Prognostic Predictive Value of Total Lesion Glycolysis From 18F-FDG PET/CT in Post-Surgical Patients With Epithelial Ovarian Cancer

Combination of circulating tumor cells and 18F-FDG PET/CT for precision diagnosis in patients with non-small cell lung cancer

PURPOSE

To investigate the value of 2-deoxy-18f-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and circulating tumor cells (CTCs) for the differential diagnosis of patients with benign lung diseases and those with NSCLC. To explore the phenotypic heterogeneity of CTCs and their correlation with FDG uptake in patients with Stage I-IV NSCLC.

METHODS

Blood specimens from patients with benign lung diseases and patients with primary NSCLC were collected for the detection of CTCs and their subtypes (epithelial, mixed, and mesenchymal) and analyzed for 18F-FDG PET/CT tumor metabolic parameters, including the maximum standardized uptake value (SUVmax), standard uptake value (SUL), metabolic tumor volume of primary lesion (MTV), total lesion glycolysis of primary lesion (TLG). Clinical data including age, gender, smoking history, tumor size, TNM stage and pathology type were also collected. The value of the two method alone and in combination for the differential diagnosis of benign and malignant was comparatively analyzed. Finally, the differences in CTC and its subtypes in different stages of NSCLC were compared, and FDG metabolic parameters were correlated with CTC subtypes.

RESULTS

There were a total of 65 patients with pulmonary diseases, including 12 patients with benign pulmonary diseases and 53 patients with NSCLC. The mean age was 67 ± 10 (38-89 years), 27 were females and 38 were males. 31 (22 males and 9 females) had a long history of smoking. The mean size of the largest diameter of all single lesions was 36 ± 22 mm with a range of 10-108 mm. Seven out of 12 benign diseases were inflammatory granulomatous lesions and 5 were inflammatory pseudotumours. Twenty-four out of 53 NSCLC were adenocarcinomas and 29 were squamous carcinomas. Twelve out of 53 patients with NSCLC were in Stage I, 10 were in Stage II, 17 were in Stage III and 14 were in Stage IV. SUVmax, SUL, MTV, TLG, total CTCs, epithelial CTCs, and mixed CTCs were all valuable in the differential diagnosis of benign and malignant. TLG combined with mixed CTCs was statistically different from all other diagnostic methods (p < 0.05) and higher than any other diagnostic criteria. In the differential diagnosis of benign and Stage I NSCLC, only total CTC (Z = -2.188 p = 0.039) and mixed CTCs (Z = -3.020 p = 0.014) had certain diagnostic efficacy, and there was no statistical difference between them (p = 0.480). Only mesenchymal CTCs differed in Stage I-IV NSCLC, with a higher number of those who developed distant metastases than those who had non-distant metastases. Epithelial CTCs correlated with SUVmax (r = 0.333, p = 0.015) and SUL (r = 0.374, p = 0.006). Mmesenchymal CTCs correlated with MTV (r = 0.342, p = 0.018) and TLG (r = 0.319, p = 0.02). Further subgroup analyses revealed epithelial CTCs were correlated with SUVmax (r = 0.543, p = 0.009) and SUL (r = 0.552, p = 0.008), and the total CTCs was correlated with SUVmax (r = 0.622, p = 0.003), SUL (r = 0.652, p = 0.003), MTV (r = 0.460, p = 0.031), and TLG (r = 0.472, p = 0.027) in the early group (Stage I-II). Only mesenchymal CTCs was associated with MTV (r = 0.369, p = 0.041), and TLG (r = 0.415, p = 0.02) in the intermediate-late group (Stage III-IV).

CONCLUSION

Both FDG PET metabolic parameters and CTCs demonstrated diagnostic value for NSCLC, and combining TLG with mixed CTCs could enhance their diagnostic efficacy. The total CTCs and mixed CTCs showed greater diagnostic value than FDG PET in distinguishing benign lesions from Stage I NSCLC. In NSCLC patients, the epithelial CTCs exhibited a positive correlation with SUVmax and SUL, while mesenchymal CTCs correlated with MTV, and TLG. Besides, epithelial CTCs showed stronger correlations with SUVmax and SUL, and total CTCs showed stronger correlations with SUVmax, SUL, MTV, and TLG in Stage I-II NSCLC. Only mesenchymal CTCs in Stage III-IV NSCLC showed correlations with MTV and TLG. Stage IV NSCLC cases displayed a higher number of mesenchymal CTCs.

Role of Positron Emission Tomography/Computed Tomography in Epithelial Ovarian Cancer

Ovarian cancer (OC) is the most lethal gynecological malignancy with majority of cases diagnosed in advanced stages and associated with high morbidity and mortality. Positron emission tomography/computed tomography (PET/CT) has emerged as an integral part of the management of several nongynecological cancers. We used PubMed search engine using MeSH words "ovarian cancer" and "PET/CT" and reviewed the current status of PET/CT in epithelial OC. Its application related to ovarian tumor including adnexal mass evaluation, baseline staging, as a triaging tool for upfront surgery or neoadjuvant chemotherapy, for response assessment and prognostication, and for relapse detection and treatment planning has been highlighted. we highlight the current guidelines and newer upcoming PET modalities and radiotracers.

Associations of whole-body 18F-FDG PET/CT parameters and SCC-Ag level with overall survival in patients with cervical cancer

OBJECTIVE

To explore the whole-body metabolic tumour volume (WBMTV), whole-body total lesion glycolysis (WBTLG) and tumour whole-body maximum standardised uptake value (WBSUVmax) of post-treatment 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) in predicting the overall survival (OS) in patients with cervical squamous cell carcinoma (SCC).

METHODS

The clinical data of 74 patients with cervical SCC who received 18F-FDG PET/CT were retrospectively analysed. WBMTV, WBTLG and WBSUVmax, as well as the serum SCC-Ag level, were measured. The Kaplan-Meier method and Cox regression were used to analyse the relationships of PET/CT parameters with OS.

RESULTS

The risk of death was 13.942-fold greater in the PET-positive group than in the PET-negative group (P < 0.001). In the PET-positive group, univariate analysis showed that OS was significantly correlated with WBMTV and WBTLG; it was not correlated with WBSUVmax, SCC-Ag, age, pathological stage or treatment after PET (P > 0.05). Patients with positive PET findings were divided into two groups according to the median of WBMTV or WBTLG; there was a significant difference in OS between the two groups. The risk of death in patients with positive PET imaging findings and high SCC-Ag level was 18.356-fold greater than in patients with negative PET imaging findings (P < 0.001).

