Tanaka N, et al. – The prostate specific antigen (PSA) value at the last follow–up of patients who underwent prostate low–dose rate brachytherapy (LDR–BT) was compared with patients who underwent intensity–modulated radiation therapy (IMRT). Results revealed significantly lower PSA value at the last follow–up of LDR–BT than that of IMRT. This result was particularly marked in patients with a normal testosterone level at the last follow–up.

Methods

• This study entailed 610 prostate cancer patients (cT1c-3bN0M0).
• Of these, 445 LDR-BT, while 165 received IMRT (74–76 Gy).
• 75 months (LDR-BT) and 78 months (IMRT) were the median follow-up period of these two groups.
• Two definitions (Phoenix definition and PSA ≥ 0.2 ng/mL) were employed to assess the biochemical recurrence (BCR)-free rate.

Results

• In the LDR-BT group, the percentage of patients who achieved PSA < 0.2 ng/mL at the last follow-up was 77.5%, and 49.7% in the IMRT group (p < 0.001).
• The percentage of those who achieved PSA < 0.2 ng/mL at the last follow-up was 79.2% in the LDR-BT group and 32.1% in the IMRT group (p < 0.001), among patients with a normal testosterone level at the last follow-up.
• 89.5 and 95.0% (p < 0.001) were the 5-year BCR-free rate by the Phoenix definition in the IMRT and LDR-BT groups.
• On the other hand, in the IMRT and LDR-BT groups, the 5-year BCR-free rate using the definition of PSA ≥ 0.2 ng/mL was 59.1 and 80.1%.