FDG-PET. A possible prognostic factor in head and neck cancer

Influence of pathological nodal status and maximal standardized uptake value of the primary tumor and regional lymph nodes on treatment plans in patients with advanced oral cavity squamous cell carcinoma

PURPOSE

A better understanding of the prognostic factors in oral cavity squamous cell carcinoma (OSCC) may optimize the therapeutic approach. In this study, we sought to investigate whether the combination of clinical information, pathologic results, and preoperative maximal standardized uptake value (SUVmax) at the primary tumor and regional lymph nodes might improve the prognostic stratification in this patient group.

METHODS AND MATERIALS

A total of 347 consecutive OSCC patients were investigated. All participants underwent fluorodeoxyglucose-positron emission tomography within 2 weeks before surgery and neck dissection. The duration of follow-up was at least 24 months in all surviving patients. The optimal cutoff values for SUVmax at the primary tumor (SUVtumor-max) and regional lymph nodes (SUVnodal-max) were selected according to the 5-year disease-free survival (DFS) rate. Independent prognosticators were identified by Cox regression analysis.

RESULTS

In multivariate analysis, a cutoff SUVtumor-max of 8.6, a cutoff SUVnodal-max of 5.7, and the presence of pathologic lymph node metastases were found to be significant prognosticators for the 5-year DFS. A scoring system using these three prognostic factors was formulated to define distinct prognostic groups. The 5-year rates for patients with a score between 0 and 3 were as follows: neck control, 94%, 86%, 77%, 59% (p < 0.0001); distant metastases, 1%, 7%, 22%, 47% (p < 0.0001); disease-specific survival, 93%, 85%, 61%, 36%, respectively (p < 0.0001).

CONCLUSION

Based on the study findings, the combined evaluation of pathologic node status and SUVmax at the primary tumor and regional lymph nodes may improve prognostic stratification in OSCC patients.

Glucose deprivation-induced metabolic oxidative stress and cancer therapy

Cancer cells (vs. normal cells) demonstrate evidence of oxidative stress, increased glycolysis, and increased pentose cycle activity. The oxidative stress in cancer cells has been hypothesized to arise from mitochondrial dysfunction leading to increased levels of hydroperoxides, and cancer cells have been proposed to compensate for this defect by increasing glucose metabolism. Glucose metabolism has also been shown to play a role in hydroperoxide detoxification via the formation of pyruvate (from glycolysis) and NADPH (from the pentose cycle). Furthermore, in cancer cells, glucose deprivation as well as treatment with 2-deoxyglucose (2 DG) has been shown to induce oxidative stress and cytotoxicity. Additionally, transformed cells have been shown to be more susceptible to glucose deprivation (and 2DG-)-induced cytotoxicity and oxidative stress than untransformed cells. These results support the hypothesis that cancer cells have a defect in mitochondrial respiration leading to increased steady state levels of O2*- and H2O2, and glucose metabolism is increased to compensate for this defect. The application of these findings to developing cancer therapies using 2DG combined with inhibitors of hydroperoxide metabolism to induce radio/chemosensitization is discussed, as well as the possibility that FDG-PET imaging may predict tumor responses to these therapies.

Prospective imaging assessment of mortality risk after head-and-neck radiotherapy

PURPOSE

The optimal roles for imaging-based biomarkers in the management of head-and-neck cancer remain undefined. Unresolved questions include whether functional or anatomic imaging might improve mortality risk assessment for this disease. We addressed these issues in a prospective institutional trial.

METHODS AND MATERIALS

Ninety-eight patients with locally advanced pharyngolaryngeal squamous cell cancer were enrolled. Each underwent pre- and post-chemoradiotherapy contrast-enhanced computed tomography (CT) and (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT imaging. Imaging parameters were correlated with survival outcomes.

RESULTS

Low post-radiation primary tumor FDG avidity correlated with improved survival on multivariate analysis; so too did complete primary tumor response by CT alone. Although both imaging modalities lacked sensitivity, each had high specificity and negative predictive value for disease-specific mortality risk assessment. Kaplan-Meier estimates confirmed that both CT and FDG-PET/CT stratify patients into distinct high- and low-probability survivorship groups on the basis of primary tumor response to radiotherapy. Subset analyses demonstrated that the prognostic value for each imaging modality was primarily derived from patients at high risk for local treatment failure (human papillomavirus [HPV]-negative disease, nonoropharyngeal primary disease, or tobacco use).

CONCLUSIONS

CT alone and FDG-PET/CT are potentially useful tools in head-and-neck cancer-specific mortality risk assessment after radiotherapy, particularly for selective use in cases of high-risk HPV-unrelated disease. Focus should be placed on corroboration and refinement of patient selection for imaging-based biomarkers in future studies.

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

Among patients with relapsed OSCC, the SUVnodal-max value may aid in selecting patients for salvage therapy.

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

BACKGROUND

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).

METHODS

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).

RESULTS

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).

CONCLUSION

SUV was significantly associated with outcome after modern definitive therapy of SCCHN.

Prognostic value of 18F-FDG PET in patients with head and neck squamous cell cancer

OBJECTIVE

This study was designed to assess whether tumor uptake of (18)F-FDG (FDG) expressed as the standardized uptake value (SUV) can be used to predict survival in patients with head and neck cancer. Furthermore, a prognostic maximum SUV was determined with univariate and bivariate analyses.

CONCLUSION

Low SUVs (</= 7.0) predicted significantly higher rates of 2-year local control (p = 0.0067) and disease-free survival (p = 0.0051) as compared with high SUVs (> 7.0). In the Cox proportional hazards model, tumor SUV was a significant and independent predictor of local control (p = 0.022) and disease-free survival (p = 0.019). In addition, in the group of high SUV, high T stage was more associated with poorer outcome than low T stage (p = 0.0502). Therefore, patients with higher tumor FDG uptake should be considered for a more aggressive treatment approach.

In vitro and in vivo study of phloretin-induced apoptosis in human liver cancer cells involving inhibition of type II glucose transporter

Phloretin (Ph), a natural product found in apples and pears with glucose transporter (GLUT) inhibitory activity, exerts antitumor effects. However, little is known about its effects on human liver cancer. The purpose of this study is to test the cytotoxic effects of Ph on HepG2 cells and to identify the underlying molecular pathways. Human hepatocellular carcinoma specimens and HepG2 show a high level of GLUT2 transporter activity in the cell membrane. Real-time PCR and MTT assays demonstrate that Ph-induced cytotoxicity correlates with the expression of GLUT2. Flow cytometry and DNA fragmentation studies show that 200 microM Ph induces apoptosis in HepG2, which was reversed by glucose pretreatment. GLUT2 siRNA knockdown induced HepG2 apoptosis, which was not reversed by glucose. Western blot analysis demonstrates that both intrinsic and extrinsic apoptotic pathways in addition to Akt and Bcl-2 family signaling pathways are involved in Ph-induced cell death in HepG2 cells. Furthermore, using flow cytometry analysis, a mitochondrial membrane potential assay and Western blot analysis, we show that cytochalasin B, a glucose transport inhibitor, enhances the Ph-induced apoptotic effect on HepG2 cells, which was reversed by pretreatment with glucose. Furthermore, we found significant antitumor effects in vivo by administering Ph at 10 mg/kg intraperitoneally to severe combined immune deficiency mice carrying a HepG2 xenograft. A microPET study in the HepG2 tumor-bearing mice showed a 10-fold decrease in (18)F-FDG uptake in Ph-treated tumors compared to controls. Taken together, these results suggest that Ph-induced apoptosis in HepG2 cells involves inhibition of GLUT2 glucose transport mechanisms.

