Proctitis crónica hemorrágica por radioterapia en el Instituto Nacional de Enfermedades Neoplásicas del Perú, 2011-2013 / Radiotherapy associated chronic hemorrhagic proctitis at the National Institute of Neoplastic Diseases of Peru, 2011-2013

Objetivo: Estudiar las características clínicas y endoscópicas de la proctitis crónica hemorrágica por radioterapia en el Instituto Nacional de Enfermedades Neoplásicas del Perú. Materiales y métodos: Estudio descriptivo, retrospectivo y longitudinal, con una población de 588 pacientes con esta patología, en el periodo 2011-2013, de donde se seleccionaron 114 pacientes por muestreo probabilístico aleatorizado. Se usó la estadística descriptiva e inferencial para el análisis de las variables cualitativas y cuantitativas. Resultados: La investigación encontró como principales resultados, un periodo de latencia de 439,96 días; la severidad de rectorragia clínica fue grado II y III en el 86,84%, la hemoglobina media fue de 11,63 gr/dl, los hallazgos endoscópicos fueron severidad moderada en el 58,77%, extensión solo rectal en el 92,11%, friabilidad leve del 43,86%, compromiso menor del 33% de la superficie rectal en el 71,93% y una longitud media de 7,28 cm. Los hallazgos inflamatorios fueron de cicatrices en el 0,88%, erosiones del 0,88%, de úlceras del 7%, de fístula del 0,88% y del 3,51% de estenosis rectales, el tratamiento de argón plasma coagulación (APC) único o combinado se ofreció en el 96% de los casos. Conclusiones: La proctitis crónica hemorrágica por radioterapia fue una complicación importante de la radioterapia pélvica, con hallazgos clínicos y endoscópicos característicos.

Objective: To study the clinical and endoscopic features of chronic hemorrhagic proctitis by radiotherapy in the National Institute of Neoplastic Diseases of Peru. Materials and methods: The study was descriptive, retrospective and longitudinal, with a population of 588 patients with this pathology, in the period 2011-2013, from which 114 patients were selected by randomized probabilistic sampling. Descriptive and inferential statistics were used for the analysis of qualitative and quantitative variables. Results: The main results were a latency period of 439.96 days; the severity of clinical rectal bleeding was grade 2 and 3 in 86.84%, the mean hemoglobin in chronic hemorrhagic proctitis by radiotherapy was 11.63 g / dl, the endoscopic findings were moderate severity in 58.77%, extension rectal only in 92.11%, slight friability of 43.86%, compromise less than 33% of the rectal surface in 71.93% and an average length of 7.28 cm. The inflammatory findings were 0.88% scars, erosions of 0.88%, ulcers of 7%, fistula of 0.88% and 3.51% of rectal stenosis, single or combined argon plasma coagulation (APC) treatment was offered in 96% of cases. Conclusion: Chronic hemorrhagic proctitis is an important complication of pelvic radiotherapy, with characteristic clinical and endoscopic findings.

Implantation of a biodegradable rectum balloon implant: Tips, Tricks and Pitfalls

ABSTRACT Introduction: A rectum balloon implant (RBI) is a new device to spare rectal structures during prostate cancer radiotherapy. The theoretical advantages of a RBI are to reduce the high radiation dose to the anterior rectum wall, the possibility of a post-implant correction, and their predetermined shape with consequent predictable position. Objective: To describe, step-by-step, our mini-invasive technique for hands-free transperineal implantation of a RBI before start of radiotherapy treatment. Materials and Methods: We provide step-by-step instructions for optimization of the transperineal implantation procedure performed by urologists and/or radiation oncologists experienced with prostate brachytherapy and the use of the real-time bi-plane transrectal ultrasonography (TRUS) probe. A RBI was performed in 15 patients with localised prostate cancer. Perioperative side-effects were reported. Results: We provide 'tips and tricks' for optimizing the procedure and proper positioning of the RBI. Please watch the animation, see video in https://vimeo.com/205852376/789df4fae4. The side-effects included mild discomfort to slight pain at the perineal region in 8 out of 15 patients. Seven patients (47%) had no complaints at all. Two patients developed redness of the skin, where prompt antibiotic regimen was started with no further sequelae. One patient revealed a temporary urine retention, which resolved in a few hours following conservative treatment. Further no perioperative complications occurred. Conclusion: This paper describes in detail the implantation procedure for an RBI. It is a feasible, safe and very well-tolerated procedure.