CONCLUSIONS

WBMTV and WBTLG have important prognostic value in the prediction of OS in post-treatment patients with cervical SCC. OS was significantly decreased in patients who had both positive PET imaging findings and high SCC-Ag level.

EANM guideline on the role of 2-[18F]FDG PET/CT in diagnosis, staging, prognostic value, therapy assessment and restaging of ovarian cancer, endorsed by the American College of Nuclear Medicine (ACNM), the Society of Nuclear Medicine and Molecular Imaging (SNMMI) and the International Atomic Energy Agency (IAEA)

In most patients with ovarian carcinoma, the diagnosis is reached when the disease is long past the initial stages, presenting already an advanced stage, and they usually have a very bad prognosis. Cytoreductive or debulking surgical procedures, platinum-based chemotherapy and targeted agents are key therapeutic elements. However, around 7 out of 10 patients present recurrent disease within 36 months from the initial diagnosis. The metastatic spread in ovarian cancer follows three pathways: contiguous dissemination across the peritoneum, dissemination through the lymphatic drainage and, although less importantly in this case, through the bloodstream. Radiological imaging, including ultrasound, CT and MRI, are the main imaging techniques in which management decisions are supported, CT being considered the best available technique for presurgical evaluation and staging purposes. Regarding 2-[¹⁸F]FDG PET/CT, the evidence available in the literature demonstrates efficacy in primary detection, disease staging and establishing the prognosis and especially for relapse detection. There is limited evidence when considering the evaluation of therapeutic response. This guideline summarizes the level of evidence and grade of recommendation for the clinical indications of 2-[¹⁸F]FDG PET/CT in each disease stage of ovarian carcinoma.

Diagnostic performance of PET/CT and PET/MR in the management of ovarian carcinoma-a literature review

Ovarian cancer is a challenging disease. It often presents at an advanced stage with frequent recurrence despite optimal management. Accurate staging and restaging are critical for improving treatment outcomes and determining the prognosis. Imaging is an indispensable component of ovarian cancer management. Hybrid imaging modalities, including positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (MRI), are emerging as potential non-invasive imaging tools for improved management of ovarian cancer. This review article discusses the role of PET/CT and PET/MRI in ovarian cancer.

18F-FDG PET/CT in ovarian cancer recurrence: Clinical impact, correlation with ceCT and CA-125, and prognostic value

AIM

To evaluate ¹⁸F-FDG-PET/CT for suspected ovarian cancer relapse with negative/inconclusive conventional imaging, or restaging potentially resectable ovarian cancer relapse.

MATERIAL AND METHODS

Thirty-six cases and 140 locations were studied. PET/CT, ceCT and serum CA-125 was conducted in all cases. Nineteen cases were requested for restaging, 17 for suspected relapse. We compared ceCT and PET/CT, assessed by histopathology or radiological follow-up, calculating sensitivity (S) and positive predictive value (PPV) by cases and lesions. We evaluated the correlation between size, number, uptake of the lesions and CA-125. We conducted survival analysis, using ROC curves to calculate the optimal cut-off of SUVmax for survival prediction. We checked whether PET/CT modify the therapeutic attitude vs. conventional imaging.

RESULTS

PET/CT and ceCT were concordant in 12 cases: 11 positives (30 lesions), all confirmed. There was 1 FN. In the 24 non-concordant, PET/CT was positive in 19 (97 lesions); ceCT in 21 (59 lesions); 54% of the lesions were concordant. Overall, PET/CT detected 127 lesions, with S = 97% and PPV = 100%. ceCT detected 89 lesions, with S = 61% and PPV = 90%. No significant correlation was found between CA-125 and the other parameters. PET/CT detected 10 positive cases, with normal CA-125. PET/CT modified therapeutic management in 15 cases. Significant differences were found in survival with SUVmax = 11.8 CONCLUSIONS: PET/CT plays an important role in ovarian cancer relapse, with sensitivity and PPV higher than ceCT, modified therapeutic management in up to 42% of cases, and could be a valuable tool for predicting survival.

18F-FDG PET/CT in ovarian cancer recurrence: Clinical impact, correlation with ceCT and CA-125, and prognostic value

AIM

To evaluate ¹⁸F-FDG-PET/CT for suspected ovarian cancer relapse with negative/inconclusive conventional imaging, or restaging potentially resectable ovarian cancer relapse.

MATERIAL AND METHODS

Thirty-six cases and 140 locations were studied. PET/CT, ceCT and serum CA-125 was conducted in all cases. Nineteen cases were requested for restaging, 17 for suspected relapse. We compared ceCT and PET/CT, assessed by histopathology or radiological follow-up, calculating sensitivity (S) and positive predictive value (PPV) by cases and lesions. We evaluated the correlation between size, number, uptake of the lesions and CA-125. We conducted survival analysis, using ROC curves to calculate the optimal cut-off of SUVmax for survival prediction. We checked whether PET/CT modify the therapeutic attitude vs. conventional imaging.

RESULTS

PET/CT and ceCT were concordant in 12 cases: 11 positives (30 lesions), all confirmed. There was 1 FN. In the 24 non-concordant, PET/CT was positive in 19 (97 lesions); ceCT in 21 (59 lesions); 54% of the lesions were concordant. Overall, PET/CT detected 127 lesions, with S=97% and PPV=100%. ceCT detected 89 lesions, with S=61% and PPV=90%. No significant correlation was found between CA-125 and the other parameters. PET/CT detected 10 positive cases, with normal CA-125. PET/CT modified therapeutic management in 15 cases. Significant differences were found in survival with SUVmax=11.8 CONCLUSIONS: PET/CT plays an important role in ovarian cancer relapse, with sensitivity and PPV higher than ceCT, modified therapeutic management in up to 42% of cases, and could be a valuable tool for predicting survival.

The role of 18F-FDG PET/CT-based quantitative metabolic parameters in patients with ovarian clear cell carcinoma

BACKGROUND

Ovarian clear cell carcinoma (CCC) is enriched in genes associated with glucose metabolism.