Comparison of cisplatin sensitivity and the 18F fluoro-2-deoxy 2 glucose uptake with proliferation parameters and gene expression in squamous cell carcinoma cell lines of the head and neck

Background

The survival of patients with locally advanced head and neck cancer is still poor, with 5-year survival rates of 24–35%. The identification of prognostic and predictive markers at the molecular and cellular level could make it possible to find new therapeutic targets and provide "taylor made" treatments. Established cell lines of human squamous cell carcinoma (HNSCC) are valuable models for identifying such markers.

The aim of this study was to establish and characterize a series of cell lines and to compare the cisplatin sensitivity and 18F fluoro-2 deoxy 2 glucose (18F-FDG) uptake of these cell lines with other cellular characteristics, such as proliferation parameters and TP53 and CCND1 status.

Methods

Explant cultures of fresh tumour tissue were cultivated, and six new permanent cell lines were established from 18 HNSCC cases. Successfully grown cell lines were analysed regarding clinical parameters, histological grade, karyotype, DNA ploidy, and index and S-phase fraction (Spf). The cell lines were further characterized with regard to their uptake of 18F-FDG, their sensitivity to cisplatin, as measured by a viability test (crystal violet), and their TP53 and CCND1 status, by fluorescence in situ hybridization (FISH), polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) with DNA sequencing and, for cyclin D1, by immunohistochemistry.

Results

Patients with tumours that could be cultured in vitro had shorter disease-free periods and overall survival time than those whose tumours did not grow in vitro, when analysed with the Kaplan-Meier method and the log-rank test. Their tumours also showed more complex karyotypes than tumours from which cell lines could not be established. No correlation was found between TP53 or CCND1 status and 18F-FDG uptake or cisplatin sensitivity. However, there was an inverse correlation between tumour cell doubling time and 18F-FDG uptake.

Conclusion

In vitro growth of HNSCC cells seem to be an independent prognostic factor, with cell lines being more readily established from aggressive tumours, a phenomenon more dependent on the molecular genetic characteristics of the tumour cells than on tumour location or TNM status.

Biologically conformal treatment: biomarkers and functional imaging in radiation oncology

'Conformal radiation therapy' is the standard of care in radiation oncology, referring to the process of shaping the radiation beam to precisely match a tumor's physical dimensions. We describe 'biologically conformal radiotherapy', in which the radiation oncologist matches the prescribed treatment to a tumor's biological characteristics and the host's predicted tolerance of radiation. This paradigm emphasizes that not all tumors are equally sensitive to radiation; conversely, some patients are especially susceptible to radiation's side effects. Patients bearing radioresistant tumors or those prone to toxicity may be best treated with the incorporation of targeted radiation modulators or, in extreme cases, by a different modality. The biological characteristics of tumors can be assessed by a wide range of techniques: functional imaging (positron emission tomography and advanced magnetic resonance imaging), single gene/protein molecular techniques and 'omic' technologies. This paper reviews the latest advances in the use of biomarkers and functional imaging in guiding patients to receive the most appropriate treatment.

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

PURPOSE

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.

METHODS AND MATERIALS

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.

RESULTS

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.

CONCLUSION

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.

FDG-PET predicts survival and distant metastasis in oral squamous cell carcinoma

High [(18)F]-2-fluorodeoxyglucose (FDG)-uptake of primary tumor, assessed by pretreatment positron emission tomography (PET), shows poor overall survival of patients after several therapies in various cancers. An association between FDG-uptake and distant metastasis-free survival in oral squamous cell carcinoma (OSCC) has not been assessed so far. An objective of this study is to investigate an association between FDG-uptake and overall survival of OSCC patients, and to ask whether FDG-uptake is related with distant metastasis-free survival in OSCC. Twenty-four patients who underwent both pretreatment FDG-PET and radical surgery without preoperative therapy were enrolled. We used the maximum standardized uptake value (SUVmax) as FDG-uptake. Overall survival, locoregional recurrence-free survival and distant metastasis-free survival were analyzed by Kaplan-Meier method. In univariate survival analysis, patients with SUVmax>or=12 exhibited significance in both shorter 3-year overall survival (p<0.01) and distant metastasis-free survival (p<0.04) than patients with SUVmax<12. Moreover, by Cox proportional hazards model of multivariate analysis, SUVmax>or=12 was found to be independent of clinical T and N categories, and exhibited significance in both shorter 3-year overall survival (p<0.02) and distant metastasis- free survival (p<0.05) than patients with SUVmax<12. These results suggest that pretreatment FDG-PET is able to provide both non-invasive and effective information for identifying a high- or low-risk group of OSCC patients with distant metastasis.

Predictive and prognostic value of FDG-PET

The predictive and prognostic value of fluorodeoxyglucose (FDG)-positron emission tomography (PET) in non-small-cell lung carcinoma, colorectal carcinoma and lymphoma is discussed. The degree of FDG uptake is of prognostic value at initial presentation, after induction treatment prior to resection and in the case of relapse of non-small cell lung cancer (NSCLC). In locally advanced and advanced stages of NSCLC, FDG-PET has been shown to be predictive for clinical outcome at an early stage of treatment. In colorectal carcinoma, limited studies are available on the prognostic value of FDG-PET, however, the technique appears to have great potential in monitoring the success of local ablative therapies soon after intervention and in the prediction and evaluation of response to radiotherapy, systemic therapy, and combinations thereof. The prognostic value of end-of treatment FDG-PET for FDG-avid lymphomas has been established, and the next step is to define how to use this information to optimize patient outcome. In Hodgkin's lymphoma, FDG-PET has a high negative predictive value, however, histological confirmation of positive findings should be sought where possible. For non-Hodgkin's lymphoma, the opposite applies. The newly published standardized guidelines for interpretation formulates specific criteria for visual interpretation and for defining PET positivity in the liver, spleen, lung, bone marrow and small residual lesions. The introduction of these guidelines should reduce variability among studies. Interim PET offers a reliable method for early prediction of long-term remission, however it should only be performed in prospective randomized controlled trials. Many of the diagnostic and management questions considered in this review are relevant to other tumour types. Further research in this field is of great importance, since it may lead to a change in the therapeutic concept of cancer. The preliminary findings call for systematic inclusion of FDG-PET in therapeutic trials to adequately position FDG-PET in treatment time lines.

