18F-FDG metabolic tumor volume and total glycolytic activity of oral cavity and oropharyngeal squamous cell cancer: adding value to clinical staging

Increased expression of the long non-coding RNA UCA1 in tongue squamous cell carcinomas: a possible correlation with cancer metastasis

OBJECTIVE

The aim of this study was to examine the expression of several cancer-related long non-coding RNAs (lncRNAs) in patients with tongue squamous cell carcinoma (TSCC) and to explore its clinical significance.

STUDY DESIGN

A total of 94 TSCC tissue specimens and matched adjacent normal tissue specimens were collected from patients undergoing surgery for TSCC. Differences in the expression of cancer-related lncRNAs were examined via quantitative reverse transcriptase polymerase chain reaction. WST-1 assay and transwell migration assay were carried out to estimate the proliferation and migration abilities of TSCC cells with different expression levels of urothelial cancer-associated 1 (UCA1) lncRNA.

RESULTS

The expression levels of lncRNA UCA1 were significantly elevated in TSCC tissues (P < .0001) and were statistically correlated with lymph node metastasis (P = .0371). Over-expression of UCA1 lncRNA could promote metastatic but not proliferation ability of TSCC cells.

CONCLUSIONS

Expression of UCA1 lncRNA was enhanced in TSCCs and may play a role in tumor metastasis.

PET/CT in the management of thyroid cancers

OBJECTIVE

Thyroid cancer is the most common endocrine cancer. This review evaluates the established use of (18)F-FDG PET/CT in papillary, follicular, Hürthle cell, anaplastic, and medullary thyroid cancers. The significance of incidental diffuse and focal thyroid FDG uptake is discussed. The evolving value of non-FDG radiotracers, including (124)I, (18)F-dihydroxyphenylalanine, and (68)Ga somatostatin analogs, is summarized.

CONCLUSION

PET/CT is a valuable imaging test, in the appropriate clinical context, for the management of thyroid cancers.

Volumetric PET/CT parameters predict local response of head and neck squamous cell carcinoma to chemoradiotherapy

It is not well established whether pretreatment ¹⁸F-FDG PET/CT can predict local response of head and neck squamous cell carcinoma (HNSCC) to chemoradiotherapy (CRT). We examined 118 patients: 11 with nasopharyngeal cancer (NPC), 30 with oropharyngeal cancer (OPC), and 77 with laryngohypopharyngeal cancer (LHC) who had completed CRT. PET/CT parameters of primary tumor, including metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum and mean standardized uptake value (SUV_max and SUV_mean), were correlated with local response, according to primary site and human papillomavirus (HPV) status. Receiver-operating characteristic analyses were made to access predictive values of the PET/CT parameters, while logistic regression analyses were used to identify independent predictors. Area under the curve (AUC) of the PET/CT parameters ranged from 0.53 to 0.63 in NPC and from 0.50 to 0.54 in OPC. HPV-negative OPC showed AUC ranging from 0.51 to 0.58, while all of HPV-positive OPCs showed complete response. In contrast, AUC ranged from 0.71 to 0.90 in LHC. Moreover, AUCs of MTV and TLG were significantly higher than those of SUV_max and SUV_mean (P < 0.01). After multivariate analysis, high MTV >25.0 mL and high TLG >144.8 g remained as independent, significant predictors of incomplete response compared with low MTV (odds ratio [OR], 13.4; 95% confidence interval [CI], 2.5–72.9; P = 0.003) and low TLG (OR, 12.8; 95% CI, 2.4–67.9; P = 0.003), respectively. In conclusion, predictive efficacy of pretreatment ¹⁸F-FDG PET/CT varies with different primary sites and chosen parameters. Local response of LHC is highly predictable by volume-based PET/CT parameters.

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.

Asphericity of pretherapeutic tumour FDG uptake provides independent prognostic value in head-and-neck cancer

OBJECTIVE

To propose a novel measure, namely the 'asphericity' (ASP), of spatial irregularity of FDG uptake in the primary tumour as a prognostic marker in head-and-neck cancer.

METHODS

PET/CT was performed in 52 patients (first presentation, n = 36; recurrence, n = 16). The primary tumour was segmented based on thresholding at the volume-reproducible intensity threshold after subtraction of the local background. ASP was used to characterise the deviation of the tumour's shape from sphere symmetry. Tumour stage, tumour localisation, lymph node metastases, distant metastases, SUVmax, SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were also considered. The association of overall (OAS) and progression-free survival (PFS) with these parameters was analysed.

RESULTS

Cox regression revealed high SUVmax [hazard ratio (HR) = 4.4/7.4], MTV (HR = 4.6/5.7), TLG (HR = 4.8/8.9) and ASP (HR = 7.8/7.4) as significant predictors with respect to PFS/OAS in case of first tumour manifestation. The combination of high MTV and ASP showed very high HRs of 22.7 for PFS and 13.2 for OAS. In case of recurrence, MTV (HR = 3.7) and the combination of MTV/ASP (HR = 4.2) were significant predictors of PFS.

