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.
Reviewer: John J. Wilson, MD
The Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 19 de junio del 2005
The RTOG (Radiation Therapy Oncology Group) initiated dose escalation protocol 93-11 for patients with stage I-III lung cancer in order to attempt improvement in local control. Three-dimensional conformal radiotherapy was used to increase the dose but minimize normal tissue toxicity to structures such as the lungs, spinal cord and esophagus. There is no clear data for the optimal dose to treat inoperable non-small cell lung cancer (NSCLC), but local control rates have shown improvement with increasing dose in prior studies. Due to the proximity of important normal structures, the tumor dose has traditionally been limited to 60-70 Gy. Arriagada et al showed only a 17% pathological local control rate after a dose of 65 Gy. From principles advocated by Fletcher, it is thought that doses approaching 100 Gy may be needed.
This study focused on the long-term toxicity associated with radiation dose escalation in non-small cell lung cancer. In order to escalate the dose safely, the study authors omitted the traditional treatment of clinically negative (but high risk) nodal regions, or so-called "elective nodal irradiation." They mention that the highest dose arm (90.3Gy) in Group 1 was too toxic. They also note that there is no obvious benefit seen with dose escalation, but remark that the trial was not designed to detect a difference, but rather only to evaluate safety.
The authors mention that one problem with dose escalation demonstrating a lack of efficacy is that the treatment is too prolonged (up to 42 fractions), and thus hypofractionation might address this problem when used with concurrent chemotherapy, as in the ongoing RTOG L-0177 trial. However, they do not mention that the only hypofractionated arm in this trial had to close early because of unacceptable lung toxicity. Also, they do not mention that one of the potential reasons for the locoregional failures might be the omission of elective nodal irradiation, as half of the isolated locoregional failures did in fact occur outside of the radiation field.
The study shows that the overall survival for the Stage III patients was superior to historical controls, but note that these patients all had had relatively low-volume disease compared to typical Stage III patients, and therefore likely represent a more favorable subset. The reported elective nodal failure was <10%, but this is for isolated failure only, and there were another 16% of patients who had locoregional failure in addition to distant metastases. Locoregional failure in itself arguably contributes to the distant failure, but there is no further data presented here as to whether the patients with combined locoregional and distant failure had locoregional failure inside or outside the radiation field.
As a follow-up to this study, the future results of the L-0177 trial evaluating dose escalation and concurrent chemotherapy will be very informative, although there is serious concern that the toxicities of this protocol will prove unacceptable. A potential new trial design might compare elective nodal irradiation to dose escalation in order to test whether "the juice is worth the squeeze", and whether omitting the elective nodes affects locoregional control and distant metastases. This comparison would be most meaningful both with and without concurrent chemotherapy, as many patients are simply not able to tolerate concurrent chemotherapy. Finally, incorporating targeted agents along with radiation may provide significant benefit and perhaps even obviate the need for dose intensification in the future.
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