Role of FDG-PET in the assessment of survival prognosis in melanoma

Positron-emission tomography (PET) employing fluorodeoxyglucose (FDG) has proven to be a highly sensitive and specific diagnostic method in the staging and restaging of various neoplasms, including melanoma, complementing morphologic imaging. FDG uptake has been correlated with proliferation rate, and thus, the degree of malignancy of a given tumor (i.e., grading). Consecutively, a relationship of survival prognosis and the extent of tumor burden as well as degree of FDG accumulation--determined by FDG-PET--has been suggested in various tumors. The aim of this study was to assess the potential of fluor-18-FDG-PET in order to evaluate the survival prognosis in melanoma. Patient data (n=95) were retrospectively analyzed, and the results of functional FDG-PET staging was correlated with survival data. Time of staging (diagnosis of primary versus recurrence) had no statistically significant effect on survival prognosis when patients were matched for pertaining node metastasis (NM) stages. Differences in survival were owing to the presence of metastatic disease rather than time of staging. Tumor (T)-stage (T1-T4) alone had no effect on survival prognosis when patients were matched for NM stages. Differences in survival were also due to higher rates of lymph node (LN) and organ metastases in higher T-stages. Detection of LN metastases (N1M0) had a statistically significant and predominant impact on 5-year survival (N0M0 80% versus N1M0 45%; p<0.01). Additional presence of distant metastases in LN-positive patients (N1M1) had only a statistically insignificant further impact on survival (5-year survival in N1M0 45% versus N1M1 29%; p>0.05). Exclusive presence of organ metastases (N0M1) showed a statistically significant drop of survival with a 5-year survival of 61% in N0M1 versus 80% in N0M0, respectively (p<0.03). Further, the combined presence of LN and distant metastases had the worst prognosis (5-year survival in N1M1 29% versus N0M1 61%; p<0.02). Based on a qualitative 4-point scoring system, patients with malignancy-typical FDG uptake showed an overall 5-year survival of 38%, as compared to patients with malignancy-suspicious lesions (71%; p <or= 0.02) or patients without evidence of disease (80%; p<0.001). When PET and computed tomography (CT) findings were compared, survival was best in patients with both studies (CT and PET) being negative (5-year survival, 83%), worst when PET and CT were positive (5-year survival, 61%; p<0.02), and showed an intermediate survival when PET was positive, but with CT still negative (5-year survival, 73%). In patients staged by FDG-PET, significant risk factors--as identified by univariate und multivariate analyses--were (i) malignancy-typical FDG uptake, (ii) detection of LN, and (iii) organ metastases. In conclusion, FDG-PET offers valid prognostic information, demonstrating a good relationship of functional TNM-stage and actual survival prognosis. The results obtained in one PET study seem to be as suitable as the combined results of conventional staging, including clinical and morphologic (e.g., CT) methods and clinical follow-up. FDG-PET was more accurate in tumor detection and seemed to detect tumor spread earlier, as compared to CT.

Integrated PET/CT system for staging and surveillance of skull base tumors

BACKGROUND

The utility of preoperative and postoperative whole body integrated positron emission tomography-computed tomography (PET-CT) scanning for staging and follow-up in patients with skull base tumors is undetermined.

METHODS

We prospectively evaluated PET-CT findings in 47 patients using 57 scans. Most (35/47, 75%) had anterior skull base tumors and the majority (74%) had advanced-stage (III-IV) disease.

RESULTS

The scans showed high sensitivity for detection of various types of malignant tumors and provided 39 items of additional information, changing the clinical staging and management of 11 patients (23%). Recurrence of primary tumors was detected in 8 patients, positive regional (neck) metastases in 3, and distant metastases in 3. The positive uptake was due to osteoradionecrosis in 2 other patients. The sensitivity of PET-CT was 0.77 and the specificity was 0.81 (0.83 positive predictive value and 0.76 negative predictive value).

CONCLUSIONS

PET-CT provides accurate data on anatomy, tumor staging, and early disease recurrence in the skull base.

Expression of glucose transporter-1, hexokinase-II, proliferating cell nuclear antigen and survival of patients with pancreatic cancer

OBJECTIVES

18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) has been shown to be useful in diagnosis and staging of pancreatic cancer. However, the prognostic value of FDG-PET remains controversial. The aim of this study was to evaluate relations between the factors suggested to be related to the FDG accumulation in tumor tissue, such as glucose transporter-1 (GLUT-1), hexokinase type-II (HK-II), proliferating cell nuclear antigen (PCNA), and survival of pancreatic cancer patients.

METHODS

Histological specimen of pancreatic cancer obtained from seventy-four consecutive patients were evaluated for the expression of GLUT-1, HK-II, and PCNA by visual analysis of immunohistochemical staining of paraffin sections from the tumor specimens using anti-GLUT-1, anti-HK-II, and anti-PCNA antibody, respectively. The percentages of cells strongly expressing GLUT-1, HK-II and PCNA were scored on a 5-point scale (1 = 0-20 percent, 2 = 20-40 percent, 3 = 40-60 percent, 4 = 60-80 percent, 5 = 80-100 percent). After initial treatment, each patient was followed-up and survival time was recorded. Median survival curves of the patients with different levels of GLUT-1, HK-II, and PCNA expression were evaluated using the Kaplan-Meier method. Statistical significance of the differences in survival was calculated with the log rank test.

RESULTS

Median survival of examined patients showed no relation with the levels of GLUT-1 expression, while patients with low expression of HK-II (HK-II index < 3) had significantly shorter survival than those with higher expression of HK-II (HK-II index >/= 3) (6.5 +/- 4.1 versus 12.9 +/- 22.4 months, respectively, p < 0.05). Median survival of examined patients also showed significant relations with the levels of PCNA expression. Patients with low expression of PCNA (PCNA index < 4) had significantly longer survival than those with higher expression of PCNA (PCNA index >/= 4) (11.9 +/- 20.1 versus, 5.8 +/- 10.8 months, respectively, p < 0.01):

CONCLUSIONS

Our results showed that the expression of GLUT-1 had no prognostic value in the examined patients with pancreatic cancer. On the other hand, high levels of HK-II expression and low levels of PCNA expression may allow accurate identification of the patient with longer survival who may benefit from intensive anticancer treatment.

Detection of local residual tumor after laryngeal cancer treatment using FDG-PET

OBJECTIVE

Fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is sometimes used as a means of follow-up after diagnosis and treatment of cancers of the head and neck region. The present study was undertaken to evaluate the ability of FDG-PET to detect local residual tumor after treatment of laryngeal cancer.

METHODS

Thirty-six patients with laryngeal cancer underwent FDG-PET before and after initial treatment. Of these patients, 20 received FDG-PET before treatment and 28 received it after treatment. The relationship between standardized uptake values (SUV) and the presence or absence of local residual tumor was investigated by setting the cut-off value of the SUV using the receiver operating characteristics (ROC) curve.

