Detection of recurrent oral squamous cell carcinoma by [18F]-2-fluorodeoxyglucose-positron emission tomography: implications for prognosis and patient management

High detection sensitivity and reliable morphological correlation of PET with a silicon photomultiplier for primary tongue squamous cell carcinoma

OBJECTIVE

A positron emission tomography (PET) scanner using a silicon photomultiplier (SiPM PET) in place of a photomultiplier tube significantly improves the spatial and time resolution. It may also improve the evaluation of smaller lesions compared to conventional (non-SiPM) PET scanners. We compared the maximum standardized uptake value (SUV_max), detection sensitivity, and morphological correlation using magnetic resonance imaging (MRI) for primary tongue squamous cell carcinoma between the SiPM PET and non-SiPM PET scanner.

METHODS

We retrospectively reviewed the F-18 fluorodeoxyglucose (FDG) PET/CT features of tongue squamous cell carcinomas in consecutive, newly diagnosed, and pathologically verified patients. Twenty-five of 46 patients were scanned using SiPM PET scanner and the remaining 21 patients were scanned with a non-SiPM PET scanner. We compared the SUV_max and visual evaluation of primary tumor detectability, and the correlation between the PET-based and MRI-based tumor size (long axis, thickness, and volume). Differences in SUV_max and detection sensitivity for the primary tumor were analyzed using Welch's t test and Fisher's exact test, respectively. Correlations among the PET-based, MRI-based tumor size, and SUV_max were assessed using Spearman's rank correlation coefficient.

RESULTS

SUV_max of both T1/T2 and T3/T4 primary tumors were significantly higher for the SiPM PET (T1/T2 mean SUV_max: 6.6 ± 4.3, T3/T4 mean SUV_max: 18.2 ± 9.8) than that for the non-SiPM PET (T1/T2 mean SUV_max: 3.4 ± 1.4, T3/T4 mean SUV_max: 10.2 ± 4.9) (P < 0.05). While all cases of T3/T4 primary tumors were detected by both PET scanners, the detection sensitivity for T1/T2 primary tumors was significantly higher for the SiPM PET (80%) than that for the non-SiPM PET (36.4%) (P < 0.05). MRI-based tumor size correlated significantly with SiPM PET-based tumor long axis (ρ = 0.74) and volume (ρ = 0.91), but not with the non-SiPM PET-based tumor long axis and volume in T1/T2 primary lesions. Correlation between MRI-based tumor size and SUV_max was significant in both PET scanners; however, no significant difference was observed between the two scanners.

CONCLUSIONS

The SiPM PET provides better detection sensitivity and a reliable morphological correlation for the T1/T2 primary tongue tumors than the non-SiPM PET due to its high performance.

The immunological Warburg effect: Can a metabolic-tumor-stroma score (MeTS) guide cancer immunotherapy?

The "glycolytic switch" also known as the "Warburg effect" is a key feature of tumor cells and leads to the accumulation of lactate and protons in the tumor environment. Intriguingly, non-malignant lymphocytes or stromal cells such as tumor-associated macrophages and cancer-associated fibroblasts contribute to the lactate accumulation in the tumor environment, a phenomenon described as the "Reverse Warburg effect." Localized lactic acidosis has a strong immunosuppressive effect and mediates an immune escape of tumors. However, some tumors do not display the Warburg phenotype and either rely on respiration or appear as a mosaic of cells with different metabolic properties. Based on these findings and on the knowledge that T cell infiltration is predictive for patient outcome, we suggest a metabolic-tumor-stroma score to determine the likelihood of a successful anti-tumor immune response: (a) a respiring tumor with high T cell infiltration ("hot"); (b) a reverse Warburg type with respiring tumor cells but glycolytic stromal cells; (c) a mixed type with glycolytic and respiring compartments; and (d) a glycolytic (Warburg) tumor with low T cell infiltration ("cold"). Here, we provide evidence that these types can be independent of the organ of origin, prognostically relevant and might help select the appropriate immunotherapy approach.

Autofluorescence imaging for recurrence detection in skin cancer postoperative scars

This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non-melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check-ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to represent the significant deviations from the value of vector angle θ. This new autofluorescence-based method can be easily integrated into the postoperative monitoring of surgical scars and can help diagnose the recurrence of skin cancer from the early stage of scar development.

A combined analysis of maximum standardized uptake value on FDG-PET, genetic markers, and clinicopathological risk factors in the prognostic stratification of patients with resected oral cavity squamous cell carcinoma

OBJECTIVE

Clinical outcomes of patients with resected oral cavity squamous cell carcinoma (OCSCC) chiefly depend on the presence of specific clinicopathological risk factors (RFs). Here, we performed a combined analysis of FDG-PET, genetic markers, and clinicopathological RFs in an effort to improve prognostic stratification.

METHODS

We retrospectively reviewed the clinical records of 2036 consecutive patients with first primary OCSCC who underwent surgery between 1996 and 2016. Of them, 345 underwent ultra-deep targeted sequencing (UDTS, between 1996 and 2011) and 168 whole exome sequencing (WES, between 2007 and 2016). Preoperative FDG-PET imaging was performed in 1135 patients from 2001 to 2016. Complete data on FDG-PET, genetic markers, and clinicopathological RFs were available for 327 patients.

