Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided high dose rate brachytherapy boost.
OBJECTIVE
To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost.


METHODS
Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml.


RESULTS
Median follow-up was 24 months (range 18-36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6.


CONCLUSIONS
We observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive.
Singh
Anurag K
AK
Radiation Oncology Branch, National Cancer Institute, NIH-DHHS, Bldg 10, CRC Rm B2-3561, 9000 Rockville Pike, Bethesda, MD 20892, USA. singan@mail.nih.gov
Guion
Peter
P
Susil
Robert C
RC
Citrin
Deborah E
DE
Ning
Holly
H
Miller
Robert W
RW
Ullman
Karen
K
Smith
Sharon
S
Crouse
Nancy Sears
NS
Godette
Denise J
DJ
Stall
Bronwyn R
BR
Coleman
C Norman
CN
Camphausen
Kevin
K
Ménard
Cynthia
C
D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D017430:Prostate-Specific Antigen / Q000096:biosynthesis*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage; D012306:Risk; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen