Prostate brachytherapy with iodine-125 seeds: analysis of a single institutional cohort

ABSTRACT Objectives: Brachytherapy (BT) with iodine-125 seeds placement is a consolidated treatment for prostate cancer. The objective of this study was to assess the clinical outcomes in patients with prostate cancer who underwent low-dose-rate (LDR) -BT alone in a single Brazilian institution. Materials and Methods: Patients treated with iodine-125 BT were retrospectively assessed after at least 5 years of follow-up. Patients who received combination therapy (External beam radiation therapy-EBRT and BT) and salvage BT were not included. Results: 406 men were included in the study (65.5% low-risk, 30% intermediate-risk, and 4.5% high-risk patients). After a median follow-up of 87.5 months, 61 (15.0%) patients developed biochemical recurrence. The actuarial biochemical failure-free survival (BFFS) at 5 and 10 years were 90.6% and 82.2%, respectively. A PSA nadir ≥ 1 ng / mL was associated with a higher risk of biochemical failure (HR = 5.81; 95% CI: 3.39 to 9.94; p ≤ 0.001). The actuarial metastasis-free survival (MFS) at 5 and 10 years were 98.3% and 94%, respectively. The actuarial overall survival (OS) at 5 and 10 years were 96.2% and 85.1%, respectively. Acute and late grade 2 and 3 gastrointestinal toxicities were observed in 5.6%, 0.5%, 4.6% and 0.5% of cases, respectively. For genitourinary the observed acute and late grade 2 and 3 toxicities rates were 57.3%, 3.6%, 28% and 3.1%, respectively. No grade 4 and 5 were observed. Conclusions: BT was effective as a definitive treatment modality for prostate cancer, and its endpoints and toxicities were comparable to those of the main series in the literature.

Prostate brachytherapy with iodine-125 seeds: analysis of a single institutional cohort.

OBJECTIVES: Brachytherapy (BT) with iodine-125 seeds placement is a consolidated treatment for prostate cancer. The objective of this study was to assess the clinical outcomes in patients with prostate cancer who underwent low-dose-rate (LDR) -BT alone in a single Brazilian institution. MATERIALS AND METHODS: Patients treated with iodine-125 BT were retrospectively assessed after at least 5 years of follow-up. Patients who received combination therapy (External beam radiation therapy-EBRT and BT) and salvage BT were not included. RESULTS: 406 men were included in the study (65.5% low-risk, 30% intermediate-risk, and 4.5% high-risk patients). After a median follow-up of 87.5 months, 61 (15.0%) patients developed biochemical recurrence. The actuarial biochemical failure-free survival (BFFS) at 5 and 10 years were 90.6% and 82.2%, respectively. A PSA nadir ≥ 1 ng / mL was associated with a higher risk of biochemical failure (HR = 5.81; 95% CI: 3.39 to 9.94; p ≤ 0.001). The actuarial metastasis-free survival (MFS) at 5 and 10 years were 98.3% and 94%, respectively. The actuarial overall survival (OS) at 5 and 10 years were 96.2% and 85.1%, respectively. Acute and late grade 2 and 3 gastrointestinal toxicities were observed in 5.6%, 0.5%, 4.6% and 0.5% of cases, respectively. For genitourinary the observed acute and late grade 2 and 3 toxicities rates were 57.3%, 3.6%, 28% and 3.1%, respectively. No grade 4 and 5 were observed. CONCLUSIONS: BT was effective as a definitive treatment modality for prostate cancer, and its endpoints and toxicities were comparable to those of the main series in the literature.

Evaluation of a composite Gel-Alanine phantom on an end-to-end test to treat multiple brain metastases by a single isocenter VMAT technique.