CONCLUSIONS

ASP of pretherapeutic FDG uptake in the primary tumour improves the prediction of tumour progression in head-and-neck cancer at first tumour presentation.

KEY POINTS

Asphericity (ASP) characterises the spatial heterogeneity of FDG uptake in tumours. ASP is a promising prognostic parameter in head-and-neck cancer. ASP is useful for identification of high-risk patients with head-and-neck cancer.

Head and neck PET/CT: therapy response interpretation criteria (Hopkins Criteria)-interreader reliability, accuracy, and survival outcomes

There has been no established qualitative system of interpretation for therapy response assessment using PET/CT for head and neck cancers. The objective of this study was to validate the Hopkins interpretation system to assess therapy response and survival outcome in head and neck squamous cell cancer patients (HNSCC).

METHODS

The study included 214 biopsy-proven HNSCC patients who underwent a posttherapy PET/CT study, between 5 and 24 wk after completion of treatment. The median follow-up was 27 mo. PET/CT studies were interpreted by 3 nuclear medicine physicians, independently. The studies were scored using a qualitative 5-point scale, for the primary tumor, for the right and left neck, and for overall assessment. Scores 1, 2, and 3 were considered negative for tumors, and scores 4 and 5 were considered positive for tumors. The Cohen κ coefficient (κ) was calculated to measure interreader agreement. Overall survival (OS) and progression-free survival (PFS) were analyzed by Kaplan-Meier plots with a Mantel-Cox log-rank test and Gehan Breslow Wilcoxon test for comparisons.

RESULTS

Of the 214 patients, 175 were men and 39 were women. There was 85.98%, 95.33%, 93.46%, and 87.38% agreement between the readers for overall, left neck, right neck, and primary tumor site response scores, respectively. The corresponding κ coefficients for interreader agreement between readers were, 0.69-0.79, 0.68-0.83, 0.69-0.87, and 0.79-0.86 for overall, left neck, right neck, and primary tumor site response, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the therapy assessment were 68.1%, 92.2%, 71.1%, 91.1%, and 86.9%, respectively. Cox multivariate regression analysis showed human papillomavirus (HPV) status and PET/CT interpretation were the only factors associated with PFS and OS. Among the HPV-positive patients (n = 123), there was a significant difference in PFS (hazard ratio [HR], 0.14; 95% confidence interval, 0.03-0.57; P = 0.0063) and OS (HR, 0.01; 95% confidence interval, 0.00-0.13; P = 0.0006) between the patients who had a score negative for residual tumor versus positive for residual tumor. A similar significant difference was observed in PFS and OS for all patients. There was also a significant difference in the PFS of patients with PET-avid residual disease in one site versus multiple sites in the neck (HR, 0.23; log-rank P = 0.004).

CONCLUSION

The Hopkins 5-point qualitative therapy response interpretation criteria for head and neck PET/CT has substantial interreader agreement and excellent negative predictive value and predicts OS and PFS in patients with HPV-positive HNSCC.

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 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.

Metabolic response to preoperative chemotherapy predicts prognosis for patients undergoing surgical resection of colorectal cancer metastatic to the liver

BACKGROUND

Biological characteristics of colorectal cancer liver metastases (CRCLM) are increasingly recognized as major determinants of patient outcome. The purpose of this study was to evaluate the prognostic value of metabolic response to preoperative chemotherapy as quantified by (18)F-FDG positron emission tomography (PET) for patients undergoing liver resection of CRCLM.

METHODS

All patients (n = 80) who had staging PET before liver resection for CRCLM at Austin Health in Melbourne between 2004 and 2011 were included. Thirty-seven patients had PET and CT imaging before and after preoperative chemotherapy. Semiquantitative PET parameters-maximum standardized uptake variable (SUVmax), metabolic tumour volume (MTV), and total glycolytic volume (TGV)-were derived. Metabolic response was determined by the proportional change in PET parameters (∆SUVmax, ∆MTV, ∆TGV). Prognostic scores, CT RECIST response, and tumour regression grading (TRG) were also assessed. Correlation to recurrence-free (RFS) and overall survival (OS) was assessed using Kaplan-Meier survival and multivariate analysis.

RESULTS

Semiquantitative parameters on staging PET before chemotherapy were not predictive of prognosis, whereas all parameters after chemotherapy were prognostic for RFS and OS. Only ∆SUVmax was predictive of RFS and OS on multivariate analysis. Patients with metabolically responsive tumours had an OS of 86 % at 3 years vs. 38 % with nonresponsive or progressive tumours (p = 0.003). RECIST and TRG did not predict outcome.

CONCLUSIONS

Tumour metabolic response to preoperative chemotherapy as quantified by PET is predictive of prognosis in patients undergoing resection of CRCLM. Assessing metabolic response uniquely characterizes tumour biology, which may allow future optimization of patient and treatment selection.

