Prognostic value of whole-body total lesion glycolysis at pretreatment FDG PET/CT in non-small cell lung cancer

Determination of Skeletal Tumor Burden on 18F-Fluoride PET/CT

The purpose of this study was to define a method to assess skeletal tumor burden with 18F-labeled sodium fluoride PET/CT (18F-fluoride PET/CT) and evaluate the reproducibility of these measurements.

METHODS

Ninety-eight consecutive patients (90 men; mean age±SD, 65.7±14.2 y) underwent 158 18F-fluoride PET/CT scans for evaluation of skeletal metastatic disease. In order to determine the mean normal bone SUV, initially a 1-cm spheric volume of interest (VOI) was placed over 5 bone sites: T12, L5, sacrum, right iliac bone, and right femur. For each patient, the mean SUVmax for all sites was generated. Afterward, a threshold value of normal bone uptake was established. Subsequently, skeletal tumor burden was determined by generating volumetric data using a whole-body segmentation method. Any SUVmax below the normal threshold was excluded from analysis, as were VOIs not related to metastatic disease. Statistics for the remaining VOIs were then generated and defined as the skeletal metastatic tumor burden by 2 parameters: total lesion fluoride uptake above an SUVmax of 10 (TLF10) and fluoride tumor volume above an SUVmax of 10 (FTV10). TLF10 and FTV10 reproducibility was determined using 2 independent and experienced PET/CT interpreters analyzing a subset of 13 18F-fluoride PET/CT scans.

RESULTS

Mean (±SD) normal bone SUVmax was 6.62±1.55 for T12, 6.11±1.73 for L5, 4.59±1.74 for sacrum, 5.39±1.72 for right iliac bone, and 3.90±1.57 for right femur. The mean normal SUVmax for all 543 sites was 5.32±0.99. On the basis of these values, an SUVmax threshold of 10 was chosen to exclude normal bone from the volumetric calculations. Semiautomated measurements of TLF10 and FTV10 exhibited high interobserver reproducibility, within ±0.77% and ±3.62% of the interinterpreter average for TLF10 and FTV10, respectively.

CONCLUSION

Determination of skeletal tumor burden with 18F-fluoride PET/CT is feasible and highly reproducible. Using an SUVmax threshold of 10 excludes nearly all normal bone activity from volumetric calculations.

Prognostic significance of standardized uptake value and metabolic tumour volume on ¹⁸F-FDG PET/CT in oropharyngeal squamous cell carcinoma

PURPOSE

Standardized uptake value (SUV) and metabolic tumour volume (MTV) measured by (18)F-FDG PET/CT are emerging prognostic biomarkers in human solid cancers. However, their prognostic significance in oropharyngeal squamous cell carcinoma (OPSCC) has been investigated in only a few studies and with small cohorts. In the present study we evaluated the ability of SUV, MTV, and total lesion glycolysis (TLG) measured on pretreatment (18)F-FDG PET/CT to predict recurrence and survival outcomes in OPSCC.

METHODS

The study included 221 patients with OPSCC who underwent pretreatment (18)F-FDG PET/CT imaging and received definitive treatment at our tertiary referral centre. The PET imaging parameters SUVmax, SUVpeak, MTV and TLG were measured in primary tumours with focal (18)F-FDG uptake. Clinical and imaging variables significantly associated with overall survival (OS) and disease-free survival (DFS) were identified by univariate and multivariate analyses using the Cox proportional hazards model.

RESULTS

Overall 5-year OS and DFS rates were 72.0 % and 79.5 %, respectively, during a median follow-up of 61 months (range 18 - 122 months). The cut-off values of tumour SUVmax, SUVpeak, MTV and TLG for prediction of DFS were 7.55, 6.80, 11.06 mL and 78.56 g, respectively. Univariate analyses showed that age >60 years, advanced tumour stage, and high tumour SUVmax, SUVpeak, MTV and TLG were significantly associated with decreased OS and DFS (P < 0.05 each). Age, tumour SUVmax and MTV remained independent variables for OS and DFS (P < 0.05 each) in the multivariate analyses.

CONCLUSION

SUVmax and MTV measured on pretreatment (18)F-FDG PET/CT may be useful in predicting the clinical outcomes in OPSCC patients. This study investigated the clinical prognostic value of imaging parameters from pretreatment (18)F-FDG PET/CT in 221 patients who underwent definitive treatment for oropharyngeal squamous cell carcinoma. High maximum standardized uptake value and metabolic tumour volume were independently associated with decreased disease-free and overall survival outcomes.

Change in volume parameters induced by neoadjuvant chemotherapy provide accurate prediction of overall survival after resection in patients with oesophageal cancer

OBJECTIVES

To assess the prognostic value of volumetric parameters measured with CT and PET/CT in patients with neoadjuvant chemotherapy (NACT) and resection for oesophageal cancer (EC).

METHODS

Patients with locally advanced EC, who were treated with NACT and resection, were retrospectively analysed. Data from CT volumetry and (18) F-FDG PET/CT (maximum standardized uptake [SUVmax], metabolic tumour volume [MTV], and total lesion glycolysis [TLG]) were recorded before and after NACT. The impact of volumetric parameter changes induced by NACT (MTVRATIO, TLGRATIO, etc.) on overall survival (OS) was assessed using a Cox proportional hazards model.

RESULTS

Eighty-four patients were assessed using CT volumetry; of those, 50 also had PET/CT before and after NACT. Low post-treatment CT volume and thickness, MTV, TLG, and SUVmax were all associated with longer OS (p < 0.05), as were CTthicknessRATIO, MTVRATIO, TLGRATIO, and SUVmaxRATIO (p < 0.05). In the multivariate analysis, only MTVRATIO (Hazard ratio, HR 2.52 [95% Confidence interval, CI 1.33-4.78], p = 0.005), TLGRATIO (HR 3.89 [95%CI 1.46-10.34], p = 0.006), and surgical margin status (p < 0.05), were independent predictors of OS.

CONCLUSIONS

MTVRATIO and TLGRATIO are independent prognostic factors for survival in patients after NACT and resection for EC.

KEY POINTS

• Change in PET parameters shows close correlation to survival in oesophageal cancer. • Association with OS is independent of changes in SUVmax and CT volume. • Metabolic parameters after NACT correlate with pathologic response and nodal status. • Metabolic parameters may be better suited than SUVmax for response assessment.

A new PET/CT volumetric prognostic index for non-small cell lung cancer

OBJECTIVES

Whole-body metabolic tumor volume (MTVWB) has been shown of prognostic value for non-small cell lung cancer (NSCLC) beyond that of TNM stage, age, gender, performance status, and treatment selection. The current TNM staging system does not incorporate tumor volumetric information. We propose a new PET/CT volumetric prognostic (PVP) index that combines the prognostic value of MTVWB and TNM stage.

MATERIALS AND METHODS

Based on 328 consecutive NSCLC patients with a baseline PET/CT scan before treatment, from which MTVWB was measured semi-automatically, we estimated hazard ratios (HRs) for ln(MTVWB) and TNM stage from a Cox proportional hazard regression model that consisted of only ln(MTVWB) and TNM stage as prognostic variables of overall survival. We used the regression coefficients, which gave rise to the HRs, as weights to formulate the PET/CT volumetric prognostic (PVP) index. We also compared the prognostic value of the PVP index against that of TNM stage alone and ln(MTVWB) alone with univariate and multivariate survival analyses and C-statistics.

