Purpose: Improvement in the prognosis of patient groups due to stage or grade reclassification is called the Will Rogers phenomenon. We determined the significance of the Will Rogers phenomenon in urological oncology.
Materials and methods: Studies referring to the Will Rogers phenomenon in urological oncology were identified through a MEDLINE search. Samples of articles not referring to the phenomenon directly but likely to be biased by it, such as articles comparing contemporary data to historical controls, were also reviewed.
Results: In prostate cancer the Will Rogers phenomenon is the result of the late 1990s acceptance that Gleason scores 2 to 4 should not be assigned on prostate biopsy. Consequently grade inflation occurred and current readings are almost 1 Gleason grade higher compared to past readings of the same biopsy. The result is an illusion of improvement in grade adjusted prognosis. In bladder cancer the Will Rogers phenomenon arises from improvement in histopathological processing of cystectomy specimens enabling the identification of microscopic perivesical fat infiltration and lymph node metastases not recognized in the past. Up staging from pT2 to pT3 and N0 to N+ may partly explain the improved stage adjusted survival after radical cystectomy observed in contemporary series. The Will Rogers phenomenon may also explain the correlation between the total number of lymph nodes removed at radical cystectomy and survival. As more lymph nodes are removed the probability of identifying metastases and up staging to N+ increases.
Conclusions: Comparison of contemporary results to historical controls may be biased by the Will Rogers phenomenon. Ignoring the possibility of stage or grade reclassification may lead to erroneous conclusions.