Fluorodeoxyglucose uptake in laryngeal carcinoma is associated with the expression of glucose transporter-1 and hypoxia-inducible-factor-1α and the phosphoinositide 3-kinase/protein kinase B pathway

High fluorodeoxyglucose (FDG) uptake by human carcinomas, including head and neck cancers, is associated with a poor prognosis. Glucose transporter-1 (Glut-1) is believed to be an intrinsic marker of hypoxia in malignant tumors. The expression of hypoxia-inducible factor-1α (HIF-1α) and correlated target genes, including Glut-1, is regulated by the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway. However, it remains unclear whether the PI3K/Akt signaling pathway is involved in regulating FDG uptake directly. In the present study, 24 consecutive patients with laryngeal carcinoma were examined pre-operatively and the standardized uptake values (SUV) of the laryngeal carcinomas were determined. Glut-1, HIF-1α, PI3K and phosphorylated-Akt (p-Akt) expression was detected by immunohistochemical staining of paraffin sections from the tumor specimens. Associations among SUV_max, Glut-1, HIF-1α, PI3K and p-Akt protein expression and the other clinical parameters were analyzed. The univariate analyses revealed a significantly shorter survival time along with higher HIF-1α (P=0.018) and PI3K (P=0.008) expression, but the survival time was not significantly correlated with Glut-1 or p-Akt expression. The multivariate analysis demonstrated that higher SUV_max (P=0.043) and PI3K expression (P=0.012) were significantly correlated with a poor survival time. Spearman’s rank analysis showed significant correlations between SUV_max and HIF-1α (r=0.577; P=0.003), PI3K (r=1.0; P<0.0001) and p-Akt (r=0.577; P=0.003) expression. PI3K was associated with poorly- and moderately-differentiated laryngeal carcinoma (P=0.012). In conclusion, a high SUV_max indicates a poor prognosis for laryngeal carcinoma. Also, a high SUV_max may be associated with the increased expression of Glut-1, HIF-1α, PI3K and p-Akt.

Diagnostic value of metabolic tumor volume assessed by 18F-FDG PET/CT added to SUVmax for characterization of thyroid 18F-FDG incidentaloma

BACKGROUND

The objective of the study was to investigate whether metabolic tumor volume (MTV) measured by fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (PET/CT) after stratification of serum thyroid stimulating hormone (TSH) levels could predict malignancy in patients with thyroid F-FDG incidentaloma.

MATERIALS AND METHODS

A total 262 patients with focal thyroid F-FDG incidentaloma undergoing cancer evaluation for nonthyroid cancer or a health checkup were enrolled in this study. We retrospectively evaluated the relationship of the maximum standardized uptake value (SUVmax) and MTV in the prediction of malignant thyroid F-FDG incidentaloma.

RESULTS

The prevalence of malignancy was 20.9% (37/177). Malignant thyroid incidentaloma had a statistically significant higher value of SUVmax (malignant: median 4.6, range 1.9-34.9; benign: median 4.1, range 0-28; P=0.030). The value of MTV4 in malignant thyroid incidentaloma was significantly higher than that of benign thyroid incidentaloma (malignant: median 0.16, range 0.02-1.19; benign: median 0.10, range 0-0.65; P=0.032). However, the values of MTV3.5, MTV3, and MTV2.5 did not differ significantly between the groups. After stratification of serum TSH levels (an SUVmax>5 was used as the cutoff point) the sensitivity and specificity for prediction of malignancy were found to be 61.1% [95% confidence interval (CI): 35.7-82.7%] and 68.7% (95% CI: 56.2-79.4%), respectively. The area under the curve (AUC) was 0.655 (95% CI: 0.545-0.755; P=0.0239). When MTV4 greater than 0.07 cm was used as the cutoff point, the sensitivity and specificity for prediction of malignancy were 81.2% (95% CI: 54.4-96.0%) and 50.0% (95% CI: 37.0-63.0%), respectively. The AUC was 0.650 (95% CI: 0.534-0.755; P=0.0451). On comparison receiver operating characteristic curve analysis, no significant difference was found between SUVmax and MTV4 in the prediction of thyroid carcinoma (P=0.4346). However, a combination of SUVmax and MTV4 resulted in an AUC of 0.669 (95% CI: 0.554-0.772; P=0.0183).

CONCLUSION

The SUVmax and MTV4 measured by F-FDG PET/CT after stratification of serum TSH levels could predict thyroid cancer in patients with thyroid F-FDG incidentaloma. A combination of SUVmax and MTV4 may be more useful for the differentiation of malignant from benign thyroid incidentaloma.

Semiautomatic methods for segmentation of the proliferative tumour volume on sequential FLT PET/CT images in head and neck carcinomas and their relation to clinical outcome

PURPOSE

Radiotherapy of head and neck cancer induces changes in tumour cell proliferation during treatment, which can be depicted by the PET tracer (18)F-fluorothymidine (FLT). In this study, three advanced semiautomatic PET segmentation methods for delineation of the proliferative tumour volume (PV) before and during (chemo)radiotherapy were compared and related to clinical outcome.

