Introduction/AimsThere is less written about failure patterns after prostate brachytherapy (BT) alone or in combination with external beam radiotherapy (EBRT) for localized prostate cancer.To analyze patterns of failure following biochemical failure for prostate cancer patients treated with I-125 BT with or without supplemental EBRT (not to pelvis) with or without neoadjuvant androgen deprivative therapy (NADT).

#1240　 Patterns of Failure Following Biochemical Failure in 1311 Prostate Cancer Patients Treated with Brachytherapy

with/without External Beam Radiation TherapyA. Yorozu, S. Saito, K. Toya, Y. Shiraishi, N. Kuroiwa, A. Takahashi, Y. Yagi, T. Nishiyama, T. Tanaka, Y. Shinya, Dept. of Radiation Oncology & Urology, Tokyo Medical Center, National Hospital Organization, Tokyo, Japan

Patients & Methods

• 1311 men with prostate cancer received I-125 BT from 2003 to 2009. We analyzed patterns of failure comprehensively, including 83 men with definitive biochemical failure according to Phoenix definition.

• Risk groups according to the NCCN guidelines;– Low-risk; 460, Intermediate-risk; 704, High-risk; 147

• 48% of men received supplemental EBRT to the prostate & seminal vesicles: 40% received NADT (median 8 months).

• Local failure was defined as a positive post-treatment biopsy (95%) and/or imaging consistent with failure in the prostate or seminal vesicles.

• First failure site was defined as the earliest anatomic relapse site. Anatomic relapse patterns were classified as a local, pelvic nodal, and distant pattern. The pattern was unable to be determined in 4 (5%).

Results: Failure patterns according to risk group

Local failureHigh risk 3.9% at 7-yrIntermediate risk 1.7%Low risk 1.3%P=0.031

Nodal failureHigh risk 6.8% Intermediate risk 1.1%Low risk 0.0%P=0.009

Distant failureHigh risk 8.6%Intermediate risk 3.8%Low risk 1.0%P<0.001

Local Nodal Distant

BED* Risk group Risk group

Risk group NADT T stage

T stage NADT

Predictive factors for failure patterns on multivariate analysis

BED*: biologically effective dose (α/β=2Gy)

Conclusions• Patients treated with BTEBRT have a low risk (<2%) of local failure or

isolated nodal failure in the low- and intermediate-risk group. • The most common first site of failure was distant pattern for the

intermediate- and high-risk patients. • A high dose improved the local control, and NADT had an impact on

the nodal and/or distant control.

Local failureBED <180 Gy2　 4.8% at 7 yrBED ≥180 Gy2　 1.2%

p=0.002

Nodal ± distant failureNADT 5.8% at 7 yrNADT+ 3.0% p=0.013