Abstract
Purpose: We establish criteria to identify a durable response to external beam radiation therapy by calculation of biochemical progression- free probability for patients who attained and maintained defined nadir prostate specific antigen (PSA) levels more than 5 years after treatment. Materials and Methods: A total of 460 patients were treated with external beam radiation monotherapy from 1976 to 1995. Patients with PSA less than 0.5 (group 1) or 0.5 to 1.0 (group 2) ng./ml. more than 5 years after treatment were identified. Treatment failure was defined as 3 consecutive increases in PSA after nadir. Progression-free probability after 60 months was calculated for each group. A comparison was also made to patients achieving the same nadir levels anytime after treatment. Results: Failure occurred at 133 months in 1 of 26 group 1 patients (4%) and at a median of 76 months in 5 of 26 group 2 patients (19%). At 10 years progression-free probability was 91% for group 1 compared to 72% for group 2 (p = 0.0575). These same nadir levels anytime after treatment were associated with higher failure rates of 55% for group 1 and 72% for group 2. Conclusions: If a PSA nadir of less than 0.5 ng./ml, was maintained 5 years after therapy, subsequent failure was rare. Although statistical significance was not reached (p = 0.0575), a higher failure rate was noted if the nadir PSA was 0.5 to 1.0 ng./ml. at 5 years. Thus, patients with PSA 0.5 to 1.0 ng./ml. require careful continued surveillance. Nadir levels less than 1.0 ng./ml. anytime before 5 years were associated with a substantial risk of subsequent progression.
Original language | English (US) |
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Pages (from-to) | 758-761 |
Number of pages | 4 |
Journal | Journal of Urology |
Volume | 162 |
Issue number | 3 I |
DOIs | |
State | Published - Sep 1999 |
Externally published | Yes |
Keywords
- Follow-up studies
- Local
- Neoplasm recurrence
- Prostate-specific antigen
- Prostatic neoplasms
- Radiotherapy
ASJC Scopus subject areas
- Urology