Comparison of the two histological subtypes of ampullary adenocarcinoma: a retrospective study.

OBJECTIVES: This study aimed to compare the intestinal and pancreatobiliary subtypes of ampullary adenocarcinoma in a large patient group due to limited data on survival and risk factors. METHODS: A retrospective analysis of the clinical and pathological findings and the survival of 184 patients with ampullary adenocarcinoma who underwent curative operation between 2007 and 2018 was performed. RESULTS: Pancreatobiliary subtype had a higher prevalence of jaundice before operation than the intestinal subtype (p < 0.05). Pancreatobiliary subtype had a larger tumor size (> 2 mm) (p < 0.01) and poorer differentiation (p < 0.05) than the intestinal subtype. Perineural invasion more frequently occurred in pancreatobiliary subtype than the intestinal subtype (p < 0.01) and pancreatobiliary subtype had a higher prevalence of positive dissected lymph nodes (p < 0.05) with an advanced disease stage (p < 0.01) than the intestinal subtype. Patients of the pancreatobiliary subtype had poorer disease-free and overall survival than patients of the intestinal subtype. No survival benefit of adjuvant chemotherapy was found in either patients of the intestinal subtype or pancreatobiliary subtype. No significant difference was found in any subtypes regarding the recurrent regions. CONCLUSIONS: Pancreatobiliary subtype exhibited a higher recurrence rate and a poorer overall survival rate with more unfavorable pathological characteristics than the intestinal subtype.

OBJETIVOS: Los datos sobre la supervivencia y los factores de riesgo del adenocarcinoma ampular son limitados debido a su rareza. Este estudio buscó comparar el subtipo intestinal y el subtipo pancreático-biliar en pacientes con adenocarcinoma ampular. MÉTODOS: Análisis retrospectivo de hallazgos clínicos y patológicos y la supervivencia de 184 pacientes con adenocarcinoma ampular tratados entre 2007 y 2018. RESULTADOS: El subtipo pancreático-biliar tuvo una mayor prevalencia de ictericia antes de la operación y un tamaño de tumor mayor, y una peor diferenciación, que el subtipo intestinal. La invasión perineural fue más frecuente en el subtipo pancreático-biliar, con una mayor prevalencia de linfonodos disecados positivos y un estadio avanzado de la enfermedad. Los pacientes del subtipo pancreático-biliar tuvieron una supervivencia libre de enfermedad y una supervivencia general peores que los pacientes del subtipo intestinal. No se encontró ningún beneficio de la quimioterapia adyuvante en pacientes del subtipo intestinal o pancreático-biliar. No hubo diferencia significativa en las regiones recurrentes. CONCLUSIÓN: El subtipo pancreático-biliar mostró una tasa de recurrencia y una tasa de supervivencia general peores, con características patológicas más desfavorables que el subtipo intestinal.

Peripheral dose measurements in cervical cancer radiotherapy: a comparison of volumetric modulated arc therapy and step-and-shoot IMRT techniques.

PURPOSE: The aim of this study was to investigate the peripheral doses resulting from volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) techniques in cervical cancer radiotherapy. METHODS: Nine patients with cervical cancer had treatment planned with both VMAT and IMRT. A specially designed phantom was used for this study, with ion chambers placed at interest points approximating the position of the breast, thyroid, and lens. The peripheral doses at the phantom interest points were measured and compared between the VMAT and IMRT techniques. RESULTS: VMAT provides a potential dosimetric advantage compared with IMRT. The mean (± standard deviation) peripheral dose to the breast point for 1 fraction (2 Gy) during VMAT measured 5.13 ± 0.96 mGy, compared with 9.04 ± 1.50 mGy for IMRT. At the thyroid and lens interest points, the mean (± standard deviation) peripheral dose during VMAT was 2.19 ± 0.33 and 2.16 ± 0.28 mGy, compared with 7.07 ± 0.76 and 6.97 ± 0.91 mGy for IMRT, respectively. VMAT reduced the monitor units used by 28% and shortened the treatment delivery time by 54% compared with IMRT. CONCLUSION: While the dosimetric results are similar for both techniques, VMAT results in a lower peripheral dose to the patient and reduces the monitor-unit usage and treatment delivery time compared with IMRT.

Peripheral dose from megavoltage cone-beam CT imaging for nasopharyngeal carcinoma image-guided radiation therapy.

The growing use of cone-beam computed tomography (CBCT) for IGRT has increased concerns over the additional radiation dose to patients. The in-field dose of IGRT and the peripheral dose (PD) from kilovoltage CBCT (KV-CBCT) imaging have been well quantified. The purpose of this work is to evaluate the peripheral dose from megavoltage CBCT (MV-CBCT) imaging for nasopharyngeal carcinoma IGRT, to determine the correlation of peripheral dose with MU protocol and imaging field size, and to estimate out-of-field organ-at-risk (OAR) dose delivered to patients. Measurements of peripheral MV-CBCT doses were made with a 0.65 cm(3) ionization chamber placed inside in a specially designed phantom at various depths and distances from the imaging field edges. The peripheral dose at reference point inside the phantom was measured with the same ionization chamber to investigate the linearity between MUs used for MV-CBCT imaging and the PD. The peripheral surface doses at the anterior, lateral, and posterior of the phantom at various distances from the imaging field edge were also measured with thermoluminescent dosimeters (TLDs). Seven nasopharyngeal carcinoma patients were selected and scanned before treatment with head-neck protocol, and the peripheral surface doses were measured with TLDs placed on the anterior, lateral, and posterior surfaces at the axial plane of 15 cm distance from the field edge. The measured peripheral doses data in the phantom were utilized to estimate the peripheral OAR dose. Peripheral dose from MV-CBCT imaging increased with increasing number of MUs used for imaging protocol and with increasing the imaging field size. The measured peripheral doses in the phantom decreased as distance from the imaging field edges increased. PD also decreased as the depth from the phantom surface increased. For the patient PD measurements, the anterior, lateral, and posterior surface doses of 15 cm distance from the field edge were 2.84 × 10(-2), 1.01 × 10(-2), and 0.78 × 10(-2) cGy/MU, respectively. The lens, thyroid, breast, and ovary and testicle, which are outside the treatment and imaging fields, were estimated to receive peripheral OAR doses from MV-CBCT imaging of 42.4 × 10(-2), 11.9 × 10(-2), 1.4 × 10(-2), 1.0 × 10(-2), and 0.5 × 10(-2) cGy/MU, respectively. In conclusion, MV-CBCT generates a peripheral dose beyond the edge of the MV-CBCT scanning field that is of a similar order of magnitude to the peripheral dose from kV-CBCT imaging. In clinic, using the smallest number of MUs allowable and reducing MV-CBCT scanning field size without compromising acquired image quality is an effective method of reducing the peripheral OAR dose received by patients.