Cosset Jean-Marc
Département d'oncologie-radiothérapie, institut Curie, 26, rue d'Ulm, 75005 Paris, France.
Cancer Radiother. 2005 Nov;9(6-7):366-73. doi: 10.1016/j.canrad.2005.09.013. Epub 2005 Oct 11.
Hypofractionation (i.e. the use of fewer higher fractional doses than usual) is not a new concept. It had actually been proposed in the early year of Radiotherapy by the German and Austrian specialists. In the seventy's, supported by the - wrong - hypotheses which gave birth to the NSD (Nominal Standard Dose), hypofractionation reappears. The consequential increase of late complications which was observed led the radiation oncologists to give up again using large doses per fraction, except for a few specific situations, such as palliative treatments. We are recently facing a new "come-back" of hypofractionation, in particular for breast and prostate cancers. In the case of breast cancer, the aim is clearly to look for more "convenience" for both the patients and the physicians, proposing shorter irradiation schedules including a lesser number of fractions. Some "modestly" hypofractionated schemes have been proposed and used, without apparently altering the efficacy/toxicity ratio, but these results have been seriously questioned. As for prostate cancer, the situation is different, since in that case new radiobiological data are at the origin of the newly proposed hypofractionation schedules. A number of papers actually strongly suggested that the fractionation sensitivity of prostate cancer could be higher than the one of the tissues responsible for late toxicity (i.e the exact opposite of the classical dogma). Based on those data, several hypofractionated schemes have been proposed, with a few preliminary results looking similar to the ones obtained by the classical schedules. However, no randomised study is available so far, and a few recent radiobiological data are now questioning the new dogma of the high fractionation sensitivity of prostate cancer. For those two - frequent - cancers, it seems therefore that prudence should prevail before altering classical irradiation schedules which have proven their efficacy, while staying open to new concepts and proposing well-designed randomised trials in specific cases.
大分割放疗（即使用比通常更少但剂量更高的分次剂量）并非新概念。实际上，早在放疗早期德国和奥地利的专家就已提出。在20世纪70年代，在导致名义标准剂量（NSD）产生的错误假设支持下，大分割放疗再次出现。观察到的晚期并发症相应增加，导致放射肿瘤学家再次放弃使用大剂量单次分割放疗，除了少数特定情况，如姑息治疗。最近我们正面临大分割放疗的又一次“回归”，尤其是在乳腺癌和前列腺癌方面。就乳腺癌而言，目的显然是为患者和医生寻求更多“便利”，提出更短的照射方案，包括更少的分割次数。已经提出并使用了一些“适度”的大分割方案，且显然未改变疗效/毒性比，但这些结果受到了严重质疑。至于前列腺癌，情况有所不同，因为在这种情况下，新的放射生物学数据是新提出的大分割放疗方案的起源。一些论文实际上强烈表明，前列腺癌的分割敏感性可能高于导致晚期毒性的组织（即与经典教条完全相反）。基于这些数据，已经提出了几种大分割方案，一些初步结果看起来与经典方案获得的结果相似。然而，目前尚无随机研究，最近的一些放射生物学数据现在也在质疑前列腺癌高分割敏感性的新教条。因此，对于这两种常见癌症，在改变已证明其疗效的经典照射方案之前似乎应谨慎行事，同时对新概念持开放态度，并在特定情况下提出精心设计的随机试验。