Long term outcome and side effects in patients receiving low-dose I125 brachytherapy: a retrospective analysis

ABSTRACT Objectives: To retrospectively evaluate the disease free survival (DFS), disease specific survival (DSS),overall survival (OS) and side effects in patients who received low-dose rate (LDR) brachytherapy with I125 stranded seeds. Materials and methods: Between july 2003 and august 2012, 274 patients with organ confined prostate cancer were treated with permanent I125 brachytherapy. The median follow-up, age and pretreatment prostate specific antigen (iPSA) was 84 months (12-120), 67 years (50-83) and 7.8 ng/mL (1.14-38), respectively. Median Gleason score was 6 (3-9). 219 patients (80%) had stage cT1c, 42 patients (15.3%) had stage cT2a, 3 (1.1%) had stage cT2b and 3 (1.1%) had stage cT2c. The median D90 was 154.3 Gy (102.7-190.2). Results: DSS was 98.5%.OS was 93.5%. 13 patients (4.7%) developed systemic disease, 7 patients (2.55%) had local progression. In 139 low risk patients, the 5 year biochemical freedom from failure rate (BFFF) was 85% and 9 patients (6.4%) developed clinical progression. In the intermediate risk group, the 5 year BFFF rate was 70% and 5 patients (7.1%) developed clinical progression. Median nPSA in patients with biochemical relapse was 1.58 ng/mL (0.21 – 10.46), median nPSA in patients in remission was 0.51 ng/mL (0.01 – 8.5). Patients attaining a low PSA nadir had a significant higher BFFF (p<0.05). Median D90 in patients with biochemical relapse was 87.2 Gy (51 – 143,1). Patients receiving a high D90 had a significant higher BFFF (p<0.05). Conclusion: In a well selected patient population, LDR brachytherapy offers excellent outcomes. Reaching a low PSA nadir and attaining high D90 values are significant predictors for a higher DFS.

Toxicity of Tomotherapy-Based Simultaneous Integrated Boost in Whole-Pelvis Radiation for Prostate Cancer

PURPOSE: The validity of tomotherapy-based simultaneous integrated boost (TOMOSIB) was assessed in terms of acute intestinal/urinary toxicity by comparing with 3-dimensional conformal radiotherapy (3DCRT) in cases of whole-pelvis radiation therapy (WPRT) for prostate cancer. MATERIALS AND METHODS: Thirty-eight consecutive patients who underwent curative WPRT were retrospectively reviewed. Twenty six (68.4%) received 3DCRT and the others (31.6%) were treated with TOMOSIB. A local boost to the prostate circumferential area was added to WPRT sequentially for 3DCRT and concomitantly for TOMOSIB. The total median prostate or prostatic bed dose was 64.8 Gy including median 45.0 Gy of WPRT. Acute toxicities were assessed according to RTOG criteria. RESULTS: Overall intestinal toxicity was lower in TOMOSIB group than 3DCRT group (p=0.008). When it was divided into rectum and non-rectum intestine (NRI), TOMOSIB showed borderline superiority only in NRI toxicity (p=0.047). For the urinary toxicity, there was no significant difference between two groups (p=0.796). On dosimetric analysis for the rectum and bladder, dose delivered to 80% (p<0.001) and volume receiving 25-40 Gy (p<0.001) were remarkably higher in 3DCRT. For the NRI, only maximum dose showed significant results between two groups (p<0.001). CONCLUSION: Intestinal toxicity should be verified with more detailed anatomic categorization such as rectum and NRI. TOMOSIB could not reduce urinary toxicity because of inevitably high dose exposure to the prostatic urethra. Current dosimetry system did not properly reflect intestinal/urinary toxicity, and suitable dosimetric guidelines are needed in TOMOSIB.

