There are many seemingly straightforward and yet unanswered questions in clinical cancer care. As an example, consider that for intact prostate cancer the radiation dose that would optimize the therapeutic ratio is unknown. Current national expert consensus guidelines recommend a dose of 75.6-81 Gy, and this range could be regarded as our current “standard of care” (1). However, if 76 Gy is sufficient for cancer control, then why increase the risk of toxicity, length of treatment, and cost by treating to 81 Gy? Would it not it be better if we knew the lowest effective dose rather than subject patients to the subjective preferences of individual physicians?

Lois Shepherd, Timothy N. Showalter & Daniel M. Trifiletti, What Is Reasonably Foreseeable? Lessons Learned from the SUPPORT Trial, International Journal of Radiation Oncology, Biology, Physics 718–720 (2015).