RESULTS

When the pre-treatment SUV threshold for laryngeal cancer was set at 7.20, the detection of local residual tumor after treatment using FDG-PET had a sensitivity of 77.78%, specificity of 81.82%, false positive rate of 18.18%, false negative rate of 22.22%, accuracy of 80% and a p value of 0.02. When the post-treatment SUV threshold for the larynx was set at 3.35, the test had a sensitivity of 93.75%, specificity of 91.67%, false positive rate of 8.33%, false negative rate of 6.25%, accuracy of 92.86% and a p value of 0.0001.

CONCLUSIONS

FDG-PET was found to be useful for determining the presence of local residual tumor after treatment of laryngeal cancer.

Occult primary head and neck carcinoma

Unknown primary carcinoma presenting as cervical lymph node metastasis accounts for approximately 5% of all head and neck malignancies. The typical presentation involves a middle-aged man with a painless neck mass that has been present for several months. Over 90% of these malignancies represent squamous cell carcinoma originating within Waldeyer's ring (lymphoid tissue of the nasopharynx, tonsil, and base of tongue). The remainder are comprised of adenocarcinoma, melanoma, and other rare histologic variants. The ability to identify the occult primary tumor is imperative because identification allows site-specific therapy and avoidance of wide-field radiation side effects. Following confirmation of metastatic cervical disease with fine-needle aspiration, all patients presenting with an unknown primary carcinoma require a thorough head and neck history and physical examination, radiographic imaging, panendoscopy with directed biopsies of Waldeyer's ring, and bilateral tonsillectomy. Positron emission tomography has proved helpful in identifying occult primary tumors of the head and neck region.

2-[18F]-Fluoro-2-deoxy-D-glucose positron emission tomography as guidance for primary treatment in patients with advanced-stage resectable squamous cell carcinoma of the larynx and hypopharynx

BACKGROUND

High uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) is associated with unfavorable results. Pretreatment FDG uptake was evaluated as a predictor of survival and guidance for primary surgery or radiotherapy (RT) in patients with squamous cell carcinoma (SCC) of the larynx and hypopharynx.

MATERIALS AND METHODS

Seventy-nine consecutive patients with newly diagnosed advanced resectable SCC of the larynx and hypopharynx underwent FDG positron emission tomography (PET) before surgical resection plus RT and chemotherapy (surgery group, n=40) or RT with chemotherapy and surgical salvage (RT group, n=39). Age, tumor stage, histological grade, treatment strategy, and standardized uptake value (SUV) were analyzed for association with local control and survival.

RESULTS

Overall local control and survival in the two groups did not differ (P>0.1). In univariate analysis, nodal positivity (P=0.014) and SUV>8.0 (P=0.007) were associated with poorer disease-free survival (DFS). In multivariate analysis, SUV remained an independent determinant of DFS (P=0.014). When patients with SUV>8.0 in the two treatment groups were analyzed separately, those in the surgery group tended to have a higher 3-year DFS than those in the RT group, despite no statistical significance (48% vs. 27%, P=0.085).

CONCLUSIONS

High FDG uptake is associated with poor survival in patients with advanced laryngopharyngeal SCC. Patients with high FDG uptake may be better treated by surgical resection followed by RT and chemotherapy.

Setup and characterization of a human head and neck squamous cell carcinoma xenograft model in nude rats

OBJECTIVE

To develop and characterize a new head and neck cancer animal model.

STUDY DESIGN

A human head and neck squamous cell carcinoma (HNSCC) xenograft model in nude rats was established via subcutaneous inoculation of a human-origin HNSCC cell line, SCC-4. The tumor was evaluated for growth characteristics, pathologic features by hematoxylin-eosin (HE) staining, and immunohistochemistry of epidermal growth factor receptor (EGFR). 2-[18F] fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET) imaging characteristics were studied too.

RESULTS

A new HNSCC animal model was successfully established. Tumor sizes reached about 1 cm3 on day 15 after tumor cell inoculation. HE staining pathology has confirmed that this tumor is a typical SCC. EGFR immunohistochemistry demonstrated this tumor model to be strongly EGFR positive. 18F-FDG PET study has shown that 18F-FDG accumulated in tumors.

CONCLUSIONS

This study has demonstrated that this tumor model is an appropriate HNSCC tumor model for animal studies on HNSCC.

PET in face and neck tumours

FDG-PET is a useful tool in the imaging of head and neck tumours. It can be used to stage the primary tumour, to assess response to therapy and most importantly for the detection of recurrent tumour. The advantages and limitations of this technique are discussed in this article.

18F-FDG-PET for evaluation of the response to concurrent chemoradiation therapy with intensity-modulated radiation technique for Stage T4 nasopharyngeal carcinoma

PURPOSE

This article evaluates [18F] fluorodeoxyglucose positron emission tomography (18F-FDG-PET) findings as a predictor for local responders (R) vs. nonresponders (NR) in nasopharyngeal carcinoma (NPC) patients with Stage T4 lesions, before and at 3 months after completion of concurrent chemotherapy and radiation therapy (CCRT).

METHODS AND MATERIALS

From January 2002 to November 2003, 39 T4 NPC patients were enrolled. All had magnetic resonance imaging and 18F-FDG-PET, both before and 3 months after CCRT. Any residual/recurrent lesions were confirmed histopathologically.

RESULTS

Of the 39 eligible patients, after a follow-up of 24.2 +/- 9.5 months, 35 became disease-free and 4 had residual or recurrent disease. Marginal differences in standard uptake values (SUV) were observed (10.9 +/- 5.3 vs. 15.6 +/- 3.4, p = 0.058) between R and NR before treatment, and value changes of SUV before and after CCRT were not significantly different. However, highly significantly lower values of SUV were noted for R than for NR 3 months after completion of CCRT (2.1 +/- 0.8 vs. 5.5 +/- 3.2, p = 0.001). One hundred percent positive and negative predictive values were observed for SUV values of 4.0, set 3 months after completion of CCRT.

CONCLUSIONS

Neither the pretreatment SUV nor the changes of SUV between pretreatment and posttreatment were significant predictors for local response. SUV at 3 months after completion of CCRT was a significant determinator for local response. The cutoff of 4.0 for SUV at 3 months after completion of CCRT was useful to be offered as a diagnostic reference for recurrent or residual tumor for NPC treatment.