RESULTS

Univariate analysis C-statistic for the PVP index (C=0.71) was statistically significantly greater than those for TNM stage alone (C=0.67, p<0.01) and for ln(MTVWB) alone (C=0.69, p=0.033). Multivariate analyses showed that the PVP index yielded significantly greater discriminatory power (C=0.74) than similar models based on either TNM stage (C=0.72, p<0.01) or ln(MTVWB) (C=0.73, p<0.01). Lower values of the PVP index were associated with significantly better overall survival (adjusted HR=2.70, 95%CI [2.16, 3.37]).

CONCLUSION

The PVP index provides a practical means for clinicians to combine the prognostic value of MTVWB and TNM stage and offers significantly better prognostic accuracy for overall survival of NSCLC patients than the current TNM staging system or metabolic tumor burden alone.

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.

Pretreatment FDG-PET metrics in stage III non-small cell lung cancer: ACRIN 6668/RTOG 0235

BACKGROUND

ACRIN 6668/RTOG 0235 evaluated the prognostic value of positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) uptake before and after definitive, concurrent, platinum-based chemoradiotherapy for locally advanced non-small cell lung cancer (NSCLC). In this secondary analysis, we evaluate volumetric pretreatment PET measures as predictors of clinical outcomes.

METHODS

Patients with stage III NSCLC underwent FDG-PET prior to treatment. A commercially available gradient-based segmentation tool was used to contour all visible hypermetabolic lesions on each scan. For each patient, the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA) for all contoured lesions were recorded. Cox proportional hazards regression models were used to evaluate clinical variables and PET metrics as predictors of overall survival (OS) and locoregional control (LRC). Time-dependent covariables were added to the models when necessary to address nonproportional hazards. All statistical tests were two-sided.

RESULTS

Complete data were available for 214 patients in the OS analysis and 189 subjects in the LRC analysis. In multivariable analysis incorporating clinical and imaging data available prior to treatment, MTV was an independent predictor of OS (HR = 1.04 per 10 cm(3) increase, 95% CI = 1.03 to 1.06, P < .001). High MTV was also associated with increased risk of locoregional failure at baseline (HR = 1.16 per 10 cm(3) increase, 95% CI = 1.08 to 1.23, P < .001) and at six months (HR = 1.05 per 10 cm(3) increase, 95% CI = 1.02 to 1.07, P < .001) but not at 12 months or later time points.

CONCLUSION

Pretreatment MTV is a predictor of clinical outcomes for NSCLC patients treated with chemoradiotherapy. Quantitative PET measures may serve as stratification factors in clinical trials for this patient population and may help guide novel trial designs.

Relationship between Overall Survival of Patients with Non-Small Cell Lung Cancer and Whole-Body Metabolic Tumor Burden Seen on Postsurgical Fluorodeoxyglucose PET Images

PURPOSE

To test the hypothesis that whole-body metabolic tumor burden (MTBWB) on postsurgical fluorodeoxyglucose (FDG) positron emission tomographic (PET)/computed tomographic (CT) images in patients with non-small cell lung cancer (NSCLC) is associated with their overall survival (OS).

MATERIALS AND METHODS

The institutional review board approved this study and waived the requirement for obtaining informed consent. One hundred forty-two patients with NSCLC (69 men, 73 women; median age, 67.7 years) who underwent postsurgical FDG PET/CT were retrospectively reviewed. The whole-body metabolic tumor volume (MTVWB), whole-body total lesion glycolysis (TLGWB), and whole-body maximum standardized uptake value (SUVWBmax) were measured. OS served as the primary end point of the study. Kaplan-Meier curves and Cox regression were used to assess the association between PET/CT markers and OS.

RESULTS

The interobserver variability was low, as demonstrated with intraclass correlation coefficients higher than 0.94 for SUVWBmax, MTVWB, and TLGWB. When compared with those with negative postsurgical FDG PET/CT findings, a significant decrease of OS was found in patients with the presence of FDG-avid tumor on the basis of both a log-rank test (P = .001) and a univariate Cox model (hazard ratio = 2.805, P = .001). In patients with FDG-avid tumor, there was a significant association between OS and ln MTVWB (P < .001), ln TLGWB (P < .001), and ln SUVWBmax (P < .010) in either univariate or multivariate analysis, after adjusting for patient age, sex, TNM restage, and therapy after postsurgical PET/CT studies. The OS differences between the groups dichotomized by the median value of MTVWB (11.54 mL, P = .004), TLGWB (32.38 mL, P < .001), or SUVWBmax (4.93, P = .023) were significant.

CONCLUSION

MTBWB and tumor maximum standardized uptake at postsurgical FDG PET/CT are related to the patient's OS in NSCLC, independent of age, sex, TNM restaging, and therapy after postsurgical PET/CT studies.

Pre-treatment FDG-PET predicts the site of in-field progression following concurrent chemoradiotherapy for stage III non-small cell lung cancer

PURPOSE

Locoregional progression following definitive chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer (NSCLC) is common. In this study, we explore the utility of pre-treatment PET for predicting sites of disease progression following CRT.

METHODS

We identified patients treated at our institution with definitive, concurrent CRT for stage III NSCLC in the years 2007-2010 who underwent staging FDG-PET/CT. Using a semiautomatic gradient-based tool, visible thoracic hypermetabolic lesions were contoured on each patient's pre-treatment PET. Post-treatment imaging was reviewed to identify specific locations of disease progression. Patients' maximum SUV (SUVmax_pat) and metabolic tumor volume (MTV_pat) were evaluated as predictors of clinical outcomes using logrank testing. Competing risks analysis was performed to examine the relationship between lesion (tumor or lymph node) MTV (MTV_les) and the risk of local disease progression. Patient death and progression in other sites were treated as competing risks.

RESULTS

28 patients with 82 hypermetabolic lesions (27 pulmonary tumors, 55 lymph nodes) met inclusion criteria. Median follow-up was 39.0 months for living patients. Median progression-free survival (PFS) was 12.4 months, and median overall survival (OS) was 31.8 months. Low MTV_pat was associated with improved PFS (median 14.3 months for MTV<60 cc vs. 9.7 months for MTV>60 cc, p=0.039). MTV_les was strongly associated with the risk of local disease progression. The 2-year cumulative incidence rate (CIR) for progression in lesions larger than 25 cc was 45%, compared to 5% for lesions under 25 cc (p<0.001).

CONCLUSION

Pre-treatment PET can be used to identify specific lesions at high risk for treatment failure following definitive CRT for locally advanced NSCLC. Selective treatment intensification to high-risk lesions should be studied as a strategy to improve clinical outcomes in this patient population.

Prognostic value of volumetric parameters of (18)F-FDG PET in non-small-cell lung cancer: a meta-analysis

PURPOSE

We conducted a comprehensive systematic review of the literature on volumetric parameters from (18)F-FDG PET and a meta-analysis of the prognostic value of metabolic tumour volume (MTV) and total lesion glycolysis (TLG) in patients with lung cancer.

METHODS

A systematic search of MEDLINE and EMBASE was performed using the keywords "positron emission tomography (PET)", "lung cancer", and "volume". Inclusion criteria were: (18)F-FDG PET used as an initial imaging tool; studies limited to non-small-cell lung cancer (NSCLC); volume measurement of lung cancer; patients who had not undergone surgery, chemotherapy, or radiotherapy before the PET scan; and studies that reported survival data. Event-free survival and overall survival were evaluated as outcomes. The impact of MTV and TLG on survival was measured in terms of the hazard ratio (HR) effect size. Data from each study were analysed using Review Manager 5.2.

