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Undetectable prostate‐specific antigen after short‐course androgen deprivation therapy for biochemically recurrent patients correlates with metastasis‐free survival and prostate cancer‐specific survival
Author(s) -
Lim Daniel M.,
Gulati Roman,
AleshinGuendel Serge,
Gawne Agnes,
Wingate Jonathan T.,
Cheng Heather H.,
Etzioni Ruth,
Yu Evan Y.
Publication year - 2018
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.23666
Subject(s) - medicine , prostate cancer , androgen deprivation therapy , prostate specific antigen , prostatectomy , metastasis , biochemical recurrence , oncology , urology , cancer , proportional hazards model , surrogate endpoint , clinical endpoint , clinical trial
Background Optimal utilization of novel therapies for advanced prostate cancer is challenging without a validated surrogate efficacy endpoint. Ongoing trials are using durable undetectable prostate‐specific antigen (PSA) levels as a marker of efficacy. The clinical relevance of prolonged undetectable PSA after a short course of androgen deprivation therapy (ADT) is uncertain. Methods The University of Washington Caisis database was queried for radical prostatectomy patients who received 6‐12 months of ADT after biochemical recurrence (BCR), defined as PSA ≥0.2 ng/mL and no radiographically detectable metastasis. Proportions of men with undetectable PSA 12 and 24 months after ending ADT were compared to a hypothesized 5% rate using exact binomial tests. Associations with patient and tumor characteristics were examined using logistic regression, and associations with risk of subsequent metastasis and death were evaluated by log‐rank tests. Results After ineligibility exclusions, 23/93 (25%; 95%CI 16‐35%; P < 0.001) and 14/93 (15%; 95%CI 9‐24%; P < 0.001) had undetectable PSA 12 and 24 months after ending ADT, respectively. Detectable PSA at 12 months was associated with increased risk of metastasis ( P = 0.006), prostate cancer‐specific death ( P = 0.028), and death from any cause ( P = 0.065). Being 1 year older at diagnosis was associated with a 14% (95%CI 5‐24%; P = 0.006) decrease in the odds of having a detectable PSA after controlling for PSA at diagnosis, PSA doubling time, grade group, and time from initial therapy to BCR. Conclusions This single‐institution retrospective analysis shows that it is not uncommon to have undetectable PSA 12 or 24 months after a short course of ADT. No baseline prognostic characteristic other than age was associated with a durable (12 month) undetectable PSA. Because a durable undetectable PSA was associated with lower risks of metastasis and prostate cancer‐specific death, it may be a reasonable clinical trial endpoint.