La TEP dans les cancers des voies aérodigestives supérieures

FDG PET is useful when cancer in the head or neck (except for tumors of the salivary glands, which cannot be characterized accurately) is diagnosed or suspected but not confirmed by biopsy. It can, for example, find evidence of suspicious lymph nodes in clinically N0 necks, detect foci suggestive of distant metastases or second cancers, and provide useful prognostic information. Because it can be very difficult to identify anatomical structures and landmarks on PET images in the head and neck region, PET/CT fusion is very helpful in this area. In early assessment of chemotherapy, the absence of a significant reduction in FDG uptake after one or two cycles predicts lack of efficacy and thus indicates the need to modify the regimen. Conversely, the disappearance of FDG foci indicates effective treatment and good prognosis but cannot rule out the persistence of any malignant tissue at the end of treatment, especially neoadjuvant. Diagnostic impact is probably greatest in monitoring for recurrence and restaging known recurrence: FDG PET should be performed - perhaps routinely - early enough that curative options are still open, but long enough after the end of treatment to avoid false positive results from inflammation. The strategy and timing of FDG PET during follow-up should be determined in more detail in the future, as should the role (if any) of fluorotyrosine (FET) PET in squamous cell carcinoma.

FDG-PET for prediction of survival of patients with metastatic colorectal carcinoma

BACKGROUND

The current study focuses on the prognostic value of pretreatment metabolic activity in metastases as measured with [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), as an indicator of survival in colorectal cancer.

PATIENTS AND METHODS

In a prospective series of 152 patients with metastatic colorectal cancer, of whom 67 were treated with resection of metastases and 85 with chemotherapy, standardized uptake values (SUV) as measured with FDG-PET, were calculated prior to treatment. Survival probabilities were estimated by Cox proportional regression analysis. For Kaplan-Meier analysis SUV was stratified by the median value. Survival differences were assessed using the log-rank test.

RESULTS

SUV in metastases was a significant predictor for overall survival (hazard ratio 1.17, 95% confidence interval 1.06-1.30, P = 0.002), independent of the subsequent treatment. According to the median value of the patient population a low (SUV <4.26) and high uptake group (SUV >4.26) was defined. The median survival and the 2- and 3-year survival rates were 32 months, 59% and 45%, respectively, in the low-uptake group and 19 months, 37% and 28%, respectively, in the high-uptake group (P = 0.017).

CONCLUSION

A significant survival benefit was observed in patients with low FDG uptake in metastases of colorectal cancer.

Radiotherapy for Head and Neck Cancer

The length and quality of head and neck cancer survivorship continues to improve. Radiotherapy has been central to this process through advances in treatment technology, fractionation schemas, radiosensitizing chemotherapy, and surgical technique. The future of head and neck radiotherapy looks brighter still with progress in radiosensitizing biologic therapy, molecular characterization, functional imaging, and rehabilitative strategies fast approaching. Head and neck cancer, a disease once fraught with nihilism and failure, is evolving into a major success story of multidisciplinary solid tumor management. Continued dedication and work on the part of provider and patient alike will be required to make this promise a reality.

The current status of positron-emission tomography scanning in the evaluation and follow-up of patients with head and neck cancer

PURPOSE OF REVIEW

Functional imaging has increasingly become an important diagnostic tool for head and neck cancer and as its availability increases so will its utilization. Positron-emission tomography using the radiotracer [18F]fluoro-2-deoxy--glucose is the most commonly used functional imaging technology and it has the potential to improve the staging and detection of head and neck tumors compared with conventional imaging techniques such as computed tomography or magnetic resonance imaging.

RECENT FINDINGS

The combination of [18F]fluoro-2-deoxy--glucose and positron-emission tomography contributes valuable information in localizing a primary tumor in patients with an unknown primary and neck metastases, in the staging of primary head and neck cancer, in the detection of residual disease following definitive chemoradiation, and in the detection of recurrent disease. New technologies have been recently introduced using the combination of computed tomography and positron-emission tomography that allows exact anatomical correlation with areas of increased tracer uptake. In addition, new tracers may allow quantification of important cellular processes related to tumor proliferation or identification of tumors that may respond to certain targeted therapies.

SUMMARY

[18F]Fluoro-2-deoxy--glucose and positron-emission tomography are increasingly being used as a clinical imaging modality in the complex management of head and neck cancer. In particular, its clinical value in the evaluation of the unknown primary, and the evaluation of recurrent or residual disease, is well established and has shown to be more accurate than conventional imaging modalities.

The current status of FDG-PET in tumour volume definition in radiotherapy treatment planning

Positron emission tomography (PET) scan, mainly using 18 F-fluoro-deoxyglucose (FDG) as a tracer, is currently widely accepted as a diagnostic tool in oncology. It may lead to a change in staging and therefore in treatment management. PET can also be used to define the target volume in radiation treatment planning and to evaluate treatment response. In this review, we focused on issues concerning the role of PET in target volume delineation, both for the primary tumour and regional lymph nodes. A literature search was performed using MEDLINE. Furthermore, the following questions were addressed: does PET allow accurate tumour delineation and does it improve the outcome of radiotherapy, in terms of reduced toxicity or a higher tumour control probability? Combined computer tomography (CT) and PET information seems to influence target volume delineation. Using (CT-) PET scan, interobserver variability is being reduced. Only few studies compared delineation based on PET with pathologic examination, showing a complex relation. Preliminary results concerning incorporation of PET information in to target volume delineation varies in different tumour sites. In the field of lung cancer, incorporation of PET seems to improve tumour coverage and spare normal tissues, which may lead to less toxicity or the possibility to escalate dose. In oesophageal cancer and in lymphoma, PET scan can be used to include PET positive lymph nodes in the target volume. In most other tumour sites not enough data are currently available to draw definitive conclusions about the role of PET in radiation treatment planning.

Potential novel application of dual time point SUV measurements as a predictor of survival in head and neck cancer

OBJECTIVES

To examine the potential of pre-treatment dual time point [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) as a tool for improving the assessment of head and neck cancer. Two main areas were investigated: (a) optimum time to start FDG scanning post-injection and (b) potential of SUV obtained from dual time point scanning as a prognostic indicator of survival.

METHODS

Twelve patients with advanced head and neck cancer were prospectively studied. Each patient was scanned using a Siemen's Ecat Exact-47 PET scanner at 1 h and 2 h post-injection. Maximum tumour uptake (SUVt) and ratio of maximum tumour/normal tissue uptake (SUVt/n) were recorded. The optimal time to initiate scanning was investigated by comparing SUVt and SUVt/n with the decision made by two experienced observers as to which scan they preferred to report from, given the choice of the 1 h and 2 h scan in each patient.

RESULTS

A significant difference between 1 h and 2 h SUVt (P<0.004, paired t-test) and between 1 h and 2 h SUVt/n (P<0.0003, paired t-test) was observed. All 2 h SUVt and SUVt/n were greater in magnitude than their respective 1 h SUVt and SUVt/n counterparts. The two observers reported an identical number of lesions from the 1 h and 2 h scans but preferred the 2 h data.

CONCLUSIONS

Tumour stage and the percentage difference in 1 h and 2 h SUVt showed potential as prognostic indicators of long-term survival.