Toxicity of Tomotherapy-Based Simultaneous Integrated Boost in Whole-Pelvis Radiation for Prostate Cancer

PURPOSE: The validity of tomotherapy-based simultaneous integrated boost (TOMOSIB) was assessed in terms of acute intestinal/urinary toxicity by comparing with 3-dimensional conformal radiotherapy (3DCRT) in cases of whole-pelvis radiation therapy (WPRT) for prostate cancer. MATERIALS AND METHODS: Thirty-eight consecutive patients who underwent curative WPRT were retrospectively reviewed. Twenty six (68.4%) received 3DCRT and the others (31.6%) were treated with TOMOSIB. A local boost to the prostate circumferential area was added to WPRT sequentially for 3DCRT and concomitantly for TOMOSIB. The total median prostate or prostatic bed dose was 64.8 Gy including median 45.0 Gy of WPRT. Acute toxicities were assessed according to RTOG criteria. RESULTS: Overall intestinal toxicity was lower in TOMOSIB group than 3DCRT group (p=0.008). When it was divided into rectum and non-rectum intestine (NRI), TOMOSIB showed borderline superiority only in NRI toxicity (p=0.047). For the urinary toxicity, there was no significant difference between two groups (p=0.796). On dosimetric analysis for the rectum and bladder, dose delivered to 80% (p<0.001) and volume receiving 25-40 Gy (p<0.001) were remarkably higher in 3DCRT. For the NRI, only maximum dose showed significant results between two groups (p<0.001). CONCLUSION: Intestinal toxicity should be verified with more detailed anatomic categorization such as rectum and NRI. TOMOSIB could not reduce urinary toxicity because of inevitably high dose exposure to the prostatic urethra. Current dosimetry system did not properly reflect intestinal/urinary toxicity, and suitable dosimetric guidelines are needed in TOMOSIB.

Análisis del volumen rectal en pacientes con cáncer de próstata: temprano durante la radioterapia conformada / Analysis of rectal volume in patients with early prostate cancer: during the 3D radiation therapy

Se realiza un estudio observacional, descriptivo y cuantitativo, con descripción numérica de los datos, con el objetivo de determinar el cambio del volumen rectal en noventa pacientes con cáncer de próstata durante el tratamiento radiante. Utilizamos técnica de radioterapia conformada y tres dimensiones. El método complementario elegido para valorar el cambio del volumen de la ampolla rectal fue una tomografía axial computarizada de pelvis durante el tratamiento radiante. En el 86% de pacientes se evidenció la ampolla rectal con material fecal y gaseoso; y en 14% restante se encontraba vacía. Los diámetros promedios fueron de: 23,4 mm para ampolla rectal vacía y 32,8 mm para la ampolla rectal dilatada, los cambios del volumen rectal alteran la posición del volumen blanco de tratamiento radiante (próstata). Recomendamos efectuar la radioterapia entre las 15 y las 18 horas de acuerdo a la fisiología y practicar a todo paciente una manometría ano-rectal.

We realized a study observational, descriptive and quantitative with numeric description of date, we carry out this work to determine the change of rectal volume in 90 patients with diagnostic of prostate cancer during radiant treatment. We utilize conformal radiation therapy technique in tree dimension. The complementary method used to valor the changes in the volume of the rectal was axial computer tomography of the pelvis during the radiation treatment. In 86% of patients we evidence the rectal blister with fecal and gaseous material the rest 14% blister was empty. The average of diameters were 23.4 mm to the blister empty and 38.8 mm to the rectal dilated blister, the changes in the rectal volume alter the volume target of the radiation treatment (prostate). Recommend do the radiation therapy between the 15 and 18 hours in relation with physiology and practice to all patients a rectal manometer study.

