Figure 1.

The use of PSMA or choline PET can cause stage migration and the Will Rogers phenomenon. In this example, patients who are metastatic by PET but not by conventional imaging (CIM) show an intermediate prognosis, which is better than that of metastatic patients and worse than that of nonmetastatic patients by CIM. Staging by PET moves these patients with intermediate prognosis to the group of patients with metastatic disease and poor prognosis. The final result is an improvement in the prognosis of both nonmetastatic and metastatic groups of patients by CIM without changing the individual prognosis of patients. It is unknown whether modifying the therapeutic approach in the subgroup of patients with intermediate prognosis could lead to an improvement in their outcome. OS: overall survival.