Comparación entre la PET 18F-FDG y las técnicas de imagen convencionales (T ACy RMN) en el diagnóstico de sospecha de recurrencia de tumores de cabeza y cuello

BACKGROUND

This study aimed to assess the results obtained with the positron emission tomography (PET) and conventional anatomic imaging methods (CT scan and MRI) in the diagnosis of suspicion of tumor recurrence in head and neck cancers.

METHODS

Thirty patients with suspicion of tumor recurrence due to head and neck cancers were reviewed retrospectively. Consequently, 34 PET studies were performed. The images were obtained in the PET Institute of Madrid. They were interpreted by visual and semiquantitative analysis. The results were confirmed with clinical follow-up, response to treatment or with histological studies in some cases.

RESULTS

Sensitivity and specificity of the PET were 95.6% and 81.8% respectively, while it was 65% and 80% for the CT scan/MRI.

CONCLUSIONS

We can conclude that PET provides better results than conventional imaging techniques in the detection of head and neck cancer recurrence.

Clinical and prognostic value of [(18)F]FDG-PET for surveillance of oral squamous cell carcinoma after surgical salvage therapy

[(18)F]FDG-PET was found to be useful for recurrence detection in patients with oral squamous cell carcinoma (OSCC), as a negative PET scan predicted a favorable outcome and survival. Here, we evaluate PET performance in the management of OSCC patients with recurrent/second primary disease after potentially curative second-line therapy. Forty one OSCC patients underwent salvage surgery and 31/41 had received radiation therapy. Thirty five/41 developed recurrent and 6/41 second primary OSCC. Patients had PET evaluation 8.4months (median) after surgery and were followed for at least 6months until disease recurrence or death. For surviving patients, the median follow-up was 33.6months after PET. In OSCC patients who had undergone potentially curative second-line therapy, PET had an overall sensitivity of 85% (92% for recurrence or second primaries, 88% for lymph node failure and 73% for distant metastases). Overall survival was 71% in the PET negative group and 35% in the PET positive group (p<0.01, log-rank test). Moderate glucose metabolism (standardized uptake value4) suggested promising outcome, while SUV>4 indicated a fatal disease course. The data suggest that [(18)F]FDG-PET can facilitate re-staging and clinical management in "high-risk" patients with OSCC.

FDG-PET/CT-guided intensity modulated head and neck radiotherapy: a pilot investigation

BACKGROUND

2-deoxy-2[(18)F]fluoro-D-glucose-positron emission tomography (FDG-PET) imaging can be registered with CT images and can potentially improve neck staging sensitivity and specificity in patients with head and neck squamous cell cancer. The intent of this study was to examine the use of registered FDG-PET/CT imaging to guide head and neck intensity modulated radiotherapy (IMRT) planning.

METHODS

Twenty patients with squamous cell carcinoma of the oral cavity, oropharynx, larynx, or hypopharynx underwent FDG-PET and contrast-enhanced CT imaging of the head and neck before neck dissection surgery. Combined FDG-PET/CT images were created by use of a nonrigid image registration algorithm. All IMRT plans were theoretical and were not used for treatment. We prescribed 66 Gy in 30 fractions to FDG-avid CT abnormalities and nodal zones directly involved with disease, without prophylactic coverage of uninvolved neck levels. Matched CT-guided IMRT plans designed according to the specifications of Radiation Therapy Oncology Group (RTOG) H-0022 were available for comparison. We investigated the feasibility of FDG-PET/CT-directed IMRT dose escalation in five patients with FDG-avid disease located away from critical normal structures. After 66 Gy, FDG-avid disease with 0.5-cm margins was boosted in 220 cGy increments until dose-limiting criteria were reached.

RESULTS

Elimination of prophylactic coverage to FDG-PET/CT-negative neck levels markedly reduced mean dose (Dmean) to the contralateral parotid gland (p < .001) and Dmean to the laryngeal cartilage (p = .001). No FDG-PET/CT-directed plan missed pathologically verified nodal disease. During the dose escalation exercise, we successfully increased the dose to 95% of the planning target volume (PTV95%) to a mean of 7490 cGy (range, 7153-8098 cGy).

CONCLUSIONS

We demonstrate early proof of the principle that FDG-PET/CT-guided IMRT planning can selectively target and intensify treatment of head and neck disease while reducing critical normal tissue doses. Routine clinical use of such planning should not be engaged until the accuracy of FDG-PET/CT is fully validated. Future directions, including refinement of treatment to gross disease and radiologically uninvolved neck nodal levels, are discussed.

Use, Accuracy, and Implications for Patient Management of [18F]-2-Fluorodeoxyglucose-Positron Emission/Computerized Tomography for Head and Neck Tumors

OBJECTIVES/HYPOTHESIS

Positron emission tomography (PET) has shown promise for early detection and accurate staging of cancer patients. A limited number of studies suggest PET/computed tomography (CT) may improve these variables; however, no published study has specifically evaluated clinical outcomes with PET/CT for head and neck (HN) tumors. The current study evaluates the use, accuracy, and implications for patient management of PET/CT scans in patients with HN tumors.

STUDY DESIGN

Retrospective cohort outcomes study at a tertiary care center.

METHODS

The authors identified 795 consecutive PET/CT at our institution. A total of 113 were obtained for HN tumors; 97 were used in the final analysis. Accuracy, use, and implications for patient care management decisions were correlated with each PET/CT scan. Multiple regression analysis was performed.

RESULTS

Accuracy, sensitivity, and specificity were measured by comparing the PET/CT results at the primary tumor site, cervical node sites, and distant sites with either pathologic or definitive clinical diagnoses. PET/CT had an overall per scan accuracy of 72% and a per patient accuracy of 69%. When stratification for rationale of obtaining the scan was performed, accuracy was 80% for staging distant disease, 67% for primary tumor evaluation, 72% for evaluation for recurrence, and 60% for unknown primary tumor evaluation.

CONCLUSIONS

PET/CT imaging is a promising tool for evaluating HN tumors; however, in clinical practice, the proper use of such technology is not well studied. In our study, PET/CT had an overall accuracy of 72% in evaluating HN tumors, and PET/CT had the most accuracy in the detection of distant metastasis.

Positron emission tomography (PET) in the management of oro-pharyngeal cancer

AIMS

To investigate the specific role of FDG-PET in the management of head and neck cancer patients.

METHODS

In a retrospective study, 112 patients with head and neck cancer treated over a 5-year period had FDG-PET scans. The image of the tumour (local, regional and distant) was compared to, clinical, CT/MRI examination, pathological findings and the clinical course of the disease.

RESULTS

FDG-PET correctly identified 95.3% of primary lesions, and 94.1% of the recurrences at the primary site. FDG-PET data was supportive of intended treatment in 31 cases and sufficient to alter the management of seven patients.

CONCLUSIONS

Overall FDG-PET has a useful role in the diagnosis of head and neck cancers, and in the demonstration of occult or hidden tumours, distant and metastatic disease.

