IMRT is a rapidly evolving technique, which affords a more precise radiation dose delivery of escalated doses, in appropriate cases, to targeted tumors, while sparing nearby healthy tissue structures. The FDA clearance of numerous devices for the technical delivery of IMRT is based on the capability of this technology to incorporate accurate dose calculation algorithms, associated with a verifiable dose distribution, as managed by the treating physician, (i.e., radiation oncologist). Although, to date, no randomized trials have matured to document long-term outcomes data and efficacy for IMRT, the scientific evidence currently available indicates that IMRT permits better treatment planning and sparing of surrounding tissues, which is of particular usefulness with “Radiosensitive” tumors of the head/neck, prostate and CNS lesions where the target volume is in close proximity to critical healthy structures that must be protected. These results may be extrapolated to the treatment of other cancers at other anatomic sites; however, a number of technical issues need to be resolved before IMRT can be recommended routinely. The NCI was sufficiently concerned aboyt these issues to issue a recently updated report for use in planning and design of clicnial trials. It can be found at http://atc.wustl.edu/home/NCI/NCI_IMRT_Guidelines_2006.pdf
A recent retrospective review of 53 uses of IMRT in anal cancer concluded: “Preliminary outcomes suggest that concurrent chemotherapy and IMRT for anal canal cancers is effective and tolerated favorably compared with historical standards.” More studies are needed.
For rectal cancer, the literature suggests that the dose is better distributed and may be better tolerated. What has not yet been proven, however, is the clinical significance of this factor. Thus far, there are no guidelines that recommend IMRT for rectal cancer.
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M.C.W.M. Bloemers, L. Portelance, R. Ruo, M. Duclos, B. Bahoric, L. Souhami A Dosimetric Analysis of IMRT versus 3D Conventional Radiation in Vulvar Cancer
International Journal of Radiation Oncology*Biology*Physics, Volume 72, Issue 1, Supplement 1, 1 September 2008, Pages S362-S363
M. Teresa Guerrero Urbano, Anthony J. Henrys, Elisabeth J. Adams, Andrew R. Norman, James L. Bedford, Kevin J. Harrington, Christopher M. Nutting, David P. Dearnaley, Diana M. Tait Intensity-modulated radiotherapy in patients with locally advanced rectal cancer reduces volume of bowel treated to high dose levels
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