RESULTS

Using log-ranked tests based on 5-year disease-free survival (DFS), the optimal cutoff points for maximum standardized uptake values (SUV-max) of the primary tumor and neck metastatic nodes were 22.8 and 9.7, respectively. The 5-year DFS rates were as follows: SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7 (n = 77) versus SUVtumor-max < 22.8 and SUVnodal-max < 9.7 (n = 250), 32%/62%, P < 0.001; positive UDTS or WES gene panel (n = 64) versus negative (n = 263), 25%/62%, P < 0.001; pN3b (n = 165) versus pN1-2 (n = 162), 42%/68%, P < 0.001. On multivariate analyses, SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7, a positive UDTS/WES gene panel, and pN3b disease were identified as independent prognosticators for 5-year outcomes. Based on these variables, we devised a scoring system that identified four distinct prognostic groups. The 5-year rates for patients with a score from 0 to 3 were as follows: loco-regional control, 80%/67%/47%/24% (P < 0.001); distant metastases, 13%/23%/55%/92% (P < 0.001); DFS, 74%/58%/28%/7% (P < 0.001); and disease-specific survival, 80%/64%/35%/7% (P < 0.001) respectively.

CONCLUSIONS

The combined assessment of tumor and nodal SUV-max, genetic markers, and pathological node status may refine the prognostic stratification of OCSCC patients.

Biomarkers: paving stones on the road towards the personalized precision medicine for oral squamous cell carcinoma

Traditional therapeutics have encountered a bottleneck caused by diagnosis delay and subjective and unreliable assessment. Biomarkers can overcome this bottleneck and guide us toward personalized precision medicine for oral squamous cell carcinoma. To achieve this, it is important to efficiently and accurately screen out specific biomarkers from among the huge number of molecules. Progress in omics-based high-throughput technology has laid a solid foundation for biomarker discovery. With credible and systemic biomarker models, more precise and personalized diagnosis and assessment would be achieved and patients would be more likely to be cured and have a higher quality of life. However, this is not straightforward owing to the complexity of molecules involved in tumorigenesis. In this context, there is a need to focus on tumor heterogeneity and homogeneity, which are discussed in detail. In this review, we aim to provide an understanding of biomarker discovery and application for precision medicine of oral squamous cell carcinoma, and have a strong belief that biomarker will pave the road toward future precision medicine.

Laryngeal squamous cell cancer with late presentation of isolated liver metastasis on fluorodeoxyglucose positron emission tomography-computed tomography

Laryngeal cancer is the second most common type of head and neck malignancy, representing approximately 45% of all head and neck cancers. Hematogenous spread to the liver rarely occurs without evidence of pulmonary and bone disease. We report a patient who had been treated 7 years earlier for laryngeal squamous cell cancer and who had isolated liver metastasis on fluorodeoxy D-glucose positron emission tomography-computed tomography.

Autofluorescence imaging in recurrent oral squamous cell carcinoma

The survival of patients with oral cancer is decreased by locoregional recurrence after an initial multimodal treatment. In order to identify lesions in the oral cavity for a possible recurrence, clinical evaluation as well as MRI or CT scanning is advised. The evaluation of mucosa lesions is hampered by changes related to radio- and chemotherapy as well as reconstruction with tissue flaps. Several techniques for easier identification of tissue abnormalities in the oral cavity have been advocated as adjuncts in order to facilitate identification. Especially methods using altered tissue fluorescence have gained much interest during the last decade. The aim of our prospective study was to evaluate fluorescence properties of undiagnosed mucosa lesions with the VELscope device in patients with multimodal treated oral cancer prior to histological confirmation. In total, 41 patients with a history of oral squamous cell carcinomas (OSCC) (19 females and 22 males) with undiagnosed mucosa lesions where included in the study. After clinical evaluation, examination and documentation using the VELscope® device were performed. Then, an incisional biopsy was performed. An autofluorescence loss indicating a malignant or dysplastic mucosa condition could be detected in six patients (14.6 %); however, only one OSCC and one SIN revealed a complete autofluorescence loss. In four patients, OSCC was present in lesions with retained autofluorescence. Sensitivity and specificity for the VELscope® examination to identify malignant oral lesions by autofluorescence were 33.3 and 88.6 %, respectively. The positive and negative predictive values were 33.3 and 88.6 %, respectively. No statistical correlation between gender and lesion appearance versus autofluorescence loss could be detected. In contrast to mucosa lesions in patients with no prior treatment, the autofluorescence evaluation with the VELscope reveals no additional information in our analysis. Accordingly, invasive biopsies as gold standard are still needed to get sufficient evidence regarding potential malignancy in patients after multimodal treatment for oral cancer.

Correlation of Primary Tumor FDG Uptake with Histopathologic Features of Advanced Gastric Cancer

PURPOSE

Histopathologic features could affect the FDG uptake of primary gastric cancer and detection rate on FDG PET/CT. The aim of this study was to evaluate the FDG uptake of primary gastric cancer by correlating it with the histopathologic features of the tumors.

METHODS

Fifty patients with locally advanced gastric adenocarcinoma who were referred for preoperative FDG-PET/CT scans were enrolled in this study. The detection rate of PET/CT and maximum standardized uptake values (SUVmax) of the primary tumor were compared using the WHO, Lauren, Ming and Borrmann classifications and tumor size and location.

