BACKGROUND: This study investigated the prognostic significance of time to the prostate-specific antigen nadir (TTPN) and its relationship to survival beyond TTPN in metastatic prostate cancer after primary androgen-deprivation therapy (ADT).
METHODS: All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. The prognostic significance of TTPN in predicting progression-free survival (PFS) beyond TTPN and overall survival (OS) beyond TTPN was analyzed using the Cox regression model. The median PFS and OS were plotted against TTPN on a monthly interval. The PFS beyond TTPN and the OS beyond TTPN with reference to TTPN were calculated and presented.
RESULTS: The study enrolled 419 patients with a median follow-up period of 38 months. The findings showed that TTPN was a significant prognostic indicator for both PFS beyond TTPN (hazard ratio [HR] 0.72, 95 % confidence interval [CI] 0.52-0.99, p = 0.04) and OS beyond TTPN (HR 0.65, 95 % CI 0.47-0.90, p = 0.01) according to Cox regression analyses. The relationship between TTPN and survival beyond TTPN consisted of three phases. In the first phase (< 3 months for PFS and < 6 months for OS), the survival beyond TTPN increased with TTPN. In the second phase (3-17 months for PFS and 6-20 months for OS), the survival beyond TTPN remained relatively static. In the third phase (>17 months for PFS and >20 months for OS), the survival beyond TTPN increased exponentially with TTPN.
CONCLUSIONS: In this study, TTPN was a good prognostic indicator for PFS beyond TTPN and OS beyond TTPN in metastatic prostate cancer cases after primary ADT. Different TTPNs had different implications for predicting survival beyond TTPN.
Teoh JY, Tsu JH, Yuen SK, Chan SY, Chiu PK, Lee WM, Wong KW, Ho KL, Hou SS, Ng CF, Yiu MK. Are you the author?
Division of Urology, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China.
Reference: Ann Surg Oncol. 2014 Sep 19. Epub ahead of print.