International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Kilovoltage imaging doses in the radiotherapy of pediatric cancer patients.
To investigate doses induced by kilovoltage cone-beam computed tomography (kVCBCT) to pediatric cancer patients undergoing radiotherapy, as well as strategies for dose reduction. ⋯ Generally speaking, kVCBCT deposits much larger doses to critical structures in children than in adults, usually by a factor of 2 to 3. Increasing the distances from OARs to CBCT field border greatly reduces doses to OARs. Depending on OARs, kVCBCT-induced doses increase linearly or exponentially with photon beam energy. Testicular shielding works more efficiently at lower kV energies. On the basis of our study, it is essential to choose an appropriate scanning protocol when kVCBCT is applied to pediatric cancer patients routinely.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 2012
Relationship between pelvic organ-at-risk dose and clinical target volume in postprostatectomy patients receiving intensity-modulated radiotherapy.
To investigate dose-volume consequences of inclusion of the seminal vesicle (SV) bed in the clinical target volume (CTV) for the rectum and bladder using biological response indices in postprostatectomy patients receiving intensity-modulated radiotherapy (IMRT). ⋯ Inclusion of the SV bed in the CTV in postprostatectomy patients receiving IMRT increases bladder and rectal dose, as well as rectal normal tissue complication probability. The magnitude of PTV-bladder and PTV-rectal volume overlap and subsequent bladder and rectum dose increase will be higher if larger PTV expansion margins are used.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2012
Redefining high-risk prostate cancer based on distant metastases and mortality after high-dose radiotherapy with androgen deprivation therapy.
Modern outcomes of high-dose external beam radiotherapy (EBRT) with androgen deprivation therapy (ADT) for high-risk (HR) prostate cancer are not well described. ⋯ A bGS of 8 to 10 is the strongest predictor of bRFS, DMFS, and PCSM after high-dose EBRT with ADT. The duration of ADT did not correlate with outcome. Future studies should account for the heterogeneity in HR prostate cancer.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2012
Improved outcomes of breast-conserving therapy for patients with ductal carcinoma in situ.
Patients treated for ductal carcinoma in situ (DCIS) with breast-conserving surgery (BCS) and radiation therapy (RT) at our center from 1976 to 1990 had a 15% actuarial 10-year local recurrence (LR) rate. Since then, improved mammographic and pathologic evaluation and greater attention to achieving negative margins may have resulted in a lower risk of LR. In addition, clinical implications of hormone receptor and HER-2 status in DCIS remain unclear. We sought to determine the following: LR rates with this more modern approach; the relation between LR and HER-2 status; and clinical and pathologic factors associated with HER-2(+) DCIS. ⋯ In an era of mammographically identified DCIS, larger excisions, widely negative margins and the use of a tumor bed boost, we observed no LR regardless of ER/PR/HER-2 status. Factors associated with HER-2(+)DCIS included more extensive DCIS, Grade III, ER(-)/PR(-), central necrosis, comedo subtype, and postmenopausal status. Further follow-up and additional studies are required to confirm these results.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2012
Comparative Study Clinical TrialA treatment planning and acute toxicity comparison of two pelvic nodal volume delineation techniques and delivery comparison of intensity-modulated radiotherapy versus volumetric modulated arc therapy for hypofractionated high-risk prostate cancer radiotherapy.
To perform a comparison of two pelvic lymph node volume delineation strategies used in intensity-modulated radiotherapy (IMRT) for high risk prostate cancer and to determine the role of volumetric modulated arc therapy (VMAT). ⋯ The RTOG guidelines for pelvic nodal volume delineation results in favorable dosimetry and acceptable acute toxicities for both the target and OARs. We are unable to conclude that VMAT provides a benefit compared with IMRT.