PURPOSE: This work aims to evaluate the application of a cylindrical phantom made of dosimetric gel containing alanine pellets distributed inside the gel volume during an end-to-end test of a single isocenter VMAT for simultaneous treatment of multiple brain metastases. The evaluation is based on the comparison of the results obtained with the composite phantom with the treatment planning system (TPS) dose distribution validated by using the clinical conventional quality control with point and planar dose measurements. METHODS: A cylindrical MAGIC-f gel phantom containing alanine dosimeters (composite phantom) was used to design the VMAT plan in the treatment planning system (TPS). The alanine dosimeters were pellets with radius of 2.5 mm and height of 3 mm, and played the role of brain metastasis inside the gel cylinder, which simulated the cerebral tissue. Five of the alanine dosimeters were selected to simulate five lesions; five planning target volumes (PTVs) were created including the dosimeters and irradiated with different doses. Conventional quality assurance (QA) was performed on the TPS plan and on the composite phantom; a phantom containing only gel (Gel 1 phantom) was also irradiated. One day after irradiation, magnetic resonance images were acquired for both phantoms on a 3T scanner. An electron spin resonance spectrometer was used to evaluate alanine doses. Calibration curves were constructed for the alanine and the gel dosimeters. All the gel only measurement was repeated (Gel 2 phantom) in order to confirm the previous gel measurement. RESULTS: The VMAT treatment plan was approved by the conventional QA. The doses measured by alanine dosimeters on the composite gel phantom agreed to the TPS on average within 3.3%. The alanine dose for each lesion was used to calibrate the gel dosimeter measurements of the concerned PTV. Both gel dose volume histograms (DVH) achieved for each PTV were in agreement with the expected TPS DVH, except for a small discrepancy observed for the Gel 2 curve of PTV1 and the Gel 1 curve of PTV5. In a 3D gamma analyses performed for each PTV volume independently, comparing both the gels' measurements to the TPS and using 3%/3 mm, 5%/2 mm, and 7%/2 mm, more than 90% of the points were approved for all the PTVs, except for the PTV5 comparison in the Gel 1 measurement and for the PTV2 comparison in the Gel 2 measurement. A 3D gamma analysis was also applied for each PTV independently, to compare both gel measurements in order to evaluate the consistence of repeated gel measurements of the same plan, and more than 94.5% of the points were approved. CONCLUSIONS: The composite Gel-Alanine phantom can be used for the end-to-end test of a single isocenter VMAT for simultaneous treatment of multiple brain metastases. The use of the alanine as the lesion cores for the treatment planning provided the precise dose measurements inside each lesion and allowed the conversion of the gel R2 values based on an accurate dose measurement inside the target.

Effects of different radiation doses on the microhardness, superficial morphology, and mineral components of human enamel.

OBJECTIVE: To evaluate the effects of three different radiotherapy doses (20, 40, and 70Gy) on the microhardness, superficial morphology, and mineral content (based on Ca and P values) of three different depths of human enamel (cervical, middle, and occlusal). DESIGN: Thirty-four third molars were cut, separated, and prepared. Microhardness samples (n=30) were embedded in acrylic resin and then polished, and depths were delimited. Microhardness tests were performed on cervical, middle, and occlusal enamel pre- and post-radiotherapy with a load of 50g for 30s. For the scanning electron microscopy (SEM) analysis (n=4) and energy dispersive X-ray spectroscopy (EDS) (n=12), samples were fixed in a 3% glutaraldehyde solution, washed in 0.1M cacodylate solution, and dehydrated in crescent concentrations of ethanol. Microhardness data were tested for significant differences using a two-way analysis of variance (ANOVA) and Tukey's test (p<0.05), while SEM and EDS were evaluated qualitatively. RESULTS: The results showed a decrease in microhardness values only in the cervical enamel, regardless of the radiation dose used; no morphological or mineral change was observed. CONCLUSION: Radiotherapy can affect the microhardness values of only cervical enamel without compromising the morphological or mineral (Ca and P) content at any depth.

Radiation dose distribution in the teeth, maxilla, and mandible of patients with oropharyngeal and nasopharyngeal tumors who were treated with intensity-modulated radiotherapy.