Brachytherapy for stage IIIB squamous cell carcinoma of the uterine cervix: survival and toxicity / Braquiterapia para carcinoma epidermóide do colo do útero estádio IIIB: sobrevida e toxicidade

OBJECTIVE: To compare survival and toxicity of three different treatments for stage IIIB cervix cancer: low-dose-rate (LDR), high-dose-rate (HDR) brachytherapy and association of HDR and chemotherapy. METHODS. Between 1985 and 2005, 230 patients with FIGO stage IIIB squamous cell carcinoma of the uterine cervix received 4-field pelvic teletherapy at doses between 40 and 50.4 Gy, with a different complementation in each group. The LDRB group, with 42 patients, received one or two insertions of LDR, with Cesium-137, in a total dose of 80 to 100Gy at point A. The HDR group, 155 patients received HDR in 4 weekly 7 Gy fractions and 9 Gy to 14.4 Gy applied to the involved parametria. The CHT group, 33 patients, were given the same treatment as the HDR group and received 5 or 6 weekly cycles of cisplatin, 40 mg per m2. RESULTS: The five-year progression-free survival (PFS) was 60 percent for the HDR group and 45 percent for the LDR group, and the two-year PFS for the CHT group was 65 percent (p = 0.02). The five-year Overall Survival (OS) was 65 percent for the HDR group and 49 percent for the LDR group. The two-year OS was 86 percent for the CHT group (p = 0.02). Rectum toxicity grade II was 7 percent for the LDR group, 4 percent for the HDR group and 7 percent for the CHT group that had one case of rectum toxicity grade IV. CONCLUSION: Patients that received HDR had better OS and PFS. The Chemotherapy-HDR association showed no benefit when compared to HDR only. Toxicity rates showed no difference between the three groups.

OBJETIVO: Comparar três diferentes tratamentos para câncer de colo do útero, estádio IIIB: braquiterapia de baixa taxa de dose (LDR), alta taxa de dose (HDR) e associação entre HDR e quimioterapia, quanto à sobrevida e toxicidade. MÉTODOS: Entre 1985 e 2005, 230 pacientes com carcinoma epidermoide de colo do útero estádio IIIB receberam teleterapia pélvica em quatro campos, doses entre 40 e 50.4 Gy, e três complementações diferentes. Grupo LDR, com 42 pacientes, recebeu uma ou duas inserções de LDR, com Césio-137, na dose total de 80 a 100Gy no ponto A. Grupo HDR, 155 pacientes, com HDR em quatro frações semanais de 7 Gy, e 9 Gy a 14.4 Gy nos paramétrios acometidos. Grupo CHT, 33 pacientes, tratadas da mesma forma que o grupo HDR, mais cinco ou seis ciclos semanais de cisplatina, 40 mg por m2. RESULTADOS: A sobrevida livre de progressão em cinco anos (PFS) foi 60 por cento no grupo HDR e 45 por cento no grupo LDR, e a PFS em dois anos para o grupo CHT foi 65 por cento (p = 0.02). A sobrevida global em cinco anos (OS) foi 65 por cento para o grupo HDR e 49 por cento para o grupo LDR. A OS em dois anos foi 86 por cento para o grupo CHT (p = 0.02). Toxicidade retal grau II foi 7 por cento no grupo LDR, 4 por cento no grupo HDR e 7 por cento no grupo CHT, que teve um caso de toxicidade retal grau IV. CONCLUSÃO: Pacientes que receberam HDR tiveram melhores índices de sobrevida. A associação quimioterapia-HDR não mostrou benefício quando comparada com apenas HDR. Os índices de toxicidade não foram diferentes.

[ dosimetric evaluation of organs at risk in prostate radiation therapy using a MAGIC gel dosimeter]

Multiple fields and presence of hetrerogeneities create complex dose distributions that need three dimentisonal dosimetry. In this work, we investigated MR-based MAGIC gel dosimetry as a three-dimentional dosimetry technique to measure the delivered dose to bladder and rectum in prostate radiation therapy. A heterogeneous slab phantom including bones was made. Paired cubes in the phantom representing bladder and prostate and a cylindrical container representing rectum were filled with MAGIC gel and placed in the anthropomorphic pelvic phantom. The phantom was irradiated with four beams as planned using a treatment planning system [TPS]. Magnetic resonance transverse relaxation rate images were acquired and turned into dose distribution maps using a calibration curve. This calibration curve was obtained by linear fitting to R2 values of 4 test tubes against their given known doses. Image processing and data analysis were preformed in MATLAB 7 software. The gel dosimeter was validated using an ionization chamber. Dose maps and dose volume histograms [DVHs] were compared with dose distributions and DVHs of the TPS. Mean "distance-to-agreement" and mean "does difference" were 2.98 mm and 6.2%, respectively, in the comparison of profiles obtained from ionization chamber and gel dostimetry. Mean relative difference of DHVs between gel dosimetry and TPs data were 3.04%, 10.4% and 11.7%,for prostate, bladder and rectum, respectively. Gel dosimetry is a good method for three dimensional dosimetry although it has a low precision in high close gradient regions. This method can be used for evaluation of complicated dose distribution accuracy in 3D conformal radiotherapy, especially in presence of heterogeneities