METHODS

The study group comprised 46 patients with 48 squamous cell carcinomas of the head and neck, treated with accelerated (chemo)radiotherapy, who underwent FLT PET/CT prior to treatment and in the 2nd and 4th week of therapy. Primary gross tumour volumes were visually delineated on CT images (GTV CT). PVs were visually determined on all PET scans (PV VIS). The following semiautomatic segmentation methods were applied to sequential PET scans: background-subtracted relative-threshold level (PV RTL), a gradient-based method using the watershed transform algorithm and hierarchical clustering analysis (PV W&C), and a fuzzy locally adaptive Bayesian algorithm (PV FLAB).

RESULTS

Pretreatment PV VIS correlated best with PV FLAB and GTV CT. Correlations with PV RTL and PV W&C were weaker although statistically significant. During treatment, the PV VIS, PV W&C and PV FLAB significant decreased over time with the steepest decline over time for PV FLAB. Among these advanced segmentation methods, PV FLAB was the most robust in segmenting volumes in the third scan (67 % of tumours as compared to 40 % for PV W&C and 27 % for PV RTL). A decrease in PV FLAB above the median between the pretreatment scan and the scan obtained in the 4th week was associated with better disease-free survival (4 years 90 % versus 53 %).

CONCLUSION

In patients with head and neck cancer, FLAB proved to be the best performing method for segmentation of the PV on repeat FLT PET/CT scans during (chemo)radiotherapy. This may potentially facilitate radiation dose adaptation to changing PV.

FDG PET/CT in Crohn's disease: correlation of quantitative FDG PET/CT parameters with clinical and endoscopic surrogate markers of disease activity

PURPOSE

The aim of this study was to determine the feasibility and potential clinical utility of assessment of Crohn's disease (CD) activity by (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT employing a new quantitative approach.

METHODS

A total of 22 subjects (mean age 37) with CD who had undergone FDG PET/CT followed by ileocolonoscopy within 1 week were included in this analysis. The CD endoscopy index of severity (CDEIS) for various bowel segments was calculated. The CD activity index (CDAI) was evaluated, and fecal calprotectin was measured. On PET, regions with increased FDG uptake in large bowel were segmented with an adaptive contrast-oriented thresholding algorithm, and metabolically active volume (MAV), uncorrected mean standardized uptake value (SUV(mean)), partial volume-corrected SUV(mean) (PVC-SUV(mean)), SUV(max), uncorrected total lesion glycolysis (TLG = MAV × SUV(mean)), and PVC total lesion glycolysis (PVC-TLG = MAV × PVC-SUV(mean)) were measured. Global CD activity score (GCDAS) was calculated as the sum of PVC-TLG over all clinically significant FDG-avid regions in each subject. Correlations between regional PET quantification measures (SUVs, TLGs) and CDEIS were calculated. Correlations between the global PET quantification measure (GCDAS, global SUVs) with CDAI, fecal calprotectin, CDEIS, and CRP level were also calculated.

RESULTS

SUV(max), PVC-SUV(mean), and PVC-TLG significantly correlated with segment CDEIS subscores (r = 0.50, r = 0.69, and r = 0.31, respectively; p < 0.05). GCDAS significantly correlated with CDAI and fecal calprotectin (r = 0.64 and r = 0.51, respectively; p < 0.05).

CONCLUSION

By employing this new quantitative approach, we were able to calculate indices of regional and global CD activity, which correlated well with both clinical and pathological disease activity surrogate markers. This approach may be of clinical importance in measuring both global disease activity and treatment response in patients with CD.

Dose escalation to high-risk sub-volumes based on non-invasive imaging of hypoxia and glycolytic activity in canine solid tumors: a feasibility study

INTRODUCTION

Glycolytic activity and hypoxia are associated with poor prognosis and radiation resistance. Including both the tumor uptake of 2-deoxy-2-[18 F]-fluorodeoxyglucose (FDG) and the proposed hypoxia tracer copper(II)diacetyl-bis(N4)-methylsemithio-carbazone (Cu-ATSM) in targeted therapy planning may therefore lead to improved tumor control. In this study we analyzed the overlap between sub-volumes of FDG and hypoxia assessed by the uptake of 64Cu-ATSM in canine solid tumors, and evaluated the possibilities for dose redistribution within the gross tumor volume (GTV).

MATERIALS AND METHODS

Positron emission tomography/computed tomography (PET/CT) scans of five spontaneous canine solid tumors were included. FDG-PET/CT was obtained at day 1, 64Cu-ATSM at day 2 and 3 (3 and 24 h pi.). GTV was delineated and CT images were co-registered. Sub-volumes for 3 h and 24 h 64Cu-ATSM (Cu3 and Cu24) were defined by a threshold based method. FDG sub-volumes were delineated at 40% (FDG40) and 50% (FDG50) of SUVmax. The size of sub-volumes, intersection and biological target volume (BTV) were measured in a treatment planning software. By varying the average dose prescription to the tumor from 66 to 85 Gy, the possible dose boost (DB) was calculated for the three scenarios that the optimal target for the boost was one, the union or the intersection of the FDG and 64Cu-ATSM sub-volumes.