RESULTS

In 45 of the 50 patients (90 %), the primary gastric tumors were detected by FDG PET/CT. On comparison using the WHO classification, the detection rate and SUVmax of the tubular type were significantly higher than those of the poorly cohesive type. On comparison using the Lauren and Ming classifications, the SUVmaxs of the intestinal type and expanding type were significantly higher than those of the diffuse and infiltrative type, respectively. On comparison using the Borrmann classification and tumor size and location, there was no significant difference in the detection rate and SUVmax of primary gastric tumors.

CONCLUSION

This study demonstrates that the poorly cohesive type according to the WHO classification, diffuse type according to the Lauren classification and infiltrative type according to the Ming classification have low FDG uptake in patients with locally advanced gastric carcinoma. Understanding the relationship between primary tumor FDG uptake and histopathologic features would be helpful in detecting the primary tumor by FDG PET/CT in patients with gastric cancer.

Effects of intratumoral inflammatory process on 18F-FDG uptake: pathologic and comparative study with 18F-fluoro-α-methyltyrosine PET/CT in oral squamous cell carcinoma

The accurate depiction of both biologic and anatomic profiles of tumors has long been a challenge in PET imaging. An inflammation, which is innate in the carcinogenesis of oral squamous cell carcinoma (OSCC), frequently complicates the image analysis because of the limitations of (18)F-FDG and maximum standardized uptake values (SUV(max)). New PET parameters, metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as well as (18)F-fluoro-α-methyltyrosine ((18)F-FAMT), a malignancy-specific amino acid-based PET radiotracer, are considered more comprehensive in tumor image analysis. Here, we showed the substantial effects of the intratumoral inflammatory process on (18)F-FDG uptake and further study the possibility of MTV and TLG to predict both tumor biology (proliferation activity) and anatomy (pathologic tumor volume).

METHODS

(18)F-FDG and (18)F-FAMT PET images from 25 OSCC patients were analyzed. SUV(max) on the tumor site was obtained. PET volume computerized-assisted reporting was used to generate a volume of interest to obtain MTV and TLG for (18)F-FDG and total lesion retention (TLR) for (18)F-FAMT. The whole tumor dissected from surgery was measured and sectioned for pathologic analysis of tumor inflammation grade and Ki-67 labeling index.

RESULTS

The high SUV(max) of (18)F-FDG was related to the high inflammation grade. The SUV(max )ratio of (18)F-FDG to (18)F-FAMT was higher in inflammatory tumors (P < 0.05) whereas the corresponding value in tumors with a low inflammation grade was kept low. All (18)F-FAMT parameters were correlated with Ki-67 labeling index (P < 0.01). Pathologic tumor volume predicted from MTV of (18)F-FAMT was more accurate (R = 0.90, bias = 3.4 ± 6.42 cm(3), 95% confidence interval = 0.77-6.09 cm(3)) than that of (18)F-FDG (R = 0.77, bias = 8.1 ± 11.17 cm(3), 95% confidence interval = 3.45-12.67 cm(3)).

CONCLUSION

(18)F-FDG uptake was overestimated by additional uptake related to the intratumoral inflammatory process, whereas (18)F-FAMT simply accumulated in tumors according to tumor activity as evaluated by Ki-67 labeling index in OSCC.

Inhibition of Glucose Transporter 1 (GLUT1) Chemosensitized Head and Neck Cancer Cells to Cisplatin

Glucose transporter 1 (GLUT1) facilitates the cellular uptake of glucose and is overexpressed in most cancers. The altered expression of GLUT1 may influence the sensitivity of tumor cells to chemotherapy. This study investigated whether the knockdown of GLUT1 expression to sensitize head and neck cancer cells to the chemotherapy drug cisplatin in vitro. Anti-GLUT1 antibody was used to block activity of GLUT1 protein, and GLUT1-shRNA was used to knock down its mRNA expression in Cal27 cells. Immunocytochemistry, Western blot, and qRT-PCR were used to detect expression of GLUT1 mRNA and protein, respectively. Lentivirus was used to carrying GLUT1-shRNA to knockdown GLUT1 expression in Cal27 cells for MTT and flow cytometry analyses of cell viability and apoptosis, respectively. Glucose uptake assay was used to assess the changes in glucose levels in Cal27 cells. It showed that GLUT1 mRNA and protein were expressed in Cal27 cells, and GLUT1 protein was localized on the cell membrane. Both anti-GLUT1 antibody and GLUT1-shRNA sensitized Cal27 cells to cisplatin treatment under both normoxia and hypoxia conditions. Anti-GLUT1 antibody and GLUT1-shRNA inhibited tumor cell growth in vitro and induced them to undergo apoptosis. GLUT1-shRNA also suppressed tumor cell uptake of glucose into the cells. Our findings suggest that inhibition of GLUT1 activity and expression can sensitize Cal27 cells to cisplatin treatment in both normoxic and hypoxic conditions. These data could be further verified in animal xenografts before potential application as a clinical adjuvant or neoadjuvant therapy of head and neck cancer with cisplatin.

Efficacy of current regular follow-up policy after treatment for head and neck cancer: Need for individualized and obligatory follow-up strategy

BACKGROUND

The purpose of this study was to report the efficacy of routine follow-up after head and neck cancer treatment.

METHOD

Data for 520 patients with head and neck cancer registered with between 2002 and 2008 were reviewed retrospectively.