Normal FDG distribution patterns in the head and neck: PET/CT evaluation

PURPOSE

To retrospectively evaluate the distribution of fluorine 18 fluorodeoxyglucose (FDG) in the head and neck region with combined positron emission tomography-computed tomography (PET/CT) in patients with no known abnormality in this region.

MATERIALS AND METHODS

The institutional review board allowed a retrospective review of PET/CT images obtained in 78 patients with non-head and neck cancer and waived the requirement for informed consent. The accumulation of FDG in 11 normal head and neck structures was visually and quantitatively assessed retrospectively. Positive rate percentage (PRP) was defined as the sum of the percentages of patients with grade 2 and grade 3 tracer uptake intensity. Standardized uptake values (SUVs) were calculated for quantitative analysis. Mean SUVs were compared between the male and female patients by using the unpaired t test, and the correlation between FDG uptake and patient age was assessed by using the Pearson correlation coefficient test.

RESULTS

Intense tracer uptake was usually seen in the palatine tonsils (PRP, 98%; mean SUV, 3.48), soft palate (PRP, 96%; mean SUV, 3.13), and lingual tonsils (PRP, 96%; mean SUV, 3.11). In the inferior concha (PRP, 4%; mean SUV, 1.56), thyroid gland (PRP, 3%; mean SUV, 1.31), and tongue (PRP, 1%; mean SUV, 1.39), uptake was typically minimal. FDG accumulation was variable in the sublingual glands (PRP, 72%; mean SUV, 2.93), spinal cord (PRP, 64%; mean SUV, 2.12), submandibular glands (PRP, 53%; mean SUV, 2.11), parotid glands (PRP, 51%; mean SUV, 1.90), and vocal cords (PRP, 19%; mean SUV, 1.77). The mean normal-tissue SUV in the soft palate was higher in male than in female patients (P <.01). A negative correlation between age and physiologic FDG uptake was seen in the palatine tonsils (r=-0.51, P <.001) and sublingual glands (r=-0.70, P <.001).

CONCLUSION

Intense FDG uptake was usually observed in the palatine tonsils, lingual tonsils, and soft palate, whereas uptake in the major salivary glands was variable.

Molecular and cellular regulation of glucose transporter (GLUT) proteins in cancer

Malignant cells are known to have accelerated metabolism, high glucose requirements, and increased glucose uptake. Transport of glucose across the plasma membrane of mammalian cells is the first rate-limiting step for glucose metabolism and is mediated by facilitative glucose transporter (GLUT) proteins. Increased glucose transport in malignant cells has been associated with increased and deregulated expression of glucose transporter proteins, with overexpression of GLUT1 and/or GLUT3 a characteristic feature. Oncogenic transformation of cultured mammalian cells causes a rapid increase of glucose transport and GLUT1 expression via interaction with GLUT1 promoter enhancer elements. In human studies, high levels of GLUT1 expression in tumors have been associated with poor survival. Studies indicate that glucose transport in breast cancer is not fully explained by GLUT1 or GLUT3 expression, suggesting involvement of another glucose transporter. Recently, a novel glucose transporter protein, GLUT12, has been found in breast and prostate cancers. In human breast and prostate tumors and cultured cells, GLUT12 is located intracellularly and at the cell surface. Trafficking of GLUT12 to the plasma membrane could therefore contribute to glucose uptake. Several factors have been implicated in the regulation of glucose transporter expression in breast cancer. Hypoxia can increase GLUT1 levels and glucose uptake. Estradiol and epidermal growth factor, both of which can play a role in breast cancer cell growth, increase glucose consumption. Estradiol and epidermal growth factor also increase GLUT12 protein levels in cultured breast cancer cells. Targeting GLUT12 could provide novel methods for detection and treatment of breast and prostate cancer.

Functional imaging in head and neck cancer

Functional imaging has become an increasingly important diagnostic tool for head and neck cancer, and as its availability increases so will its utilization. Positron emission tomography (PET) with the radiotracer 18-fluorodeoxyglucose (18FDG) is the most commonly used functional imaging technology, and it has the potential to improve the staging and detection of head and neck tumors compared with conventional cross-sectional imaging techniques such as CT or magnetic resonance imaging. Specifically, PET contributes valuable information for localizing a primary tumor in patients with an unknown primary and neck metastasis, in the staging of untreated head and neck cancer, in the detection of residual disease after definitive radiotherapy or chemoradiotherapy, and in the detection of recurrent disease. New technologies have been introduced using the combination of CT and PET, which allows exact anatomic correlation with areas of increased tracer uptake. In addition, new tracers may allow quantification of important cellular processes related to tumor proliferation or identification of tumors that may respond to certain targeted therapies. This strategy will eventually enable physicians to tailor therapy to molecular characteristics and therefore improve outcomes for patients with head and neck cancer.

Prognostic significance of preoperative [18-F] fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging in patients with resectable soft tissue sarcomas

OBJECTIVE

The objective of this study was to evaluate the prognostic significance of preoperative positron emission tomography (PET) using 2-fluoro-2-deoxy-D-glucose (FDG) by calculating the mean standardized uptake values (SUV) in patients with resectable soft tissue sarcomas (STS).

SUMMARY AND BACKGROUND DATA

FDG-PET might be used as an adjunctive tool (in addition to biopsy and radiologic tomography) in the preoperative prognostic assessment of resectable STS.

METHODS

A total of 74 adult patients with STS underwent preoperative FDG-PET imaging with calculation of the SUV. Clinicopathologic data and the SUV were analyzed for an association with the clinical outcome. The first and the third quartiles of the SUV distribution function were used as cutoff values (1.59 and 3.6). Survival was estimated by the Kaplan-Meier method. Univariate and multivariate analyses were performed using log-rank test and the Cox proportional hazards regression model.

RESULTS

In 55 cases, STS were completely resected (follow up 40 months): 5-year recurrence-free survival rates in patients with SUV <1.59, 1.59 to <3.6, and > or =3.6 were 66%, 24%, and 11%, respectively (P = 0.0034). SUV was a predictor for overall survival (5-year rates: 84% [SUV <1.59], 45% [SUV 1.59 to <3.6], and 38% [SUV > or =3.6]; P = 0.057) and local tumor control (5-year rates: 93% [SUV <1.59], 43% [SUV 1.59 to <3.6], and 15% [SUV > or =3.6]; P = 0.0017). By multivariate analysis, SUV was found to be predictive for recurrence-free survival. The prognostic differences with respect to the SUV were associated with tumor grade (P = 0.002).

CONCLUSION

The semiquantitative FDG uptake, as measured by the mean SUV on preoperative PET images in patients with resectable STS, is a useful prognostic parameter. SUV with cutoff values at the first and the third quartiles of the SUV distribution predicted overall survival, recurrence-free survival, and local tumor control. Therefore, FDG-PET can be used to improve the preoperative prognostic assessment in patients with resectable STS.

