Volume changes during head-and-neck radiotherapy and its impact on the parotid dose – A single-institution observational study

Aims: This study aims at assessing the volume changes that occur in the targets (gross tumor volume and planning target volume [PTV]) and the organs at risk in squamous cell carcinoma of the head and neck during radiotherapy and assessing the dose changes that occur as a result of them. Settings and Design: This was a prospective observational study in a tertiary care center after obtaining the appropriate scientific and ethics committee clearance. Subjects and Methods: Forty-five patients diagnosed with squamous cell carcinoma of the head and neck, who were treated with intensity-modulated radiotherapy in the time period from March 2018 to May 2019, were enrolled in the study. A planning computed tomography (CT) scan (CTplan) was done for all patients, followed by scans after 15 fractions (CT15) and after 25 fractions (CT25). The volume changes and the subsequent dose changes were assessed and recorded. Statistical Analysis Used: Data entry was done in MS Excel spreadsheet. The continuous variables were expressed as mean + standard deviation. The comparison of normally distributed continuous variables was done by paired t-test. Data analysis was done by SPSS (Statistical Package for the Social Sciences) version 16.0. P < 0.05 was considered statistically significant. A multivariate linear regression model was constructed to study the correlation between mean dose to the parotid glands and the other variables. All statistical modeling and analysis were done using SAS (Statistical Analysis Software) version 9.4. Results: Of the 45 patients, 25 were male and 20 were female. The majority of the patients had malignancies in the oral cavity (16) and hypopharynx (14). Most of them had Stage III/IV (AJCC v 8) disease (41). There were a 36% decrease in the PTV-high risk (PTV-HR) volume and a 6.05% decrease in the PTV-intermediate risk (PTV-IR) volume CT15. In CT25, the volume decrease in the PTV-HR and the PTV-IR was 47% and 9.06%, respectively. The parotid glands also underwent a reduction in their volume which has been quantified as 21.7% and 20.9% in the ipsilateral and contralateral parotids in CT15 and 36% and 33.6% in CT25, respectively. The D2 (dose received by 2% of the volume) and D98 (dose received by 98% of the volume) of the PTV-IR showed changes of +3.5% and –0.2% in CT15 and + 4.6% and –0.31% in CT25, respectively. The homogeneity index and conformity number of the PTV-IR changes by 0.03 and 0.08 in CT15 and by 0.04 and 0.12 in CT25, respectively. The mean dose to the ipsilateral parotid gland increased by 14% in CT15 and 19% in CT25. The mean dose to the contralateral parotid gland increased by 17% in CT15 and 25% in CT25. Conclusion: The dose to the parotid glands increases as a result of the changes that occur during the course of radiation. The changes are significant after 15 fractions of radiation. A replanning at this juncture might be considered to reduce the dose to the parotid glands

Parotiditis crónica recurrente infantil: una revisión actualizada de la literatura / Recurrent chronic parotiditis in childhood: an update of the literature

La parotiditis crónica recurrente infantil (PCRI) es una patología relevante. Su diagnóstico es principalmente clínico, pero se apoya en exámenes imagenológicos. El enfoque actual del tratamiento es diverso. El objetivo es realizar una revisión actualizada sobre las características clínicas, exámenes complementarios, modelos etiopatogénicos y protocolos terapéuticos. MATERIAL Y MÉTODO: Se realizó una búsqueda bibliográfica en PUBMED utilizando los términos libres y términos MESH: PCRI, parotiditis recurrente, parotiditis crónica y parotiditis. Los filtros utilizados fueron pacientes humanos, hasta 18 años, con resumen. En el buscador Scielo se incluyeron los términos libes Parotiditis y crónica. Se incluyeron artículos publicados en idiomas inglés, español o portugués hasta el año 2017. RESULTADOS: En el buscador PUBMED se encontraron 119 artículos de los cuales sólo se incluyeron 44. La exclusión de los artículos restantes se debió a idioma, acceso al artículo o ausencia de relación entre el artículo y la revisión propuesta. En el buscador Scielo se encontraron 6 artículos de los cuales 5 fueron seleccionados. La evaluación multidisciplinaria permite el tratamiento oportuno. Su diagnóstico es clínico pero se apoya en exámenes imagenológicos, como la ecografía y la sialografía. CONCLUSIONES: El enfoque actual de tratamiento es conservador, y la mejor evidencia disponible apoya el uso de sialendoscopia con irrigación y administración de antibióticos y/o corticoides vía conducto parotídeo, sin embargo, existirían buenos resultados con lavados intraglandulares con soluciones fisiológicas sin necesidad de sialendoscopio.

