Should Upfront Therapy With Androgen Receptor Signaling Inhibitors Be Used in All Japanese Patients With Metastatic...

Treatment strategies for metastatic castration-sensitive prostate cancer (mCSPC) have become complex. This study aimed to investigate the role of androgen receptor signaling inhibitors (ARSI) as upfront therapy for Japanese patients with mCSPC.

This retrospective study was conducted using the MAHOROBA database. A total of 418 patients who received ARSI as first-line treatment (group A, n=143) or vintage hormonal therapy as first-line and ARSI as second-line treatment (group B, n=275) were extracted. Propensity score matching (PSM) was conducted to minimize differences between the groups. In group B, secondary progression was defined as progression with ARSI as the second-line treatment after progression to castration-resistant prostate cancer (CRPC). We compared adverse events, first progression-free survival (PFS) rate, second PFS rate, and overall survival (OS) rates.

Grade 2 or higher adverse events after first-line treatment were observed in 22.4% of patients in Group A and 7.6% of patients in Group B. A total of 234 patients (117 in each group) were identified after PSM. The median follow-up periods for groups A and B were 23 and 47 months, respectively. There was no significant difference in OS between the two groups (p=0.46). The first PFS rate was significantly higher in group A than in group B (p<0.001). However, when comparing the first PFS rate in group A group with the second PFS in group B, there was no significant difference (p=0.35).

Upfront ARSI therapy for Japanese patients with mCSPC significantly extended the time to CRPC but did not demonstrate a benefit in OS compared to vintage hormonal therapy.