International journal of radiation oncology, biology, physics
-
Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Can histopathologic assessment of circumferential margin after preoperative pelvic chemoradiotherapy for T3-T4 rectal cancer predict for 3-year disease-free survival?
This study set out to determine the impact of a positive circumferential resection margin (CRM) (R1-R2) and pathologic downstaging on local recurrence and survival in patients with borderline resectable or unresectable rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy (CRT). ⋯ After 5-fluorouracil-based CRT, a positive CRM predicted for a high risk of subsequent local recurrence and a 3-year disease-free survival rate of only 9%. For this reason, the CRM should be considered a major prognostic factor and should be validated in future trials as an early alternative clinical endpoint.
-
Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Whole pelvic radiotherapy for prostate cancer using 3D conformal and intensity-modulated radiotherapy.
To investigate the correlations between observed clinical morbidity and dosimetric parameters for whole pelvic radiotherapy (WPRT) for prostate cancer using either three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT). ⋯ Compared to conventional 2D planning, conformal planning for WPRT resulted in significant reductions in the doses delivered to the bowel, rectum, and bladder. IMRT was superior to 3D-CRT in limiting the volume of bowel and rectum within high-dose regions. These dosimetric findings correlated with low rates of acute and late GI morbidity.
-
Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Spinal reirradiation after short-course RT for metastatic spinal cord compression.
To investigate the feasibility and effectiveness of reirradiation (re-RT) for in-field recurrence of metastatic spinal cord compression after primary RT with 1 x 8 Gy or 5 x 4 Gy. ⋯ Spinal re-RT with 1 x 8 Gy, 5 x 3 Gy, or 5 x 4 Gy for in-field recurrence of metastatic spinal cord compression appears safe and effective. Myelopathy seems unlikely, if the cumulative biologically effective dose is < or = 100 Gy2.
-
Int. J. Radiat. Oncol. Biol. Phys. · Nov 2005
Changes in tumor cell response due to prolonged dose delivery times in fractionated radiation therapy.
Dynamic radiation therapy, such as intensity-modulated radiation therapy, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The cellular damage after a full treatment may depend on the dose rate, because sublethal radiation damage can be repaired more efficiently during prolonged dose delivery. The goal of this study was to investigate the significance of this effect in fractionated radiation therapy. ⋯ If the total dose delivery time for a treatment fraction in radiation therapy increases to about 20 min, a correction for dose rate effects may have to be considered in treatment planning. Adjustments in effective dose may be necessary when comparing intensity-modulated radiation therapy with conventional treatment plans.