Beneficial effects of intraoperative radiotherapy on tumor microenvironment could improve outcomes (Int J Radiat Oncol Biol Phys 2008;72:1575-1581).

摘要

Herksind and colleagues have created an elegant and plausible model that simulates the effects of radiation on tissues surrounding a source typically applicable to targeted intraoperative radiotherapy (TARGIT). Their model suggests that the "sphere of equivalence" with TARGIT could be large enough to achieve local control for breast cancer. A mathematical model (1) arrived at a similar conclusion via a different concept, namely, that peritumoral tissues harbor cells that have a loss of heterozy-gosity in key tumor suppressor genes. These cells may survive fractionated radiotherapy but may not be able to survive the relatively high dose delivered locally, potentially yielding a superior result. Results from both models concur with clinical data from a large pilot series of 300 patients who received a TARGIT boost and achieved a very low local recurrence rate (1.52% actuarial at 5 years), far below that expected for that average risk population (2, 3). There is however an altogether different aspect to consider. Traditionally, radiotherapy is meant to work by killing cancer cells. However, its effect on patients with close margins is very similar to that on patients with wider margins, a two-thirds proportional reduction in recurrence risk, so radiotherapy perhaps beneficially alters the "soil" (4).