Avaliação da dose no reto em pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino / Rectal dose assessment in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer

OBJETIVO: O objetivo deste trabalho foi desenvolver um sistema dosimétrico termoluminescente capaz de avaliar as doses administradas ao reto de pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino. MATERIAIS E MÉTODOS: O material termoluminescente utilizado para a avaliação da dose no reto foi o LiF:Mg,Ti,Na na forma de pó. O pó foi separado em pequenas porções de 34 mg, que foram acomodadas em um tubo capilar. Este tubo foi colocado em uma sonda retal, que era introduzida no reto da paciente. RESULTADOS: As doses administradas ao reto de seis pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino foram avaliadas com dosímetros termoluminescentes e apresentaram boa concordância com os valores planejados, com base em duas radiografias ortogonais da paciente, imagens ântero-posterior e lateral. CONCLUSÃO: O sistema de dosimetria termoluminescente utilizado no presente trabalho é simples e de fácil utilização quando comparado a outros métodos de dosimetria do reto. Ele mostrou-se eficiente na avaliação da dose no reto de pacientes submetidas a braquiterapia de alta taxa de dose para o tratamento do câncer do colo uterino.

OBJECTIVE: The present study was aimed at developing a thermoluminescent dosimetric system capable of assessing the doses delivered to the rectum of patients submitted to high-dose-rate brachytherapy for uterine cervix cancer. MATERIALS AND METHODS: LiF:Mg,Ti,Na powder was the thermoluminescent material utilized for evaluating the rectal dose. The powder was divided into small portions (34 mg) which were accommodated in a capillary tube. This tube was placed into a rectal probe that was introduced into the patient's rectum. RESULTS: The doses delivered to the rectum of six patients submitted to high-dose-rate brachytherapy for uterine cervix cancer evaluated by means of thermoluminescent dosimeters presented a good agreement with the planned values based on two orthogonal (anteroposterior and lateral) radiographic images of the patients. CONCLUSION: The thermoluminescent dosimetric system developed in the present study is simple and easy to be utilized as compared to other rectal dosimetry methods. The system has shown to be effective in the evaluation of rectal doses in patients submitted to high-dose-rate brachytherapy for uterine cervix cancer.

Efeitos adversos tardios subseqüentes ao tratamento radioterápico para câncer de colo uterino na bexiga, reto e função sexual / Late adverse effects subsequent to radiotherapy for cervical cancer in the bladder, rectum and sexual function

O diagnóstico de câncer de colo uterino no Brasil ainda ocorre em estádios avançados, em muitos casos, o que implica na utilização da radioterapia de forma exclusiva ou combinada, com finalidade curativa ou paliativa. Os avanços tecnológicos nesta área têm propiciado melhores taxas de sobrevida e de remissão da doença. No entanto, os efeitos adversos ocasionados pela radioterapia sobre as áreas sadias adjacentes à área irradiada foram observados em muitas pesquisas realizadas em centros de radioterapia do mundo inteiro. Para mensurar a ocorrência dos efeitos adversos tardios subseqüentes à radioterapia para câncer de colo uterino na bexiga, reto e função sexual em mulheres que freqüentam o ambulatório de ginecologia do INCA, conduziu-se um estudo observacional em que foram incluídas 300 mulheres em seguimento ambulatorial em 2007, diagnosticadas entre os estágios IB e IIIB. As informações foram colhidas através de entrevistas com as pacientes no momento de comparecimento à consulta ambulatorial de seguimento e junto ao prontuário das mesmas. Os dados revelaram que a população de estudo se declarou predominantemente branca, com idade entre 40 e 60 anos, com baixa escolaridade e baixa renda. O efeito adverso mais freqüente registrado no prontuário foi a estenose vaginal. A curva de sobrevida livre de efeitos adversos tardios foi obtida através do Estimador de Kaplan - Meier. O tempo mediano até a ocorrência da estenose vaginal foi de 49,2 meses. Esse tempo variou de acordo com o estádio da doença, sendo de 59,6 meses para o grupo com estádio até IIB e de 26,3 meses para o grupo com estádios mais avançados. Só foram encontrados quatro registros de encaminhamento para o tratamento desse efeito adverso com exercícios fisioterápicos e dilatação vaginal. Levando-se em conta a diminuição da qualidade de vida das pacientes após o desenvolvimento de efeitos adversos tardios, torna-se importante o diagnóstico e o tratamento precoces dentro da rotina de seguimento ambulatorial das pacientes no HCII do INCA.