RESULTS

Thirteen eligible studies including 1,581 patients were analysed. Patients with high MTV showed a worse prognosis with an HR of 2.71 (95% CI 1.82 - 4.02, p < 0.00001) for adverse events and an HR of 2.31 (95% CI 1.54 - 3.47, p < 0.00001) for death. Patients with high TLG also showed a worse prognosis with an HR of 2.35 (95% CI 1.91 - 2.89, p < 0.00001) for adverse events and an HR of 2.43 (95% CI 1.89 - 3.11, p < 0.00001) for death. The prognostic value of MTV and TLG remained significant in a subgroup analysis according to TNM stage as well as the methods for defining cut-off values and tumour delineation.

CONCLUSION

Volumetric parameters from (18)F-FDG PET are significant prognostic factors for outcome in patients with NSCLC. Patients with a high MTV or TLG are at higher risk of adverse events and death. MTV and TLG were significant prognostic factors in patients with TNM stage I/II and stage III/IV NSCLC.

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.

Whole-body total lesion glycolysis measured on fluorodeoxyglucose positron emission tomography/computed tomography as a prognostic variable in metastatic breast cancer

Background

In this retrospective study, the authors evaluated the prognostic value of whole-body total lesion glycolysis (WTLG) on FDG/PET images in metastatic breast cancer (MBC) patients.

Methods

We retrospectively evaluated 54 MBC patients who were diagnosed as having one or more metastatic lesions between June 2005 and March 2013. Twenty-four patients were diagnosed at the initial presentation (group A) and 30 patients were diagnosed for the first time at some point after a surgery (group B). Patients were excluded if they had received chemotherapy within 30 days before PET/CT. SUV_max and total TLG were calculated for all lesions in each patient and the highest SUV_max and the whole-body TLG (WTLG) values were used as independent variables for the analyses. Mean ages and the proportions of histopathological subtypes were compared between two groups using Mann–Whitney U test and Fisher’s exact test, respectively. The prognostic significance of PET parameters was assessed using Cox proportional hazards regression analysis.

Results

For groups A and B, the median follow-up period was 26 months (range, 3–58 months) and 40.5 months (range, 3–69 months), and the median age was 61 years (range, 42–81 years) and 59 years (range, 24–74 years), respectively. There were no significant differences between two groups in age (p = 0.294) or histopathological subtype (p = 0.384). In the univariate analyses, WTLG was found to be significantly associated with overall survival (OS) for patients of group A (p = 0.012). In the multivariate analysis, WTLG was also significantly associated with OS (p = 0.015). Only hormonal receptor level was a significant indicator of longer OS in patients with recurrent MBC (group B).

Conclusions

This study demonstrated that WTLG on PET/CT is an independent prognostic factor for survival in breast cancer patients with metastases at the initial presentation.

PET/CT evaluation of response to chemotherapy in non-small cell lung cancer: PET response criteria in solid tumors (PERCIST) versus response evaluation criteria in solid tumors (RECIST)

BACKGROUND

(18)F-FDG PET/CT is increasingly used in evaluation of treatment response for patients with non-small cell lung cancer (NSCLC). There is a need for an accurate criterion to evaluate the effect and predict the prognosis. The aim of this study is to evaluate therapeutic response in NSCLC with comparing PET response criteria in solid tumors (PERCIST) to response evaluation criteria in solid tumors (RECIST) criteria on PET/CT.

METHODS

Forty-four NSCLC patients who received chemotherapy but no surgery were studied. Chemotherapeutic responses were evaluated using (18)F-FDG PET and CT according to the RECIST and PERCIST methodologies. PET/CT scans were obtained before chemotherapy and after 2 or 4-6 cycles' chemotherapy. The percentage changes of tumor longest diameters and standardized uptake value (SUV) (corrected for lean body mass, SUL) before and after treatment were compared using paired t-test. The response was categorized into 4 levels according to RECIST and PERCIST: CR (CMR) =1, PR (PMR) =2, SD (SMD) =3, PD (PMD) =4. Pearson chi-square test was used to compare the proportion of four levels in RECIST and PERCIST. Finally the relationship between progression-free survival (PFS) and clinicopathologic parameters (such as TNM staging, percentage changes in diameters and SUL, RECIST and PERCIST results etc.) were evaluated using univariate and multivariate Cox proportional hazards regression method.

RESULTS

The difference of percentage changes between diameters and SUL was not significant using paired t-test (t=-1.69, P=0.098). However the difference was statistically significant in the 40 cases without increasing SUL (t=-3.31, P=0.002). The difference of evaluation results between RECIST and PERCIST was not significant by chi-square test (χ(2)=5.008, P=0.171). If RECIST evaluation excluded the new lesions which could not be found or identified on CT images the difference between RECIST and PERCIST was significant (χ(2)=11.759, P=0.007). Reduction rate of SULpeak (%), RECIST and PERCIST results were significant factors in univariate Cox analysis. But Multivariate Cox proportional hazards regression analysis demonstrated that only PERCIST was a significant factor for predicting DFS [hazard ratio (HR), 3.20; 95% (CI), 1.85-5.54; P<0.001].

CONCLUSIONS

PERCIST and RECIST criteria have good consistency and PERCIST (or PET) is more sensitive in detecting complete remission (CR) and progression. PERCIST might be the significant predictor of outcomes. The combination of PERCIST and RECIST would provide clinicians more accurate information of therapeutic response in earlier stage of treatment.

Prognostic value of metabolic tumor burden in lung cancer

Accurate prognosis in patients with lung cancer is important for clinical decision making and treatment selection. The TNM staging system is currently the main method for establishing prognosis. Using this system, patients are grouped into one of four stages based on primary tumor extent, nodal disease, and distant metastases. However, each stage represents a range of disease extent and may not on its own be the best reflection of individual patient prognosis. (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) can be used to evaluate the metabolic tumor burden affecting the whole body with measures such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG). MTV and TLG have been shown to be significant prognostic factors in patients with lung cancer, independent of TNM stage. These metabolic tumor burden measures have the potential to make lung cancer staging and prognostication more accurate and quantitative, with the goal of optimizing treatment choices and outcome predictions.

Visual versus quantitative assessment of intratumor 18F-FDG PET uptake heterogeneity: prognostic value in non-small cell lung cancer

The goal of this study was to compare visual assessment of intratumor (18)F-FDG PET uptake distribution with a textural-features (TF) automated quantification and to establish their respective prognostic value in non-small cell lung cancer (NSCLC).

METHODS

The study retrospectively included 102 consecutive patients. Only primary tumors were considered. Intratumor heterogeneity was visually scored (3-level scale [Hvisu]) by 2 nuclear medicine physicians. Tumor volumes were automatically delineated, and heterogeneity was quantified with TF. Mean and maximum standardized uptake value were also included. Visual interobserver agreement and correlations with quantitative assessment were evaluated using the κ test and Spearman rank (ρ) coefficient, respectively. Association with overall survival and recurrence-free survival was investigated using the Kaplan-Meier method and Cox regression models.

RESULTS

Moderate correlations (0.4 < ρ < 0.6) between TF parameters and Hvisu were observed. Interobserver agreement for Hvisu was moderate (κ = 0.64, discrepancies in 27% of the cases). High standardized uptake value, large metabolic volumes, and high heterogeneity according to TF were associated with poorer overall survival and recurrence-free survival and remained an independent prognostic factor of overall survival with respect to clinical variables.

