Dosimetric comparison and assessment of second cancer risk between helical tomotherapy and intensity-modulated radiotherapy in children with craniospinal irradiation / 中华放射肿瘤学杂志

Objective To investigate the dosimetric characteristics between helical tomotherapy ( HT) and intensity-modulated radiotherapy ( IMRT) plans in children receiving craniospinal irradiation and estimate the risk of radiogenic second cancer according to the excess absolute risk ( EAR) model. Methods Computer-tomography scans of 15 children who received craniospinal irradiation between 2012 and 2017 were selected. HT and IMRT plans were designed for each patient after contouring the volumes of tumors and organ at risks ( OARs) and then the homogeneous index ( HI) , conformity index ( CI) , the maximum dose and the mean dose of OAR,V10 and V20 were analyzed to optimize the clinical treatment plan. The second cancer risk was estimated by DVH of each organ and EAR model and statistically compared between HT and IMRT. Results Both two plans met the clinical requirements in target coverage ( 100％ dose≥95％ target volume).The HI in the HT group was significantly superior to that in the IMRT group (P=0. 000) whereas no significant difference was noted in CI between two groups. Compared with the IMRT plan, HT plan possessed absolute advantage in protecting hippocampus and the D2％ and Dmean were significantly lower ( P=0. 000).As for the protection of OAR, the Dmax, Dmean and V20 of thyroid (P=0. 001,0. 002 and 0. 014) and Dmax,V10 of heart ( P=0. 001 and 0. 003) in the HT plan were significantly lower than those in the IMRT plan. In terms of second cancer risk, HT plan yielded a significantly higher second cancer risk for thyroid and lung compared with IMRT the EAR in thyroid was 28. 666 vs. 26. 926 ( P=0. 010 ) and 20. 496 vs. 18.922( P=0. 003) in lung. Both plans yielded a relatively high second cancer risk for stomach ( P=0. 248), whereas a low second cancer risk for liver (P=0. 020). Conclusions HT plan is superior to IMRT plan in the hippocampus-sparing craniospinal irradiation in children. However, HT plan yields a high second cancer risk for thyroid and lung. Consequently, the balance between the carcinogenic risk and the effect on other normal tissues should be assessed in the establishment of therapeutic plan.

Experiencia clínica en segundos cánceres primarios / Second primary cancer: review of 196 cases

Background: A second primary cancer is that occurring in patients who have survived a previous cancer and its frequency is 16 percent. Aim: To identify and characterize patients with a second primary cancer treated in a clinical hospital. Material and methods: Review of the database of the Clinical Oncology Unit of a surgical department between 2004 and 2012. Among 4,007 patients operated for cancer, 196 (mean age 63 years, 51 percent women) had a previous history of cancer, whose medical records were reviewed. Results: In the study period the frequency of a second primary cancer in endocrinological, thoracic and digestive surgery was 4.9 percent. There was a mean lapse of 8.2 years between the first and second cancer and 24 percent of patients had a family history of cancer. The second primary lesions were located in colon in 26 percent, stomach in 19 percent, thyroid in 16 percent, rectum in 12 percent, pancreas in 8 percent and lung in 8 percent. Sixty five percent of lesions was diagnosed in stage IV with peritoneal and lung metastases in 38 and 25 percent respectively. Conclusions: Second primary cancer is uncommon in this series. The high frequency of colon cancer must be highlighted. Due to the lapse between the first and second tumor, follow up of patients treated for cancer should be maintained for at least eight years.

Introducción: El segundo cáncer primario (SCP) es aquel ocurrido en pacientes sobrevivientes de cáncer y tiene una frecuencia de 16 por ciento según Surveillance Epidemiology and End Results. Objetivo: Identificar y caracterizar a los pacientes con SCP en nuestro hospital entre los años 2004 y 2012. Materiales y métodos: Estudio observacional descriptivo retrospectivo. Revisión en base de datos registrados en la Unidad de Oncología Clínica del Departamento de Cirugía entre 2004-2012. De un total de 4.007 pacientes operados por cáncer, se identificaron 196 con antecedentes previos de cáncer. Revisión de fichas Clínicas, Registro en programa Excel y análisis en sistema Stata v11. Resultados: El SCP en cirugía endocrinológica, torácica, coloproctológica y digestiva tiene una frecuencia de 4,9 por ciento en el período estudiado. La edad promedio de presentación es 63 años, 51 por ciento mujeres y 48 por ciento varones. Intervalo promedio de 8,2 años entre el primer y el segundo cáncer. 23,47 por ciento tenía antecedentes familiares. Los pacientes presentaron cáncer de colon en un 26,02 por ciento, seguido de cáncer gástrico 18,88 por ciento, cáncer de tiroides 15,8 por ciento, cáncer de recto 11,73 por ciento, cáncer de páncreas 8,16 por ciento, cáncer de pulmón 7,65 por ciento. El 65,5 por ciento fue diagnosticado en etapa IV, siendo las metástasis más frecuentes al peritoneo (37,5 por ciento) y pulmón (25 por ciento). Conclusión: El segundo primario es una entidad poco frecuente en nuestro medio, destacando la alta incidencia de cáncer de colon. El intervalo de presentación sugiere mantener un seguimiento prolongado de al menos 8 años.

Second Malignanat Solid Neoplasms in Children Treated with Radiotherapy: Report of Two Cases and Review of Literature / 대한치료방사선과학회지

Radiotehrapy and chemotherapy can effectively control cancer but can also cause new second cancers to develop as long-term complications especially in childhood cancer. We experienced two patients with second malignant solid neoplasm who had been treated with radiation and chemotherapy for childhood cancers. One female patients with rhabdomyosarcoma of the right popliteal fossa was treated with radiotherapy at total dose of 54 Gy. Three years and seven months later, osterosarcoma developed in the field of radiation therapy. The other male patient with non-Hodgkin's lymphoma of the small bowel was treated with radiotherapy and leiomyosarcoma developed in the field of radiotherapy 18 years later. We reviewed the literature of the second malignant neoplasm in children in respect of risk factors. The risk for a second primay cancer following radiotherapy or chemotherapy emphasizes the need for life long follow-up of patients receiving such treatments. Particularly patients treated for childhood cancers.