RESULTS

The potential boost volumes represented a fairly large fraction of the total GTV: Cu3 49.8% (26.8-72.5%), Cu24 28.1% (2.4-54.3%), FDG40 45.2% (10.1-75.2%), and FDG50 32.5% (2.6-68.1%). A BTV including the union (∪) of Cu3 and FDG would involve boosting to a larger fraction of the GTV, in the case of Cu3∪FDG40 63.5% (51.8-83.8) and Cu3∪FDG50 48.1% (43.7-80.8). The union allowed only a very limited DB whereas the intersection allowed a substantial dose escalation.

CONCLUSIONS

FDG and 64Cu-ATSM sub-volumes were only partly overlapping, suggesting that the tracers offer complementing information on tumor physiology. Targeting the combined PET positive volume (BTV) for dose escalation within the GTV results in a limited DB. This suggests a more refined dose redistribution based on a weighted combination of the PET tracers in order to obtain an improved tumor control.

Molecular PET imaging for biology-guided adaptive radiotherapy of head and neck cancer

Integration of molecular imaging PET techniques into therapy selection strategies and radiation treatment planning for head and neck squamous cell carcinoma (HNSCC) can serve several purposes. First, pre-treatment assessments can steer decisions about radiotherapy modifications or combinations with other modalities. Second, biology-based objective functions can be introduced to the radiation treatment planning process by co-registration of molecular imaging with planning computed tomography (CT) scans. Thus, customized heterogeneous dose distributions can be generated with escalated doses to tumor areas where radiotherapy resistance mechanisms are most prevalent. Third, monitoring of temporal and spatial variations in these radiotherapy resistance mechanisms early during the course of treatment can discriminate responders from non-responders. With such information available shortly after the start of treatment, modifications can be implemented or the radiation treatment plan can be adapted tailing the biological response pattern. Currently, these strategies are in various phases of clinical testing, mostly in single-center studies. Further validation in multicenter set-up is needed. Ultimately, this should result in availability for routine clinical practice requiring stable production and accessibility of tracers, reproducibility and standardization of imaging and analysis methods, as well as general availability of knowledge and expertise. Small studies employing adaptive radiotherapy based on functional dynamics and early response mechanisms demonstrate promising results. In this context, we focus this review on the widely used PET tracer (18)F-FDG and PET tracers depicting hypoxia and proliferation; two well-known radiation resistance mechanisms.

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.

The role of PET/CT in the management of cervical cancer

OBJECTIVE. Cervical cancer is the second most common malignancy in women worldwide and the third most common cause of cancer mortality in the United States. The aim of this article is to describe cervical cancer and outline the value of (18)F-FDG PET/CT in the management of cervical malignancy. CONCLUSION. The value of PET/CT has been found in staging and treatment strategy for cervical cancer. FDG PET/CT facilitates decision-making and radiation treatment planning and provides important information about treatment response, disease recurrence, and long-term survival.

Textural features of pretreatment 18F-FDG PET/CT images: prognostic significance in patients with advanced T-stage oropharyngeal squamous cell carcinoma

Previous studies have shown that total lesion glycolysis (TLG) may serve as a prognostic indicator in oropharyngeal squamous cell carcinoma (OPSCC). We sought to investigate whether the textural features of pretreatment (18)F-FDG PET/CT images can provide any additional prognostic information over TLG and clinical staging in patients with advanced T-stage OPSCC.

METHODS

We retrospectively analyzed the pretreatment (18)F-FDG PET/CT images of 70 patients with advanced T-stage OPSCC who had completed concurrent chemoradiotherapy, bioradiotherapy, or radiotherapy with curative intent. All of the patients had data on human papillomavirus (HPV) infection and were followed up for at least 24 mo or until death. A standardized uptake value (SUV) of 2.5 was taken as a cutoff for tumor boundary. The textural features of pretreatment (18)F-FDG PET/CT images were extracted from histogram analysis (SUV variance and SUV entropy), normalized gray-level cooccurrence matrix (uniformity, entropy, dissimilarity, contrast, homogeneity, inverse different moment, and correlation), and neighborhood gray-tone difference matrix (coarseness, contrast, busyness, complexity, and strength). Receiver-operating-characteristic curves were used to identify the optimal cutoff values for the textural features and TLG.

RESULTS

Thirteen patients were HPV-positive. Multivariate Cox regression analysis showed that age, tumor TLG, and uniformity were independently associated with progression-free survival (PFS) and disease-specific survival (DSS). TLG, uniformity, and HPV positivity were significantly associated with overall survival (OS). A prognostic scoring system based on TLG and uniformity was derived. Patients who presented with TLG > 121.9 g and uniformity ≤ 0.138 experienced significantly worse PFS, DSS, and OS rates than those without (P < 0.001, < 0.001, and 0.002, respectively). Patients with TLG > 121.9 g or uniformity ≤ 0.138 were further divided according to age, and different PFS and DSS were observed.

