To address concerns about the increased risk of radiation-induced cancer with the increasing number of cancer patients surviving long term, Herman Suit and his colleagues have examined data on radiation-induced neoplastic transformation of mammalian cells in vitro and on the risk of an increase in cancer incidence after radiation exposure in animals and in various human populations. The results of their comprehensive analyses appear in the January issue of the journal Radiation Research.
The authors found that there is great heterogeneity in the risk of radiation-associated cancer between species, strains of a species, and organs within a species. Currently, the heterogeneity between and within patient populations of virtually every parameter considered in risk estimation results in substantial uncertainty in quantification of a general risk factor.
One implication of their review is that reduced risks of secondary cancer should be achieved by any technique that achieves a dose reduction down to ~0.1 Gy (i.e., the dose to tissues distant from the target). Based on their study, they conclude that the proportionate gain should be greatest for dose decrement to less than 2 Gy.