OBJECTIVE

To evaluate the 18F-FDG PET/CT-based metabolic variables and the correlations with clinicopathologic features in OCCC patients.

METHODS

We measured quantitative parameters including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG).

RESULTS

A total of 22 patients were included. PET/CT-based metabolic parameters were calculated for 20 patients because two had low glucose-uptake tumor. The median SUVmax was 7.25 (range 2.50-14.80). Spearman's correlation test revealed that the level of pre-operative serum cancer antigen 125 (CA 125) correlated significantly with MTV (P= 0.020) and TLG (P= 0.023). Interestingly, platinum-sensitive patients tended to have higher MTV/TLG though significance not achieved. On univariate analysis, the following four variables (stage, residual disease, platinum sensitivity and MTV50) were significant for both progression-free survival and overall survival. Besides, four metabolic parameters (MTV40, TLG40, TLG50 and TLG60) were significantly associated with patients' overall survival. Out of expectation, ovarian CCC patients with higher level of MTV/TLG tended to have better survival.

CONCLUSIONS

18F-FDG PET/CT-based metabolic volumetric parameters might be predicators for survival in ovarian CCC patients. Cautions should be taken when interpreting the results due to the small sample size.

Correlations between circulating tumor cell phenotyping and 18F-fluorodeoxyglucose positron emission tomography uptake in non-small cell lung cancer

PURPOSE

The epithelial-to-mesenchymal transition (EMT) phenotype-based subsets of circulating tumor cells (CTCs) might be predictors of tumor progression. We evaluated the clinical properties of different phenotypic CTCs in patients with non-small cell lung cancer (NSCLC). Secondly, we explored the association between different phenotypic CTCs and the uptake of 18F-fluorodeoxyglucose (FDG) by the primary tumor on a positron emission tomographic (PET) scan.

METHODS

Venous blood samples from 34 pathologically confirmed Stage IIB-IVB NSCLC patients were collected prospectively. CTCs were immunoassayed using a SE-i·FISH®CTC kit. We identified CTCs into cytokeratin positive (CK⁺) and cytokeratin negative (CK^-) phenotypes. CTC classifications were correlated with the maximum standardized uptake value (SUVmax) measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). Overall survival (OS) and progression-free survival (PFS) curves were produced using the Kaplan-Meier method.

RESULTS

CTCs were detected in 91.2% of NSCLC patients. CTC counting was associated with TNM stage (P = 0.014) and distant metastasis (P = 0.007). The number of CK^-CTCs was also positively associated with TNM stage (P = 0.022) and distant metastasis (P = 0.007). Both total CTC counting and CK^-CTC counting did not show association with SUVmax value (P = 0.959, P = 0.903). Kaplan-Meier survival analysis demonstrated that patients with ≥ 7 CTCs had shorter OS (P = 0.003) and PFS (P = 0.001) relative to patients with < 7 CTCs). Notably, the number of CK^-CTCs can act as independent risk factors for PFS (P = 0.044) and OS (P = 0.043) in NSCLC patients. However, SUVmax value was not associated with OS (P = 0.895) and PFS (P = 0.686).

CONCLUSION

The CTC subpopulations could be useful evidence for testing metastasis and prognosis in NSCLC patients. The SUVmax value of the primary tumor was not related to prognosis in patients with NSCLC.

18F-FDG PET/CT-based metabolic metrics in recurrent tumors of ovarian clear cell carcinoma and their prognostic implications

Background

Glucose metabolism has been suggested as a therapeutic target in ovarian clear cell carcinoma (CCC). We attempted to clarify ¹⁸F-FDG PET/CT-based metabolic metrics in the recurrent ovarian CCC patients and their prognostic values.

Methods

Quantitative metabolic parameters included maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). Two different methods were employed for defining the threshold SUV to delineate MTV: 1) SUV of 2.5 (designated as MTV); 2) a fixed ratio including 40% (MTV40), 50% (MTV50) and 60% (MTV60) of SUVmax. The Kaplan-Meier model and Cox regression were used in survival analysis.

Results

Among the 35 patients, platinum-resistant recurrence accounted for 34.3% and the median progression-free survival was 13 months (range, 2–135). Fifteen (42.9%) patients presented with single tumor recurrence, while 51 recurrent lesions were identified, with the most common sites in pelvis (29.4%), followed by lymph node metastases (19.6%) and peritoneal carcinomatosis (15.7%). Except four patients with FDG-inavid tumor, the median SUVmax of the 31 patients with high glucose metabolic activity was 7.10 (range, 3.00–20.60). After a median follow-up of 36.5 months (range, 7–155), 22 patients (64.7%) were dead from disease. The median post-relapse survival (PRS) was 17 months (range, 4–126). Platinum-resistant recurrence, peritoneal carcinomatosis and high TLG60 proved to be negative predicators of overall survival after multivariate analysis.

Conclusions

TLG60, platinum-resistant recurrence and peritoneal carcinomatosis were independent negative predicators of overall survival. Whether patients with higher TLG60 required more aggressive treatment warranted further study.

Prognostic value of volume-based metabolic parameters of 18F-FDG PET/CT in ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis on the prognostic value of ¹⁸F-FDG PET-derived volume-based parameters regarding metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in patients with ovarian cancer.

METHODS

Pubmed and EMBASE databases were searched up to February 12, 2018 for studies which evaluated MTV or TLG as a prognostic factor in ovarian cancer with progression-free (PFS) and overall survival (OS) as the endpoints. Hazard ratios (HRs) were meta-analytically pooled using the random-effects model. Multiple subgroup analyses based on clinicopathological and PET variables were performed.

RESULTS

Eight studies with 473 patients were included. The pooled HRs of MTV and TLG for PFS were 2.50 (95% CI 1.79-3.48; p < 0.00001) and 2.42 (95% CI 1.61-3.65; p < 0.0001), respectively. Regarding OS, the pooled HRs of MTV and TLG were 8.06 (95% CI 4.32-15.05; p < 0.00001) and 7.23 (95% CI 3.38-15.50; p < 0.00001), respectively. Multiple subgroup analyses consistently showed that MTV and TLG were significant prognostic factors for PFS with pooled HRs ranging from 2.35 to 2.58 and from 1.73 to 3.35, respectively.

