We extend earlier large-scale studies of clinical trial statistics by focusing on the performance of oncology trials. Using 108,248 data points between January 1, 2005, and September 31, 2018, compiled from the Citeline database, we investigate the duration of clinical trials and compute the probabilities of success of 24,448 oncology drug development programs by disease group. While the overall phase 1 to approval rate for all oncology-related drug development programs is 3.3%, individual disease groups have approval rates ranging from 0% to 10.1%. Similar patterns can be seen for oncology orphan drug development programs, where the overall probability of success ranges from 0% to 8.3%, with an overall average of 1.9%. We find overwhelming evidence that using biomarkers for patient selection is effective in almost all disease groups within oncology, raising the overall probability of success by an average of 13.3%.