CONCLUSION

Uniformity extracted from the normalized gray-level cooccurrence matrix represents an independent prognostic predictor in patients with advanced T-stage OPSCC. A scoring system was developed and may serve as a risk-stratification strategy for guiding therapy.

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.

An automated algorithm to identify and quantify brown adipose tissue in human 18F-FDG-PET/CT scans

OBJECTIVE

To develop an algorithm to identify and quantify BAT from PET/CT scans without radiologist interpretation.

DESIGN AND METHODS

Cases (n = 17) were randomly selected from PET/CT scans with documented "brown fat" by the reviewing radiologist. Controls (n = 18) had no documented "brown fat" and were matched with cases for age (49.7 [31.0-63.0] vs. 52.4 [24.0-70.0] yrs), outdoor temperature at scan date (51.8 [38.9-77.0] vs. 54.9 [35.2-74.6] °F), sex (F/M: 15/2 cases; 16/2 controls) and BMI (28.2 [20.0-45.7] vs. 26.8 [21.4-37.1] kg/m(2) ]). PET/CT scans and algorithm-generated images were read by the same radiologist blinded to scan identity. Regions examined included neck, mediastinum, supraclavicular fossae, axilla and paraspinal soft tissues. BAT was scored 0 for no BAT; 1 for faint uptake possibly compatible with BAT or unknown; and 2 for BAT positive.

RESULTS

Agreement between the algorithm and PET/CT scan readings was 85.7% across all regions. The algorithm had a low false negative (1.6%) and higher false positive rate (12.7%). The false positive rate was greater in mediastinum, axilla and neck regions.

CONCLUSION

The algorithm's low false negative rate combined with further refinement will yield a useful tool for efficient BAT identification in a rapidly growing field particularly as it applies to obesity.

Head and neck squamous cell cancer (stages III and IV) induction chemotherapy assessment: value of FDG volumetric imaging parameters

INTRODUCTION

To evaluate whether the change in the metabolic tumour volume (MTV) or total lesion glycolysis (TLG) of the primary tumour, before and after induction chemotherapy, predicts outcome for patients with advanced head and neck squamous cell cancer (SCC).

METHODS

Twenty-eight patients with advanced (American Joint Committee on Cancer stage III and IV) head and neck SCC who underwent positron emission tomography (PET)/CT were included in this retrospective study. Primary tumour MTV and TLG were measured using gradient and fixed percentage threshold segmentations. Outcome endpoint was disease progression or mortality. Pearson correlation, Bland-Altman and receiver operator characteristic analysis were performed.

RESULTS

The Pearson's correlation coefficients between percentage changes (pre- and post-induction chemotherapy) from gradient MTV (MTVG) and the 38% SUVmax threshold MTV (MTV38) was 0.96 and between MTVG and the 50% threshold MTV (MTV50) was 0.95 (P < 0.0001). The corresponding Pearson r between TLGG and TLG38 was 0.94 and between TLGG and TLG50 was 0.96 (P < 0.0001). The least bias was 1.89% (standard deviation = 25.30%) between the percentage changes of MTVG and MTV50. The areas under the curve for predicting progression or mortality were 0.76 (P = 0.03) for MTVG and 0.82 for TLGG (P = 0.009). Optimum cut points of a 42% reduction in MTVG and a 55% reduction in the TLGG predict event-free survival with a sensitivity of 62.5% and a specificity of 90% and a hazards ratio of 6.25.

CONCLUSION

A reduction in primary tumour MTV of at least 42% or in TLG of at least 55% after induction chemotherapy may predict event-free survival in patients with advanced head and neck SCC.

Evolving role of FDG PET/CT in multiple myeloma imaging and management

OBJECTIVE

Multiple myeloma is the most common cause of primary malignancy in bones. Radiography has been the imaging reference standard for decades. However, the growing use of CT, MRI, and PET technology has led to earlier diagnosis of multiple myeloma, more accurate therapy assessment, and better prediction of patient outcome. This article is focused on the evolving role of (18)F-FDG PET/CT in multiple myeloma diagnosis, therapy assessment, and prognosis.

CONCLUSION

FDG PET/CT is a valuable imaging modality in diagnosis, therapy assessment, and prognosis of multiple myeloma.

PET-based primary tumor volumetric parameters and survival of patients with non-small cell lung carcinoma

OBJECTIVE

The purpose of the study was to assess metabolic tumor volume and total glycolytic activity of the primary tumor as prognostic parameters for outcome in patients with non-small cell lung carcinoma (NSCLC).

MATERIALS AND METHODS

Thirty-nine patients who had undergone a baseline staging PET/CT examination at our institution for the diagnosis of NSCLC were retrospectively identified. The maximum standardized uptake value (SUV(max)), metabolic tumor volume, and total glycolytic activity were segmented from PET using the gradient method; 12-month survival and overall survival at the end of follow-up were used as outcome measures. Multivariate logistic regression, receiver operating characteristic curve analysis, and Kaplan-Meier curves for survival analysis were generated and compared using the Mantel-Cox log-rank test.