RESULTS

The mean ± SD follow-up period taken into account was 34.7 ± 22.8 months. The pickup rate for recurrence using our follow-up protocol in this cohort was 1 in every 79 visits (1.26%). High pickup rates were observed in patients older than 70 years and patients with advanced T classification, whereas low pickup rates were observed in patients who had received treatment including surgery. The only factor on multivariate analysis to influence follow-up visits was surgical treatment (p = .043).

CONCLUSION

Individualized and obligatory follow-up policy is desirable considering various factors, especially age, T classification, and whether treatment modality includes surgery or not.

Optimal timing of post-treatment [18F]fluorodeoxyglucose-PET/CT for patients with head and neck malignancy

OBJECTIVES

The aims of this study were to evaluate the ability of [F]fluorodeoxyglucose (F-FDG)-PET/computed tomography (CT) to identify tumor recurrence, nodal metastases, and distant metastases for surveillance and discuss the optimal timing of F-FDG-PET/CT examination after the completion of treatment for head and neck malignancy.

METHODS

A total of 319 patients who underwent a post-treatment F-FDG-PET/CT examination for head and neck malignancy were studied. F-FDG-PET/CT findings were compared with the final diagnosis confirmed by histopathological examinations or clinical and radiological follow-up for at least 6 months. Patients were divided into two groups according to the presence or absence of clinical suspicion of recurrent disease. The diagnostic accuracy of F-FDG-PET/CT was analyzed for each group. Patients were also categorized according to the time interval between the completion of treatment and the post-treatment F-FDG-PET/CT examination. Differences in diagnostic accuracy due to the time interval were also evaluated.

RESULTS

The diagnostic accuracy of F-FDG-PET/CT was high for both groups. The overall accuracy of F-FDG-PET/CT performed within 2 months (69%) after the completion of treatment was significantly inferior to that performed after 2 months (93%).

CONCLUSION

F-FDG-PET should be performed immediately for patients with clinically suspected recurrent disease. In others, it should be performed at later than 2 months after the completion of the treatment.

Prognostic value of (18)F-fluorodeoxyglucose positron emission tomography, computed tomography and magnetic resonance imaging in oral cavity squamous cell carcinoma with pathologically positive neck lymph node

Purpose

To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN.

Materials and Methods

In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative ¹⁸F-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of ¹⁸F-FDG PET and CT/MRI.

Results

Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by ¹⁸F-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by ¹⁸F-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value (SUV_max) on clinical outcomes. Notably, SUV_max showed significant correlation with tumor size in LN (p < 0.01, R² = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, R² = 0.37 and p < 0.01, R² = 0.48, respectively).

Conclusion

¹⁸F-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of SUV_max.

Warburg phenotype in renal cell carcinoma: high expression of glucose-transporter 1 (GLUT-1) correlates with low CD8(+) T-cell infiltration in the tumor

Many tumor cells are characterized by a dysregulated glucose metabolism associated with increased glycolysis in the presence of oxygen ("Warburg Effect"). Here, we analyzed for the first time a possible link between glucose metabolism and immune cell infiltration in renal cell carcinoma (RCC). RCC specimens revealed a highly significant increase in the expression of lactate dehydrogenase A (LDHA) and glucose-transporter 1 (GLUT-1) compared to the corresponding normal kidney tissue on mRNA level. Accordingly, tumor cell lines of different origin such as RCC, melanoma and hepatocellular carcinoma strongly expressed LDHA and GLUT-1 compared to their nonmalignant counterparts. In line with this finding, tumor cells secreted high amounts of lactate. High expression of GLUT-1 and LDH5, a tetramer of 4 LDHA subunits, was confirmed by tissue microarray analysis of 249 RCC specimens. Overall, 55/79 (69.6%) and 46/71 (64.7%) cases of clear cell carcinoma showed a constitutive, but heterogeneous expression of GLUT-1 and LDH5, respectively. The number of CD3(+), CD8(+) and FOXP3(+) T cells was significantly elevated in RCC lesions compared to normal kidney epithelium, but effector molecules such as granzyme B and perforin were decreased in tumor infiltrating T cells. Of interest, further analysis revealed an inverse correlation between GLUT-1 expression and the number of CD8(+) T cells in RCC lesions. Together, our data suggest that an accelerated glucose metabolism in RCC tissue is associated with a low infiltration of CD8(+) effector T cells. Targeting the glucose metabolism may represent an interesting tool to improve the efficacy of specific immunotherapeutic approaches in RCC.

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.

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.

Positron-Emission Tomography for Surveillance of Head and Neck Cancer

OBJECTIVES/HYPOTHESIS

To determine the diagnostic accuracy and the ideal timing of fluoro-fluorodeoxyglucose positron-emission tomography (PET) in the posttreatment surveillance of head and neck mucosal squamous cell carcinoma (HNSCC).

STUDY DESIGN

Retrospective chart review.

METHODS

Our sample includes 103 adult patients with 118 posttreatment PET scans who had undergone treatment for HNSCC. We correlated PET results with surgical pathology and clinical outcome in the subsequent 6 months.