CONCLUSION

Quantification of (18)F-FDG uptake heterogeneity in NSCLC through TF was correlated with visual assessment by experts. However, TF also constitutes an objective heterogeneity quantification, with reduced interobserver variability, and independent prognostic value potentially useful for patient stratification and management.

Value of ¹⁸F-FDG uptake on PET/CT and CEA level to predict epidermal growth factor receptor mutations in pulmonary adenocarcinoma

PURPOSE

The identification of the mutation status of the epidermal growth factor receptor (EGFR) is important for the optimization of treatment in patients with pulmonary adenocarcinoma. The acquisition of adequate tissues for EGFR mutational analysis is sometimes not feasible, especially in advanced-stage patients. The aim of this study was to predict EGFR mutation status in patients with pulmonary adenocarcinoma based on (18)F-fluorodeoxyglucose (FDG) uptake and imaging features in positron emission tomography/computed tomography (PET/CT), as well as on the serum carcinoembryonic antigen (CEA) level.

METHODS

We retrospectively reviewed 132 pulmonary adenocarcinoma patients who underwent EGFR mutation testing, pretreatment FDG PET/CT and serum CEA analysis. The associations between EGFR mutations and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, serum CEA level and CT imaging features were analyzed. Receiver-operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors.

RESULTS

EGFR mutations were identified in 69 patients (52.2 %). Patients with SUVmax ≥6 (p = 0.002) and CEA level ≥5 (p = 0.013) were more likely to have EGFR mutations. The CT characteristics of larger tumors (≥3 cm) (p = 0.023) and tumors with a nonspiculated margin (p = 0.026) were also associated with EGFR mutations. Multivariate analysis showed that higher SUVmax and CEA level, never smoking and a nonspiculated tumor margin were the most significant predictors of EGFR mutation. The combined use of these four criteria yielded a higher area under the ROC curve (0.82), suggesting a good discrimination.

CONCLUSION

The combined evaluation of FDG uptake, CEA level, smoking status and tumor margins may be helpful in predicting EGFR mutation status in patients with pulmonary adenocarcinoma, especially when the tumor sample is inadequate for genetic analysis or genetic testing is not available. Further large-scale prospective studies are needed to validate these results.

Prognostic value of pretreatment 18F-FDG PET/CT parameters including visual evaluation in patients with head and neck squamous cell carcinoma

OBJECTIVE

The purpose of this study was to determine whether pretreatment quantitative and visual parameters seen on PET/CT using (18)F-FDG add prognostic information for clinical staging in patients with head and neck cancer.

MATERIALS AND METHODS

We enrolled 108 patients with histologically proven oral, oropharyngeal, hypopharyngeal, and laryngeal squamous cell carcinomas who underwent FDG PET/CT before treatment and, later, definitive therapy in our study. PET/CT parameters-maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and uptake pattern (sphere-shaped or ring-shaped)-were recorded. The prognostic value of these parameters was evaluated using univariate and multivariate Cox regression analyses.

RESULTS

In the univariate analysis, all of the FDG PET/CT parameters--SUVmax (> 10 g/mL) of the primary tumor, MTV (> 20 cm(3)), TLG (> 70 g), and uptake pattern (ring-shaped)--were significantly associated with negative effects on disease-specific survival (DSS) and disease-free survival (DFS). In the multivariate analysis, the MTV and uptake pattern remained associated with DSS after corrections for the Union for International Cancer Control (UICC) stage and definitive therapy (p = 0.023 and < 0.001, respectively). Another multivariate model that included MTV as a continuous variable, uptake pattern, and UICC stage showed that the uptake pattern remained significantly associated with DSS, whereas the association between DSS and MTV was not significant (p < 0.001 and = 0.332, respectively).

CONCLUSION

Our data indicate that the pretreatment PET/CT parameters had prognostic value. In particular, a qualitative factor, uptake pattern, provided better prognostic information to the clinical staging of head and neck squamous cell carcinomas than the other PET/CT parameters.

Prognostic Value of Fluoro-D-glucose Uptake of Primary Tumor and Metastatic Lesions in Advanced Nonsmall Cell Lung Cancer

To assess the prognostic value of maximum standardized uptake value (maxSUV) of the primary tumor (maxSUVpt), maxSUV of whole-body tumors (maxSUVwb) and sum of maximum standardized uptake value (sumaxSUV) measured by the sum of maxSUVs of the primary tumor, metastatic lymph nodes, and metastatic lesions per each organ on fluoro-D-glucose-positron emission tomography/computed tomography in advanced non-small cell lung cancer (NSCLC). Eighty-three patients (49 male, 34 female) with advanced NSCLC were enrolled. Seventeen patients had Stage IIIA, 21 Stage IIIB, and 45 Stage IV. maxSUVpt, maxSUVwb, sumaxSUV, age, gender, tumor-cell type, T stage, N stage, overall stage, primary tumor size, and specific treatment were analyzed for correlation with overall survival. Median follow-up duration was 13 months. Fifty patients were dead during a median follow-up time of 11 months and 33 patients were alive with a median time of 15 months. Univariate analysis revealed that overall survival was significantly correlated with sumaxSUV (≥35 vs. <35, P = 0.004), T stage (T4 vs. T1-T3, P = 0.025), overall stage (IV vs. III, P = 0.002), gender (male vs. female, P = 0.029) and specific treatment (no vs. yes, P = 0.011). maxSUVpt and maxSUVwb were not correlated with overall survival with P value of 0.139 and 0.168, respectively. Multivariate analysis identified sumaxSUV, T stage, gender, and specific treatment as independent prognostic indicators. Patients with a sumaxSUV of ≥35 were 1.921 times more likely to die than those with a sumaxSUV of < 35 (P = 0.047). Median survival time was 14 months for patients with sumaxSUV ≥ 35 compared with 20 months for those with sumaxSUV < 35. In patients with metastatic NSCLC, sumaxSUV with cut-off of 35 was much more significant for survival prognosis (P = 0.021). sumaxSUV is a new prognostic measure, independent of tumor stage, gender, and specific treatment in advanced NSCLC. sumaxSUV may be better than maxSUVpt and maxSUVwb in prediction of survival. A large prospective cohort study is necessary to validate these results.

Prognostic significance of novel ¹⁸F-FDG PET/CT defined tumour variables in patients with oesophageal cancer

PURPOSE

(18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) is now established as a routine staging investigation of oesophageal cancer (OC). The aim of the study was to determine the prognostic significance of PET/CT defined tumour variables including maximum standardised uptake value (SUVmax), tumour length (TL), metastatic length of disease (MLoD), metabolic tumour volume (MTV), total lesion glycolysis (TLG) and total local nodal metastasis count (PET/CT LNMC).

MATERIALS AND METHODS

103 pre-treatment OC patients (76 adenocarcinoma, 25 squamous cell carcinoma, 1 poorly differentiated and 1 neuroendocrine tumour) were staged using PET/CT. The prognostic value of the measured tumour variables were tested using log-rank analysis of the Kaplan-Meier method and Cox's proportional hazards method. Primary outcome measure was survival from diagnosis.

RESULTS

Univariate analysis showed all variables to have strong statistical significance in relation to survival. Multivariate analysis demonstrated three variables that were significantly and independently associated with survival; MLoD (HR 1.035, 95% CI 1.008-1.064, p=0.011), TLG (HR 1.002, 95% CI 1.000-1.003, p=0.018) and PET/CT LNMC (HR 0.048-0.633, 95% CI 0.005-2.725, p=0.015).

