This paper has similar finding to the Sweeney et al. 2015 paper. It again presents the case for combining chemotherapy with ADT in patients who are at high risk of disease progression, even though their disease is still hormone sensitive.
There are a variety of differences in the design of this experiment versus the NEJM paper. Here, the chemotherapy was estramustine and docetaxel rather than docetaxel alone. The sample size was smaller and the drug dosing was different. But, the general conclusion was the same. Early chemo is beneficial when given with ADT to patients with undeniably high risk disease.
Fizazi K, Le Maitre A, Hudes G, Berry WR, Kelly WK, Eymard JC, Logothetis CJ, Pignon JP, Michiels S. 2007. Addition of estramustine to chemotherapy and survival of patients with castration-refractory prostate cancer: a meta-analysis of individual patient data. Lancet Oncol 8(11):994-1000. www.ncbi.nlm.nih.gov/pubmed/17942366