Diagnosis of cervical cancer in Brazil still occurs in advanced stages, in many cases, which implies in the use of radiotherapy for exclusive or combined treatment for curative or palliative purpose. Technological advances in this area have offered better survival rates and remission of the disease. However, side effects caused by radiation on the healthy areas adjacent to the irradiated area were observed in several studies conducted in radiotherapy centers worldwide. To measure occurrence of late side effects subsequent to radiotherapy for cervical cancer on bladder, rectum and sexual function in women attending INCA gynecology clinic during 2007, an observational study was conducted including 300 follow-up outpatients, diagnosed in stages IB to IIIB. Information was collected through patient interview during follow-up visit and by review of medical records. The results showed that the study population was predominantly white, aged between 40 and 60 years, with low education and income level. The most frequent late side effect recorded was vaginal stexnosis. Slopes of late side effects-free survival were obtained from Kaplan-Meier estimator. The median time to occurrence of vaginal stenosis was 49.2 months. This time varied according to the disease stage, with 59.6 months for the reference group (disease stage until IIB) and 26.3 months for patients in more advanced stages. Only four records were found for the vaginal stenosis treated with physiotherapy exercises and vaginal dilation. Taking into account the decrease of quality of life of patients after the development of late side effects, early diagnosis becomes very important as well as early treatment within the follow-up routine of patients in HCII of INCA.

Colitis quística profunda posradioterapia: Caso clínico / Colitis cystica profunda: Report of one case

Colitis cystica profunda is a benign condition that can be confused with adenocarcinoma. We report a 35year-old woman that received radiotherapy for a uterine cervical carcinoma who presented intermittent hematochezia three times after ending the therapy. This episode was diagnosed and treated as a radiation colitis and the patient remained asymptomatic for six years. After this period she presented again intermittent hematochezia and a rectal mass that was surgically removed. The pathology report disclosed a colitis cystica profunda.

High-dose-rate-intracavitary brachytherapy applications and the difference in the bladder and rectum doses: a study from rural centre of Maharashatra, India.

AIM: To report the difference in the bladder and rectum doses with different applications by the radiotherapists in the same patient of the carcinoma of the uterine cervix treated by multiple fractions of high-dose-rate (HDR) intracavitary brachytherapy (ICBT). MATERIALS AND METHODS: Between January 2003 to December 2004, a total of 60 cases of the carcinoma uterine cervix were selected randomly for the retrospective analyses. All 60 cases were grouped in six groups according to the treating radiotherapist who did the HDR-ICBT application. Three radiotherapists were considered for this study, named A, B and C. Ten cases for each radiotherapist in whom all three applications were done by the same radiotherapist. And 10 cases for each radiotherapist with shared applications in the same patient (A+B, A+C and B+C). The bladder and rectal doses were calculated in reference to point "A" dose and were limited to 80% of prescribed point "A" dose, as per ICRU-38 recommendations. Received dose grouped in three groups--less then 80% (< 80%), 80-100% and above 100% (>100%). A total of 180 applications for 60 patients were calculated for the above analyses. RESULTS: There is a lot of difference in the bladder and rectal doses with the application by the different radiotherapists, even in the same patient with multiple fractions of HDR-ICBT. Applications by 'A' radiotherapist were within the limits in the self as well as in the shared groups more number of times, by 'B' radiotherapist was more times exceeding the limit and by 'C' radiotherapist doses were in between the A and B. DISCUSSION AND CONCLUSION: For the rectal and bladder doses most important factors are patient's age, disease stage, duration between EBRT and HDR-ICRT and patient anatomy, but these differences can be minimized to some extent by careful application, proper packing and proper fixation.