CONCLUSIONS

MTV and TLG from ¹⁸F-FDG PET were significant prognostic factors in patients with ovarian cancer. Despite the clinical heterogeneity and difference in methodology between the studies, patients with a high MTV or TLG have a higher risk of disease progression or death.

Prognostic Value of Volume-Based Positron Emission Tomography/Computed Tomography in Nasopharyngeal Carcinoma Patients after Comprehensive Therapy

Objective

We assessed the prognostic value of standardized uptake value (SUV) and volume-based methods including whole-body metabolic tumor volume (WBMTV) and whole-body total lesion glycolysis (WBTLG) using ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) of patients with nasopharyngeal carcinoma (NPC) after therapy.

Methods

A total of 221 posttherapy NPC cases were enrolled, all of whom had undergone PET/CT scanning and follow-up in this retrospective study. The diagnostic results of PET/CT were analyzed and compared with histopathological diagnosis or clinical follow-up. Receiver operator characteristic curves, the Kaplan-Meier method, and the log-rank test were used to assess the optimal cutoff values for WBMTV and WBTLG to identify independent predictors of survival.

Results

The detection rates of the threshold SUV were 2.5, 20%, and 40%, and SUV background methods were 65.6% (378/576), 80.2% (462/576), 71.5% (412/576), and 90.4% (521/576), respectively (P < 0.005). Patients with a WBMTV < 8.10 and/or a WBTLG < 35.58 had significantly better 5-year overall survival than those above the cutoffs (90.7% versus 51.2%, P < 0.001; 91.7% versus 50.4%, P < 0.001), respectively. Multivariate Cox regression modeling showed both WBTLG (RR, 1.002; P = 0.004) and age (RR, 1.046; P = 0.006) could be used to predict overall survival. WBTLG (RR, 1.003; P < 0.001) may have predictive relevance in estimating disease-free survival.

Conclusions

SUV volume-based threshold background methodology had a significantly higher detection rate for metastatic lesions. WBTLG could be used as an independent prognostic indicator for posttherapy NPC.

Incorporation of circulating tumor cells and whole-body metabolic tumor volume of 18F-FDG PET/CT improves prediction of outcome in IIIB stage small-cell lung cancer

Objective

We investigated the correlation between the number of circulating tumor cells (CTCs) and whole-body metabolic tumor volume (WBMTV) measured by ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). The aim was to evaluate the value of the incorporation of CTC number and WBMTV in the prognostic prediction of stage III small-cell lung cancer (SCLC).

Methods

One hundred and twenty-nine patients were enrolled in this study. All patients were treated with four cycles of a platinum-based regimen and concurrent chest irradiation, followed by prophylactic cranial irradiation. Blood samples for CTC analysis were obtained from 112 patients before the initiation of chemotherapy (as a baseline), after cycle 1 and after cycle 4. CTCs were measured using the CELLSEARCH^® system. The patients underwent pretreatment FDG PET/CT WBMTV, which included all malignant lesions. The Spearman rank test was used to determine the correlation among CTC counts, WBMTV and disease stage. Overall survival (OS) and progression-free survival (PFS) curves were produced using the Kaplan-Meier method, and survival differences between groups were assessed by the log-rank test.

Results

The number of CTCs at baseline did not correlate with WBMTV before the initiation of therapy (P=0.241). The number of CTCs at baseline and the WBMTV before the initiation of therapy were independent relevant factors for PFS and OS. The subgroup analysis (Group A: CTC count >19.5 and a WBMTV >266.5 cm ³; Group B: CTC count >19.5 and a WBMTV ≤266.5 cm ³; Group C: CTC count ≤19.5 and a WBMTV >266.5 cm ³; Group D: CTC count ≤19.5 and a WBMTV ≤266.5 cm³) showed that the differences were statistically significant in the median PFS (Group A vs. D, P<0.001; Group Bvs. D, P=0.018; Group C vs. D, P=0.029) and in the median OS (Group A vs. D, P<0.001; Group Bvs. D, P=0.012).

Conclusions

CTC number and WBMTV are related to progression and death in patients with SCLC. The incorporation of CTC number and WBMTV scans can provide a detailed prognostic prediction for SCLC.

Predictive and prognostic value of 18F-DOPA PET/CT in patients affected by recurrent medullary carcinoma of the thyroid

INTRODUCTION

Medullary thyroid carcinoma (MTC) is a malignancy accounting for about 5-8% of thyroid cancers. Serum calcitonin and carcinoembryonic antigen (CEA) levels are widely used to monitor disease progression. However, prognostic factors able to predict outcomes are highly desirable. We, therefore, aimed to assess the prognostic role of ¹⁸F-DOPA PET/CT in patients with recurrent MTC.

MATERIALS AND METHODS

60 patients (mean age 64 ± 13 years, range 44-82) with recurrent MTC were eligible from a multicenter database. All patients underwent a restaging ¹⁸F-DOPA PET/CT, performed at least 6 months after surgery. CEA/calcitonin levels, local recurrences, nodal involvement and metastases at PET/CT were recorded. SUVmax, SUVmean (also normalized to mediastinal uptake) and metabolic tumor volume were automatically calculated for each lesion, by placing a volume of interest around the lesion with 40% of peak activity as threshold for the automatic contouring. The patients were clinically and radiologically followed up for 21 ± 11 months. Rate of progression-free survival (PFS), disease-specific survival (DSS) and incremental prognostic value of ¹⁸F-DOPA PET/CT over conventional imaging modalities were assessed by Kaplan-Meier curves and Log-Rank test. Cox regression univariate and multivariate analyses were performed for assessing predictors of prognosis.

RESULTS

¹⁸F-DOPA PET/CT showed abnormal findings in 27 patients (45%) and resulted unremarkable in 33 (55%). PFS was significantly longer in patients with an unremarkable PET/CT scan (p = 0.018). Similarly, an unremarkable PET/CT study was associated with a significantly longer DSS (p = 0.04). ¹⁸F-DOPA PET/CT added prognostic value over other imaging modalities both for PFS and for DSS (p < 0.001 and p = 0.012, respectively). Neither semiquantitative PET parameters nor clinical or laboratory data were predictive of a worse PFS and DSS in patients with recurrent MTC.

CONCLUSION

¹⁸F-DOPA PET/CT scan has an important prognostic value in predicting disease progression and mortality rate.