CONCLUSION

MLoD, TLG, and PET/CT LNMC are important prognostic indicators in OC. This is the first study to demonstrate an independent statistical association between TLG, MLoD and survival by multivariable analysis, and highlights the value of staging OC patients with PET/CT using functional tumour variables.

PET/CT in therapy evaluation of patients with lung cancer

FDG-PET/CT is a well documented and widespread used imaging modality for the diagnosis and staging of patient with lung cancer. FDG-PET/CT is increasingly used for the assessment of treatment effects during and after chemotherapy. However, PET is not an accepted surrogate end-point for assessment of response rate in clinical trials. The aim of this review is to present current evidence on the use of PET in response evaluation of patients with lung cancer and to introduce the pearls and pitfalls of the PET-technology relating to response assessment. Based on this and relating to validation criteria, including stable technology, standardization, reproducibility and broad availability, the review discusses why, despite numerous studies on response assessment indicating a possible role for FDG-PET/CT, PET still has no place in guidelines relating to response evaluation in lung cancer.

Prognosis Related to Metastatic Burden Measured by ¹⁸F-Fluorocholine PET/CT in Castration-Resistant Prostate Cancer

This study investigated the prognostic significance of metabolically active tumor volume (MATV) measurements applied to (18)F-fluorocholine PET/CT in castration-resistant prostate cancer (CRPC).

METHODS

(18)F-fluorocholine PET/CT imaging was performed on 30 patients with CRPC. Metastatic disease was quantified on the basis of maximum standardized uptake value (SUV(max)), MATV, and total lesion activity (TLA = MATV × mean standardized uptake value). Tumor burden indices derived from whole-body summation of PET tumor volume measurements (i.e., net MATV and net TLA) were evaluated as variables in Cox regression and Kaplan-Meier survival analyses.

RESULTS

Net MATV ranged from 0.12 cm(3) to 1,543.9 cm(3) (median, 52.6 cm(3)). Net TLA ranged from 0.40 to 6,688.7 g (median, 225.1 g). Prostate-specific antigen level at the time of PET correlated significantly with net MATV (Pearson r = 0.65, P = 0.0001) and net TLA (r = 0.60, P = 0.0005) but not highest lesional SUV(max) of each scan. Survivors were followed for a median 23 mo (range, 6-38 mo). On Cox regression analyses, overall survival had a significant association with net MATV (P = 0.0068), net TLA (P = 0.0072), and highest lesion SUV(max) (P = 0.0173) and a borderline association with prostate-specific antigen level (P = 0.0458). Only net MATV and net TLA remained significant in univariate-adjusted survival analyses. Kaplan-Meier analysis demonstrated significant differences in survival between groups stratified by median net MATV (log-rank P = 0.0371), net TLA (log-rank P = 0.0371), and highest lesion SUV(max) (log-rank P = 0.0223).

CONCLUSION

Metastatic prostate cancer detected by (18)F-fluorocholine PET/CT can be quantified on the basis of volumetric measurements of tumor metabolic activity. The prognostic value of (18)F-fluorocholine PET/CT may stem from this capacity to assess whole-body tumor burden. With further clinical validation, (18)F-fluorocholine PET-based indices of global disease activity and mortality risk could prove useful in patient-individualized treatment of CRPC.

Early response monitoring to neoadjuvant chemotherapy in osteosarcoma using sequential ¹⁸F-FDG PET/CT and MRI

PURPOSE

We evaluated the potential of sequential fluorine-18 fluorodeoxyglucose ((18) F-FDG) positron emission tomography (PET)/computed tomography (CT) and MRI (PET/MRI) after one cycle of neoadjuvant chemotherapy to predict a poor histologic response in osteosarcoma.

METHODS

A prospective study was conducted on 30 patients with osteosarcoma treated with two cycles of neoadjuvant chemotherapy and surgery. All patients underwent PET/MRI before, after one cycle, and after the completion of neoadjuvant chemotherapy, respectively. Imaging parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor volume based on magnetic resonance (MR) images (MRV)] and their % changes were calculated on each PET/MRI data set, and histological responses were evaluated on the postsurgical specimen.

RESULTS

A total of 17 patients (57%) exhibited a poor histologic response after two cycles of chemotherapy. Unlike the little volumetric change in MRI, PET parameters significantly decreased after one and two cycles of chemotherapy, respectively. After one cycle of chemotherapy, SUVmax, MTV, and TLG predicted the poor responders. Among these parameters, either MTV ≥ 47 mL or TLG ≥ 190 g after one cycle of chemotherapy was significantly associated with a poor histologic response on multivariate logistic regression analysis (OR 8.98, p = 0.039). The sensitivity, specificity, and accuracy of these parameters were 71%, 85% and 77%; and 71%, 85% and 77 %, respectively.

CONCLUSION

The histologic response to neoadjuvant chemotherapy in osteosarcoma can be predicted accurately by FDG PET after one course of chemotherapy. Among PET parameters, MTV and TLG were independent predictors of the histologic response.

PET quantification with a histogram derived total activity metric: superior quantitative consistency compared to total lesion glycolysis with absolute or relative SUV thresholds in phantoms and lung cancer patients

INTRODUCTION

The increasing use of molecular imaging probes as biomarkers in oncology emphasizes the need for robust and stable methods for quantifying tracer uptake in PET imaging. The primary motivation for this research was to find an accurate method to quantify the total tumor uptake. Therefore we developed a histogram-based method to calculate the background subtracted lesion (BSL) activity and validated BSL by comparing the quantitative consistency with the total lesion glycolysis (TLG) in phantom and patient studies.

METHODS

A thorax phantom and a PET-ACR quality assurance phantom were scanned with increasing FDG concentrations. Volumes of interest (VOIs) were placed over each chamber. TLG was calculated with a fixed threshold at SUV 2.5 (TLG2.5) and a relative threshold at 42% of SUVmax (TLG42%). The histogram for each VOI was built and BSL was calculated. Comparison with the total injected FDG activity (TIA) was performed using concordance correlation coefficients (CCC) and the slope (a). Fifty consecutive patients with FDG-avid lung tumors were selected under an IRB waiver. TLG42%, TLG2.5 and BSL were compared to the reference standard calculating CCC and the slope.

RESULTS

In both phantoms, the CCC for lesions with a TIA ≤50ml*SUV between TIA and BSL was higher and the slope closer to 1 (CCC=0.933, a=1.189), than for TLG42% (CCC=0.350, a=0.731) or TLG2.5 (CCC=0.761, a=0.727). In 50 lung lesions BSL had a slope closer to 1 compared to the reference activity than TLG42% (a=1.084 vs 0.618 - for high activity lesions) and also closer to 1 than TLG2.5 (a=1.117 vs 0.548 - for low activity lesions).

CONCLUSION

The histogram based BSL correlated better with TIA in both phantom studies than TLG2.5 or TLG42%. Also in lung tumors, the BSL activity is overall more accurate in quantifying the lesion activity compared to the two most commonly applied TLG quantification methods.

Recent Trends in PET Image Interpretations Using Volumetric and Texture-based Quantification Methods in Nuclear Oncology

Image quantification studies in positron emission tomography/computed tomography (PET/CT) are of immense importance in the diagnosis and follow-up of variety of cancers. In this review we have described the current image quantification methodologies employed in (18)F-fluorodeoxyglucose ((18)F-FDG) PET in major oncological conditions with particular emphasis on tumor heterogeneity studies. We have described various quantitative parameters being used in PET image analysis. The main contemporary methodology is to measure tumor metabolic activity; however, analysis of other image-related parameters is also increasing. Primarily, we have identified the existing role of tumor heterogeneity studies in major cancers using (18)F-FDG PET. We have also described some newer radiopharmaceuticals other than (18)F-FDG being studied/used in the management of these cancers. Tumor heterogeneity studies are being performed in almost all major oncological conditions using (18)F-FDG PET. The role of these studies is very promising in the management of these conditions.