BACKGROUND: The purpose of this study was to evaluate the distribution of the intensity-modulated radiotherapy (IMRT) dose delivered to the teeth, maxilla, and mandible. METHODS: The mean dose (Dmean) and maximum dose (Dmax) of radiation for the maxilla, mandible, and teeth of 63 patients with oropharyngeal (n = 44) or nasopharyngeal (n = 19) tumors were retrospectively evaluated. RESULTS: The posterior regions of the mandible received the highest doses, and the teeth received lower doses than the bones (maximum dose, p < .001; average dose, p < .001). The Dmax (p < .001) and Dmean (p < .001) depended on primary tumor location. The superior bones and teeth of patients with nasopharyngeal tumors received more radiation than those of patients with oropharyngeal tumors. CONCLUSION: A dose distribution map was generated based on the estimated doses received, which could allow prediction of the areas most affected by radiation and facilitate further correlations with dental complications after radiotherapy. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

Effects of Different Radiation Doses on the Bond Strengths of Two Different Adhesive Systems to Enamel and Dentin.

PURPOSE: To evaluate the effects of three different radiation doses on the bond strengths of two different adhesive systems to enamel and dentin. MATERIALS AND METHODS: Eighty human third molars were randomly divided into four groups (n = 20) according to the radiation dose (control/no radiation, 20 Gy, 40 Gy, and 70 Gy). The teeth were sagittally sectioned into three slices: one mesial and one distal section containing enamel and one middle section containing dentin. The sections were then placed in the enamel and dentin groups, which were further divided into two subgroups (n = 10) according to the adhesive used. Three restorations were performed in each tooth (one per section) using Adper Single Bond 2 (3M ESPE) or Universal Single Bond (3M ESPE) adhesive system and Filtek Z350 XT (3M ESPE) resin composite and subjected to the microshear bond test. Data were analyzed using a two-way ANOVA followed by Tukey's test. Failure modes were examined under a stereoscopic loupe. RESULTS: Radiotherapy did not affect the bond strengths of the adhesives to either enamel or dentin. In dentin, the Universal Single Bond adhesive system showed higher bond strength values when compared with the Adper Single Bond adhesive system. More adhesive failures were observed in the enamel for all radiation doses and adhesives. CONCLUSION: Radiotherapy did not influence the bond strength to enamel or dentin, irrespective of the adhesive or radiation dose used.

Biochemical control of prostate cancer with iodine-125 brachytherapy alone: experience from a single institution.

AIM: Brachytherapy is an adequate option as monotherapy for localised prostate cancer. The objective of this study was to evaluate and compare biochemical failure free survival (BFFS) after low-dose-rate brachytherapy (LDRB) alone for patients with prostate cancer using ASTRO and Phoenix criteria, and detect prognostic factors. METHODS: Data on 220 patients treated between 1998 and 2002 with LDRB were retrospectively analysed. Neoadjuvant hormone therapy was used in 74 (33.6%) patients. RESULTS: Median follow-up was 53.5 months (24-116). Five year BFFS was 83.0% and 83.7% using, respectively, the ASTRO and Phoenix criteria. Low -and intermediate- risk patients presented, respectively, 86.7% and 77.8% 5-year BFFS using the ASTRO definition (p=0.069), and 88.5% and 78.6% considering the Phoenix criteria (p=0.016). Bounce was observed in 66 (30%) patients. Multivariate analysis detected PSA at diagnosis <10 ng/ml and less than 50% positive biopsy fragments as favourable prognostic factors, regarding BF using both criteria. For the Phoenix criteria, also Gleason score <7 and low-risk group were identified as independent favourable prognostic factors. CONCLUSIONS: LDRB alone should be considered mostly for low-risk patients. PSA level was a strong independent prognostic factor. We support the use of the Phoenix criteria for detection of BF in patients submitted to LDRB alone.

Role of intra- or periprostatic calcifications in image-guided radiotherapy for prostate cancer.

