Emission Tomography Standardized Uptake Value Research Articles

Correlation of [18F]‐2‐fluoro‐deoxy‐D‐glucose positron emission tomography standard uptake values with the cellular composition of stage I nonsmall cell lung cancer

The aim of the current study was to determine whether the [18F]-2-fluoro-deoxy-D-glucose (FDG) positron emission tomography (PET) standardized uptake value (SUV) in patients with a new diagnosis of stage I lung cancer correlates with a specific cellular component in the primary tumor. This study was Health Insurance Portability and Accountability Act compliant and approved by our Institutional Review Board with a waiver of informed consent. Forty patients with stage I nonsmall cell lung cancer (NSCLC) who underwent FDG-PET imaging at the time of diagnosis followed by surgical resection were retrospectively identified. Histologic sections of the primary tumor were reviewed by a pathologist without any clinical data and scored according to the percentage of each cellular component (tumor cells, normal stroma, inflammatory cells, necrosis, fibrosis, and other). Each component was compared with maximal (SUV(max)) and mean (SUV(mean)) SUVs using Pearson correlation coefficient analysis. The mean SUV(max) and SUV(mean) values for 40 stage I NSCLC tumors were 8.8 and 5.4, respectively. The mean histologic composition of tumor specimens in order of frequency was as follows: tumor cells (38.9%), fibrosis (30.8%), inflammatory cells (14.8%), normal stroma (5.2%), necrosis (5.8%), and other components (4.5%); however, there was considerable variation noted among individual tumors. There was no statistically significant correlation between SUV(max) (r = .19; P = .24) or SUV(mean) (r = .017; P = .29) and the proportion of tumor cells in the tumor mass or any other cellular components. The cellular composition of stage I NSCLC appears to be highly variable, with no correlation noted between a specific tumor cellular component and FDG activity.

Predictive Value of Initial PET-SUVmax in Patients with Locally Advanced Esophageal and Gastroesophageal Junction Adenocarcinoma

We have previously shown that in early clinical stage esophageal adenocarcinoma, a positron emission tomography standardized uptake values (PET SUVmax) of <4.5 is associated with earlier pathologic stage and predicts better survival. In this study, we analyze the impact of the pretreatment PET SUVmax in patients with locally advanced esophageal adenocarcinoma who undergo preoperative chemoradiotherapy. We performed a retrospective analysis, selecting patients with adenocarcinoma of the esophagus who had a pretreatment PET scan and who received chemoradiotherapy before esophagectomy. Data recorded included demographics, PET SUVmax, treatment details, pathologic details, and survival data. Comparison of categorical variables was done by chi analysis, continuous variables by t test, survival analysis by the Kaplan-Meier method, and comparisons of survival using the log-rank test. Between January 1996 and September 2007, 189 patients were appropriate for this analysis. The initial PET SUVmax was <4.5 in 28 patients and >or=4.5 in 161 patients. The two groups were similar with regards to demographics and treatment details. Patients in the low SUV group were less likely to show evidence of treatment response after chemoradiotherapy, including a higher likelihood of residual nodal disease and a lower likelihood of a pathologic complete response and estimated treatment response. However, both groups had similar survival. Although the initial PET SUVmax does not predict survival in patients with locally advanced esophageal adenocarcinoma who receive preoperative chemoradiotherapy, patients with a high initial SUVmax respond better to preoperative therapy. These results can be used to better select esophageal cancer patients for combined modality treatment.

Preoperative [18F]-fluorodeoxyglucose positron emission tomography standardized uptake value of neck lymph nodes may aid in selecting patients with oral cavity squamous cell carcinoma for salvage therapy after relapse

Relapse of tumours in patients with oral cavity squamous cell carcinoma (OSCC) is associated with a dismal outcome. In this prospective study, we sought to investigate the clinical significance of the preoperative maximal standardized uptake value (SUVmax) at the neck lymph nodes in selecting patients with OSCC for salvage therapy after relapse. Between 2002 and 2007, 108 patients with early relapse of OSCC (n=75) or late relapse of OSCC (n=33) were identified. Salvage therapy was performed in 47 patients. All patients underwent 2-deoxy-2[(18)F]-fluoro-D: -glucose positron emission tomography during the 2 weeks before surgery and neck dissection. All patients were followed for 12 months or more after surgery or until death. The optimal cut-off value for the neck lymph node SUVmax (SUVnodal-max) was selected according to the 5-year disease-specific survival (DSS) rate. Independent risk factors were identified by Cox regression analysis. The mean follow-up for all patients was 20.3 months (41.1 months for surviving patients). In the early relapse group, several prognostic factors were identified in univariate and multivariate analyses, including a SUVnodal-max value of >or=4.2. A scoring system based on univariate analysis was formulated. Patients with a score of 0 had a better 5-year DSS than those with scores of 1 or higher (58% vs. 5%, p=0.0003). In patients with late relapse, a SUVnodal-max value of >or=4.2 had the highest prognostic value for predicting the 5-year DSS (45% vs. 0%, p=0.0005). Among patients with relapsed OSCC, the SUVnodal-max value may aid in selecting patients for salvage therapy.