RESULTS

For the detection of locoregional persistent or recurrent HNSCC, PET scans had a sensitivity of 82%, specificity of 92%, positive predictive value (PPV) of 64%, negative predictive value (NPV) of 97%, and overall accuracy of 90%. For the detection of distant metastases, PET scans had a sensitivity of 89%, specificity of 97%, PPV of 85%, NPV of 98%, and overall accuracy of 96%. PET scans of the head and neck region performed greater than 1 month after the completion of radiation compared with scans performed within 1 month had a significantly higher sensitivity of 95% versus 55% (P < .01) and NPV of 99% versus 90% (P < .01).

CONCLUSION

PET is effective in detecting distant metastases in the posttreatment surveillance for HNSCC patients. A negative PET is highly reliable for all sites. However, a positive PET in the head and neck region is unreliable because of a high false-positivity rate. PET of the head and neck region has a statistically significant risk of a false-negative reading when performed within 1 month of radiation.

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.

Does 18F-FDG PET/CT improve the detection of posttreatment recurrence of head and neck squamous cell carcinoma in patients negative for disease on clinical follow-up?

Posttreatment surveillance for the recurrence of head and neck squamous cell carcinoma (HNSCC) is a diagnostic challenge. Tissue distortion from radiation and surgery can obscure early detection of recurrence by conventional follow-up approaches such as physical examination, CT, and MRI. Several studies have shown that 18F-FDG PET may be an effective technique for the detection of persistent, recurrent, and distant metastatic HNSCC after treatment. The aim of this prospective study was to determine the benefits of hybrid 18F-FDG PET/CT in detecting a subclinical locoregional recurrence of HNSCC and distant metastases. The study patients were considered cured of HNSCC on the basis of 12 mo of negative findings on conventional follow-up. We also assessed the diagnostic accuracy of 18F-FDG PET/CT in these patients.

METHODS

Ninety-one patients cured of HNSCC without any clinical evidence of recurrence were included. Whole-body 18F-FDG PET/CT examination was performed 11.6+/-4.4 mo after the end of the treatment. The gold standard was histopathology or 6 mo of imaging follow-up.

RESULTS

The whole-body 18F-FDG PET/CT examinations had negative results in 52 patients and positive results in 39. Nine of these patients who exhibited abnormal 18F-FDG uptake in the head and neck area did not have recurrent HNSCC (false-positive). Thirty had proven recurrence. The sensitivity and specificity of 18F-FDG PET/CT in this study for the diagnosis of HNSCC recurrence were 100% (30/30) and 85% (52/61), respectively. The positive predictive value was 77% (30/39). The negative predictive value was 100% (52/52). The overall accuracy was 90% (82/91).

CONCLUSION

The results of our study confirm the high effectiveness of 18F-FDG PET/CT in the assessment of HNSCC recurrence and suggest that 18F-FDG PET/CT is more accurate than conventional follow-up physical examination alone in the assessment of recurrence after previous curative treatment for HNSCC and could be proposed systematically at 12 mo of the usual follow-up.

Does 18fluoro-fluorodeoxyglucose positron emission tomography improve recurrence detection in patients treated for head and neck squamous cell carcinoma with negative clinical follow-up?

BACKGROUND

The aim of this study was to determine the benefits of 18fluoro-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in the detection of head and neck squamous cell carcinoma (HNSCC) recurrence in patients with negative clinical follow-up.

METHODS

Whole-body 18FDG-PET was performed in 30 patients treated for HNSCC without any clinical element for recurrence.

RESULTS

Twenty-one negative PET and 9 positive results were seen. One patient with abnormal 18F-FDG uptake in the laryngeal area did not have recurrent HNSCC (false positive). Eight had proven recurrence. The sensitivity and specificity of 18F-FDG PET for the diagnosis of HNSCC recurrence were 100% (8/8) and 95% (21/22), respectively. The positive predictive value was 89% (8/9). The negative predictive value was 100% (21/21). The overall accuracy was 97% (29/30).

CONCLUSION

The results of our study confirm the high effectiveness of 18F-FDG PET in assessment of HNSCC recurrence and suggest that it is more accurate than conventional physical examination follow-up alone.

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.

Benign ulceration as a manifestation of soft tissue radiation necrosis: imaging findings

BACKGROUND AND PURPOSE

The purpose of this study was to review CT imaging findings of soft tissue mucosal ulceration in patients following radiation treatment for head and neck malignancies and to correlate these with patient outcomes.

MATERIALS AND METHODS

The CT examinations in 20 patients with soft tissue ulceration after radiation therapy for treatment of head and neck cancer were reviewed. External beam radiation therapy was completed between 3 and 61 months (mean, 11.5 months) before the initial diagnosis of soft tissue ulceration. In all 20 patients, the initial diagnosis was made or confirmed on CT examination.

RESULTS

Of the 20 ulcerations, 12 did not demonstrate enhancement, and the results of biopsy in 9 of these 12 were negative. Of the 12 nonenhancing ulcerations, biopsy was not performed in 3, but they have been followed clinically and radiologically for 15.7 months without evidence of recurrence. Of the 20 ulcerations, 8 demonstrated adjacent enhancement, and the results of a biopsy in 4 were positive for recurrent cancer and negative in 2; these 2 have been followed for 16.3 months without evidence of recurrence. Biopsy was not performed in 2 ulcerations, but they have been followed for 15.0 months without evidence of recurrence.