Recurrent childhood chronic parotiditis (RCCP) is a relevant pathology. Its diagnosis is mainly clinical, but it relies on imaging tests. The current treatment approach is diverse. The aim of this article is to update the clinical features, complementary tests, etiopathogenic models and therapeutic protocols of this disease. MATERIAL AND METHOD: A bibliographic search was performed in PUBMED using the free terms and MESH terms: RCCP, recurrent parotiditis, chronic parotiditis and parotiditis. The filters used were human patients, up to 18 years old, with abstract. In SCIELO the free terms included were Parotiditis and chronic. Articles published in English, Spanish or Portuguese until 2017 were included. RESULTS: In PUBMED 119 articles were found and 44 were included. The exclusion of the remaining articles was due to language, access to the article or absence of relationship between the article and the proposed revision. In SCIELO 6 articles were found 6 of which 5 were selected. The multidisciplinary asses of patients with RCCP is considered the appropriate treatment. Its diagnosis is clinical but it relies on imaging tests, such as echography and sialography. CONCLUSIONS: The current treatment approach is conservative, and the best available evidence supports the use of sialendoscopy with irrigation and administration of antibiotics and/or corticosteroids via the parotid duct. However, there would be proper results with intraglandular lavage with physiological solutions without the need for a sialendoscope.

Radioprotective Effect of Vitamin E in Parotid Glands: a Morphometric Analysis in Rats

The aim of this study was to evaluate the radioprotective effect of vitamin E on rat parotid glands by morphometric analysis. Sixty male rats were divided into 5 groups (n=6): control, in which animals received olive oil solution; olive oil/irradiated, in which animals received olive oil and were irradiated with a dose of 15 Gy of gamma radiation; irradiated, in which animals were irradiated with a dose of 15 Gy gamma radiation; vitamin E, which received α-tocopherol acetate solution; vitamin E/irradiated, which received α-tocopherol acetate solution before irradiation with a dose of 15 Gy gamma rays. Half of the animals were euthanized at 8 h, and the remaining at 30 days after irradiation. Both parotid glands were surgically removed and morphometric analysis of acinar cells was performed. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Morphometric analysis showed a significant reduction in the number of parotid acinar cells at 30 days in olive oil/irradiated and irradiated groups. In groups evaluated over time a significant reduction was shown at 30 days in olive oil/irradiated and irradiated groups, indicating that ionizing radiation caused tissue damage. The vitamin E/irradiated group presented more acinar cells than the irradiated group, but no statistically significant difference was observed (p>0.05). In conclusion, vitamin E seems to have failed as a radioprotective agent on acinar cells in rat parotid glands.

O objetivo neste estudo foi avaliar o efeito radioprotetor da vitamina E sobre glândulas parótidas de ratos por meio de análise morfométrica. Sessenta ratos machos foram divididos em cinco grupos: controle, no qual os animais receberam solução de óleo de oliva; óleo de oliva irradiado, em que os animais receberam óleo de oliva e foram irradiados com uma dose de 15 Gy de radiação gama; irradiado, em que os animais foram irradiados com uma dose de 15 Gy de radiação gama; vitamina E, no qual receberam solução de acetato α-tocoferol; vitamina E irradiado, os quais receberam solução de acetato de α-tocoferol antes da irradiação com uma dose de 15 Gy de radiação gama. Metade dos animais foi eutanasiada em 8 h, e o restante aos 30 dias após a irradiação. Ambas as glândulas parótidas foram removidas cirurgicamente e análise morfométrica das células acinares foi realizada. Os dados foram submetidos à Análise de Variância com 2 fatores e teste de Tukey (α=0,05). A análise morfométrica mostrou uma redução significativa no número de células acinares da glândula parótida aos 30 dias nos grupos óleo irradiado e irradiado. Nos grupos avaliados ao longo do tempo uma redução significativa foi mostrada aos 30 dias nos grupos óleo irradiado e irradiado, indicando que a radiação ionizante causou danos teciduais. O grupo vitamina E/irradiado apresentou mais células acinares que o grupo irradiado, mas diferença estatisticamente significante não foi observada. Em conclusão, a vitamina E parece ter fracassado como um agente radioprotetor nas células acinares das glândulas parótidas de ratos.

Epidermal growth factor receptors, testosterone levels and parotid gland changes in rats infected with Trypanosoma cruzi

It has been demonstrated that parotid glands of rats infected with Trypanosoma cruzi present severe histological alterations; changes include reduction in density and volume of the acini and duct systems and an increase in connective tissue. We evaluated the association between morphological changes in parotid glands, circulating testosterone levels and epidermal growth factor receptor (EGF-R) expression in experimental Chagas disease in rats. Animals at 18 days of infection (acute phase) showed a significant decrease in body weight, serum testosterone levels and EGF-R expression in the parotid gland compared with a control group. Since decreases in body weight could lead to a reduction in circulating testosterone concentration, we believe that the reduction in EGF-R expression in parotid glands of infected rats is due to alterations in testosterone levels and atrophy of parotid glands is caused by changes in EGF-R expression. Additionally, at 50 days (chronic phase) of infection parotid glands showed a normal histological aspect likely due to the normalization of the body weight. These findings suggest that the testosterone-EGF-R axis is involved in the histological changes.