RESULTS

The mean gradient-based metabolic tumor volume and gradient-based total glycolytic activity were significantly greater in the patients who died (93.3 mL and 597.5 g) than in those who survived (19.3 mL and 193.9 g, respectively) (p < 0.003 and p < 0.031). There was no statistically significant difference in the mean SUV(max) between the patients who survived (12.7) at 12 months and those who had died (13.1) (p = 0.85). On multivariate analysis, gradient-based metabolic tumor volume was the only variable associated with 12-month mortality when adjusted for all other factors.(.) The area under the curve (AUC) for gradient-based metabolic tumor volume was 0.77 (p < 0.006). A significant difference in the time to survival was observed between high and low gradient-based metabolic tumor volume (log-rank p < 0.05) cohorts using the median gradient-based metabolic tumor volume (9.7 mL) as the cut point.

CONCLUSION

PET-based volumetric imaging parameters are potential prognostic markers of outcome in patients with NSCLC.

Metabolic tumor volume predicts disease progression and survival in patients with squamous cell carcinoma of the anal canal

PET imaging has become a useful diagnostic tool in patients with anal cancer. We evaluated the prognostic value of metabolic tumor volume (MTV) in patients with anal cancer treated with definitive chemoradiotherapy.

METHODS

Patients with anal cancer who underwent PET imaging for pretreatment staging or radiation therapy planning from 2003 to 2011 were included. PET parameters included MTV and maximum standardized uptake value (SUVmax). Total MTV (MTV-T) was defined as the sum of the volumes above a standardized uptake value 50% of the SUVmax within the primary tumor and involved nodes. Kaplan-Meier and Cox regression models were used to test for associations between metabolic or clinical endpoints and overall survival (OS), progression-free survival (PFS), and event-free survival (EFS).

RESULTS

Thirty-nine patients were included. Median follow-up for the cohort was 22 mo. Overall, 6 patients died and 9 patients had disease progression. The 2-y OS, PFS, and EFS for the entire cohort were 88%, 74%, and 69%, respectively. Higher MTV-T was associated with worse OS (P = 0.04), PFS (P = 0.004), and EFS (P = 0.002) on univariate analysis. Patients with an MTV greater than 26 cm(3) had worse PFS than did those with an MTV of 26 cm(3) or less (33% vs. 82%, P = 0.003). SUVmax was not prognostic for any outcome. Higher T classification (T3/T4 vs. T1/T2) was associated with worse PFS and EFS. When adjusting for T classification, MTV-T remained a significant predictor for PFS (P = 0.01) and EFS (P = 0.02).

CONCLUSION

MTV-T yields prognostic information on PFS and EFS beyond that of established prognostic factors in patients with anal cancer.

FDG-PET/CT imaging biomarkers in head and neck squamous cell carcinoma

This article discusses the value of ¹⁸F-fluoro-2-deoxyglucose PET/CT imaging biomarkers in head and neck squamous cell carcinoma. ¹⁸F-fluoro-2-deoxyglucose PET/CT is valuable at baseline staging, radiotherapy planning, therapy response assessment and in the follow-up of patients with head and neck squamous cell carcinoma. Maximum and peak standardized uptake value (SUV_max and SUV_peak), metabolic tumor volume and total lesion glycolysis are the common ¹⁸F-fluoro-2-deoxyglucose quantitative parameters that have been studied, along with qualitative assessments. These parameters will be evaluated with respect to their established or potential role as noninvasive biomarkers for patient risk stratification, treatment response and survival outcome.

Predictive and prognostic value of metabolic tumour volume and total lesion glycolysis in solid tumours

Data available in patients suffering from squamous cell carcinoma of the head and neck, lung carcinoma, oesophageal carcinoma and gynaecological malignancies suggest that metabolic tumour volume and to a lesser extent total lesion glycolysis have the potential to become valuable in the imaging of human solid tumours as prognostic biomarkers for short- to intermediate-term survival outcomes, adding value to clinical staging, for assessment of response to treatment with neoadjuvant and concurrent chemotherapy, and for treatment optimization; for example, based on early treatment response assessment using changes in metabolic tumour volume over time, it might be possible to select patients who require a more aggressive treatment to improve their outcome. Prospective studies enrolling consecutive patients, adopting standardized protocols for FDG PET acquisition and processing, adjusting for potential confounders in the analysis (tumour size and origin) and determining the optimal methodology for determination of these novel markers are mandatory.

Metabolic Tumor Volume Measured by F-18 FDG PET/CT can Further Stratify the Prognosis of Patients with Stage IV Non-Small Cell Lung Cancer

PURPOSE

This study aimed to further stratify prognostic factors in patients with stage IV non-small cell lung cancer (NSCLC) by measuring their metabolic tumor volume (MTV) using F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT).