Correlations between selected tumor markers and fluorodeoxyglucose maximal standardized uptake values in esophageal cancer☆

Esophageal cancer tumor biology is best assessed clinically by 2-[18F]fluoro-2-deoxy-d-glucose (FDG)-PET. Both FDG-PET maximal positron emission tomography (PET) standardized uptake values (SUVmax) and selected tumor markers have been shown to correlate with stage, nodal disease, and survival in esophageal cancer. Interestingly, there is limited data examining the relationship between FDG-PET SUVmax and expression of these tumor markers in esophageal cancer. The purpose of this study was to determine the correlation of tumor markers with FDG-PET SUVmax in esophageal cancer. FDG-PET SUVmax was calculated in 67 patients with esophageal cancer of which 59 (88%) had adenocarcinoma. Neoadjuvant radiotherapy and/or chemotherapy were administered to 42% (28/67) of patients. Esophageal tumor tissue and surrounding normal tissue was obtained and tissue microarrays were created. Immunohistochemical analysis was performed for five known esophageal cancer tumor markers (GLUT-1, p53, cyclin D1, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF)). Assessment of each tumor marker was made by two independent, blinded pathologists using common grading criteria of intensity and percentage of cells stained. A p value <0.05 was considered significant. There were 55 men (82%) and 12 women (18%) with a median age of 63 years (range 40-83). Pathologic staging included stage I (n=29, 43%), stage II (n=19, 28%), stage III disease (n=18, 27%), and stage IV disease (n=1, 2%). PET SUVmax correlated with T stage (p=0.001). In patients undergoing surgery without induction therapy, increasing SUVmax values correlated with increased expression of GLUT-1 transporter (p=0.01). There was no correlation between SUVmax and EGFR, cyclin D1, VEGF, or p53 expression in primary tumor. FDG-PET SUVmax correlates with an increased expression of GLUT-1 transporter in esophageal cancer specimens not subjected to induction therapy. No significant difference in tumor marker expression was noted between patients undergoing induction therapy or surgery alone except p53 expression decreased in primary tumors following induction therapy. Failure of SUVmax values to correlate with known prognostic esophageal cancer tumor markers suggests that FDG-PET may have limited clinical utility in assessing response to therapies targeting these markers.

Preoperative [18F]Fluorodeoxyglucose Positron Emission Tomography Standardized Uptake Value of Neck Lymph Nodes Predicts Neck Cancer Control and Survival Rates in Patients With Oral Cavity Squamous Cell Carcinoma and Pathologically Positive Lymph Nodes

Survival in oral cavity squamous cell carcinoma (OSCC) depends heavily on locoregional control. In this prospective study, we sought to investigate whether preoperative maximum standardized uptake value of the neck lymph nodes (SUVnodal-max) may predict prognosis in OSCC patients. A total of 120 OSCC patients with pathologically positive lymph nodes were investigated. All subjects underwent a [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) scan within 2 weeks before radical surgery and neck dissection. All patients were followed up for at least 24 months after surgery or until death. Postoperative adjuvant therapy was performed in the presence of pathologic risk factors. Optimal cutoff values of SUVnodal-max were chosen based on 5-year disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS). Independent prognosticators were identified by Cox regression analysis. The median follow-up for surviving patients was 41 months. The optimal cutoff value for SUVnodal-max was 5.7. Multivariate analyses identified the following independent predictors of poor outcome: SUVnodal-max >or=5.7 for the 5-year neck cancer control rate, distant metastatic rate, DFS, DSS, and extracapsular spread (ECS) for the 5-year DSS and OS. Among ECS patients, the presence of a SUVnodal-max >or=5.7 identified patients with the worst prognosis. A SUVnodal-max of 5.7, either alone or in combination with ECS, is an independent prognosticator for 5-year neck cancer control and survival rates in OSCC patients with pathologically positive lymph nodes.

