Prognostic value of preoperative metabolic tumor volume and total lesion glycolysis measured by 18F-FDG PET/CT in salivary gland carcinomas

Nerve Sheath Tumors in Neurofibromatosis Type 1: Assessment of Whole-Body Metabolic Tumor Burden Using F-18-FDG PET/CT

Purpose

To determine the metabolically active whole-body tumor volume (WB-MTV) on F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) in individuals with neurofibromatosis type 1 (NF1) using a three-dimensional (3D) segmentation and computerized volumetry technique, and to compare PET WB-MTV between patients with benign and malignant peripheral nerve sheath tumors (PNSTs).

Patients and Methods

Thirty-six NF1 patients (18 patients with malignant PNSTs and 18 age- and sex-matched controls with benign PNSTs) were examined by F-18-FDG PET/CT. WB-MTV, whole-body total lesion glycolysis (WB-TLG) and a set of semi-quantitative imaging-based parameters were analyzed both on a per-patient and a per-lesion basis.

Results

On a per-lesion basis, malignant PNSTs demonstrated both a significantly higher MTV and TLG than benign PNSTs (p < 0.0001). On a per-patient basis, WB-MTV and WB-TLG were significantly higher in patients with malignant PNSTs compared to patients with benign PNSTs (p < 0.001). ROC analysis showed that MTV and TLG could be used to differentiate between benign and malignant tumors.

Conclusions

WB-MTV and WB-TLG may identify malignant change and may have the potential to provide a basis for investigating molecular biomarkers that correlate with metabolically active disease manifestations. Further evaluation will determine the potential clinical impact of these PET-based parameters in NF1.

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.

State-Of-The-Art and Recent Advances in Quantification for Therapeutic Follow-Up in Oncology Using PET

¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET) is an important tool in oncology. Its use has greatly progressed from initial diagnosis to staging and patient monitoring. The information derived from ¹⁸F-FDG-PET allowed the development of a wide range of PET quantitative analysis techniques ranging from simple semi-quantitative methods like the standardized uptake value (SUV) to “high order metrics” that require a segmentation step and additional image processing. In this review, these methods are discussed, focusing particularly on the available methodologies that can be used in clinical trials as well as their current applications in international consensus for PET interpretation in lymphoma and solid tumors.

Assessing tumor hypoxia in head and neck cancer by PET with ⁶²Cu-diacetyl-bis(N⁴-methylthiosemicarbazone)

PURPOSE

The aim of this study was to investigate the potential of PET imaging with a hypoxia-selective tracer ⁶²Cu-diacetyl-bis(N⁴-methylthiosemicarbazone) (⁶²Cu-ATSM) for evaluating the prognosis of patients with head and neck cancer (HNC).

METHODS

Twenty-five patients with HNC including stage II to IV underwent both ⁶²Cu-ATSM and ¹⁸F-FDG PET before the initiation of treatment. Volumes of interest were placed on the tumor and sternocleidomastoid muscles to obtain SUVmax and to calculate the tumor-to-muscle activity ratio (TMR). The PET results were correlated with clinical follow-up, and the receiver operating characteristic analysis was used to determine the optimal cutoff values. Progression-free survival (PFS) and cause-specific survival (CSS) were statistically analyzed.

RESULTS

Patients were followed up for periods ranging from 4 to 32 months. Twelve patients died from local recurrence or metastasis of a primary cancer, and 2 had recurrence of the 13 remaining patients. Mean (SD) periods of PFS and CSS were 15.5 (12.5) and 18.6 (11.0) months, respectively. Optimal cutoff values for each PET index were as follows: SUVs of ⁶²Cu-ATSM (SUVATSM) and FDG were 3.6 and 7.9; TMRs of ATSM (TMRATSM) and FDG were 3.2 and 5.6. When the cutoff for TMRATSM was set at 3.2, patients with a greater TMRATSM had significantly worse PFS (P = 0.014) and CSS (P = 0.031). Two-year PFS and CSS rates were 73% and 80% for patients with a lower TMRATSM (≤3.2); however, they were 20% and 33% for those with hypoxic tumors (TMRATSM, >3.2), respectively. F-FDG-related indices did not show any significant difference in either PFS or CSS.

CONCLUSIONS

Pretreatment ⁶²Cu-ATSM PET is useful for predicting the prognosis of patients with HNC.