FDG PET/CT metabolic tumor volume and total lesion glycolysis predict prognosis in patients with advanced lung adenocarcinoma

PURPOSE

We investigated fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT)-assessed metabolic tumor volume (MTV) and total lesion glycolysis (TLG) as prognostic factors in lung adenocarcinoma patients.

METHODS

This retrospective study included 106 patients (19 stage I/II and 87 stage III/IV lung adenocarcinoma) who underwent FDG PET/CT before treatment. Standardized uptake value (SUV), MTV, and TLG (MTV × mean SUV) of each malignant lesion were measured. Whole MTV and whole TLG were the summation of all the MTV and TLG values in each patient. Survival analysis and FDG PET/CT parameters regarding epidermal growth factor receptor (EGFR) gene mutation status were evaluated.

RESULTS

Univariate survival analysis of stage III/IV patients identified high whole MTV (≥90), high whole TLG (≥600), and stage IV as significant predictors of poor progression-free survival. For overall survival, high whole MTV (≥90), high whole TLG (≥600), EGFR mutation-negative, and stage IV were significant poor prognostic predictors. After multivariate survival analysis, high whole MTV (P = 0.001), high whole TLG (P = 0.027), and stage IV (P = 0.006) were independent predictors of poor progression-free survival. High whole MTV (P < 0.001), high whole TLG (P = 0.001), and EGFR mutation-negative (P = 0.001) were independent prognostic predictors for poor overall survival. In a survival analysis of stage I/II patients, none was an independent prognostic predictor. No significant differences were found in FDG PET/CT parameters for EGFR mutation-negative and EGFR mutation-positive patients.

CONCLUSIONS

Assessment of MTV and TLG by FDG PET/CT in advanced lung adenocarcinoma patients provides useful information regarding prognosis.

Advanced imaging (positron emission tomography and magnetic resonance imaging) and image-guided biopsy in initial staging and monitoring of therapy of lung cancer

The results of the National Lung Screening Trial strongly support early detection and definitive treatment to reduce lung cancer mortality. Once lung cancer is discovered, accurate staging at baseline is imperative to maximize patient benefit and cost-effective use of health care resources. Although computed tomography (CT) remains a powerful tool for staging of lung cancer, advances in other imaging modalities, specifically positron emission tomography/CT and magnetic resonance imaging, can improve baseline staging over CT alone and can allow a more rapid and accurate assessment of response to treatment. Although noninvasive imaging is extremely useful, tissue diagnosis remains the criterion standard for staging lung cancer and monitoring treatment response. Accordingly, tissue sampling using advanced bronchoscopic imaging guidance, such as ultrasound or electromagnetic navigation, allows precise tissue location and sampling of mediastinal nodes or lung nodules in the least invasive manner. In the future, bronchoscopy may allow real-time microscopic analysis.

The relationship between 18F-FDG metabolic volumetric parameters and clinicopathological factors of breast cancer

OBJECTIVES

This study was conducted to evaluate the relationship between fluorine-18 fluorodeoxyglucose metabolic parameters [maximum standardized uptake value (SUV(max)), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)] and clinicopathological factors of breast cancer.

METHODS

The study comprised 93 patients. A volumetric region of interest was drawn over the abnormal focal uptake of breast cancer. Spearman's rank correlation, the Kruskal-Wallis test, and receiver operating characteristic analysis were used to investigate the relationship between clinicopathological factors and metabolic parameters and determine which metabolic parameters were most highly associated with clinicopathological factors.

RESULTS

All parameters had a statistically significant relationship with pathological T stage (p-T stage), pathological N status (p-N status), pathological stage (p-stage), and triple-negative type (TN) (all P values were <0.05). There were statistically significant differences between SUV(max) and TLG in relation to lymphatic invasion, estrogen receptor, and nuclear grade (P<0.05). High MTV showed a tendency toward association with estrogen receptor negativity, but the relation did not reach the level of statistical significance (P=0.056). No statistically significant relationship was observed between MTV and lymphatic invasion or nuclear grade. In the receiver operating characteristic analysis of p-T stage and p-stage, the AUC for TLG was significantly larger than that for SUV(max) (P=0.0003 and 0.048, respectively). There were marginally significant differences between TLG and MTV in relation to p-stage (P=0.058).

CONCLUSION

TLG may reflect tumor metabolism for clinicopathological factors of breast cancer better than SUV(max) or MTV.

The correlation between cell-free DNA and tumour burden was estimated by PET/CT in patients with advanced NSCLC

Background:

Cell-free DNA (cfDNA) circulating in the blood holds a possible prognostic value in malignant diseases. Under malignant conditions, the level of cfDNA increases but the biological mechanism remains to be fully understood. We aimed to examine the correlation between cfDNA and total tumour burden defined by positron emission tomography (PET) parameters.

Methods:

Patients with advanced non-small cell lung cancer (NSCLC) were enrolled into a prospective biomarker trial. Before treatment, plasma was extracted and the level of cfDNA was determined by qPCR. An ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/computed tomography (CT) scan was performed and evaluated in terms of metabolic tumour volume (MTV) and total lesion glycolysis (TLG). Tumour contours were delineated semi-automatically by a threshold standardised uptake value (SUV) of 2.5. The primary end point was correlation among cfDNA, MTV and TLG. The secondary end point was overall survival (OS) according to cfDNA, MTV and TLG.

Results:

Fifty-three patients were included. There were no correlations between cfDNA and MTV (r=0.1) or TLG (r=0.1). cfDNA >75th percentile was correlated with shorter OS (P=0.02), confirmed in a multivariate analysis. MTV>the median was associated with a significantly shorter OS (P=0.02). There was no significant difference in OS according to TLG (P=0.08).

Conclusion:

Cell-free DNA may not be a simple measure of tumour burden, but seems to reflect more complex mechanisms of tumour biology, making it attractive as an independent prognostic marker.

Prognostic significance of preoperative metabolic tumour volume and total lesion glycolysis measured by (18)F-FDG PET/CT in squamous cell carcinoma of the oral cavity

PURPOSE

Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) from (18)F-FDG PET/CT are emerging prognostic biomarkers in human solid cancers; yet few studies have investigated their clinical and prognostic significance in oral cavity squamous cell carcinoma (OSCC). The present retrospective study evaluated the utility of pretreatment MTV and TLG measured by (18)F-FDG PET/CT to predict survival and occult metastasis (OM) in OSCC.

METHODS

Of 162 patients with OSCC evaluated preoperatively by (18)F-FDG PET/CT, 105 who underwent definitive surgery with or without adjuvant therapy were eligible. Maximum standardized uptake value (SUVmax), MTV and TLG were measured. For calculation of MTV, 3-D regions of interest were drawn and a SUV threshold of 2.5 was used for defining regions. Univariate and multivariate analyses identified clinicopathological and imaging variables associated with OM, disease-free survival (DFS) and overall survival (OS).