Pretreatment FDG‐PET standardized uptake value as a prognostic factor for outcome in head and neck cancer

We studied the potential prognostic significance of pretreatment 18-fluorodeoxyglucose-positron emission tomography (FDG-PET) standardized uptake value (SUV) in squamous cell carcinoma of the head and neck (SCCHN). A retrospective review of the pretreatment FDG-PET scans of 60 patients with SCCHN was performed. All patients received radiotherapy and 37 also received concurrent chemotherapy. SUV was calculated by 2 nuclear-medicine physicians who were blinded to the clinical data. Disease-free survival (DFS) was analyzed with respect to SUV (and other potential prognostic factors). The median SUV was 7.2 (range, 1-24.7); 34 patients (57%) had SUV < 9.0 compared with 26 patients (43%) with an SUV > or = 9.0. The group with low SUV had significantly better 2-year DFS compared with the high SUV group (72% vs 37%), p = .007. On multivariate analysis, stage and age were also associated with DFS, but SUV remained an independent predictor of DFS (hazard ratio: 1.08; p = .016). SUV was significantly associated with outcome after modern definitive therapy of SCCHN.

Correlation of Positron Emission Tomography Standard Uptake Value and Pathologic Specimen Size in Cancer of the Head and Neck

To correlate positron emission tomography (PET) standard uptake value (SUV) with pathologic specimen size in patients with head-and-neck cancers. Eighteen patients with Stage II-IVB head-and-neck cancer with 27 tumors who underwent PET and computed tomography (CT) imaging of the head and neck followed by surgical resection were selected for this study. Various SUV thresholds were examined, including the software default (SUV(def)), narrowing the window by 1 standard deviation (SD) of the maximum (SUV-1SD), and SUV cutoff values of 2.5 or greater (SUV2.5) and 40% or greater maximum (SUV40). Volumetric pathologic data were available for 12 patients. Tumor volumes based on pathologic examination (gold standard), CT, SUV(def), SUV-1SD, SUV2.5, and SUV40 were analyzed. PET identified five tumors not seen on CT. The sensitivity of PET for identifying primary tumors was 94% (17 of 18). The Sensitivity of PET for staging the neck was 90% (9 of 10), whereas the specificity was 78% (7 of 9). The SUV2.5 method was most likely to overestimate tumor volume, whereas SUV(def) and SUV-1SD were most likely to underestimate tumor volume. The PET scan provides more accurate staging of primary tumors and nodal metastases for patients with advanced head-and-neck cancer than CT alone. Compared with the gold standard, significant variability exists in volumes obtained by using various SUV thresholds. A combination of clinical, CT, and PET data should continue to be used for optimal treatment planning. The SUV40 method appears to offer the best compromise between accuracy and reducing the risk of underestimating tumor extent.

Correlation of PET standard uptake value and CT window-level thresholds for target delineation in CT-based radiation treatment planning

To develop standardized correlates of [18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) standard uptake value (SUV) to computed tomography (CT)-based window and levels. Nineteen patients with non-small-cell lung cancer who underwent imaging with positron emission tomography (PET) and CT were selected. A method of standardizing SUV within CT planning software was developed. A scale factor, determined by a sensitivity calibration of the PET scanner, converts voxel counts to activity per gram in tissue, allowing SUVs to be correlated to CT window and levels. A method of limiting interobserver variations was devised to enhance "edges" of regions of interest based on SUV thresholds. The difference in gross tumor volumes (GTVs) based on CT, PET SUV >or= 2.5, and regions of 40% maximum SUV were analyzed. The mean SUV was 9.3. Mean GTV volumes were 253 cc for CT, 221 cc for SUV >or= 2.5, and 97 cc for SUV40%Max. Average volume difference was -259% between >or=2.5 SUV and CT and -162% between SUV40%Max and CT. Percent difference between GTV >or= 2.5 SUV and SUV40%Max remained constant beyond SUV > 7. For SUVs 4-6, best correlation among SUV thresholds occurred at volumes near 90 cc. Mean percent change from GTVs contoured according to CT (GTV CT) was -260% for GTV2.5 and -162% for GTV40%Max. Using the SUV40%Max threshold resulted in a significant alteration of volume in 98% of patients, while the SUV2.5 threshold resulted in an alteration of volume in 58% of patients. Our method of correlating SUV to W/L thresholds permits accurate displaying of SUV in coregistered PET/CT studies. The optimal SUV thresholds to contour GTV depend on maximum tumor SUV and volume. Best correlation occurs with SUVs >6 and small volumes <100 cc. At SUVs >7, differences between the SUV threshold filters remain constant. Because of variability in volumes obtained by using SUV40%Max, we recommend using SUV >or= 2.5 for radiotherapy planning in non-small-cell lung cancer.