Análisis dosimétrico en braquiterapia ginecológica de alta tasa de dosis / Dosimetric analysis in high dose rate gynecological brachytherapy

OBJETIVO: Analizar la dosimetría en braquiterapia ginecólogica para el dispositivo Fletcher-Suit-Delclos con alta tasa de dosis, mediante placas radiográficas ortogonales (anteroposterior y lateral) versus tomografía axial computada (TAC). MATERIAL Y MÉTODOS: Se compararon dosimetrías de 4 implantes, realizadas con placas ortogonales y TAC pélvico en la Unidad de Braquiterapia del Instituto Nacional del Cáncer durante el mes de febrero del año 2006. Se prescribieron dosis de 8 Gy/fracción a punto H y se evaluó dosis a vejiga, recto y vagina según norma internacional. RESULTADOS: Las dosimetrías por TAC mostraron puntos calientes superiores a las placas ortogonales, para recto un 133% y para vejiga un 260% más aproximadamente. El porcentaje de volumen blanco incluido es subestimado con la dosimetría efectuada por placas ortogonales. CONCLUSIONES: La dosimetría por placas ortogonales muestra menor exactitud que el TAC. Los volúmenes blanco no son satisfactoriamente cubiertos por la curva de isodosis prescrita. La dosis acumulada, probablemente, sea más relevante que la dosis fracción.

OBJECTIVE: We analyze the gynecologycal high dose rate brachytherapy dosimetry using the Fletcher-Suit-Delclos device, comparing orthogonal films (anteroposterior and lateral) versus axial computarized tomography. METHODS: 4 implants were analized with orthogonal films and axial computarized tomography in the Brachyhterapy Unit of the National Cancer Institute on February 2006. The dose/fraction was 8 Gy to the H point. The bladder, rectal and vaginal dose point were evaluated according to international specifications. RESULTS: Axial computarized tomography reveals hot points higher than orthogonal films dosimetries (133% and 260% for bladder and rectum respectively). The target volumen included was underestimated with the classical orthogonal film dosimetry. CONCLUSIONS: The orthogonal film dosimetry shows smaller accuracy than axial computarized tomography. The target volumens were not satisfactorily covered by the prescribed isodosis curve. The dose accumulated could, probably, be more prominent than the dose/fraction.

Three dimensional conformal radiation therapy in prostate adenocarcinoma: survival and rectal toxicity.

Technological advances in radiation beam planning and linear accelerator based radiation delivery have led to the development of three dimensional conformal radiation therapy (3D-CRT). The 3D-CRT clinical treatment in our hospital was started in September 1998 and till December 2002, 51 patients with M(0) stage prostate carcinoma were treated. Treatment method consisted of pelvis and leg immobilization, planning CT scan, marking of planning target volume and organs at risk and 3D beam plan using multileaf collimated beam shaping through beam's eye view display. Network controlled 3D conformal radiation therapy was delivered with portal image verification. The median 3D-CRT dose was 72 Gy. Of the 51 patients, 35 were followed-up till December 2002 (minimum follow-up 2 years) in whom 32 were disease free and 3 had progressive disease. Eleven patients died, 8 of progressive disease, one due to second malignancy and two of intercurrent illness. Five patients were lost for follow up during 0 - 29 months period, after 3D-CRT. The acute rectal reaction (RTOG criteria) in 51 patients was grade 0 in 4, grade I in 31 and grade II in 16. None had greater than grade II rectal toxicity. The late rectal toxicity in 49 patients who had a minimum 6 months follow-up was grade 0 in 41, grade I in 3 and grade II in 5. Our experience suggests that a dose of 72 Gy by 3D-CRT can be safely delivered to the prostate and gastrointestinal tolerance during treatment and follow-up period was excellent.