RESULTS

The median (range) SUVmax, MTV and TLG were 7.3 (0.7-41.9), 4.5 ml (0.7-115.1 ml) and 18.3 g (2.4-224.1 g), respectively. Of 53 patients with clinically negative lymph nodes, OM was detected in 19 (36%). By univariate and multivariate analyses, MTV (P = 0.018) and TLG (P = 0.011) were both independent predictive factors for OM, although they were not independent of each other. The 4-year DFS and OS rates were 53.0% and 62.0%, respectively. Univariate and multivariate analyses revealed that MTV (P = 0.001) and TLG (P = 0.006), with different cut-off levels, were both independent predictive factors for DFS, although they were not independent of each other, and MTV (P = 0.001), TLG (P = 0.002) and the involved resection margin (P = 0.007) were independent predictive factors for OS.

CONCLUSION

Pretreatment MTV and TLG may be useful in stratifying the likelihood of survival and predicting OM in OSCC.

Incorporating prognostic imaging biomarkers into clinical practice

A prognostic imaging biomarker can be defined as an imaging characteristic that is objectively measurable and provides information on the likely outcome of the cancer disease in an untreated individual and should be distinguished from predictive imaging biomarkers and imaging markers of response. A range of tumour characteristics of potential prognostic value can be measured using a variety imaging modalities. However, none has currently been adopted into routine clinical practice. This article considers key examples of emerging prognostic imaging biomarkers and proposes an evaluation framework that aims to demonstrate clinical efficacy and so support their introduction into the clinical arena. With appropriate validation within an established evaluation framework, prognostic imaging biomarkers have the potential to contribute to individualized cancer care, in some cases reducing the financial burden of expensive cancer treatments by facilitating their more rational use.

Prediction for recurrence using F-18 FDG PET/CT in pathologic N0 lung adenocarcinoma after curative surgery

BACKGROUND

The aim of this study was to investigate risk factors for recurrence in patients with lung adenocarcinoma (LAD) who were pathologically N0 (pN0) after curative surgical resection.

METHODS

A total of 102 LAD patients (M/F = 55/47, mean age, 62.6 ± 9.4 years) diagnosed as pN0 after curative surgery were included in this study. Clinical, biochemical, radiologic, and pathologic findings were reviewed and analyzed for recurrence. Metabolic parameters [SUVmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG)] on pretreatment F-18 FDG PET/CT were also obtained and analyzed for recurrence.

RESULTS

Of 102 patients, 38 (37.3%) were found to experience recurrence for 33.6 ± 16.3 months. SUVmax, MTV, and TLG were significantly higher in patients with recurrence. The optimal cutoff values determined using a receiver-operating characteristic curve were 6.90 for SUVmax, 10.78 cm(3) for MTV, and 39.68 for TLG. Univariate analysis showed that tumor size, tumor marker, SUVmax, MTV, and TLG were prognostic factors for recurrence. In multivariate analyses, after adjusting for age, sex, tumor size, pathologic T stage, and tumor marker, high SUVmax, MTV, and TLG showed an association with an increased risk of recurrence.

CONCLUSIONS

Metabolic parameters on pretreatment F-18 FDG PET/CT can predict recurrence in pN0 LAD patients who underwent curative surgery. Therefore, patients with high metabolic parameters on PET can be considered as candidates for adjuvant therapy to reduce recurrence and should be monitored carefully for early detection of possible recurrence.

Prediction of survival by [18F]fluorodeoxyglucose positron emission tomography in patients with locally advanced non-small-cell lung cancer undergoing definitive chemoradiation therapy: results of the ACRIN 6668/RTOG 0235 trial

PURPOSE

In this prospective National Cancer Institute-funded American College of Radiology Imaging Network/Radiation Therapy Oncology Group cooperative group trial, we hypothesized that standardized uptake value (SUV) on post-treatment [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) correlates with survival in stage III non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients received conventional concurrent platinum-based chemoradiotherapy without surgery; postradiotherapy consolidation chemotherapy was allowed. Post-treatment FDG-PET was performed at approximately 14 weeks after radiotherapy. SUVs were analyzed both as peak SUV (SUVpeak) and maximum SUV (SUVmax; both institutional and central review readings), with institutional SUVpeak as the primary end point. Relationships between the continuous and categorical (cutoff) SUVs and survival were analyzed using Cox proportional hazards multivariate models.

RESULTS

Of 250 enrolled patients (226 were evaluable for pretreatment SUV), 173 patients were evaluable for post-treatment SUV analyses. The 2-year survival rate for the entire population was 42.5%. Pretreatment SUVpeak and SUVmax (mean, 10.3 and 13.1, respectively) were not associated with survival. Mean post-treatment SUVpeak and SUVmax were 3.2 and 4.0, respectively. Post-treatment SUVpeak was associated with survival in a continuous variable model (hazard ratio, 1.087; 95% CI, 1.014 to 1.166; P = .020). When analyzed as a prespecified binary value (≤ v > 3.5), there was no association with survival. However, in exploratory analyses, significant results for survival were found using an SUVpeak cutoff of 5.0 (P = .041) or 7.0 (P < .001). All results were similar when SUVmax was used in univariate and multivariate models in place of SUVpeak.

CONCLUSION

Higher post-treatment tumor SUV (SUVpeak or SUVmax) is associated with worse survival in stage III NSCLC, although a clear cutoff value for routine clinical use as a prognostic factor is uncertain at this time.

Prognostic value of quantitative fluorodeoxyglucose measurements in newly diagnosed metastatic breast cancer

The aim of this study was to determine the prognostic value of quantitative fluorodeoxyglucose (FDG) measurements (maximum standardized uptake value [SUVmax ], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) in patients with newly diagnosed metastatic breast cancer (MBC). An IRB-approved retrospective review was performed of patients who underwent FDG positron emission tomography (PET)/computed tomography (CT) from 1/02 to 12/08 within 60 days of diagnosis MBC. Patients with FDG-avid lesions without receiving chemotherapy in the prior 30 days were included. Target lesions in bone, lymph node (LN), liver, and lung were analyzed for SUVmax , MTV, and TLG. Medical records were reviewed for patient characteristics and overall survival (OS). Cox regression was used to test associations between quantitative FDG measurements and OS. A total of 253 patients were identified with disease in bone (n = 150), LN (n = 162), liver (n = 48), and lung (n = 66) at the time of metastatic diagnosis. Higher SUVmax tertile was associated with worse OS in bone metastases (highest vs. lowest tertile hazard ratio [HR] = 3.1, P < 0.01), but not in LN, liver or lung (all P > 0.1). Higher MTV tertile was associated with worse OS in LN (HR = 2.4, P < 0.01) and liver (HR = 3.0, P = 0.02) metastases, but not in bone (P = 0.22) or lung (P = 0.14). Higher TLG tertile was associated with worse OS in bone (HR = 2.2, P = 0.02), LN (HR = 2.3, P < 0.01), and liver (HR = 4.9, P < 0.01) metastases, but not in lung (P = 0.19). We conclude measures of FDG avidity are prognostic biomarkers in newly diagnosed MBC. SUVmax and TLG were both predictors of survival in breast cancer patients with bone metastases. TLG may be a more informative biomarker of OS than SUVmax for patients with LN and liver metastases.

FDG PET-CT aids in the preoperative assessment of patients with newly diagnosed thymic epithelial malignancies

INTRODUCTION

Advanced thymoma (stage III and IV) is difficult to detect by computed tomography (CT), yet it is important to distinguish between early (stage I and II) and advanced disease before surgery, as patients with locally advanced tumors require neoadjuvant chemotherapy to enable effective resection. This study assessed whether the amount of fluorodeoxyglucose (FDG) uptake can predict advanced thymoma and whether it can separate thymoma from thymic cancer.

