Información sobre riesgo, prevención, detección, síntomas, diagnosis, tratamiento y apoyo para el cáncer.
Información sobre el tratamiento del cáncer incluyendo quirúrgica, quimioterapia, radioterapia, estudios clínicos, terapia con protón, medicina complementaria avanzadas.
OncoLink se complace en ofrecer una amplia lista de lista completa de los agentes quimioterapéuticos más comúnmente usados??. Esta guía de referencia incluye información sobre la forma en que cada fármaco se administra, cómo funcionan, y los pacientes los efectos secundarios comunes pueden experimentar.
Maneras que los pacientes de cáncer y las personas que le cuidan puedan enfrentar el cáncer, los efectos secundarios, nutrición, cuestiones en general sobre el apoyo para el cáncer, duelo/decisiones sobre el termino de vida, y experiencias compartidas por sobrevivientes.
Profesionales de la salud / / / /
Reviewer: Eric Shinohara MD, MSCI
Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 26 de mayo del 2008
Presenter: Frederick Vernimmen
Presenter's Affiliation: Stellenbosch University
Type of Session: Scientific
Materials and Methods
This is a retrospective single institution review of long term control in AVM, meningiomas and acoustic neuromas treated with fractionated stereotactic proton therapy. A total of 500 patients have been treated at Ithemba labs since 1993 and of these 500 patients, 81 were treated for AVM, 41 for meningioma, and 64 for acoustic neuroma. The majority of the 500 patients were treated with radiosurgery as the beam was available only two days a week. Only small fields were available due to limitation related to the passive scatter beam that was used.All patients were treated with 3-4 fields with two to three fractions. Fractions were given twice a week (Monday and Friday) and all fields were treated daily. A fixed 200 MeV passive scatter photon beam was used for treatment and custom collimation was used for each patient. Each patient was treated using a non-invasive stereophotogrammatic patient support and positioning system. A mask and bite block was used for immobilization. Markers on the mask were monitored using a video camera system and aligned using a computerized adjustable chair. Treatment planning was done using Voxelplan with the addition of Proxelplan for the Bragg peak dose calculation model. No distal beam shaping was used.
Current radiotherapy techniques with gamma knife and linac based stereotactic radiotherapy have been fairly effective in the treatment of the above mentioned benign conditions. How then do protons potentially improve on what can be achieved with photon based radiosurgery? There is the potential for better conformality with proton beam therapy due to the ability to control the distal boarder of the treatment field. Spot scanning beam proton therapy may allow even greater control of the dose distribution and spare even more normal tissue, which due to the location of these masses is critical. Specifically, in acoustic neuromas hearing preservation as well as sparing of the facial nerve is important and it may be possible to improve on the rates of nerve damage with proton therapy, perhaps best with fractionated therapy rather than radiosurgery. The present study appears to show a high rate of preservation of the facial nerve and hearing despite the higher dose used in the present study. The AVM, acoustic neuromas and meningiomas tended to be larger in this study and it is possible that proton based radiosurgery may be able to address larger tumors than can be treated with gammaknife safely. However, the proton range is not absolute and there is some uncertainty about where the distal boarder ends. Hence, until we are better able to account for this it critical to consider this uncertainty during treatment planning.
Whenever treating benign disease with radiation it is always important to consider serious side effects as these diseases can often be treated with other modalities and are usually not fatal. Secondary malignancy is one of the most serious potential late effects and unfortunately more follow up is needed for all three groups. In theory, there should be less dose delivered to normal tissues with proton therapy reducing the risk for secondary malignancy. Retrospective data from Harvard suggest that secondary malignancy is uncommon with proton treatment, despite concerns about neutron contamination. Hence, secondary malignancy may not be a large problem in the long term follow up of these patients.
For proton therapy to become a standard indication for treatment of these lesions, clinical trials showing superiority over conventional stereotactic and gamma knife are needed due to the cost of this therapy over the other modalities. This is particularly important in a disease where currently available treatments are tolerated well and successful.
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