Correlation of 18F-FDG uptake on PET/CT with Ki67 immunohistochemistry in pre-treatment epithelial ovarian cancer

OBJECTIVE

Standardised uptake value (SUV) and volumetric parameters such as metabolic tumour volume (MTV) and total lesion glycolysis (TLG) from ¹⁸F-FDG PET/CT are useful criteria for disease prognosis in pre-operative and post-treatment epithelial ovarian cancer (EOC). Ki67 is another prognostic biomarker in EOC, associated with tumour aggressiveness. The aim of this study is to evaluate the association between ¹⁸F-FDG PET/CT measurements and Ki67 in pre-treatment EOC to determine if PET/CT parameters could non-invasively predict tumour aggressiveness.

MATERIAL AND METHODS

A pre-treatment PET/CT was performed on 18 patients with suspected or newly diagnosed EOC. Maximum SUV (SUVmax), mean SUV (SUVmean), whole-body MTV (wbMTV), and whole-body TLG (wbTLG) with a threshold of 30% and 40% of the SUVmax were obtained. Furthermore, Ki67 index (mean and hotspot) was estimated in tumour tissue specimens. Immunohistochemical findings were correlated with PET parameters.

RESULTS

The mean age was 57.0 years old (standard deviation 13.6 years). A moderate correlation was observed between mean Ki67 index and SUVmax (r=0.392), SUVmean 30% (r=0.437), and SUVmean 40% (r=0.443), and also between hotspot Ki67 index and SUVmax (r=0.360), SUVmean 30% (r=0.362) and SUVmean 40% (r=0.319). There was a weaker correlation, which was inversely negative, between mean and hotspot Ki67 and volumetric PET parameters. However, no statistical significant differences were found for any correlations.

CONCLUSIONS

SUVmax and SUVmean were moderately correlated with Ki67 index, whereas volumetric PET parameters overall, showed a weaker correlation. Thus, SUVmax and SUVmean could be used to assess tumour aggressiveness in pre-treatment EOC.

An update on the role of PET/CT and PET/MRI in ovarian cancer

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as ¹⁸F-fluorothymidine (FLT) or ¹¹C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer.

Systematic Review on the Accuracy of Positron Emission Tomography/Computed Tomography and Positron Emission Tomography/Magnetic Resonance Imaging in the Management of Ovarian Cancer: Is Functional Information Really Needed?

Ovarian cancer (OC) often presents at an advanced stage with frequent relapses despite optimal treatment; thus, accurate staging and restaging are required for improving treatment outcomes and prognostication. Conventionally, staging of OC is performed using contrast-enhanced computed tomography (CT). Nevertheless, recent advances in the field of hybrid imaging have made positron emission tomography/CT (PET/CT) and PET/magnetic resonance imaging (PET/MRI) as emerging potential noninvasive imaging tools for improved management of OC. Several studies have championed the role of PET/CT for the detection of recurrence and prognostication of OC. We provide a systematic review and meta-analysis of the latest publications regarding the role of molecular imaging in the management of OC. We retrieved 57 original research articles with one article having overlap in both diagnosis and staging; 10 articles (734 patients) regarding the role of PET/CT in diagnosis of OC; 12 articles (604 patients) regarding staging of OC; 22 studies (1429 patients) for detection of recurrence; and 13 articles for prognostication and assessment of treatment response. We calculated pooled sensitivity and specificity of PET/CT performance in various aspects of imaging of OC. We also discussed the emerging role of PET/MRI in the management of OC. We aim to give the readers and objective overview on the role of molecular imaging in the management of OC.

Recurrent bladder carcinoma: clinical and prognostic role of 18 F-FDG PET/CT

AIM

A small number of studies evaluated the detection rate of lesions from bladder carcinoma (BC) of 18 F-FDG PET/CT in the restaging process. However, the prognostic role of FDG PET/CT still remains unclear. The aim of the present study was to evaluate the accuracy, the effect upon treatment decision, and the prognostic value of FDG PET/CT in patients with suspected recurrent BC.

MATERIALS AND METHODS

Forty-one patients affected by BC underwent FDG PET/CT for restaging purpose. The diagnostic accuracy of visually interpreted FDG PET/CT was assessed compared to histology (n = 8), other diagnostic imaging modalities (contrast-enhanced CT in 38/41 patients and MRI in 15/41) and clinical follow-up (n = 41). Semiquantitative PET values (SUVmax, SUVmean, SUL, MTV, TLG) were calculated using a graph-based method. Progression-free survival (PFS) and overall survival (OS) were assessed by using Kaplan-Meier curves. The risk of progression (hazard ratio, HR) was computed by Cox regression analysis by considering all the available variables.

RESULTS

PET was considered positive in 21 of 41 patients. Of these, recurrent BC was confirmed in 20 (95 %). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET/CT were 87 %, 94 %, 95 %, 85 %, 90 %. AUC was 0.9 (95 %IC 0.8-1). Bayesian positive and negative likelihood ratios were 14.5 and 0.13, respectively. FDG PET/CT findings modified the therapeutic approach in 16 patients (modified therapy in 10 PET-positive patients, watch-and-wait in six PET-negative patients). PFS was significantly longer in patients with negative scan vs. those with pathological findings (85 % vs. 24 %, p < 0.05; HR = 12.4; p = 0.001). Moreover, an unremarkable study was associated with a longer OS (88 % vs. 47 % after 2 years and 87 % vs. 25 % after 3 years, respectively, p < 0.05). Standardized uptake value (SUV)max > 6 and total lesion glycolysis (TLG) > 8.5 were recognized as the most accurate thresholds to predict PFS (2-year PFS 62 % for SUVmax < 6 vs. 15 % for SUVmax > 6, p = 0.018; 2-year PFS 66 % for TLG < 8.5 vs. 18 % for TLG > 8.5, p = 0.09).

CONCLUSION

A very good diagnostic performance for FDG PET/CT was confirmed in patients with suspected recurrent BC. FDG PET/CT allowed for a change in treatment decision in about 40 % of cases and showed an important prognostic value in assessing PFS and OS.

Reproducibility and uptake time dependency of volume-based parameters on FDG-PET for lung cancer

Background

Volume-based parameters, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), on F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) are useful for predicting treatment response in nonsmall cell lung cancer (NSCLC). We aimed to examine intra- and inter-operator reproducibility to measure the MTV and TLG, and to estimate their dependency on the uptake time.