Positron emission tomography in cancer of the head and neck

The use of positron emission tomography (PET) has increased in oncology and in the assessment of head and neck tumours, where it is most useful for recurrent disease. It has good sensitivity and specificity for diagnosis and staging but is generally not necessary except in difficult cases. Quantitative measures of uptake on PET at diagnosis and after treatment do seem to have prognostic value independent of other information about the tumour and so PET may influence management. It also has a role in the identification of an unknown primary site and of synchronous primaries and metastases (often missed by other imaging). Fusion imaging with magnetic resonance (MRI) or computed tomography (CT) adds a new dimension with improved value for each technique.

Positron emission tomography in uro-oncology

Positron emission tomography (PET) in uro-oncology has been one of the slowest areas to develop. There are problems because of the excretion of tracer through the renal tract. Its use in prostate cancer has generally being disappointing, with PET being unable to differentiate malignancy from benign prostatic hypertrophy. In more advanced disease and in the search for the site of recurrence, PET can be of more use. Also, new tracers may prove to be more effective. PET has been shown to be of value in testicular cancer, particularly in defining recurrent disease in residual masses and in patients with raised markers. There is a clear place for PET in some of these cases. Early studies at staging are promising but more work is required to define its exact place. In renal and bladder cancer, PET may be a useful adjunct to conventional imaging in difficult cases and may assist in local staging. In all tumours it is valuable to differentiate fibrosis from recurrent disease in the treatment bed, an area of difficulty for CT/MR.

Dual-phase 18F-fluoro-2-deoxy-D-glucose positron emission tomography as a prognostic parameter in patients with pancreatic cancer

PURPOSE

Recently, dual-phase 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) was shown to be useful in the differentiation between malignant and benign pancreatic lesions. The aim of this prospective study was to evaluate the value of dual-phase FDG-PET as a prognostic parameter in patients with pancreatic cancer.

METHODS

Sixty-five consecutive patients with pancreatic cancer underwent dual-phase FDG-PET. Standardised uptake values at 1 h (SUV1) and 2 h (SUV2) following the injection of FDG were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1. The prognostic value of SUV1, SUV2 and RI was analysed, along with the various clinical and biochemical parameters.

RESULTS

Multivariate analysis showed that only three factors had an independent association with longer patient survival: female gender (p<0.01), TNM stage I-III (p<0.05) and RI>10% (p<0.01). Neither SUV1 nor SUV2 showed any prognostic significance. Combination of tumour stage and RI allowed more accurate prognostic evaluation. Patients at stage I-III with RI>10% survived longer than did patients at the same stage with RI<10% (15.3 vs 11.5 months, p<0.01). Patients at stage IV with RI>10% had an intermediate prognosis, with a median survival of 9.5 months; patients at stage IV with RI<10% showed the worst prognosis, with a median survival of 4.9 months (p<0.05).

CONCLUSION

RI calculated with dual-phase FDG-PET can be used not only as a tool for initial diagnosis and staging of pancreatic cancer but also as a strong independent prognostic parameter that can allow accurate identification of those patients who will benefit from intensive anticancer treatment at different stages of the disease.

Prediction of outcome in head-and-neck cancer patients using the standardized uptake value of 2-[18F]fluoro-2-deoxy-D-glucose

PURPOSE

Tumor uptake of 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG) may relate to outcome in cancer patients. Pretreatment FDG uptake was evaluated as a predictor of local control (LC) and disease-free survival (DFS) in patients with head-and-neck cancer managed primarily either by radiotherapy (RT) or surgery.

PATIENTS AND METHODS

Tumor FDG uptake using the Standardized Uptake Value (SUV) was measured in 120 patients studied prospectively using positron emission tomography (PET). Treatment consisted of either radical RT with or without chemotherapy (73 patients) or radical surgery with or without postoperative RT (47 patients). Median follow-up of the surviving patients was 48 months.

RESULTS

The median SUV was higher in 46 patients who failed treatment than in the remaining controlled patients (5.8 vs. 3.6, p = 0.002). In monovariate analysis, patients with tumors having high FDG uptake (SUV > median, 4.76) had poorer LC (p = 0.003) and DFS (p = 0.005). This difference was also observed when the RT and surgery groups were analyzed separately. In the multivariate analysis T-category (p = 0.005) and SUV (p = 0.046) remained independent adverse factors for LC, whereas N-category (p = 0.004), T-category (p = 0.02) and SUV (p = 0.05) were independent determinants of DFS.

CONCLUSION

These results suggest that pretreatment tumor FDG uptake represents an independent prognostic factor in patients with head-and-neck cancers, whatever the primary treatment modality. Tumors having high FDG uptake are at greater risk of failure and should be considered for more aggressive multimodality therapy.

Analysis of gene expression profiles of hepatocellular carcinomas with regard to 18F-fluorodeoxyglucose uptake pattern on positron emission tomography

PURPOSE

18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan has been found to reflect tumour aggressiveness and prognosis in various types of cancer. In this study, the gene expression profiles of hepatocellular carcinomas (HCCs) were evaluated to determine whether HCCs with high 18F-FDG uptake have more aggressive biological potential than those with low uptake.

METHODS

Surgical specimens were obtained from ten patients with HCC (six males and four females, age range 38-68 years). The tumour samples were divided into two groups based on the 18F-FDG PET scan findings: high 18F-FDG uptake (n=4) and low 18F-FDG uptake (n=6).

RESULTS

The pathological tumour grade was closely correlated with the 18F-FDG uptake pattern: HCCs with high 18F-FDG uptake were pathologically Edmondson-Steiner grade III, while those with low uptake were either grade II or grade II with a focal area of grade III. The total RNA was extracted from the frozen tissues of all HCCs (n=10) and adjacent non-cancerous tissue (n=7). The gene expression profiles were evaluated using an oligoDNA microarray. The HCCs with high 18F-FDG uptake showed increased expression of 11 genes--including vascular cell adhesion molecule-1, vinexin beta and core 1 UDP-galactose:N-acetylgalactosamine-alpha-R-beta 1,3-galactosyltransferase and the natural killer cell inhibitory receptor--compared to those with low uptake (p<0.005). Nine genes, including regulator of mitotic spindle assembly 1, grb2-related adaptor protein and beta-1,3-n-acetylglucosaminyltransferase, were repressed.

CONCLUSION

Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, HCCs with high 18F-FDG uptake appear to have more aggressive biological properties than those with low uptake.

Functional Anatomic Imaging in Radiation Therapy Planning

Improvements in techniques for the delivery of curative radiation have paralleled the advances in three-dimensional imaging devices, specifically, computed tomography and magnetic resonance imaging. These modalities supply the high-resolution image data which, when transferred to radiotherapy computers, allows the construction of a "virtual patient" and calculation of radiation dose that can be delivered within a three-dimensional volume. Although anatomic methods have long been the main stay of cancer imaging, it now clear that functional imaging, provided by positron emission tomography and other nuclear medicine techniques, provides additional critical information regarding tumor biologic activity. The additional step of fusion of functional and anatomic images further refines radiation treatment planning.