Are risks and benefits of oncological research protocols both incommensurable and incompensable?

Institutional review boards (IRBs) are legally required to determine whether the balance between the risks and benefits (the risk-benefit ratio or RBR) of a proposed study is "reasonable" or "proportional". This obligation flows from their duty to protect the interests of research subjects. It has been argued that it is difficult, perhaps even impossible for IRBs to determine the RBR of studies, because the risks and benefits are not only heterogeneous, but also incommensurable. After arguing that the relevant meaning of incommensurability is incomparability, we discuss whether the risks of participating in a trial and the benefits are comparable. We conclude that at least the risks and the benefits to participants are comparable. In the last section we show that the main problem of RBR analyses is that of interpersonal incompensability. IRBs have to assume that risks to research subjects be compensated by benefits to others. The question is: To what extent? When does it become unreasonable to ask that patients accept the risks of participating in a trial for the benefit of science and/or future patients?