Methods

Fifty NSCLC patients underwent preoperative FDG-PET. After an injection of FDG, the whole body was scanned twice: at the early phase (61.4 ± 2.8 min) and delayed phase (117.7 ± 1.6 min). Two operators independently defined the tumor boundary using three different delineation methods: (1) the absolute SUV threshold method (MTV_p and TLG_p; p = 2.0, 2.5, 3.0, 3.5), (2) the fixed% SUVmax threshold method (MTV_q% and TLG_q%; q = 35, 40, 45), and (3) the adaptive region-growing method (MTV_ARG and TLG_ARG). Parameters were compared between operators and between phases.

Results

Both the intra- and inter-operator reproducibility were high for all parameters using any method (intra-class correlation > 0.99 each). MTV_3.0 and MTV_3.5 resulted in a significant increase from the early to delayed phase (P < 0.05 for both), whereas MTV_2.0 and MTV_2.5 neither increased nor decreased (P = n.s.). All of the MTV_q% values significantly decreased over time (P < 0.01), whereas MTV_ARG and TLG with any delineation method increased significantly (P < 0.05).

Conclusions

High reproducibility of MTV and TLG was obtained by all of the methods used. MTV_2.0 and MTV_2.5 were the least sensitive to uptake time, and may be good alternatives when we compare images acquired with different uptake times, although applying constant uptake time is important for volume measurement.

Correlation between histological grade and positron emission tomography parameters in cervical carcinoma

The aim of the present study was to evaluate the changes in cervical cancer glucose metabolism for different levels of cellular differentiation. The metabolic activity was measured by standardized uptake value (SUV), SUV normalized to lean body mass, metabolic tumor volume and total lesion glycolysis using fluorine-18 fluorodeoxyglucose positron emission tomography (PET). A correlation study of these values could be used to facilitate therapeutic choice and to improve clinical practice and outcome. This study considered 32 patients with diagnosed cervical cancers, at different International Federation of Gynecology and Obstetrics stages. Glucose metabolism was assessed by PET examination, and histological specimens were examined to determine their initial grade of differentiation. A correlation study of these values was evaluated. Histological examination showed that all cases were of squamous cell carcinoma. Regarding the differentiation of the tumor, 19 well- to moderately-differentiated tumors and 13 poorly-differentiated tumors were determined. Negative findings for correlations between metabolic parameters and initial grade of histological differentiation were found, and considering that histological grade has been shown to have no consistent prognostic value in cervical cancer treatment, PET imaging could play a significant role in cervical cancer prognosis.

Posttreatment FDG PET/CT in predicting survival of patients with ovarian carcinoma

BACKGROUND

The purposes of this study are to evaluate the prognostic value of posttreatment (18)F-FDG PET/CT in predicting the survival of patients with ovarian carcinoma and to determine incremental value of combining posttreatment PET/CT with traditional prognostic factors in a multivariate model.

METHODS

This was an IRB-approved retrospective study. From July 2001 to July 2011, 48 patients who completed initial therapy for ovarian carcinoma with concurrent 3- to 9-month initial posttreatment (18)F-FDG PET/CT and serum CA-125 were identified from the radiology database. Prognostic value of posttreatment PET/CT, CA-125, age, race, and tumor stage were determined from Cox proportional hazard model using univariate and multivariate analyses. Time-dependent receiver operator curves were also calculated at various follow-up intervals.

RESULTS

In a univariate model, overall survival (OS) was associated with PET/CT (hazard ratio = 4.18; 95 % CI 1.49-11.70) and CA-125 (hazard ratio = 11.09; 95 % CI 4.27-28.79). When the effects of posttreatment PET/CT and CA-125 were combined in the multivariate analysis, hazard ratio for PET/CT increased to 4.84 (95 % CI 1.59-14.73, p = 0.005) and hazard ratio for CA-125 increased to 14.43 (95 % CI 4.65-44.84, p < 0.001). In the subset of patients with negative CA-125, posttreatment PET/CT had a hazard ratio of 2.98 (95 % CI 0.86-10.37), supporting the role of posttreatment PET/CT in risk stratification of patients with negative CA-125. Time-dependent receiver operator curves showed that the combination of PET/CT and CA-125 improved prognostic accuracy compared to PET/CT or CA-125 alone at 12-, 24-, 30-, and 36-month follow-up.

CONCLUSIONS

Posttreatment PET/CT can predict the survival of patients with ovarian carcinoma. The addition of posttreatment PET/CT to the CA-125 serum biomarker has an incremental value in improving prognostic accuracy, particularly in the subset of patients with negative CA-125.

Predictive value of (18)F-FDG PET/CT in restaging patients affected by ovarian carcinoma: a multicentre study

PURPOSE

Ovarian cancer is the eighth most common malignancy among women and has a high mortality rate. Prognostic factors able to drive an effective therapy are essential. (18)F-Fluoro-2-deoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) has been investigated in patients with epithelial ovarian cancer and showed promise in diagnosing, staging, detecting recurrent lesions and monitoring treatment response. Conversely, its prognostic role remains unclear. We aimed at assessing the prognostic value of (18)F-FDG PET/CT performed in the restaging process in a multicentre study.

METHODS

We evaluated 168 patients affected by ovarian carcinoma, who underwent a restaging (18)F-FDG PET/CT. The presence of local recurrences, lymph node involvement and distant metastasis was recorded as well as lesion dimensions, maximum and mean standardized uptake values (SUVmax and SUVmean, respectively). Progression-free survival (PFS) and overall survival (OS) at 3 and 4 years were computed by using Kaplan-Meier curves. Increased odds ratio was assessed using Cox regression analysis testing all lesion parameters measured by PET/CT.

RESULTS

PFS was significantly longer in patients with a negative than a positive restaging PET/CT study (3- and 4-year PFS 64 and 53% vs 23 and 12%, respectively; p < 0.001). Similarly, a negative study was associated with a significantly higher OS rate after 4 years of follow-up (67 vs 25% in negative and positive groups, respectively; p < 0.001). Lymph node or distant involvement were also independently associated with an increased risk of disease progression [hazard ratio (HR) 1.6 and 2.2, respectively; p = 0.003]. Moreover, PET/CT showed an incremental prognostic value compared to the International Federation of Gynecology and Obstetrics (FIGO) staging system. In the analysis of patient subsets, individuals with the same FIGO stage I-II but with negative PET had a significantly better 4-year OS than patients with low FIGO stage but positive PET. This implies that patients with the same FIGO stage can be further prognostically stratified using PET (p = 0.01). At receiver-operating characteristic (ROC) analysis, no thresholds for semiquantitative parameters were predictive of a worse outcome.