CONCLUSION

For soft tissue ulceration occurring after radiation treatment, if there is no enhancement or clinical evidence of recurrence, it is likely benign and follow-up without biopsy seems warranted. If the ulceration is associated with adjacent enhancement, then differentiation between radiation necrosis and recurrent tumor is difficult. In these cases, correlation with clinical examination with close interval follow-up is necessary if a biopsy is not performed.

Pathology and FDG PET correlation of residual lymph nodes in head and neck cancer after radiation treatment

BACKGROUND

This study determines if postradiotherapy [18F]fluorodeoxyglucose positron emission tomography (FDG PET) can predict the pathology status of residual cervical lymph nodes in patients undergoing definitive radiotherapy for head and neck squamous cell carcinoma (HNSCC).

METHODS

Patients with stage N2 or higher HNSCC underwent PET and CT imaging after definitive radiotherapy. Patients with radiographically persistent lymphadenopathy underwent either neck dissection or fine needle aspiration (FNA) of the lymph nodes under ultrasound guidance. PET scan results were correlated with the pathologic findings of the residual lymphadenopathy.

RESULTS

Twenty-four hemi-necks in 23 patients with residual lymphadenopathy had neck dissection or FNA. The pathology correlated strongly with the post-RT FDG PET studies. All patients with a negative post-RT FDG PET and those with a maximum standardized uptake value (SUVmax) of less than 3.0 in the post-RT FDG PET were found to be free from residual viable tumor. Using a SUVmax of less than 3.0 as the criterion for a negative FDG PET study, the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 84.2%, 62.5%, and 100%, respectively.

CONCLUSIONS

A negative post-RT FDG PET is very predictive of negative pathology in the residual lymph node after definitive radiotherapy for advanced HNSCC. A prospective clinical trial is warranted to determine if neck dissection can be withheld in these patients.

Utility of FDG PET in patients with squamous cell carcinomas of the oral cavity

BACKGROUND

The utility of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in oral cavity cancer has received little attention in a clinician's perspective. We systematically evaluated the clinical roles of FDG PET in patients with oral cavity squamous cell carcinomas (SCCs).

METHODS

Between August 2001 and February 2005, 82 new patients with resectable oral cavity SCCs underwent CT/MRI and FDG PET at initial staging and follow-up. The sensitivity and specificity of CT/MRI and FDG PET for neck metastases were compared with histopathologic reference of 67 patients who underwent neck dissection. The relationships between the maximal standardized uptake value (SUV) of primary tumors and clinicopathologic parameters, such as gender, age, tumor thickness, local invasiveness, T and N categories, tumor-node-metastasis stage, and histological grade, as well as with disease-free survival (DFS), were assessed.

RESULTS

FDG PET was more sensitive than CT/MRI for detecting cervical metastases on a level-by-level basis (38/43 vs. 28/43; P=0.002). Age, T and N categories, tumor thickness (>8mm) and SUV (>5.0) were also significant variables of 3-year DFS in univariate analysis. T category was an independent determinant of DFS in multivariate analysis (P<0.05). During a mean follow-up of 36 months, FDG PET correctly diagnosed locoregional recurrences in 20 patients, distant metastases in six and second cancers in five.

CONCLUSION

FDG PET may have potential roles in initial staging, survival prediction, and the detection of recurrences and second cancers.

Role of positron emission tomography in decisions on treatment strategies for pancreatic cancer

BACKGROUND/PURPOSE

The purpose of this study was to estimate the usefulness of positron emission tomography (PET) in deciding on strategies for the treatment of pancreatic cancer. The following two parameters were evaluated: the ability of PET to provide an estimation of the progression of pancreatic cancer, and the ability of PET to predict survival and the effect of chemoradiotherapy.

METHODS

Forty-two patients underwent PET as part of the procedure for making a diagnosis of pancreatic tumors. The maximum standardized uptake value (SUVmax) levels were compared with clinicopathological factors and analyzed.

RESULTS

PET provided a sensitivity of 87%, a specificity of 67%, and an overall accuracy of 85% for the diagnosis of pancreatic malignancy. Tumors with distant metastases showed significantly higher SUV levels than tumors without metastasis. In the patients who received chemoradiotherapy, the overall survival of the group in which SUVmax was less than 7.0 was better than that of the group in which SUVmax was more than 7.0.

CONCLUSIONS

We conclude that PET is a useful tool for determining pathological status and distant metastasis in pancreatic cancer, and for predicting the prognosis of patients receiving chemoradiotherapy.

Utility of 18F-fluorodeoxyglucose positron emission tomography in the preoperative staging of squamous cell carcinoma of the oropharynx

BACKGROUND

18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to be superior to computed tomography (CT)/magnetic resonance imaging (MRI) in the evaluation of head and neck cancers, but little is known about its usefulness in oropharyngeal squamous cell carcinoma (SCC). We therefore compared FDG PET and CT/MRI in the preoperative staging of previously untreated oropharyngeal SCC.

METHODS

Thirty-two consecutive patients with oropharyngeal SCC underwent FDG PET and CT/MRI before surgery. Each method was interpreted separately to assess primary tumor and cervical node status. Their sensitivity and specificity were compared relative to histopathologic analysis.

