SAN ANTONIOSome prostate cancer patients may not require
salvage radiation therapy (RT) following postprostatectomy PSA failure if they
exhibited a low preoperative PSA velocity and have a persistent, nearly stable
postoperative PSA level. Anthony V. D’Amico, MD, PhD, presented the findings at
the 100th Annual Meeting of the American Urological Association (abstract
1678). Although PSA failure following radical prostatectomy can present a
significant risk to the patient, certain PSA failures may not indicate a
life-threatening situation. In these cases, subjecting patients to the toxicity
associated with radiation therapy may be unnecessary. Dr. D’Amico, of the
Dana-Farber Cancer Institute and Brigham and Women’s Hospital, Boston, and his
colleagues investigated whether these patients with benign PSA failure could be
identified based on diagnostic factors.
Dr. D’Amico and his colleagues, including William J.
Catalona, MD, of Northwestern University, studied 1,011 men with localized
prostate cancer and evaluated the ability of different factors to predict
mortality, including 1-year PSA velocity prior to diagnosis, baseline PSA,
Gleason score, and clinical tumor category. The investigators attempted to
correlate these variables with postoperative PSA doubling time, and PSA
doubling time with cancer-specific and overall mortality rates.
A short postoperative PSA doubling time, defined as less
than 3 months, clearly predicted death due to cancer (P = .006) and all
causes (P = .007). In turn, a short PSA doubling time occurred
significantly more often in patients with a preoperative PSA velocity greater
than 2.0 ng/mL/yr (P = .001) and a biopsy Gleason score of 7 (P =
.007) or 8 to 10 (P = .003). This correlation indicates a higher
mortality risk for these patients.
Conversely, certain characteristics were associated with a
postoperative PSA doubling time of at least 12 months or no PSA failure
(postoperative PSA concentration of 0.2 ng/mL or less). These baseline
parameters included a PSA level of less than 10 ng/mL (P = .005), a
nonpalpable tumor (P =.0006), Gleason score of 6 or less (P <
.0001), and a preoperative PSA velocity of 0.5 mg/mL/yr or less (P =
A total of 4% of the cohort (n = 40) exhibited these
favorable baseline characteristics and had a very long postoperative PSA
doubling time of 12 months or more. These patients exhibited favorable
prostatectomy T category, Gleason score, and margin status that were not
significantly different from those of the subset of patients with similar
baseline characteristics who did not experience PSA failure.
While PSA levels persisted above 0.2 ng/mL in 31 of these 40
patients, after a median follow-up of 3.6 years, 24 of these 31 patients had
PSA levels that remained stable at 0.25 ng/mL or less (a total of 77% of those
with persistent detectable PSA). Dr. Catalona explained, "In these patients
with protracted PSA rise, we may be able to go years without additional
therapy; however, if the doubling time did begin to shorten, we could then
institute adjuvant therapy."