Identifying a risk profile for thyroid cancer

The large use of simple and effective diagnostic tools has significantly contributed to the increase in diagnosis of thyroid cancer over the past years. However, there is compelling evidence that most micropapillary carcinomas have an indolent behavior and may never evolve into clinical cancers. Therefore, there is an urgent need for new tools able to predict which thyroid cancers will remain silent, and which thyroid cancers will present an aggressive behavior. There are a number of well-established clinical predictors of malignancy and recent studies have suggested that some of the patientÆs laboratory data and image methods may be useful. Molecular markers have also been increasingly tested and some of them appear to be very promising, such as BRAF, a few GST genes and p53 polymorphisms. In addition, modern tools, such as immunocytochemical markers, and the measure of the fractal nature of chromatin organization may increase the specificity of the pathological diagnosis of malignancy and help ascertain the prognosis. Guidelines designed to select nodules for further evaluation, as well as new methods aimed at distinguishing carcinomas of higher aggressiveness among the usually indolent thyroid tumors are an utmost necessity.

O uso cada vez mais freqüente de métodos diagnósticos simples e efetivos tem contribuído significativamente para um aumento no diagnóstico de câncer da tiróide nos últimos anos. Entretanto, existem importantes evidências de que muitos dos microcarcinomas papilíferos têm um comportamento indolente e podem nunca evoluir para cânceres clínicos. Existe, portanto, uma necessidade urgente de desenvolver novas ferramentas capazes de predizer quais os tumores tiroidianos que permanecerão silenciosos e quais desenvolverão comportamento agressivo. Há uma série de marcadores clínicos de evolução bem estabelecidos e alguns estudos recentes sugerem que dados laboratoriais e métodos de imagem podem ser úteis. Marcadores moleculares também vêm sendo ativamente investigados e alguns, como BRAF, os genes GST e polimorfismos de p53, parecem promissores. Além disso, marcadores imunocitoquímicos e a medida da natureza fractal da cromatina podem aumentar a especificidade do diagnóstico anatomopatológico e ajudar a predizer o prognóstico. Existe uma necessidade imperiosa de elaborarmos diretrizes destinadas a selecionar os nódulos que merecem prosseguimento em sua avaliação, assim como novos métodos capazes de identificar lesões mais agressivas entre os geralmente indolentes tumores tiroidianos.

Overexposure of radiation therapy patients in Panama: problem recognition and follow-up measures

This report summarizes and analyzes the responses of various organizations that provided assistance to the National Oncology Institute (Instituto Oncológico Nacional, ION) of Panama following the overexposure of 28 radiation therapy patients at the ION in late 2000 and early 2001. The report also looks at the long-term measures that were adopted at the ION in response to the overexposure incident, as well as implications that the incident has for other cancer treatment centers worldwide. In March 2001, the director of the ION was notified of serious overreactions in patients undergoing radiation therapy for cancer treatment. Of the 478 patients treated for pelvic cancers between August 2000 and March 2001, 3 of them had died, possibly from an overdose of radiation. In response, the Government of Panama invited international experts to carry out a full investigation of the situation. Medical physicists from the Pan American Health Organization (PAHO) were among those invited. They ascertained that 56 patients treated with partially blocked teletherapy fields for cancers of the uterine cervix, endometrium, prostate, or rectum, had had their treatment times calculated using a computerized treatment planning system. PAHO's medical physicists calculated the absorbed doses received by the patients and found that, of these 56 patients, only 11 had been treated with acceptable errors of ±5 percent. The doses received by 28 of the 56 patients had errors ranging from +10 to +105 percent. These are the patients identified by ION physicists as overexposed. Twenty-three of the 28 overexposed patients had died by September 2005, with at least 18 of the deaths being from radiation effects, mostly rectal complications. The clinical, psychological, and legal consequences of the overexposures crippled cancer treatments in Panama and prompted PAHO to assess radiation oncology practices in the countries of Latin American and the Caribbean. ION clinicians...

Este informe resume y analiza la respuesta de varias organizaciones que brindaron asistencia al Instituto Oncológico Nacional (ION) de Panamá después de la sobreexposición de 28 pacientes sometidos a radioterapia que ocurrió en el ION a finales de 2000 y principios de 2001. Además, se examinan las medidas de largo plazo adoptadas en el ION en respuesta al accidente de sobreexposición y las implicaciones que tiene este accidente para todos los centros de tratamiento oncológico en el mundo. En marzo de 2001 se le comunicaron al director del ION las reacciones adversas graves sufridas por algunos pacientes sometidos a radioterapia contra el cáncer. De los 478 pacientes tratados entre agosto de 2000 y marzo de 2001 por cánceres localizados en la región pélvica, tres habían fallecido, presumiblemente por sobredosis de radiación. A raíz de ello, el Gobierno de Panamá invitó a expertos internacionales a realizar una investigación a fondo de la situación. Entre los especialistas invitados se encontraban físicos médicos de la Organización Panamericana de la Salud (OPS), quienes comprobaron que 56 pacientes con cáncer cérvico-uterino, de endometrio, de próstata o de recto tratados mediante campos de teleterapia parcialmente bloqueados recibieron dosis calculadas mediante un sistema computarizado de planificación de tratamientos. Los físicos médicos de la OPS comprobaron que solo 11 de esos 56 pacientes recibieron una dosis absorbida dentro de los límites aceptables de ±5 por ciento. Veintiocho de los 56 pacientes recibieron dosis con errores entre +10 y +105 por ciento. De esos 28 pacientes que fueron sobreexpuestos, según los físicos del ION, 23 murieron antes de septiembre de 2005; de ellos, 18 murieron a causa de los efectos de las radiaciones, principalmente complicaciones rectales. Las consecuencias clínicas, psicológicas y jurídicas de esta sobreexposición menoscabaron gravemente los tratamientos contra el cáncer en Panamá y llevaron...

Nuclear, biological and chemical warfare. Part I: Medical aspects of nuclear warfare.

Casualties in earlier wars were due much more to diseases than to weapons. Mention has been made in history of the use of biological agents in warfare, to deny the enemy food and water and to cause disease. In the first world war chemical agents were used to cause mass casualties. Nuclear weapons were introduced in the second world war. Several countries are now involved in developing nuclear, biological and chemical weapon systems, for the mass annihilation of human beings, animals and plants, and to destroy the economy of their enemies. Recently, natural calamities and accidents in nuclear, chemical and biological laboratories and industries have caused mass instantaneous deaths in civilian population. The effects of future wars will not be restricted to uniformed persons. It is time that physicians become aware of the destructive potential of these weapons. Awareness, immediate protective measures and first aid will save a large number of persons. This series of articles will outline the medical aspects of nuclear, biological and chemical weapon systems in three parts. Part I will deal with the biological effects of a nuclear explosion. The short and long term effects due to blast, heat and associated radiation are highlighted. In Part II, the role of biological agents which cause commoner or new disease patterns is mentioned. Some of the accidents from biological warfare laboratories are a testimony to its potential deleterious effects. Part III deals with medical aspects of chemical warfare agents, which in view of their mass effects can overwhelm the existing medical resources, both civilian and military.(ABSTRACT TRUNCATED AT 250 WORDS)