PURPOSE: Image-guided radiotherapy (IGRT) allows more precise localization of the prostate, thus minimizing errors resulting from organ motion and set-up during treatment of prostate cancer. Using megavoltage cone-beam computed tomography (MVCBCT), references such as bones, the prostate itself or implanted fiducial markers can be used as surrogates to correct patient positioning immediately before each treatment fraction. However, the use of fiducials requires an invasive procedure and may increase costs. We aimed to assess whether intra- or periprostatic calcifications (IPC) could be used as natural fiducials. METHODS AND MATERIALS: Data on patients treated with IGRT for prostate cancer with clearly visible IPC and implanted fiducials in both planning CT and MVCBCT images were reviewed. IPC were classified as central when inside the prostate and peripheral when within the planning target volume. Daily deviations in lateral, longitudinal, and vertical directions from baseline positioning using fiducials and using IPC were compared. RESULTS: A total of 287 MVCBCT images were obtained and analyzed from 10 patients. The mean ± standard deviation daily deviation (mm) in the lateral, longitudinal, and vertical coordinates were 0.55 ± 3.11, 0.58 ± 3.45, and -0.54 ± 4.03, respectively, for fiducials, and 0.72 ± 3.22, 0.63 ± 3.58, and -0.69 ± 4.26, for IPC. The p values for comparisons (fiducials vs. IPC) were 0.003, 0.653, and 0.078 for lateral, longitudinal, and vertical coordinates, respectively. When cases with central IPC were analyzed (n = 7), no significant difference was found in such comparisons. Central IPC and fiducials exhibited a similar pattern of displacement during treatment, with equal values for daily displacements in the three directions for more than 90% of measurements. CONCLUSIONS: Our data suggest that centrally located IPC may be used as natural fiducials for treatment positioning during IGRT for prostate cancer, with potential reductions in the risks and costs associated with fiducial implantation.

Educação a Distância (EaD) em Física Médica / Distance education within medical physics / Educación a Distancia (EaD) en Física Médica

A formação inicial e continuada de profissionais de física médica possui características peculiares por ser uma área interdisciplinar, de evolução tecnológica constante. Em países como o Brasil, existem barreiras como: pequeno número de profissionais, geograficamente mal distribuídos, baixos recursos financeiros, e poucas opções em termos de acesso à informação, dificultando a incorporação e disseminação de novas técnicas que impactam na qualidade do atendimento em saúde. Esta revisão da literatura se propôs a avaliar o papel da EaD na educação de físicos médicos, retratando sua aplicabilidade mediante a identificação de experiências relevantes. Os trabalhos mostram que a EaD tem características interessantes para a área, tais como alta efetividade pedagógica e eficiência econômica, possibilitando o uso massivo de recursos multimídia, com grande abrangência geográfica e de forma gerenciável. Portanto tem potencial para superar as barreiras e suprir carências da área.

Pre-service and in-service education relating to medical physics have peculiar characteristics since this is an interdisciplinary field with constant technological evolution. In countries like Brazil, several barriers exist, such as small numbers of professionals who are geographically poorly distributed, low financial resources and few options for information access, thereby hindering and delaying the incorporation and dissemination of new techniques that could have an impact on healthcare quality. This literature review evaluated the role of distance education within medical physics, and portrayed its applicability through identifying relevant experiences. Studies have shown that distance education within this field presents interesting characteristics, such as high pedagogical effectiveness and economic efficiency, which enables massive use of multimedia resources with wide geographical coverage, in a manageable way. Therefore, distance education has potential to overcome the barriers and meet the needs.

La formación y la educación continua de profesionales en física médica tiene características únicas, es un campo interdisciplinario, donde la tecnología está en evolución constante. Países como Brasil, tienen barreras como: número reducido de profesionales, geográficamente distribuidos de forma desigual, escasos recursos financieros y pocas opciones en términos de acceso a información, dificultando la incorporación y difusión de nuevas técnicas que afectan la calidad de atención en salud. Esta revisión de literatura evalúa el papel de EaD en la educación de físicos médicos, retratando su aplicabilidad mediante identificación de experiencias relevantes. Artículos muestran que EaD tiene características interesantes para la física médica, como alta eficacia pedagógica y eficiencia económica, permitiendo uso masivo de recursos mediáticos, con amplia cobertura geográfica y de forma manejable. Por lo tanto, la herramienta tiene potencial para superar los obstáculos y satisfacer las necesidades del área.

The value of positron-emission tomography/computed tomography for radiotherapy treatment planning: a single institutional series.

