Correlation between PET-CT and ct in the staging after the treatment of head and neck squamous cell carcinoma.

OBJECTIVE: The aim of this study is to find out if a single imaging test is enough to follow-up on an oncological post-treatment patient. In such a case, we would know which was more valuable after comparing the two, by CT or PET-CT. METHODS: Between January 2012 and July 2018, we collected data from all patients with previous medical history who were treated with a head and neck squamous cell carcinoma in our hospital, through surgery or by using an organ preservation protocol which we had done. Patients were required to have a CT and a PET-CT performed in a maximum period of 30 days between techniques. We compared the post post-treatment stage given to each case by using only the physical examination (only the CT and the PET-CT), with the ones given by the Tumor Board. After treatment, we analysed the similarity through Cramer's V statistic test. RESULTS: We performed a comparative analysis, obtaining a correlation of 0.426 between the stages given by the Tumor Board and the one assigned based on physical examination, without imaging techniques. By only using the computed tomography as an imaging method the correlation was 0.565, whereas with only the use of positron emission computed technology, it was estimated at 0.858. When we compared the statistical association between stages using exclusively one of the two imaging techniques, the correlation was 0.451. CONCLUSION: Independent of the modality, we have demonstrated that in patients who have received previous treatment, there was a higher correlation in the stages with respect to the diagnostic method conducted by the Tumor Board using PET-CT as the sole image. LEVEL OF EVIDENCE: Level 1.

Correlation between PET/CT and CT in the staging prior to the treatment of head and neck squamous cell carcinoma / Correlação entre PET/TC e TC no estadiamento pré tratamento do carcinoma espinocelular de cabeça e pescoço

Abstract Introduction: Head and neck squamous cell carcinoma is the seventh most common malignant tumor. The advances in treatment have improved the global survival rates in the past years, although the prognosis is still grave. Objective: The aim of the present study is to evaluate the correlation between positron emission computed tomography and computed tomography at the time of staging a previously untreated head and neck squamous cell carcinoma, and to determine which of the two imaging techniques gives us more information at the time of initial diagnosis. Methods: Data from all patients diagnosed in our hospital of head and neck squamous cell carcinoma by a biopsy of any location or unknown primary tumor was collected, between January 2012 and July 2017. In all cases, computed tomography and positron emission computed tomography were performed with a maximum of 30 days difference between them and patients had not received any prior treatment to staging. The stage given to each case was compared based solely on the physical examination, only on the computed tomography/positron emission computed tomography, with respect to the stage given by the tumor board, observing the concordance obtained through Cramer's V statistical test. Results: We performed a comparative analysis obtaining a correlation of 0.729 between the stage given by the tumor board and the one assigned based on the physical examination without imaging techniques. When only using computed tomography as an imaging method, the correlation was 0.848, whereas with only the use of positron emission computed tomography it was estimated at 0.957. When comparing the statistical association between staging using exclusively one of the two imaging techniques, correlation was 0.855. Conclusion: Positron emission computed tomography is useful for the diagnosis of head and neck squamous cell carcinoma, improving the patient's staging especially when detecting cervical and distant metastases. Therefore, we consider that the use of positron emission computed tomography for the staging of patients with head and neck squamous cell carcinoma is a diagnostic test to be considered.

Resumo Introdução: O carcinoma espinocelular de cabeça e pescoço é o sétimo tumor maligno mais comum. Os avanços no tratamento melhoraram as taxas de sobrevida global nos últimos anos, embora o prognóstico ainda seja grave. Objetivo: Avaliar a correlação entre a tomografia computadorizada por emissão de pósitrons e a tomografia computadorizada no estadiamento de carcinomas espinocelulares da cabeça e pescoço não tratados previamente e verificar qual das duas técnicas de imagem nos fornece mais informações no momento do diagnóstico inicial. Método: Os dados de todos os pacientes diagnosticados em nosso hospital com carcinoma espinocelular de cabeça e pescoço por biópsia de qualquer região ou adenopatias de origem desconhecida foram colhidos no período entre janeiro de 2012 e julho de 2017. Em todos os casos, uma tomografia computadorizada e uma tomografia computadorizada por emissão de pósitrons foram realizadas com um máximo de 30 dias de diferença entre elas. Nenhum paciente deveria ter recebido tratamento antes do estadiamento. O estadiamento atribuído a cada caso foi comparado com base apenas no exame físico, pela tomografia computadorizada ou apenas pela tomografia computadorizada por emissão de pósitrons, com relação ao estadiamento concedido pela margem tumoral, observou-se a concordância obtida pelo teste estatístico de V de Cramer. Resultado: Realizamos a análise comparativa obtendo uma correlação de 0,729 entre o estadio concedido pela margem tumoral e aquele atribuído com base no exame físico sem técnicas de imagem. Usando apenas a tomografia computadorizada como método de imagem, a correlação foi de 0,848, enquanto que a correlação com a tomografia computadorizada por emissão de pósitrons foi estimada em 0,957. Ao comparar a associação estatística entre o estadiamento usando exclusivamente uma das duas técnicas de imagem, foi de 0,855. Conclusão: Tomografia computadorizada por emissão de pósitrons é útil para o diagnóstico de carcinoma espinocelular de cabeça e pescoço, melhora o estadiamento, especialmente na detecção de metástases cervicais e à distância. Portanto, concluimos que seu uso para o estadiamento de pacientes com carcinoma espinocelular de cabeça e pescoço é um exame diagnóstico a ser considerado.

