MP15-10: Impact of disease status heterogeneity of the STAMPEDE trial arm J population on oncological outcomes in high-risk nonmetastatic prostate cancer

Shingo Hatakeyama*, Toshikazu Tanaka, Takuma Narita, Daisuke Noro, Teppei Okamoto, Noritaka Ishi, Ryuma Tanaka, Takuya Oishi, Hikari Miura, Takahiro Yoneyama, Chikara Ohyama, Hirosaki, Japan

Introduction: A recent clinical trial showed a novel risk model for nonmetastatic high-risk prostate cancer (nm-high-risk PC) in the STAMPEDE trial arm J population including node-positive or >=2 of T3-4, PSA>=40, and GS8-10. However, the impact of disease status heterogeneity of this population remains unclear. We investigated the effect of disease status and treatment modality on prognosis in those patients.

Methods: We investigated 382 patients with nm-high-risk PC treated with androgen deprivation therapy (ADT), ADT + radical prostatectomy (ADT+RP), or ADT + radiation therapy (ADT+RT) between May 2004 and Jan. 2021. We compared castration-resistant PC (CRPC)-free survival and overall survival between the organ-confined disease (OCD: T3N0) and non-OCD (T4 or N+). Risk factors for poor prognosis in this population were evaluated by a multivariable Cox regression analysis.

Results: We identified 255 and 127 patients in the OCD and non-OCD groups, respectively. CRPC-FS and OS were significantly different between the groups. Multivariate Cox regression analysis showed T4 and local therapy were significantly associated with CRPC-FS and OS. CRPC-FS and OS were not significantly different between the patients with T4N0 and TanyN+ in the non-OCD group.

Conclusions: We observed a meaningful heterogeneity of background for outcome in the STAMPEDE trial arm J population. The effect of local therapy on prognosis was significant in patients with nm-high-risk PC.

Source of Funding: none