CONCLUSION

(18)F-FDG PET/CT has an important prognostic value in assessing the risk of disease progression and mortality rate. An efficacious therapy planning might therefore effectively rely on (18)F-FDG PET/CT findings. Semiquantitative data were not proven to be an effective tool to predict disease progression.

Prognostic value of (18)F-FDG PET/CT volumetric parameters in recurrent epithelial ovarian cancer

OBJECTIVE

Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) from (18)F-FDG PET/CT are emerging prognostic biomarkers in various solid neoplasms. These volumetric parameters and the SUVmax have shown to be useful criteria for disease prognostication in preoperative and post-treatment epithelial ovarian cancer (EOC) patients. The purpose of this study was to evaluate the utility of (18)F-FDG PET/CT measurements to predict survival in patients with recurrent EOC.

MATERIAL AND METHODS

Twenty-six patients with EOC who underwent a total of 31 (18)F-FDG PET/CT studies for suspected recurrence were retrospectively included. SUVmax and volumetric parameters whole-body MTV (wbMTV) and whole-body TLG (wbTLG) with a threshold of 40% and 50% of the SUVmax were obtained. Correlation between PET parameters and progression-free survival (PFS) and the survival analysis of prognostic factors were calculated.

RESULTS

Serous cancer was the most common histological subtype (76.9%). The median PFS was 12.5 months (range 10.7-20.6 months). Volumetric parameters showed moderate inverse correlation with PFS but there was no significant correlation in the case of SUVmax. The correlation was stronger for first recurrences. By Kaplan-Meier analysis and log-rank test, wbMTV 40%, wbMTV 50% and wbTLG 50% correlated with PFS. However, SUVmax and wbTLG 40% were not statistically significant predictors for PFS.

CONCLUSION

Volumetric parameters wbMTV and wbTLG 50% measured by (18)F-FDG PET/CT appear to be useful prognostic predictors of outcome and may provide valuable information to individualize treatment strategies in patients with recurrent EOC.

Diagnostic and prognostic evaluation of fluorodeoxyglucose positron emission tomography/computed tomography and its correlation with serum cancer antigen-125 (CA125) in a large cohort of ovarian cancer patients

OBJECTIVE

We evaluated the efficacy of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in recurrent disease, response to therapy, and long-term follow-up of ovarian cancer (OC) patients in relation to cancer antigen-125 (CA125) levels and the prognostic meaning of this modality in this subset of subjects.

MATERIAL AND METHODS

Between 2005 and 2015, we retrospectively evaluated 125 patients affected by OC who underwent FDG PET/CT imaging at our institution. The indications for PET/CT were recurrence of disease in 78 patients, therapy response assessment in 29, and follow-up in 18. The results of FDG PET/CT were compared with those of histopathology and clinical and radiological progression during follow-up for at least 6 months. The median long-term follow-up was 33 months. The diagnostic accuracies for the different clinical settings were evaluated. The relationships among global survival (GS), FDG PET/CT results, and CA125 levels were evaluated by both Kaplan-Meier and Cox regression analysis.

RESULTS

CA125 results were positive (>35 UI/mL) in 62 patients and negative in 63 (49% vs. 51%). The sensitivity and specificity of CA125 were 72% and 91%, respectively. PET/CT imaging showed a sensitivity of 98.6% and a specificity of 77.8% for the assessment of recurrent disease, and a sensitivity of 72.7% and a specificity of 88.9% for therapy evaluation. Meanwhile, in 18 patients evaluated during follow-up, the specificity was 82.3%. GS was significantly higher in case of negative CA125 values at the time of FDG PET/CT, of a negative PET/CT scan and when no evidence of peritoneum recurrence and distant metastases was determined by PET. Multivariate regression analysis showed that only age and peritoneum recurrence as determined by PET were identified as independent predictors of poor prognosis.

CONCLUSION

Metabolic imaging with FDG PET/CT proved useful in patients where OC recurrence was suspected, even when the value of tumor marker CA125 was in a normal range. A positive PET/CT scan and the presence of peritoneum recurrence at PET were associated with a poor prognosis after approximately 30 months.

Prognostic value of volume-based measurements on (11)C-methionine PET in glioma patients

PURPOSE

(11)C-methionine (MET) PET is an established diagnostic tool for glioma. Studies have suggested that MET uptake intensity in the tumor is a useful index for predicting patient outcome. Because MET uptake is known to reflect tumor expansion more accurately than MRI, we aimed to elucidate the association between volume-based tumor measurements and patient prognosis.

METHODS

The study population comprised 52 patients with newly diagnosed glioma who underwent PET scanning 20 min after injection of 370 MBq MET. The tumor was contoured using a threshold of 1.3 times the activity of the contralateral normal cortex. Metabolic tumor volume (MTV) was defined as the total volume within the boundary. Total lesion methionine uptake (TLMU) was defined as MTV times the mean standardized uptake value (SUVmean) within the boundary. The tumor-to-normal ratio (TNR), calculated as the maximum standardized uptake value (SUVmax) divided by the contralateral reference value, was also recorded. All patients underwent surgery (biopsy or tumor resection) targeting the tissue with high MET uptake. The Kaplan-Meier method was used to estimate the predictive value of each measurement.

RESULTS

Grade II tumor was diagnosed in 12 patients (3 diffuse astrocytoma, 2 oligodendroglioma, and 7 oligoastrocytoma), grade III in 18 patients (8 anaplastic astrocytoma, 6 anaplastic oligodendroglioma, and 4 anaplastic oligoastrocytoma), and grade IV in 22 patients (all glioblastoma). TNR, MTV and TLMU were 3.1 ± 1.2, 51.6 ± 49.9 ml and 147.7 ± 153.3 ml, respectively. None of the three measurements was able to categorize the glioma patients in terms of survival when all patients were analyzed. However, when only patients with astrocytic tumor (N = 33) were analyzed (i.e., when those with oligodendroglial components were excluded), MTV and TLMU successfully predicted patient outcome with higher values associated with a poorer prognosis (P < 0.05 and P < 0.01, respectively), while the predictive ability of TNR did not reach statistical significance (P = NS).

