SPIE-AAPM-NCI PROSTATEx Challenges-The PROSTATEx Challenge (" SPIE-AAPM-NCI Prostate MR Classification Challenge”) focused on quantitative image analysis methods for the diagnostic classification of clinically significant prostate cancers and was held in conjunction with the 2017 SPIE Medical Imaging Symposium. PROSTATEx ran from November 21, 2016 to January 15, 2017, though a "live" version has also been established at https://prostatex.grand-challenge.org which serves as an ongoing way for researchers to benchmark their performance for this task. The PROSTATEx-2 Challenge (" SPIE-AAPM-NCI Prostate MR Gleason Grade Group Challenge" ) was focused on the development of quantitative multi-parametric MRI biomarkers for the determination of Gleason Grade Group in prostate cancer.