Correlation between PET/CT and CT in the staging prior to the treatment of head and neck squamous cell carcinoma.

INTRODUCTION: Head and neck squamous cell carcinoma is the seventh most common malignant tumor. The advances in treatment have improved the global survival rates in the past years, although the prognosis is still grave. OBJECTIVE: The aim of the present study is to evaluate the correlation between positron emission computed tomography and computed tomography at the time of staging a previously untreated head and neck squamous cell carcinoma, and to determine which of the two imaging techniques gives us more information at the time of initial diagnosis. METHODS: Data from all patients diagnosed in our hospital of head and neck squamous cell carcinoma by a biopsy of any location or unknown primary tumor was collected, between January 2012 and July 2017. In all cases, computed tomography and positron emission computed tomography were performed with a maximum of 30 days difference between them and patients had not received any prior treatment to staging. The stage given to each case was compared based solely on the physical examination, only on the computed tomography/positron emission computed tomography, with respect to the stage given by the tumor board, observing the concordance obtained through Cramer's V statistical test. RESULTS: We performed a comparative analysis obtaining a correlation of 0.729 between the stage given by the tumor board and the one assigned based on the physical examination without imaging techniques. When only using computed tomography as an imaging method, the correlation was 0.848, whereas with only the use of positron emission computed tomography it was estimated at 0.957. When comparing the statistical association between staging using exclusively one of the two imaging techniques, correlation was 0.855. CONCLUSION: Positron emission computed tomography is useful for the diagnosis of head and neck squamous cell carcinoma, improving the patient's staging especially when detecting cervical and distant metastases. Therefore, we consider that the use of positron emission computed tomography for the staging of patients with head and neck squamous cell carcinoma is a diagnostic test to be considered.

Structural Characterization of the Fla2 Flagellum of Rhodobacter sphaeroides.

UNLABELLED: Rhodobacter sphaeroides is a free-living alphaproteobacterium that contains two clusters of functional flagellar genes in its genome: one acquired by horizontal gene transfer (fla1) and one that is endogenous (fla2). We have shown that the Fla2 system is normally quiescent and under certain conditions produces polar flagella, while the Fla1 system is always active and produces a single flagellum at a nonpolar position. In this work we purified and characterized the structure and analyzed the composition of the Fla2 flagellum. The number of polar filaments per cell is 4.6 on average. By comparison with the Fla1 flagellum, the prominent features of the ultra structure of the Fla2 HBB are the absence of an H ring, thick and long hooks, and a smoother zone at the hook-filament junction. The Fla2 helical filaments have a pitch of 2.64 µm and a diameter of 1.4 µm, which are smaller than those of the Fla1 filaments. Fla2 filaments undergo polymorphic transitions in vitro and showed two polymorphs: curly (right-handed) and coiled. However, in vivo in free-swimming cells, we observed only a bundle of filaments, which should probably be left-handed. Together, our results indicate that Fla2 cell produces multiple right-handed polar flagella, which are not conventional but exceptional. IMPORTANCE: R. sphaeroides possesses two functional sets of flagellar genes. The fla1 genes are normally expressed in the laboratory and were acquired by horizontal transfer. The fla2 genes are endogenous and are expressed in a Fla1(-) mutant grown phototrophically and in the absence of organic acids. The Fla1 system produces a single lateral or subpolar flagellum, and the Fla2 system produces multiple polar flagella. The two kinds of flagella are never expressed simultaneously, and both are used for swimming in liquid media. The two sets of genes are certainly ready for responding to specific environmental conditions. The characterization of the Fla2 system will help us to understand its role in the physiology of this microorganism.

In Rhodobacter sphaeroides, chemotactic operon 1 regulates rotation of the flagellar system 2.

Rhodobacter sphaeroides is able to assemble two different flagella, the subpolar flagellum (Fla1) and the polar flagella (Fla2). In this work, we report the swimming behavior of R. sphaeroides Fla2(+) cells lacking each of the proteins encoded by chemotactic operon 1. A model proposing how these proteins control Fla2 rotation is presented.