CONCLUSION

MTV and TLMU may be useful for predicting outcome in patients with astrocytic tumor.

Value of (18)F-FDG PET/CT in the Detection of Ovarian Malignancy

PURPOSE

Ovarian cancer is a leading cause of gynecologic malignancy. As symptoms of ovarian cancer are nonspecific, only 20 % of ovarian cancers are diagnosed while they are still limited to the ovaries. Thus, early and accurate detection of disease is important for an improved prognosis. For the accurate and effective diagnosis of ovarian malignancy on (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT), we analyzed several parameters, including visual assessment.

METHOD

A total of 51 peritoneal lesions in 19 patients who showed ovarian masses with diffuse peritoneal infiltration were enrolled. Twelve patients were confirmed to have ovarian malignancy and seven patients with benign disease by pathologic examination. All patients were examined by (18)F-FDG PET/CT, and an additional 2-h delayed (18)F-FDG PET/CT was also performed for 15 patients with 42 peritoneal lesions. We measured semiquantitative parameters including maximum and mean standardized uptake values (SUVmax, SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) on a 1-h initial (18)F-FDG PET/CT image (Parameter1) and on a 2-h delayed image (Parameter2). Additionally, retention indices of each parameter were calculated, and each parameter among the malignant and benign lesions was compared by Mann-Whitney U test. We also assessed the visual characteristics of each peritoneal lesion, including metabolic extent, intensity, shape, heterogeneity, and total visual score. Associations between visual grades and malignancy were analyzed using linear by linear association methods. Moreover, a receiver operating characteristic (ROC) curve was analyzed to compare the effectiveness of significant parameters.

RESULT

In a comparison between the malignant and benign groups in the analysis of 51 total peritoneal lesions, SUVmax1, SUVmean1, and TLG1 showed significant differences. Also, in the analysis of 42 peritoneal lesions that underwent an additional 2-h (18)F-FDG PET/CT examination, SUVmax1,2, SUVmean1,2, TLG2, and the RI of TLG showed significant differences between the malignant and benign groups. MTV did not show significant differences in either the analysis of 51 peritoneal lesions or of 42 lesions. Regarding visual assessments, metabolic intensity, shape, heterogeneity, and total visual score showed an association with malignancy. In the ROC analysis, the AUC of the visual score was larger than the AUC of other parameters in both the analyses of 51 peritoneal lesions and of 42 lesions.

CONCLUSION

Although further study with a larger patient population is needed, the visual assessment of (18)F-FDG PET/CT imaging has a primary role in the detection of malignancy in ovarian cancer patients with assistance from other semi-quantitative parameters.

A semi-automated technique determining the liver standardized uptake value reference for tumor delineation in FDG PET-CT

BACKGROUND

18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) has been an essential modality in oncology. We propose a semi-automated algorithm to objectively determine liver standardized uptake value (SUV), which is used as a threshold for tumor delineation.

METHODS

A large spherical volume of interest (VOI) was placed manually to roughly enclose the right lobe (RL) of the liver. For each voxel in this VOI, a coefficient of variation of voxel values (CVv) was calculated for neighboring voxels within a radius of d/2. The voxel with the minimum CVv was then selected, where a 30-mm spherical VOI was placed at that voxel in accordance with PERCIST criteria. Two nuclear medicine physicians independently defined 30-mm VOIs manually on 124 studies in 62 patients to generate the standard values, against which the results from the new method were compared.

RESULTS

The semi-automated method was successful in determining the liver SUV that was consistent between the two physicians in all the studies (d = 80 mm). The liver SUV threshold (mean +3 SD within 30-mm VOI) determined by the new semi-automated method (3.12±0.61) was not statistically different from those determined by the manual method (Physician-1: 3.14±0.58, Physician-2: 3.15±0.58). The semi-automated method produced tumor volumes that were not statistically different from those by experts' manual operation. Furthermore, the volume change in the two sequential studies had no statistical difference between semi-automated and manual methods.

CONCLUSIONS

Our semi-automated method could define the liver SUV robustly as the threshold value used for tumor volume measurements according to PERCIST. The method could avoid possible subjective bias of manual liver VOI placement and is thus expected to improve clinical performance of volume-based parameters for prediction of cancer treatment response.

The role of metabolic tumor volume and total lesion glycolysis on ¹⁸F-FDG PET/CT in the prognosis of epithelial ovarian cancer

PURPOSE

This study assessed the prognostic value of pre-operative 2-[(18)F] fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) volumetric parameters, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG), in patients with epithelial ovarian cancer.

METHODS

A total of 175 patients with epithelial ovarian cancer who underwent (18) F-FDG PET/CT and subsequent cytoreductive surgery were retrospectively enrolled. Maximum standardized uptake value (SUVmax) on (18)F-FDG PET/CT was measured for all patients. Because nine patients showed low tumor-to-background uptake ratios, MTV and TLG were measured in 166 patients. Univariate and multivariate analyses were performed to evaluate the prognostic significance of SUVmax, MTV, TLG, and clinicopathological factors for disease progression-free survival.

RESULTS

Disease progressed in 78 (44.6 %) of the 175 patients, and the 2-year disease progression-free survival rate was 57.5 %. Univariate analysis showed that tumor stage, histopathological type, presence of regional lymph node metastasis, residual tumor after cytoreductive surgery, pre-operative serum carbohydrate antigen 125 (CA125) level, SUVmax, MTV, and TLG were significant prognostic factors (p < 0.05). Among these variables, tumor stage (p = 0.0006) and TLG (p = 0.008) independently correlated with disease progression-free survival on multivariate analysis. The disease progression rate was only 2.3 % in stage I-II patients with low TLG (≤100.0), compared to 80.0 % in stage III-IV patients with high TLG (>100.0).

CONCLUSION

Along with tumor stage, TLG is an independent prognostic factor for disease progression after cytoreductive surgery in patients with epithelial ovarian cancer. By combining tumor stage and TLG, one can further stratify the risk of disease progression for patients undergoing cytoreductive surgery.