ASCO GU 2020: Preliminary Outcomes of A Prospective Observational Study of Combinatorial Abiraterone Acetate/Enzalutamide and Radical Radiotherapy in Nonmetastatic Node-Positive Prostate Cancer

San Francisco, CA (UroToday.com) The treatment paradigm for node-positive prostate cancer has evolved with the introduction of multiple options for upfront abiraterone or enzalutamide and or radiotherapy in combination with androgen deprivation therapy (ADT). So far, the optimal treatment protocol for this subgroup of patients is unclear.  In this presented poster, the authors investigated PSA, testosterone and toxicity profiles of patients with node-positive prostate cancer treated with a combination of abiraterone or enzalutamide with ADT and radiotherapy.

This was a prospective observational study conducted between 2017 and 2019. The study population was matched against a historical cohort of patients treated between 2012 and 2018 who were treated with only ADT and radiotherapy. The primary endpoints were PSA less than 0.1 at 6 months. The secondary endpoints included PSA less than 0.1 at 12 months, testosterone less than 0.7 at 6 and 12 months, and toxicity profiles.

The patient cohort is shown in Figure 1, and the treatment protocol is shown in figure 2. All important clinical data are shown in table 1.

Figure 1 –

ASCO GU 2020 fig 1 patient cohort

Figure 2-

ASCO GU 2020 fig 2 conventional treatment backbone

Table 1 –

ASCO GU 2020 table 1 cc

Figure 3 shows the percentage of patients with PSA less than 0.1 and testosterone less than 0.7 for the two patient subgroups. It is clearly seen that a higher percentage of patients in the abiraterone/enzalutamide +ADT+radiotherapy subgroup had PSA of less than 0.1 and testosterone of less than 0.7. This was consistent across all time points.

Figure 3 - PSA and testosterone results:

ASCO GU 2020 figure 3 PSA and testosterone

Figure 4 shows the toxicity profile in both subgroups. This includes genitourinary, gastrointestinal, hormonal and liver enzyme dysfunction rates.

Figure 4 – Toxicity profiles:

ASCO GU 2020 figure 4 toxicity profiles

The authors concluded that the combination treatment of abiraterone or enzalutamide with ADT and radiotherapy can induce a more pronounced PSA response at 6 and 12 months in node-positive prostate cancer disease. Importantly, there was no significant increase in acute and late toxicities in the investigated cohort. However, despite these promising results, it still needs to be determined if this will ultimately result in superior survival outcomes as well.


Presented by: Mark Tan, MD, National Cancer Center, Singapore

Written By: Hanan Goldberg, MD, Urology Department, SUNY Upstate Medical University, Syracuse, NY, USA @GoldbergHanan at the 2020 Genitourinary Cancers Symposium, ASCO GU #GU20, February 13-15, 2020, San Francisco, California
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