International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Aug 2005
Multicenter Study Comparative StudyLack of benefit from a short course of androgen deprivation for unfavorable prostate cancer patients treated with an accelerated hypofractionated regime.
High-dose radiotherapy, delivered in an accelerated hypofractionated course, was utilized to treat prostate cancer. Therapy consisted of external beam radiotherapy (EBRT) and transrectal ultrasound (TRUS)-guided conformally modulated high-dose rate (HDR) brachytherapy. The purpose of this report is (1) to assess long-term comparative outcomes from three trials using similar accelerated hypofractionated regimes; and (2) to examine the long-term survival impact of a short course of < or =6 months adjuvant/concurrent androgen deprivation when a very high radiation dose was delivered. ⋯ Accelerated hypofractionated pelvic EBRT integrated with TRUS-guided conformally modulated HDR administered to 1,260 patients in three institutions was an excellent method of delivering very high radiation dose to the prostate in 5 weeks. Similar high overall, cause-specific, and biochemical no evidence of disease survival rates achieved show that prostate HDR can be successfully delivered in academic and community settings. At 8 years, the addition of a course of < or =6 months of neoadjuvant/concurrent androgen deprivation therapy to a very high radiation dose did not confer a therapeutic advantage but added side effects and cost. Furthermore, for the most unfavorable group, there was a higher rate of distant metastasis and more prostate cancer-related deaths. We question the value of a short course of androgen deprivation therapy when used with high-dose radiation.
-
Int. J. Radiat. Oncol. Biol. Phys. · Aug 2005
Comparative StudyImportance of protocol target definition on the ability to spare normal tissue: an IMRT and 3D-CRT planning comparison for intraorbital tumors.
We selected five intraorbital tumor sites that are frequently found in clinical practice in children diagnosed with orbital rhabdomyosarcoma and performed three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated photon radiotherapy (IMRT) planning. Results of target coverage and doses to critical structures were compared. The goal of this study was to evaluate and to document realistic expectations as to organ-sparing capabilities of modern radiation therapy planning technologies with a focus on lens-sparing irradiation. Furthermore, we investigated potential added benefits of IMRT compared with 3D-CRT and the influence of protocol volume criteria definitions on the ability to obtain normal tissue dose sparing using the orbit as an example of a complex anatomic site. ⋯ Strict adherence to IRS-V protocol criteria prohibits at present lens sparing within compliance criteria for the majority of intraorbital tumor locations because of protocol-specific CTV and PTV target definitions. Changing protocol definitions by prescribing to the volume rather than to a dose constraint, IMRT planning significantly reduced lens doses. This was not accomplished to the same degree with 3D-CRT. Our study underlines the importance of appropriate selection of planning objectives to maximize the specific capabilities and advantages of IMRT in terms of sufficient target coverage and simultaneous sparing of critical structures. Our results can add to the ongoing discussion in the design of future 3D-CRT/IMRT protocols.
-
Int. J. Radiat. Oncol. Biol. Phys. · Aug 2005
Review Clinical TrialDose-volume analysis of predictors for chronic rectal toxicity after treatment of prostate cancer with adaptive image-guided radiotherapy.
We analyzed our experience treating localized prostate cancer with image-guided off-line correction with adaptive high-dose radiotherapy (ART) in our Phase II dose escalation study to identify factors predictive of chronic rectal toxicity. ⋯ In our ART dose escalation study, rectal wall or rectum relative > or =V50 are closely predictive for chronic rectal toxicity. If rectal dose-volume histogram constraints are used to select the dose level, the risk of chronic rectal toxicity will reflect the risk of toxicity of the selected constraint rather than the dose selected as found in our study using an adaptive process. To select the prescribed dose, different dose-volume histogram constraints may be used including the rectal wall V70. Patients experiencing acute rectal toxicity are more likely to experience chronic toxicity.
-
Int. J. Radiat. Oncol. Biol. Phys. · Aug 2005
ReviewVaginal brachytherapy alone is sufficient adjuvant treatment of surgical stage I endometrial cancer.
To determine the efficacy and complications of adjuvant vaginal high-dose-rate brachytherapy alone for patients with Stage I endometrial cancer in whom complete surgical staging had been performed. ⋯ Adjuvant vaginal high-dose-rate brachytherapy alone may be a safe and effective alternative to pelvic external beam radiotherapy for surgical Stage I endometrial cancer.