Open AccessProstate‐specific antigen nadir within 12 months as an early surrogate marker of biochemical failure and distant metastasis after low‐dose‐rate brachytherapy or external beam radiotherapy for localized prostate cancer
Author(s) -
Nishimura Shuichi,
Ohashi Toshio,
Momma Tetsuo,
Sakayori Masanori,
Eriguchi Takahisa,
Tanaka Tomoki,
Yamashita Shoji,
Kosaka Takeo,
Oya Mototsugu,
Shigematsu Naoyuki
Publication year - 2018
Publication title -
cancer medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 53
ISSN - 2045-7634
DOI - 10.1002/cam4.1443
Subject(s) - medicine , prostate cancer , brachytherapy , urology , prostate specific antigen , external beam radiotherapy , surrogate endpoint , androgen deprivation therapy , radiation therapy , prostate , cancer , surgery
Prostate‐specific antigen nadir ( nPSA ) after radiotherapy for localized prostate cancer has been investigated as a predictor. However, nPSA usually requires several years, limiting its clinical utility. We investigated the significance of nPSA within 12 months ( nPSA 12) after low‐dose‐rate prostate brachytherapy ( LDR ‐ PB ) or external beam radiotherapy ( EBRT ) on treatment outcomes. Between 2006 and 2014, 663 patients with prostate cancer were treated with LDR ‐ PB or EBRT at two institutions. Four hundred and seventy‐four men received LDR ‐ PB and 189 men received EBRT , without androgen deprivation therapy. The Kaplan–Meier method was used for biochemical failure ( BF )‐free survival ( BFFS ) and distant metastasis ( DM )‐free survival ( DMFS ) analyses, and multivariable Cox regression analysis was performed. The median follow‐up was 61.3 months. The median nPSA 12 in the LDR ‐ PB and EBRT cohorts was 0.7 and 1.0 ng/ mL , respectively. The 7‐year BFFS and DMFS rates in LDR ‐ PB patients with nPSA 12 ≤ 0.7 ng/ mL were 99.1% and 99.5%, respectively; when nPSA 12 was >0.7 ng/ mL , they were 90.2% and 94.8%, respectively. In EBRT patients with nPSA 12 ≤ 1.0 ng/ mL , BFFS and DMFS rates were 85.4% and 98.5%, respectively; when nPSA 12 was >1.0 ng/ mL , they were 67.1% and 87.2%, respectively. nPSA 12 was an independent predictor of BF and DM in both cohorts ( LDR ‐ PB , P = 0.004 and 0.020, respectively; EBRT , P = 0.005 and 0.041, respectively). The nPSA 12 after LDR ‐ PB or EBRT is significantly associated with treatment outcomes of prostate cancer. Higher nPSA 12 may identify patients at high risk of relapse who might benefit from salvage treatment.