The predictive value of baseline fluoro-deoxy-glucose positron emission tomography (FDG-PET) standardized uptake value (SUV) for overall survival in patients (pts) with locally advanced esophageal and gastroesophageal junction (GEJ) cancer

4062 Background: The predictive value of FDG-PET SUV in pts with esophageal and GEJ cancer has been subject of recent interest. The heterogeneity of disease stages and treatments made interpretation of reported data difficult.We evaluated the value of baseline FDG-PET SUV in a homogeneous patient (pt) population treated in a uniform fashion. Methods: Retrospective analysis of 71 pts with stages II-IVa esophageal and GEJ cancer treated on 2 phase 2 trials at the Cleveland Clinic Foundation. Data was collected on baseline pt and tumor characteristics, baseline SUV uptake, and outcomes. Results: All pts were treated with preoperative concurrent fluorouracil/cisplatin chemoradiotherapy (CRT); 69 pts proceeded to esophagectomy and 58 pts received additional postoperative adjuvant CRT. Median pt age was 60 (range 33–75) years, 86% were male, 89% had adenocarcinoma, 35%, 41% and 24% had stage II, III and IVa disease respectively. Pts have been followed for a median of 14 (range 3–50) months. All pts underwent a baseline FDG-PET scan with a mean primary site SUV of 8.9 (range 0–28.2). Pathological response (complete or partial) was achieved after induction CRT in 54% and was more likely in those with a baseline primary site SUV ≥ 7.3 (OR: 3.95, 1.43–10.9, P=0.008). Recurrence developed in 33 pts (46.5%) with distant metastases identified in 31 of these 33. The Kaplan-Meier 2-year projected overall survival for all 71 pts is 58% with a median of 31 months. Mortality was less in pts with baseline SUV ≥ 5.0 (HR: 0.44, 0.20–0.94, P = 0.033). After adjusting for clinical stage at diagnosis, tumor location and histology, baseline SUV ≥ 5 was still predictive of improved survival in multivariate analysis (HR: 0.35, 0.15–0.85, P = 0.02). Conclusions: In this retrospective analysis, esophageal and GEJ cancer pts with a higher baseline primary site SUV were more likely to respond to induction CRT and had better overall survival. This observation suggests that the subset of pts with more metabolically active tumor may derive greater benefit from multimodality treatments that include CRT. A prospectively designed trial would be required to confirm this hypothesis. No significant financial relationships to disclose.

Preoperative 18[F]-Fluorodeoxyglucose Positron Emission Tomography Standardized Uptake Values Predict Survival After Esophageal Adenocarcinoma Resection

Clinical staging modalities for esophageal cancer are inaccurate at determining prognosis, especially in early-stage patients. We performed a retrospective review of patients with esophageal adenocarcinoma imaged by positron emission tomography before surgical resection to determine whether 18[F]-fluorodeoxyglucose uptake predicted overall survival independently of clinical and pathologic stage. The study is a retrospective review of patients with adenocarcinoma of the esophagus treated by surgery. All patients were imaged with computed tomography and positron emission tomography imaging, and most patients had an endoscopic ultrasound. We compared positron emission tomography standardized uptake values (SUVmax) with clinical and pathologic stage and survival. Prognostic variables were assessed by log-rank test, and survival by the method of Kaplan and Meier. From January 1996 through June 2004, 50 patients meeting study eligibility criteria were analyzed. Median follow-up for surviving patients was 27 months. The median SUVmax was 4.5. Stratification of patients by the median SUVmax predicted survival. The 3-year survival was 57% for patients with an SUVmax greater than 4.5 and 95% for patients with an SUVmax of 4.5 or less (p = 0.02). The survival advantage of the SUVmax 4.5 or less group was also seen in clinically early-stage patients (defined as no adenopathy on computed tomography and positron emission tomography, and by endoscopic ultrasound T1-2 N0), as well as in patients with pathologically early-stage disease (T-2 N0). In surgically managed esophageal adenocarcinoma patients, SUVmax predicts overall survival. Moreover, SUVmax identifies patients who have a poor prognosis from a subset of patients that would otherwise be considered to have early-stage disease.

Standardized Uptake Value and Influx

Useful characterizing parameters have been derived from historical positron emission tomography (PET) standardized uptake values (SUV) and influx constants K. Meta-analysis was performed on 30 multipatient PET oncological studies providing same patient SUVs and K’s. Averaged results for fluorine-18 fluorodeoxyglucose (FDG) and l-methionine respectively were: SUV vs. K correlation coefficients = 0.89 and 0.80; SUV/K ratios = 192 and 63 minutes as average tracer clearance times T in these populations. For cancers, coefficients of variation (CV) for K’s were 0.61 and 0.46, notably larger than the CVs (0.50 and 0.40) for SUVs. A Monte Carlo simulation model, matching these results, represents 1/T as (an effective tracer clearance rate) × (its initial distribution volume). We conclude that T is a characteristic tracer clearance time that is independent of cancer type. A measurement model is introduced that might help improve protocols. The higher CVs of K’s vs. SUVs is worth noting clinically when seeking an effective diagnostic marker. Also, SUV conversions to K can provide some quality assurance in K measurements.