RESULTS

Histopathology revealed metastases in 29 of 39 dissected neck sides and in 47 of 163 dissected cervical levels. FDG PET had higher sensitivities than CT/MRI for primary tumor detection (25/32 vs. 30/32, P=0.063) and for identification of cervical metastases on neck side (22/29 vs. 28/29, P<0.05) and level-by-level (37/47 vs. 45/47, P<0.05) bases. In contrast, the specificity of the two methods did not differ significantly (P>0.5). FDG PET correctly interpreted the false-negative results of CT/MRI in 6 of 7 primary tumors and 8 of 10 cervical levels.

CONCLUSIONS

The improved preoperative staging of FDG PET may help in planning treatment, but its accuracy is insufficient to replace pathologic staging based on neck dissection.

Comparison between PET and PET/CT in recurrent head and neck cancer and clinical implications

The aim of this retrospective study was to compare the diagnostic accuracy between positron emission tomography (PET) and combined PET/computed tomography (PET/CT) in the detection of recurrent head and neck squamous cell carcinoma (HNSCC) and to evaluate the degree of interobserver agreement. Thirty-two patients who had undergone curative treatment for HNSCC and who presented with a suspicion of recurrent local disease were studied with fluoro-2-deoxy-D-glucose (FDG)-PET imaging. All patients had undergone an inconclusive conventional workup (nasofibroscopy, CT scan and/or MRI). PET and PET/CT were reviewed by two nuclear medicine physicians independently. Performances of PET and PET/CT were compared using biopsy and/or clinical follow-up of at least 8 months as gold-standard. ROC curves were employed for statistical analysis. Out of 32 patients, 18 (56%) had a local recurrence. Intraclass correlation coefficients were strong (>90) and statistically significant (P < 0.0001) for the two reviewers in all cases. The sensitivity, specificity and accuracy of PET were found to be 94%, between 36 and 50% and between 69 and 75%, respectively, depending on the consideration of equivocal cases. Results for PET/CT were found to be 94, 57 and 78%. The utility scores of PET and PET/CT were 0.72 and 0.78, respectively. PET/CT could have a direct impact on patient care with the avoidance of 8/14 (57%) unnecessary invasive procedures (panendoscopy under general anaesthesia). Combined PET/CT is more accurate than PET alone for detection of recurrent HNSCC. The findings of this study are reinforced by the strong interobserver agreement in the interpretation of the results.

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.

Effects of hyperoxygenation on FDG-uptake in head-and-neck cancer

PURPOSE

Tumor hyperoxygenation results in high response rates to ARCON (accelerated radiotherapy with carbogen and nicotinamide). The effect of hyperoxygenation on tumor metabolism using [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) was investigated.

METHODS

Within one week, FDG-PET was performed without and with hyperoxygenation by carbogen breathing and/or nicotinamide administration in 22 patients, eligible for ARCON for head-and-neck cancer. Maximum standardized uptake values (SUV(max)) in both scans and the relative change were calculated in the primary tumor and in normal muscle.

RESULTS

Alteration of the tumor oxygenation state induced profound, but variable, metabolic changes (median DeltaSUV(max) -4%; range -61% to +30%). Metabolism in normal muscle was not affected. In three patients who did not achieve local tumor control, the SUV(max) after hyperoxygenation differed less than 5% change as compared to baseline, whereas 13 of the 16 patients with local tumor control showed a larger difference (p<0.05).

CONCLUSION

Given the heterogeneous response pattern of nicotinamide and carbogen on FDG-uptake in head-and-neck carcinoma, the prognostic significance of semiquantitative FDG-PET before and after hyperoxygenation remains uncertain and requires confirmation in larger clinical studies before introducing the procedure as a predictive tool for oxygenation modifying treatments.

[Contribution of 18-F-FDG PET for detection of head and neck carcinomas with an unknown primary tumor]

OBJECTIVES

To evaluate the usefulness of fusioning positron emission tomography with computed tomography (PET/CT) for the detection of head and neck carcinomas of unknown primary.

METHODS

This prospective study included 20 patients with cervical lymph node of squamous cell carcinoma of unknown primary after standard initial workup (nasofibroscopy and CT scan of the chest and head and neck). Patients underwent PET/CT and panendoscopy of the upper airways and upper digestive tract with PET/CT directed biopsies. The follow-up was 6 months minimum in all patients.

RESULTS

A potential primary tumor was found in 10 of the 20 cases and confirmed by histology in 7 cases (3 bases of tongue, 1 tonsillar pillar, 1 vallecula, 1 tonsillar fossa, 1 piriform sinus). Four of these seven patients presented a normal endoscopy (diagnosis was made with submucosal PET/CT directed biopsies). PET/CT was normal in 10 of 20 cases with 3 false negatives. The sensitivity of PET/CT was 70%, the specificity was 70% and the accuracy was 70%.

CONCLUSION

PET/CT seems to be of interest in the detection of head and neck carcinoma of unknown primary. PET/CT detected 15% of unknown primary tumors with treatment-related implications.

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.

The role of FDG PET in management of neck metastasis from head-and-neck cancer after definitive radiation treatment

PURPOSE

The role of neck dissection after definitive radiation for head-and-neck cancer is controversial. We select patients for neck dissection based on postradiation therapy (post-RT), computed tomography (CT), and [18F] fluorodeoxyglucose positron emission tomography (FDG PET). We summarize the clinical outcomes of patients treated with this policy to further elucidate the role of FDG PET in decision making for neck dissection after primary radiotherapy.

