ASCO 2018: Optimal Patient Selection/Stratification Perspective

Chicago, IL ( Charles Ryan, MD, gave an excellent talk on the optimal patient selection for prostate cancer. When assessing early failure and early death in studies comparing abiraterone and androgen deprivation therapy (ADT), it is evident that approximately 22% of patients are dead 2 years after starting ADT + abiraterone. This death rate rises to 33% after 3 years of follow-up.

Dr. Ryan moved on and discussed the three P’s of the goal of care. Framing pre-therapy discussions can help patients understand all that an effective therapy can do for them, and also help in the selection of patient timing. The 3 P’s include:

  • Preserve (quality of life, performance status)
  • Prevent (pain prevention, complications, and decline in performance status)
  • Prolong life
Next, Dr. Ryan discussed how to select the right drug for the right patient. This will involve age and demographic factors and might involve extent of disease. There is some emerging data that black race responds slightly better to abiraterone than people of white race (Dan George ASCO 2018).  The paradox of HSPC data, whereby lower volume metastatic disease responds less favorably compared to high volume disease, is not entirely clear, and counterintuitive (Figure 1). Also, in HSPC many patients will receive docetaxel or abiraterone, but many will probably receive both.

Figure 1: Disease Burden and Benefit from Docetaxel:
Docetaxel disease burden benefit

The next topic discussed by Dr. Ryan was whether different variants drive specific therapies. Aggressive variant PC (AVPC) are a subset of PCs that share the clinical therapy response and molecular profiles of the small cell PC. This is a histopathological variant of the disease, that responds poorly to androgen receptor (AR) directed therapy. In AVPC there are combined tumor suppressor defects, and >-2 alteration in TP53, RB1, and/or PTEN.

In summary, Dr. Ryan tried to give several take-home messages on who should be treated with abiraterone and docetaxel. Abiraterone should probably be received by older, black race, lower disease burden, and intent for radiation patients. In contrast, docetaxel should be given to fitter, younger man, with higher disease burden.

Presented by: Charles Ryan, The University of Minnesota, Minneapolis, MN, USA 

Written By: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, Twitter: @GoldbergHanan at the 2018 ASCO Annual Meeting - June 1-5, 2018 – Chicago, IL USA