Evaluation de la toxicite aigue chez 50 patients atteints de cancer de la prostate traites par radiotherapie conformationnelle

Purpose: To report our experience with 3D conformal radiotherapy for prostate cancer material and methods: We reviewed our first 50 patients diagnosed with prostate cancer. Median follow-up was 27 months [16-40 m]. Median age 68 [52-74] T stage was T1c = 12 T2a = 14 T2b = 10 T2c = 2 T3a = 10 T3b = 1 and T3c = 1. Gleason score [GS] 4-6 50% and GS 7-8 50%. Pretreatment PSA.value of < 10 ng/ml 36%, 10-20 ng/ml 32% and >20 ng/ml 32%. Forty patients received androgen ablation therapy 2 to 6 months before radiation. 3D conformal radiotherapy was used to allow a smaller amount of rectum and bladder to be in the high dose volume. An 18 Mv linear accelerator was used. The first 21 patients received 66 Gy, 28 patients received 70 Gy and one 74 Gy.The mean prostate volume was 45 cc for patients who received androgen ablation and 54 for the others [p = 0.02]. The percentage of volume receiving more than 50 Gy [V50] was calculated for the rectum and bladder. The median V50 was 30% [10-55] for the rectum and 36% [5-70] for the bladder. Based on the RTOG grading [gr] for acute toxicity, there was no gr 3 gastrointestinal [GI] toxicity and only 1 gr 3 genitourinary [GU] toxicity. There were 9 gr 1 and 5 gr 2 GI toxicity, 10 gr 1 and 5 gr 2 GU toxicity. With our actual follow-up we have 2 late morbidities: gr 2 GLI and one erectile failure.3D conformal radiotherapy for prostate cancer has a good toxicity profile. Longer follow-up is needed to assess late toxicity and clinical outcome in this series

A rat model for radiation-induced proctitis

Radiation proctitis is a frequent acute complication encountered with pelvic irradiation. This study was aimed at establishing the optimal radiation dose for radiation-induced proctitis in rats. Female Wistar rats were used. The rectal specimens were examined morphologically at 5th and 10th day following 10-30 Gy irradiation in single fraction. With increasing dose, mucosal damage became worse, and there was a prominent reaction after > or =15 Gy. We selected 17.5 Gy as an optimal dose for radiation proctitis and examined specimens at day 1-14 and at week 4, 6, 8, and 12 after 17.5 Gy. The rectal mucosa revealed characteristic histological changes with time. An edema in lamina propria started as early as 1-2 days after irradiation and progressed into acute inflammation. On day 7 and 8, regeneration was observed with or without ulcer. Four weeks later, all regeneration processes have been completed with end result of either fibrosis or normal appearing mucosa. This study showed that the radiation injury of the rectum in rat develops in dose-dependent manner as it has reported in previous studies and suggested that 17.5 Gy in single fraction is the optimum dose to evaluate the protective effect of various medications for radiation proctitis in face of the clinical situation.

WR2721 intestinal radioprotection: morphometrical analysis

En base al elevado grado de radio-sensibilidad de la mucosa intestinal, ha sido estudiada la acción radio-protectora del acido S-2(3-an-dnopropilamino) etilfosforotioico (WR272 1) sobre el epitelio de recto de ratones expuestos cuerpo entereo a los rayos X, dosis única de 7 Gy, y sacrificados después de 1, 3, 6 y 10 días. Al comparar las muestras de segmentos del recto de animales protegidos y no protegidos, fue observado, de manera general, que en los protegidos, ha ocurrido aumento estadísticamente significativo en el número de células de la crypta por crypta (CrC/Cr) después de 1, 3, 6 y 10 días luego de la irradiación, y en el número de figuras de mitosis por crypta (MF/Cr) después de 3, 6 y 10 días. Se puede concluir que los parámetros morfométricos referidos, permitieron estimar cuantitativamente la radio-protección por el WR2721 en el recto de los ratones, evaluada por la celularidad de la cripta y por la cinética de las células epiteliales intestinales