Brachytherapy for Prostate Cancer: A Direct Radiation Therapy

Brachytherapy (internal radiation) places radioactive sources directly into the prostate.

Types

• Low-dose rate (LDR): Permanent implantation of 80–120 iodine-125 or palladium-103 seeds (rice-grain size). Radiation decays over months.
• High-dose rate (HDR): Temporary catheters placed; iridium-192 source dwells in each for minutes. Multiple fractions (1–2). Catheters removed.

Indications

• Low-risk localized prostate cancer (Gleason ≤6, PSA <10, T1–T2a).
• Selected intermediate-risk (with EBRT boost).
• Salvage after EBRT failure (HDR).

Advantages

• Conformal dose: high dose to prostate, rapid fall-off sparing rectum/bladder.
• Outpatient (LDR) or short stay (HDR).
• Single procedure (LDR) vs. weeks of EBRT.
• Preserves sexual function better than surgery in some studies.

Side Effects

• Urinary: frequency, urgency, retention (5–15% transient).
• Rectal: proctitis, bleeding (less than EBRT).
• Erectile dysfunction: 20–40% at 5 years (age-dependent).
• Seed migration (rare, LDR).

Multidisciplinary evaluation (urology, radiation oncology) determines suitability.