The proposed physiology-based FDG PET/CT criteria in reducing false-positive results in advanced head and neck cancer after chemoradiotherapy.

BACKGROUND: Distinguishing benign complications after concurrent chemoradiotherapy (CCRT) from a local residual tumor in advanced head and neck squamous cell carcinoma (HNSCC) remains a clinical challenge. In this study, we propose criteria when considering physiological uptake patterns on F-18-fluorodeoxyglucose (FDG) PET/CT in patients with advanced HNSCC after CCRT. METHODS: We retrospectively reviewed FDG PET/CT images of 62 patients with advanced HNSCC, which were taken within 16 weeks following CCRT. Visual interpretation criteria were rated by three nuclear medicine physicians, independently, according to the uptake patterns of the primary site. The Cohen k coefficient was calculated to assess inter-reader agreement. The histology of the primary site within a 1 month of the PET/CT study was used as the gold standard for sensitivity, specificity, positive predictive value and negative predictive value. RESULTS: PET/CT was arranged at a median interval of 10.5 weeks (range 4-16 weeks) after CCRT, and the pathologic residual rate was 55.7% at the primary site. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of identifying residual disease were 91.1%, 50.0%, 68.9%, 82.3%, and 72.6%, respectively, by the previously established criteria, and 88.2%, 92.9%, 93.8%, 86.7%, and 90.3%, respectively, by our physiology-based criteria. Our visual rating criteria corrected 12 of 14 (84.6%) false-positive results from the established criteria, while two more false-negative cases identified with our criteria were proven to be small residual tumors. CONCLUSIONS: By incorporating physiological changes following CCRT, our visual rating criteria improved the accuracy of the currently used FDG PET/CT visual rating system, especially the number of false-positive cases with advanced HNSCC after CCRT.

AMACR amplification and overexpression in primary imatinib-naïve gastrointestinal stromal tumors: a driver of cell proliferation indicating adverse prognosis.

Non-random gains of chromosome 5p have been observed in clinically aggressive gastrointestinal stromal tumors, whereas the driving oncogenes on 5p remain to be characterized. We used an integrative genomic and functional approach to identify amplified oncogenes on 5p and to evaluate the relevance of AMACR amplification at 5p13.3 and its overexpression in gastrointestinal stromal tumors. Thirty-seven tumor samples, imatinib-sensitive GIST882 cell line, and imatinib-resistant GIST48 cell line were analyzed for DNA imbalances using array-based genomic profiling. Forty-one fresh tumor samples of various risk categories were enriched for pure tumor cells by laser capture microdissection and quantified for AMACR mRNA expression. AMACR-specific fluorescence in situ hybridization and immunohistochemistry were both informative in tissue microarray sections of 350 independent primary gastrointestinal stromal tumors, including 213 cases with confirmed KIT /PDGFRA genotypes. To assess the oncogenic functions of AMACR, GIST882 and GIST48 cell lines were stably silenced against their endogenous AMACR expression. In 59% of cases featuring 5p gains, two major amplicons encompassed discontinuous chromosomal regions that were differentially overrepresented in high-risk cases, including the one harboring the mRNA-upregulated AMACR gene. Gene amplification was detected in 19.7% of cases (69/350) and strongly related to protein overexpression (p<0.001), although 52% of AMACR-overexpressing cases exhibited no amplification. Both gene amplification and protein overexpression were significantly associated with epithelioid histology, larger size, increased mitoses, higher risk levels, and unfavorable genotypes (all p≦0.03). They were also independently predictive of decreased disease-free survival (overexpression, p<0.001; amplification, p=0.020) in the multivariate analysis. Concomitant with downregulated cyclin D1, cyclin E, and CDK4, AMACR knockdown suppressed cell proliferation and induced G1-phase arrest, but did not affect apoptosis in both GIST882 and GIST48 cells. In conclusion, AMACR amplification is a mechanism driving increased mRNA and protein expression and conferring aggressiveness through heightened cell proliferation in gastrointestinal stromal tumors.

Scintigraphic assessment of salivary function after intensity-modulated radiotherapy for head and neck cancer: correlations with parotid dose and quality of life.

