Prostate HDR Brachytherapy

1. Prostate Brachytherapy
Ali Bagheri M.D
Assistant Professor in Radiation Oncology
Director of Brachytherapy Services at Ahvaz Golestan Hospital
Ahvaz Jundishapur University of Medical Sciences

2. • Brachytherapy (BT) is derived from the
ancient Greek word brachy with
means “short distance”.
• This technique consists of placing
sealed radioactive sources in contact
with the tumor tissue.
• Because the absorbed dose falls off
rapidly with increasing distance from
the sources (thanks to the inverse
square law), high doses can be
delivered safely to a localized target
region over a short time.
• This modality is the most conformal
type of radiation therapy.
The Art of Brachytherapy

3. • Brachytherapy for prostate cancer has
a 100-year track record.
• In 1914, Pasteu and Degrais used a
radium source inserted through a
urethral catheter.
• In 1917, Barringer first used radium
needles inserted into the prostate
through the perineum, using the
guidance of a finger placed in the
rectum.
History

4. Brachytherapy vs. External Beam
Radiation Therapy (EBRT)

5. Technique

6. Low Dose Rate
(LDR)
High Dose Rate
(HDR)
Types

7. LDR Brachytherapy

8. HDR Brachytherapy

9. Needle Implantation

10. 3.5 mm
Equipment

11. Stepping Source Technology

12. Dosimetry

13. 50%
80%
100%
125%
150%
200%
Bladder
Rectum
Sagittal View Axial View
Coronal View

14. Monotherapy
↓
Low Risk
Favorable Intermediate Risk
Boost + EBRT
↓
Unfavorable Intermediate Risk
High Risk
Salvage after EBRT
Indications

15. Absolute
↓
High operative risk
No rectum
Limited life expectancy (<10 years)
Distant metastasis
Ataxia telangiectasia
Relative
↓
High IPSS (> 15–18)
Prior pelvic RT
Prior TURP
large median lobe
Gland volume >60 cc
Inflammatory bowel disease
Contraindications

16. Less dose to bladder and rectum
which allows for dose escalation.
Radiobiologic advantage from
hypofractionation (Only with
HDR).
Shorter treatment course and
less cost.
No issues with setup variation
and prostate motion.
Advantages over EBRT

17. Evidence

18. Monotherapy

19. RTOG 0232 Trial
• Randomized 588 men (Intermediate risk)
• Trial arms:
• EBRT + LDR BT boost
• LDR BT monotherapy
• Median follow up = 6.7 years
• PFS rate at 5 years post-treatment was 85% for EBRT+BT patients and 86%
for BT patients (HR=1.02).
• Toxicity:
• Acute: Similar, Late: More in EBRT+ BT arm.

20. Boost

21. • Randomized 398 men (69% high-risk)
• Trial arms:
• ADT + 3D conformal EBRT (Whole Pelvis EBRT + EBRT boost)
• ADT + Whole Pelvis EBRT + LDR BT boost
• Median follow up = 6.5 years
• LDR BT boost associated with significantly lower rates of biochemical
failure than EBRT boost with no difference in OS.
• 7-year biochemical RFS 86% vs. 75% (HR=0.47; 95% CI 0.29–0.76; P=0.002).
• Adding BT was associated with increased risk of urinary toxicity.
ASCENDE-RT Trial

22. RP vs. EBRT vs. EBRT+BT

23. • Retrospective cohort study
• 1809 patients with Gleason score 9–10 prostate cancer included.
• Exposures: RP vs. EBRT + ADT vs. EBRT + BT boost + ADT
• EBRT+BT was associated with significantly lower prostate cancer–specific
mortality than either RP or EBRT (HR=0.38 [95% CI = 0.21–0.68] and 0.41
[95% CI = 0.24–0.71]).
• Adjusted 5-year prostate cancer–specific mortality rates were 12% for those treated
with RP; 13% for those treated with EBRT; and 3% for those treated with EBRT+BT.
• Within the first 7.5 years of follow-up, EBRT+BT was associated with
significantly lower all-cause mortality (HR=0.66 [95% CI = 0.46–0.96] for RP
and 0.61 [95% CI = 0.45–0.84] for EBRT).
RP vs. EBRT vs. EBRT+BT

24. Acute
↓
o Worsening of urinary symptoms
(frequency, urgency, hesitancy, and weak
stream)
o Acute urinary retention (Rare, ∼3% require
catheterization)
Late
↓
o Relatively common: Impotence, mild
increased urinary irritative/obstructive
symptoms, and mild rectal bleeding.
o Rare: Significant late GU toxicity (e.g.,
urethral strictures), significant rectal
bleeding.
o Very rare: Rectal fistula, seed embolization,
2nd cancers
Toxicities

25. Thank You For Your Time. Any Questions?, Comments?