METHODS

We retrospectively reviewed FDG positron emission tomography (PET)-CT scans of 51 consecutive newly diagnosed patients with thymic epithelial malignancy. PET-CT findings documented focal FDG activity: SUVmax, SUVmean, SUVpeak, and total body volumetric standardized uptake value (SUV) measurements. These were correlated with Masaoka-Koga staging and World Health Organization classification. Wilcoxon ranked sum tests were used to assess association between SUV and pathological stage, cancer type, and classification.

RESULTS

Among the study patients, 37 had thymoma, 12 thymic carcinoma, and 2 thymic carcinoid. Higher focal FDG uptake was seen in patients with type B3 thymoma than in those with type A, AB, B1, or B2 thymoma (p < 0.006). FDG uptake was higher in patients with thymic carcinoma or carcinoid than in patients with thymoma (p < 0.0003), with more variable associations with volumetric SUV measurements. There was no significant association observed between higher focal FDG uptake and advanced-stage disease in thymoma patients (p > 0.09), although greater FDG-avid tumor volume was significantly associated with advanced disease (p < 0.03).

CONCLUSIONS

Focal FDG uptake cannot predict advanced thymoma but is helpful in distinguishing thymoma from thymic carcinoma, or the more aggressive thymoma, type B3.

Volume-based assessment by (18)F-FDG PET/CT predicts survival in patients with stage III non-small-cell lung cancer

PURPOSE

We evaluated the prognostic impact of volume-based assessment by (18)F-FDG PET/CT in patients with stage III non-small-cell lung cancer (NSCLC).

METHODS

We reviewed 194 consecutive patients with stage IIIA NSCLC treated with surgical resection (surgical group) and 115 patients treated with nonsurgical therapy (nonsurgical group: 50 stage IIIA, 65 stage IIIB). Metabolic tumour volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) of primary tumours were measured using pretreatment (18)F-FDG PET/CT. Overall survival was assessed using the Kaplan-Meier method. The prognostic significance of PET parameters and other clinical variables was assessed using Cox proportional hazards regression analyses. To evaluate and compare the predictive performance of PET parameters, time-dependent receiver operating characteristic (ROC) curve analysis was used.

RESULTS

In the Cox proportional hazards models, MTV (HR=1.27 for a doubling of MTV, P=0.008) and TLG (HR=1.22 for a doubling of TLG, P=0.035) were significantly associated with an increased risk of death after adjusting for age, gender, histological cell type, T stage, N stage, and treatment variables in the surgical group. SUVmax was not a significant prognostic factor in either the surgical or nonsurgical group. In the time-dependent ROC curve analysis, volume-based PET parameters predicted survival better than SUVmax.

CONCLUSION

The volume-based PET parameters (MTV and TLG) are significant prognostic factors for survival independent of tumour stage and better prognostic imaging biomarkers than SUVmax in patients with stage IIIA NSCLC after surgical resection.

Initial metabolic tumor volume measured by 18F-FDG PET/CT can predict the outcome of osteosarcoma of the extremities

We evaluated the ability of metabolic and volumetric parameters measured by pretreatment (18)F-FDG PET/CT to predict the survival of patients with osteosarcoma of the extremities.

METHODS

The records of 83 patients with American Joint Committee on Cancer stage II extremity osteosarcoma treated with surgery and chemotherapy were retrospectively reviewed. Imaging parameters (maximum standardized uptake value, metabolic tumor volume [MTV], total lesion glycolysis, and tumor volume based on MR images) were measured before treatment, and histologic responses to neoadjuvant chemotherapy were assessed by examination of postsurgical specimens. Receiver-operating-characteristic curve analyses and the Cox proportional hazards model were used to analyze whether imaging and clinicopathologic parameters could predict metastasis-free survival.

RESULTS

Of the imaging parameters, MTV at the fixed standardized uptake value threshold of 2.0 (MTV(2.0)) most accurately predicted metastasis by receiver-operating-characteristic curve analysis (area under the curve = 0.679, P = 0.011). By multivariate analysis, MTV(2.0) > 105 mL (relative risk, 3.93; 95% confidence interval, 1.55-9.92) and poor response to neoadjuvant chemotherapy (relative risk, 4.83; 95% confidence interval, 1.64-14.21) independently shortened metastasis-free survival (P = 0.004 for both parameters). The stratification of patients by the combined criteria of MTV(2.0) and histologic response predicted outcome in more detail.

CONCLUSION

MTV is an independent predictor of metastasis in patients with osteosarcoma of the extremities. The combination of MTV and histologic response predicts survival more accurately than the chemotherapeutic response alone.

New positron emission tomography derived parameters as predictive factors for recurrence in resected stage I non-small cell lung cancer

BACKGROUND

The recurrence rate for stage I non-small cell lung cancer is high, with 20-40% of patients that relapse after surgery. The aim of this study was to evaluate new F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) derived parameters, such as standardized uptake value index (SUVindex), metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as predictive factors for recurrence in resected stage I non-small cell lung cancer.

METHODS

We retrospectively reviewed 99 resected stage I non-small cell lung cancer patients that were grouped by SUVindex, TLG and MTV above or below their median value. Disease free survival was evaluated as primary end point.

RESULTS

The 5-year overall survival and the 5-year disease free survival rates were 62% and 73%, respectively. The median SUVindex, MTL and TLG were 2.73, 2.95 and 9.61, respectively. Patients with low SUVindex, MTV and TLG were more likely to have smaller tumors (p ≤ 0.001). Univariate analysis demonstrated that SUVindex (p = 0.027), MTV (p = 0.014) and TLG (p = 0.006) were significantly related to recurrence showing a better predictive performance than SUVmax (p = 0.031). The 5-year disease free survival rates in patients with low and high SUVindex, MTV and TLG were 84% and 59%, 86% and 62% and 88% and 60%, respectively. The multivariate analysis showed that only TLG was an independent prognostic factor (p = 0.014) with a hazard ratio of 4.782.

CONCLUSION

Of the three PET-derived parameters evaluated, TLG seems to be the most accurate in stratifying surgically treated stage I non-small cell lung cancer patients according to their risk of recurrence.

18F-FDG PET early response evaluation of locally advanced non-small cell lung cancer treated with concomitant chemoradiotherapy

The potential of (18)F-FDG PET changes was evaluated for prediction of response to concomitant chemoradiotherapy in patients with locally advanced non-small cell lung cancer (NSCLC).

METHODS

For 28 patients, (18)F-FDG PET was performed before treatment, at the end of the second week of treatment, and at 2 wk and 3 mo after the completion of treatment. Standardized uptake value (SUV), maximum SUV, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained. Early metabolic changes were defined as fractional change (ΔTLG) when (18)F-FDG PET at the end of the second week was compared with pretreatment (18)F-FDG PET. In-treatment metabolic changes, as measured by serial (18)F-FDG PET, were correlated with standard criteria of response evaluation of solid tumors by means of CT imaging (Response Evaluation Criteria In Solid Tumors 1.1). Parameters were analyzed for stratification in progression-free survival (PFS).

RESULTS

When compared with early metabolic nonresponders, a ΔTLG decrease of 38% or more was associated with a significantly longer PFS (1-y PFS 80% vs. 36%, P = 0.02). Pretreatment TLG was found to be a prognostic factor for PFS.

CONCLUSION

The degree of change in TLG was predictive for response to concomitant chemoradiotherapy as early as the end of the second week into treatment for patients with locally advanced NSCLC. Pretreatment TLG was prognostic for PFS.