to within 25% in all but one case, and correlation coefficient was 0.92. Maximum SUV ranged between 4.9 and 25.2 for PET-MR and between 5.8 and 30.4 for PET-CT for primary tumors and between 1.5 and 18.8 for PET-MR and between 1.8 and 20.8 for PET-CT for nodes. However, clinical reads often varied significantly between PET/MR and PET/CT. This suggests that SUV is similar on PET/MR and PET/CT although the differing anatomic modalities available for correlation may make the difference in terms of qualitative interpretation.

Roles of posttherapy 18F-FDG PET/CT in patients with advanced squamous cell carcinoma of the uterine cervix receiving concurrent chemoradiotherapy

PURPOSE

To assess the clinical roles of [¹⁸F]fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) performed 2-3 months after completion of concurrent chemoradiotherapy (CCRT), along with pretherapy characteristics, in patients with advanced squamous cell carcinoma of the uterine cervix enrolled in a prospective randomized clinical trial.

METHODS

Posttherapy PET/CT in patients with advanced FIGO stage or positive pelvic or para-aortic lymph node (PALN) defined on pretherapy PET/CT was classified as positive, equivocal, or negative. Overall survival (OS) rates between patients with different PET/CT results are compared. Pretherapy characteristics are examined for association with posttherapy PET/CT results and for prognostic significance in patients with equivocal or negative PET/CT.

RESULTS

PET/CT scans (n = 55) were positive, equivocal and negative in 9, 13 and 33 patients, respectively. All patients with positive scans were confirmed to have residual or metastatic disease and died despite salvage therapies. There is a significant OS difference between patients with positive and equivocal scans (P < .001) but not between patients with equivocal and negative scans (P = .411). Positive pretherapy PALN is associated with positive posttherapy PET/CT (P = .033) and predicts a poorer survival in patients with equivocal or negative posttherapy PET/CT (P < .001).

CONCLUSIONS

Positive PET/CT 2-3 months posttherapy implies treatment failure and novel therapy is necessary to improve outcomes for such patients. A more intense posttherapy surveillance may be warranted in patients with positive pretherapy PALN.

Efficacy of qualitative response assessment interpretation criteria at 18F-FDG PET-CT for predicting outcome in locally advanced cervical carcinoma treated with chemoradiotherapy

Objectives

To evaluate the utility of a standardized qualitative scoring system for treatment response assessment at 18F-FDG PET-CT in patients undergoing chemoradiotherapy for locally advanced cervical carcinoma and correlate this with subsequent patient outcome.

Methods

Ninety-six consecutive patients with locally advanced cervical carcinoma treated with radical chemoradiotherapy (CRT) in a single centre between 2011 and 2014 underwent 18F-FDG PET-CT approximately 3 months post-treatment. Tumour metabolic response was assessed qualitatively using a 5-point scale ranging from background level activity only through to progressive metabolic disease. Clinical and radiological (MRI pelvis) follow-up was performed in all patients. Progression-free (PFS) and overall survival (OS) was calculated using the Kaplan-Meier method (Mantel-Cox log-rank) and correlated with qualitative score using Chi-squared test.

Results

Forty patients (41.7 %) demonstrated complete metabolic response (CMR) on post-treatment PET-CT (Score 1/2) with 38 patients (95.0 %) remaining disease free after a minimum follow-up period of 18 months. Twenty-four patients (25.0 %) had indeterminate residual uptake (ID, Score 3) at primary or nodal sites after treatment, of these eight patients (33.3 %) relapsed on follow-up, including all patients with residual nodal uptake (n = 4Eleven11 of 17 patients (64.7 %) with significant residual uptake (partial metabolic response, PMR, Score 4) subsequently relapsed. In 15 patients (15.6 %) PET-CT demonstrated progressive disease (PD, Score 5) following treatment. Kaplan-Meier analysis showed a highly statistically significant difference in PFS and OS between patients with CMR, indeterminate uptake, PMR and PD (Log-rank, P < 0.0001). Chi-squared test demonstrated a highly statistically significant association between increasing qualitative score and risk of recurrence or death (P < 0.001).

Conclusion

Use of a 5-point qualitative scoring system to assess metabolic response to CRT in locally advanced cervical carcinoma predicts survival outcome and this prognostic information may help guide further patient management.

Molecular Imaging and Precision Medicine: PET/Computed Tomography and Therapy Response Assessment in Oncology

A variety of methods have been developed to assess tumor response to therapy. Standardized qualitative criteria based on 18F-fluoro-deoxyglucose PET/computed tomography have been proposed to evaluate the treatment effectiveness in specific cancers and these allow more accurate therapy response assessment and survival prognostication. Multiple studies have addressed the utility of the volumetric PET biomarkers as prognostic indicators but there is no consensus about the preferred segmentation methodology for these metrics. Heterogeneous intratumoral uptake was proposed as a novel PET metric for therapy response assessment. PET imaging techniques will be used to study the biological behavior of cancers during therapy.