BACKGROUND: This study aimed to compare the clinical target volumes (CTV) delineated by computed tomography (CT) and positron emission tomography (PET)/CT using fluoro-deoxy-glucose to assess the impact of using PET information for radiotherapy (RT) planning. METHODS: We retrospectively reviewed data on patients with tumors from different sites who had indications for RT and had undergone RT treatment planning with PET/CT at our institution between July 2003 and July 2009. Statistical analysis included the comparison of CTV planned for treatment only by CT (CTV(CT)) with that by PET/CT (CTV(PET)) using the Wilcoxon test for paired samples. RESULTS: Of 105 patients eligible for analysis, 56.2% were men. The most common diagnoses were head and neck cancer (28.6%), lung cancer (21.9%), lymphoma (11.4%), upper gastrointestinal (10.5%), and others (14.3%). Comparison of CTV(CT) and CTV(PET) revealed that RT planning has changed in 77% of cases because of PET/CT additional information, with impact on treatment volume varying according to diagnosis. Despite the absolute difference observed between median CTVs, there was no significant difference between CTV(CT) and CTV(PET) (114 vs. 90.4 ml, respectively; P=0.1266), considering all patients. Nonetheless, a significant difference between CTVs delineated by CT and PET/CT was found when only head and neck, lung and lymphoma cases--representing more than 60% of the sample--were examined (112.5 and 80.7 ml, respectively; P=0.0053). CONCLUSION: We have shown that PET/CT use promotes significant changes in the CTV delineated for treatment of different tumors, modifying RT planning. Our data suggest that PET/CT has a good potential for optimizing RT treatment planning, especially in head and neck, lung, and lymphoma tumors.

Mycosis fungoides: case report treated with radiotherapy.

Mycosis fungoides is a rare type of non-Hodgkin's lymphoma of T cells that primarily affects the skin. It is characterized by the presence of erythematous plaques that evolve into ulcerated lesions, tumors throughout the skin or even bone marrow infiltration in advanced stages. Chemotherapy and topical steroids, phototherapy and radiotherapy are treatment options for early cases. This study reports the case of patient with multiple tumor lesions in the skin already biopsied with diagnosis of mycosis fungoides. The patient was refractory to both treatments with topical chemotherapy and phototherapy. It was then indicated total skin irradiation with electrons.

Micose fungoide: relato de caso tratado com radioterapia / Mycosis fungoides: case report treated with radiotherapy

Micose fungoide é um tipo de linfoma não Hodgkin de células T raro que acomete primariamente a pele. Caracteriza-se pela presença de placas eritematosas que evoluem para lesões ulceradas, tumores em toda a pele ou ainda infiltração de medula óssea em estágios avançados. Como opção de tratamento para os casos iniciais, tem-se quimioterapia e corticoterapia tópica, fototerapia e radioterapia. Este estudo relata o caso de um doente com múltiplas lesões tumorais na pele já biopsiadas com diagnóstico de micose fungoide. O paciente foi refratário ao tratamento com quimioterapia tópica e fototerapia, sendo então indicada irradiação total da pele com elétrons.

Mycosis fungoides is a rare type of non-Hodgkin's lymphoma of T cells that primarily affects the skin. It is characterized by the presence of erythematous plaques that evolve into ulcerated lesions, tumors throughout the skin or even bone marrow infiltration in advanced stages. Chemotherapy and topical steroids, phototherapy and radiotherapy are treatment options for early cases. This study reports the case of patient with multiple tumor lesions in the skin already biopsied with diagnosis of mycosis fungoides. The patient was refractory to both treatments with topical chemotherapy and phototherapy. It was then indicated total skin irradiation with electrons.

Braquiterapia endobrônquica de alta taxa de dose: técnica de tratamento / High dose rate endobronchial brachytherapy: treatment technique

A braquiterapia endobrônquica de alta taxa de dose é um tratamento paliativo eficiente para neoplasias endobrônquicas obstrutivas. Entretanto, seu papel na melhora da sobrevida dos pacientes com tumores de pulmäo ainda näo está comprovado. Sua utilizaçäo tem sido crescente, principalmente no nosso meio. O objetivo deste trabalho é apresentar a técnica de tratamento utilizada pelo Serviço de Radioterapia do HC-FMUSP, com base na experiência de 60 casos tratados, num total de 180 procedimentos. Algumas sugestöes práticas e normas adotadas no Serviço säo descritas. O índice de complicaçäes severas é de 6,7 por cento, demonstrando uma adequada seleçäo de pacientes associada à técnica utilizada