OBJECTIVE: We investigated salivary function using quantitative scintigraphy and sought to identify functional correlations between parotid dose and quality of life (QoL) for head and neck cancer (HNC) patients receiving intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: Between August, 2007 and June, 2008, 31 patients treated IMRT for HNC were enrolled in this prospective study. Salivary excretion function (SEF) was previously measured by salivary scintigraphy at annual intervals for 2 years after IMRT. A dose-volume histogram of each parotid gland was calculated, and the normal tissue complication probability (NTCP) was used to determine the tolerance dose. QoL was longitudinally assessed by the EORTC QLQ-C30 and H&N35 questionnaires prior to RT, and at one, three, 12 and 24 months after RT. RESULTS: A significant correlation was found between the reduction of SEF and the mean parotid dose measured at 1 year (correlation coefficient, R(2)=0.651) and 2 years (R(2)=0.310) after IMRT (p<0.001). The TD(50) of the parotid gland at 1 year after IMRT is 43.6 Gy, comparable to results from western countries. We further found that contralateral parotid and submandibular gland function preservation was correlated with reduced sticky saliva and a better QoL compared to the functional preservation of both parotid glands, as determined by the EORTC QLQ-H&N35 questionnaire. CONCLUSION: A significant correlation was found between the reduction of SEF and the mean parotid dose. Preservation of contralateral parotid and submandibular gland function predicts a better QoL compared to preservation of the function of both parotid glands.

EGFR nuclear import in gallbladder carcinoma: nuclear phosphorylated EGFR upregulates iNOS expression and confers independent prognostic impact.

BACKGROUND: The understanding of epidermal growth factor receptor (EGFR) deregulation in carcinogenesis remains incomplete. We investigated the implications of EGFR gene status and EGFR nuclear translocation in gallbladder carcinoma (GBCA). METHODS: Subcellular localization of EGFR and phosphorylated EGFR (pEGFR) was analyzed by fractional immunoblotting and confocal immunofluorescence in GBCA cell lines. pEGFR binding to iNOS promoter was assessed by chromatin immunoprecipitation with iNOS promoter activity evaluated by luciferase assay. EGFR, pEGFR, and iNOS were immunohistochemically assessable for localization and level in the training set of 104 GBCAs on tissue microarrays, with 76 cases analyzed for EGFR gene by chromogenic in situ hybridization (CISH) and mutant-enriched PCR targeting exons 19 and 21. The prognostic impact of nuclear pEGFR (N-pEGFR) immunoexpression was reaffirmed on whole sections of 58 GBCAs in the test set. RESULTS: Nuclear expression of EGFR and pEGFR was substantiated in vitro with augmented activity of iNOS promoter elicited by pEGFR binding upon EGF treatment. Despite no mutation, EGFR amplification, identified in 11 cases (15%) by CISH, strongly correlated with cytoplasmic EGFR expression (P < 0.001) but not with disease-specific survival (DSS). Immunoexpression of nuclear EGFR (N-EGFR), cytoplasmic pEGFR, and N-pEGFR was strongly related to that of iNOS (all ≤0.005). N-pEGFR independently predicted worse DSS in both training (P = 0.0468, HR = 2.024) and test sets (P = 0.0223, HR = 5.573). CONCLUSIONS: N-EGFR and N-pEGFR express in GBCA, conferring clinical aggressiveness partly through iNOS transactivation. Lacking response-predicting mutation, EGFR gene status, albeit amplified in 15% of GBCA, is neither related to nuclear EGFR translocation nor prognostically useful.

Left brachiocephalic vein perforation: computed tomographic features and treatment considerations.

OBJECTIVE: To report the clinical and computed tomographic findings of 5 cases of left brachiocephalic vein perforation (LBCVP). METHODS: The clinical and imaging features of 5 patients with LBCVP (1 woman, 4 men; mean age, 57.6 years) encountered over the last 2 decades were reviewed. RESULTS: Etiologies included left jugular central catheter penetration in 2 patients, blunt trauma in 2, and idiopathic in 1. All patients manifested acute chest pain with a widened mediastinum on chest radiographs. Characteristic computed tomographic features included a cord-like hematoma along the course of the left brachiocephalic vein associated with a left upper anterior mediastinal hematoma (AMH). Three clinically stable patients with AMH smaller than 5 cm convalesced after conservative treatment and 2 clinically unstable patients with AMH bigger than 7 cm recovered well after surgery. CONCLUSIONS: Computed tomography is helpful in diagnosing LBCVP. Under close surveillance, patients with stable LBCVP with AMH smaller than 5 cm may be managed conservatively. However, emergency surgery is warranted if there are any signs of instability.

Retrotracheal thymoma masquerading as esophageal submucosal tumor.

A 42-year-old man presented with a two-year history of progressive dysphagia and hoarseness. Esophagogram and endoscopy revealed submucosal mass effect on the upper esophagus. Computed tomography and magnetic resonance imaging revealed an elongated mass in the retrotracheal region of the lower neck with extension to the posterior mediastinum. Partial tumor resection and histopathological evaluation revealed a WHO type B2 thymoma. Adjuvant radiation and chemotherapy were subsequently administered resulting in complete tumor regression. To our knowledge, this is the first report of ectopic retrotracheal thymoma with clinical and imaging manifestations mimicking those for esophageal submucosal tumor.