Increased evidence for the prognostic value of primary tumor asphericity in pretherapeutic FDG PET for risk stratification in patients with head and neck cancer

PURPOSE

In a previous study, we demonstrated the first evidence that the asphericity (ASP) of pretherapeutic FDG uptake in the primary tumor provides independent prognostic information in patients with head and neck cancer. The aim of this work was to confirm these results in an independent patient group examined at a different site.

METHODS

FDG-PET/CT was performed in 37 patients. The primary tumor was delineated by an automatic algorithm based on adaptive thresholding. For the resulting ROIs, the metabolically active part of the tumor (MTV), SUVmax, SUVmean, total lesion glycolysis (TLG) and ASP were computed. Univariate Cox regression with respect to progression free survival (PFS) and overall survival (OS) was performed. For survival analysis, patients were divided in groups of high and low risk according to the parameter cut-offs defined in our previous work. In a second step, the cut-offs were adjusted to the present data. Univariate and multivariate Cox regression was performed for the pooled data consisting of the current and the previously described patient group (N = 68). In multivariate Cox regression, clinically relevant parameters were included.

RESULTS

Univariate Cox regression using the previously published cut-off values revealed TLG (hazard ratio (HR) = 3) and ASP (HR = 3) as significant predictors for PFS. For OS MTV (HR = 2.7) and ASP (HR = 5.9) were significant predictors. Using the adjusted cutoffs MTV (HR = 2.9/3.3), TLG (HR = 3.1/3.3) and ASP (HR = 3.1/5.9) were prognostic for PFS/OS. In the pooled data, multivariate Cox regression revealed a significant prognostic value with respect to PFS/OS for MTV (HR = 2.3/2.1), SUVmax (HR = 2.1/2.5), TLG (HR = 3.5/3.6), and ASP (HR = 3.4/4.4).

CONCLUSIONS

Our results confirm the independent prognostic value of ASP of the pretherapeutic FDG uptake in the primary tumor in patients with head and neck cancer. Moreover, these results demonstrate that ASP can be determined unambiguously across different sites.

Prognostic significance of volume-based FDG PET/CT parameters in patients with locally advanced pancreatic cancer treated with chemoradiation therapy

PURPOSE

We investigated the prognostic role of volume-based parameters measured on 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) scans in patients with locally advanced pancreatic cancer (LAPC) treated with chemoradiation therapy (CRT).

MATERIALS AND METHODS

We enrolled 60 patients with LAPC who underwent FDG PET/CT before CRT. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary pancreatic cancers were measured on FDG PET/CT scans. Treatment response was evaluated according to the Response Evaluation Criteria in Solid Tumors. Survival analysis was performed using the Kaplan-Meier method, and Cox proportional hazard models were used to determine independent prognostic factors.

RESULTS

The progression-free survival (PFS), locoregional progression-free survival (LRFPS), and overall survival (OS) for this population were 6.2, 10.9, and 13.2 months, respectively. The overall treatment response rate was 16.7% at 4 weeks after CRT, and the disease control rate (DCR) was 80.0%. DCR was significantly higher in patients with low SUVmax, MTV, or TLG, and showed strong correlation with longer survival times. On univariate analysis, MTV and TLG were significant prognostic factors for PFS, LRPFS, and OS, together with pre-CRT and post-CRT CA19-9 levels. Multivariate analyses demonstrated that MTV together with the pre-CRT CA19-9 level were independent prognostic factors for PFS, LRPFS, and OS, as was TLG for LRPFS and OS.

CONCLUSION

MTV and the pre-CRT CA19-9 level provided independent prognostic information in patients with LAPC treated with CRT. Volume-based PET/CT parameters may be useful in identifying which subgroup of patients would benefit from radiation therapy as a part of CRT.

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.

Prognostic Value of Metabolic Tumor Volume Estimated by (18) F-FDG Positron Emission Tomography/Computed Tomography in Patients with Diffuse Large B-Cell Lymphoma of Stage II or III Disease

PURPOSE

The purpose of this study was to evaluate the prognostic value of metabolic tumor volume (MTV) measured by (18)F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) in patients with diffuse large B-cell lymphoma (DLBCL) treated with rituximab-containing immunochemotherapy.

