D'Amico AV et al. (2007) Time to an undetectable prostate-specific antigen (PSA) after androgen suppression therapy for postoperative or postradiation PSA recurrence and prostate cancer-specific mortality. Cancer 109: 1290–1295

Androgen deprivation therapy (ADT) is administered to treat PSA recurrence following surgery or radiotherapy for prostate cancer. Men who achieve undetectable (<0.2 ng/ml) PSA levels within 8 months of ADT have improved survival. D'Amico and colleagues, therefore, conducted a retrospective study to investigate whether the time to achieve an undetectable PSA level influenced the time to prostate-cancer-specific mortality.

The analysis included 585 men (median age 69 years) who received ADT to treat rising PSA levels after radical prostatectomy (n = 415) or radiation therapy (n = 170), and who subsequently achieved undetectable PSA levels.

In total, 23 patients died; 4 deaths were caused by prostate cancer. The median time to achieve undetectable PSA levels was 4.6 months (range 2.8–7.8 months). After adjustment for known prognostic factors, a long time to reach undetectable PSA levels, a short PSA doubling time before introduction of ADT, and high-grade prostate cancer were all associated with early prostate-cancer-specific mortality. Those men who took longer than the median time to achieve undetectable PSA levels also had shorter times to death from all causes. Men whose PSA became undetectable within 4.6 months had an estimated 5-year prostate-cancer-specific mortality of 12% and 5-year all-cause mortality of 0%—compared with 23% and 7%, respectively, among those who took longer than 4.6 months.

The authors suggest that men who take a long time to achieve undetectable PSA levels after the introduction of ADT should be considered for enrollment into randomized trials of immediate versus delayed chemotherapy.