MATERIALS AND METHODS

The subjects of this retrospective study were 57 patients with stage IV NSCLC. MTV, total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured on F-18 FDG PET/CT in both the primary lung lesion as well as metastatic lesions in torso. Optimal cutoff values of PET parameters were measured by receiver operating characteristic (ROC) curve analysis. Kaplan-Meier survival curves were used for evaluation of progression-free survival (PFS). The univariate and multivariate Cox proportional hazards models were used to select the significant prognostic factors.

RESULTS

Univariate analysis showed that both MTV and TLG of primary lung lesion (MTV-lung and TLG-lung) were significant factors for prediction of PFS (P < 0.001, P = 0.038, respectively). Patients showing lower values of MTV-lung and TLG-lung than the cutoff values had significantly longer mean PFS than those with higher values. Hazard ratios (95 % confidence interval) of MTV-lung and TLG-lung measured by univariate analysis were 6.4 (2.5-16.3) and 2.4 (1.0-5.5), respectively. Multivariate analysis revealed that MTV-lung was the only significant factor for prediction of prognosis. Hazard ratio was 13.5 (1.6-111.1, P = 0.016).

CONCLUSION

Patients with stage IV NSCLC could be further stratified into subgroups of significantly better and worse prognosis by MTV of primary lung lesion.

Intra-reader reliability of FDG PET volumetric tumor parameters: effects of primary tumor size and segmentation methods

OBJECTIVE

To establish the effects of size and segmentation methods on intra-reader reliability of primary tumor metabolic tumor volume (MTV) and total glycolytic activity (TGA) in human solid tumors.

METHODS

This is a retrospective study of 121 patients who had a baseline FDG PET/CT scan for oncologic staging. Volumetric parameter readings were performed in random order on two separate occasions, 12 weeks apart, by the same reader. The MTV and TGA were segmented using gradient and fixed maximum standardized uptake value (SUVmax) threshold methods. Intra-reader reliability was established by the intraclass correlation coefficient (ICC) and Bland-Altman analysis.

RESULTS

The biases for MTV were 2.95, 14.76 and 11.13% for gradient segmentation, 38 and 50% SUVmax fixed threshold segmentations, respectively (p < 0.0001). For TGA, the corresponding biases were 0.76, 10.36 and 7.46% (p < 0.0001). There were no statistically significant differences in the biases between the first and second reads for MTV segmented for small and large volume tumors by the gradient method (p < 0.34) or 50% SUVmax threshold segmentation (p < 0.08). However, there were statistically significant differences in the corresponding biases for the 38% SUVmax threshold segmentation (p < 0.04). There were no statistically significant differences in the biases between the first and second reads for TGA segmented for small and large volume tumors (p < 0.98).

CONCLUSION

Intra-reader reliability for primary tumor FDG MTV and TGA is affected by the tumor size and segmentation methods. The segmentation bias was smaller for gradient method than percentage fixed threshold method for MTV. The segmentation biases were smaller for TGA than MTV.

Superior prognostic utility of gross and metabolic tumor volume compared to standardized uptake value using PET/CT in head and neck squamous cell carcinoma patients treated with intensity-modulated radiotherapy

OBJECTIVE

To compare the prognostic utility of the 2-[(18)F] fluoro-2-deoxy-D: -glucose (FDG) maximum standardized uptake value (SUV(max)), primary gross tumor volume (GTV), and FDG metabolic tumor volume (MTV) for disease control and survival in patients with head and neck squamous cell carcinoma (HNSCC) undergoing intensity-modulated radiotherapy (IMRT).

METHODS

Between 2007 and 2011, 41 HNSCC patients who underwent a staging positron emission tomography with computed tomography and definitive IMRT were identified. Local (LC), nodal (NC), distant (DC), and overall (OC) control, overall survival (OS), and disease-free survival (DFS) were assessed using the Kaplan-Meier product-limit method.

RESULTS

With a median follow-up of 24.2 months (range 2.7-56.3 months) local, nodal, and distant recurrences were recorded in 10, 5, and 7 patients, respectively. The median SUV(max), GTV, and MTV were 15.8, 22.2 cc, and 7.2 cc, respectively. SUV(max) did not correlate with LC (p = 0.229) and OS (p = 0.661) when analyzed by median threshold. Patients with smaller GTVs (<22.2 cc) demonstrated improved 2-year actuarial LC rates of 100 versus 56.4 % (p = 0.001) and OS rates of 94.4 versus 65.9 % (p = 0.045). Similarly, a smaller MTV (<7.2 cc) correlated with improved 2-year actuarial LC rates of 100 versus 54.2 % (p < 0.001) and OS rates of 94.7 versus 64.2 % (p = 0.04). Smaller GTV and MTV correlated with improved NC, DC, OC, and DFS, as well.

CONCLUSION

GTV and MTV demonstrate superior prognostic utility as compared to SUV(max), with larger tumor volumes correlating with inferior local control and overall survival in HNSCC patients treated with definitive IMRT.