First, is marker decline an outcome predictor? Toner and colleagues showed in the 1990s that inadequate marker decline conferred worse OS. Patients in the inadequate marker-decline group had approximately 20% OS at 5 years. However, Motzer and colleagues indicated recently that the 5-year OS of patients with inadequate marker decline is around 60%. This discreprancy raises doubts about these trials. Furthermore, in none of these studies were the REMARK criteria used, which are necessary to define a biomarker.
Second, have trial data shown efficacy? Only marginally would be the answer. The GETUG 13 phase-III trial found an 11%, 3-eary failure-free-survival decline in the inadequate marker-decline group. Other trials, however, described similar results without incorporating marker decline in the decision making process.
Lastly, are prospective trials conclusive? The answer is definitely No. OS is not better if markers are added to the treatment algorithm. More importantly, the selection criteria are quite different between trials. The definition of marker decline was different from trial to trial and, thus, a unified conclusion cannot be drawn regarding the use of marker decline for treatment intensification.
Presenter:George J. Bosl, MD, MACP, FASCO, Memorial Sloan Kettering Cancer Center, USA
Written By: Miki Haifler, MD, M.Sc, Fox Chase Cancer Center
at the 2017 Genitourinary Cancers Symposium - February 16 - 18, 2017 – Orlando, Florida USA