METHODS

Patients with newly diagnosed DLBCL who underwent pre-treatment torso FDG-PET/CT scan taken within 10 days before treatment were included. MTV was defined as the volume of hypermetabolic tissue with a standardized uptake value (SUV) greater than a threshold value of 2.5 and calculated using volume viewer software. Association of MTV with patient characteristics and survival were compared.

RESULTS

A total of 96 patients were evaluated. During a median follow-up period of 27.8 months, 3-year event-free survival (EFS) and overall survival was 69.5 % and 72.9 %, respectively. The Ann Arbor staging showed a limitation of prognosis because there was no difference of EFS between patients with Ann Arbor stage II and those with stage III. On the contrary, among patients with Ann Arbor stage II or III disease (n = 53), the higher MTV group showed significantly inferior EFS compared with the lower MTV group.

CONCLUSIONS

In the current study, we identified the pre-treatment MTV measured by FDG-PET/CT as a potential predictor of survival in patients with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), at least in Ann Arbor stage II and III disease.

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.

Prognostic value of metabolic tumor volume and total lesion glycolysis in head and neck cancer: a systematic review and meta-analysis

We conducted a comprehensive systematic review of the literature on volumetric parameters and a meta-analysis of the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in patients with head and neck cancer (HNC).

METHODS

A systematic search of MEDLINE and EMBASE was performed using the key words PET, head and neck, and volume. Inclusion criteria were (18)F-FDG PET used as an initial imaging tool; studies limited to HNC; patients who had not undergone surgery, chemotherapy, or radiotherapy before PET scans; and studies reporting survival data. Event-free survival and overall survival were considered markers of outcome. The impact of MTV or TLG on survival was measured by the effect size hazard ratio (HR). Data from each study were analyzed using Review Manager.

RESULTS

Thirteen studies comprising 1,180 patients were included in this study. The combined HR for adverse events was 3.06 (2.33-4.01, P < 0.00001) with MTV and 3.10 (2.27-4.24, P < 0.00001) with TLG, meaning that tumors with high volumetric parameters were associated with progression or recurrence. Regarding overall survival, the pooled HR was 3.51 (2.62-4.72, P < 0.00001) with MTV and 3.14 (2.24-4.40, P < 0.00001) with TLG. There was no evidence of significant statistical heterogeneity at an I(2) of 0%.

CONCLUSION

MTV and TLG are prognostic predictors of outcome in patients with HNC. Despite clinically heterogeneous HNC and the various methods adopted between studies, we can confirm that patients with a high MTV or TLG have a higher risk of adverse events or death.

Prognostic Value of Metabolic Tumor Volume and Total Lesion Glycolysis on Preoperative ¹⁸F-FDG PET/CT in Patients with Pancreatic Cancer

In this study, we aimed to assess the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured on (18)F-FDG PET/CT in pancreatic cancer patients who underwent resection with curative intent.

METHODS

Eighty-seven patients with pancreatic ductal adenocarcinoma who underwent (18)F-FDG PET/CT and subsequent surgical resection with curative intent with (30 patients) or without (57 patients) neoadjuvant therapy were retrospectively enrolled. The maximum standardized uptake value (SUVmax), MTV, and TLG were measured on (18)F-FDG PET/CT in all patients. The prognostic significances of PET/CT parameters and tumor factors for recurrence-free survival (RFS) and overall survival (OS) were evaluated by univariate and multivariate analyses.

RESULTS

Of the 87 patients, 57 (64%) experienced recurrence during the follow-up period. The tumor size, pathologic T (pT) stage, SUVmax, MTV, and TLG were significant prognostic factors for both RFS and OS (P < 0.05) on univariate analyses, and the presence of lymph node metastasis showed significance only for predicting RFS (P < 0.05). On multivariate analyses, the tumor size, MTV, and TLG were independent prognostic factors for RFS, and pT stage, MTV, and TLG were independent prognostic factors for OS. For the 57 patients who did not undergo neoadjuvant treatment, MTV and TLG remained significant predictive factors for tumor recurrence, along with tumor size and SUVmax.

CONCLUSION

MTV and TLG are independent prognostic factors for predicting RFS and OS in patients with pancreatic cancer. Thus, (18)F-FDG PET/CT can provide useful prognostic information for patients undergoing resection of pancreatic cancer with curative intent irrespective of neoadjuvant treatment.