METHODS AND MATERIALS

Between December 1999 and February 2004, 53 eligible patients were identified. These patients had stage N2A or higher head-and-neck squamous cell carcinoma and had complete response of the primary tumor after definitive radiation with or without chemotherapy. PET or computed tomography (CT) scans were performed within 6 months after treatment. Neck dissection was performed in patients with residual lymphadenopathy (identified by clinical examination or CT) and a positive PET scan. Those without residual lymph nodes and a negative PET were observed without neck dissection. For patients with residual lymphadenopathy, but a negative PET scan, neck dissection was performed at the discretion of the attending surgeon and decision of the patient. There was a total of 70 heminecks available for analysis (17 patients had bilateral neck disease).

RESULTS

There were 21 heminecks with residual lymphadenopathy identified on CT imaging or clinical examination and negative PET. Of these, 4 had neck dissection and were pathologically negative. The remaining 17 were observed without neck dissection. There was a total of 42 heminecks without residual lymph nodes on post-RT CT imaging or clinical examination with a negative PET. They were also observed without neck dissection. Seven heminecks had a positive PET scan and residual lymphadenopathy. Six of them had neck dissection and 1 had fine-needle aspiration of a residual node; 3 contained residual viable cancer and 4 were pathologically negative. At median follow up of 26 months (range, 12-57 months), no regional failure was identified. The negative predictive value of PET was 100% and positive predictive value was 43%.

CONCLUSION

For patients who have no evidence of residual lymphadenopathy and a negative FDG PET scan 12 weeks after definitive radiation, neck dissection can be safely withheld. Even in cases in which small residual lymphadenopathy was observed, regional recurrences have not occurred when the post-RT PET scan was negative and neck dissection was withheld. For patients with large residual lymphadenopathy (greater than 2.0-3.0 cm in size) but a negative post-RT FDG PET, further studies with longer follow-up are necessary to determine the appropriateness of withholding neck dissection.

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.

Value of FDG PET in assessment of treatment response and surveillance in head-and-neck cancer patients after intensity modulated radiation treatment: A preliminary report

PURPOSE

[(18)F] fluorodeoxyglucose positron emission tomography (FDG PET) imaging has been shown to be valuable in early detection of persistent and recurrent head-and-neck cancer after treatment. Previous studies have reported its use in patients treated with conventional radiation. Many patients are now treated with intensity-modulated radiation treatment (IMRT). We evaluated the value of FDG PET in the assessment of treatment response and surveillance in head-and-neck cancer patients treated with IMRT.

METHODS AND MATERIALS

We performed a retrospective review of 85 head-and-neck cancer patients treated with IMRT at our institution between December 2000 and September 2003 who had FDG PET in their follow-up. Of these, 58 were treated with primary IMRT with or without chemotherapy, and 27 were treated with postoperative IMRT.

RESULTS

Sixty-four patients had negative initial FDG PET after treatment. Forty of them, who had 6 to 24 months of follow-up after the imaging study, had no evidence of local or regional recurrence, although three of them developed distant disease. Twenty-one patients had a positive initial FDG PET after treatment, with 11 positive at the primary site, 9 positive in the neck, and 3 positive distantly. Six of 11 patients with a positive FDG PET at the primary site were true positive, and 3 had salvage surgery. Eight of 9 patients positive in the neck had a salvage neck dissection. One had fine needle aspiration of the lymph node with positive cytology but refused surgery later. For patients with follow-up of 6 months and longer, only 1 of 45 patients with a negative initial FDG PET at the primary site developed a local recurrence. None of 49 patients with a negative initial FDG PET in the neck developed a regional recurrence. Two cases are presented in which abnormal FDG PET preceded laryngoscopy or computed tomography in detection of tumor recurrences.

CONCLUSIONS

FDG PET is useful in the posttreatment management of head-and-neck cancer patients treated with IMRT. It is highly accurate in the detection of persistent and recurrent disease after treatment and allows salvage treatment to be initiated in a timely manner. It also provides prognostic information concerning the risk of recurrence after curative therapy.

Positron emission imaging of head and neck cancer, including thyroid carcinoma

Most positron emission tomography (PET) imaging studies in head and neck cancer are performed using the radiotracer 18-fluorodeoxyglucose ((18)FDG). PET with FDG has become a standard clinical imaging modality in patients with head and neck cancer. It contributes valuable information in localizing a primary tumor in patients with neck nodal metastases from an unknown primary, in the staging of primary head and neck cancer, and in the detection of recurrent disease. In addition, FDG-PET provides independent prognostic information in patients with newly diagnosed and recurrent head and neck cancer. PET/CT improves lesion localization and accuracy of FDG-PET and is strongly recommended in patients with head and neck cancer. After thyroidectomy, FDG-PET has proven useful in patients with clinical or serological evidence of recurrent or metastatic thyroid carcinoma but negative whole body iodine scan. PET shows metastatic disease in up to 90% of these patients, thereby providing a rational basis for further studies and therapy. In patients with medullary thyroid cancer with elevated calcitonin levels following thyroidectomy, FDG-PET has a sensitivity of 70-75% for localizing metastatic disease. Occasionally incidental intense FDG uptake is observed in the thyroid gland on whole body PET studies performed for other indications. Although diffuse FDG uptake usually indicates thyroiditis, focal uptake has been related to thyroid cancer in 25-50% of cases and should therefore be evaluated further if a proven malignancy would cause a change in patient management.