Brachytherapy: Comprehensive Overview + Physiotherapy Role

1. Definition & Core Principle

"Brachytherapy refers to a treatment in which a radioisotope is placed onto or inside the volume to be treated… dose falls off rapidly, obeying the inverse square law… This allows very high doses to be administered to the target volume." — Grainger & Allison's Diagnostic Radiology

2. Radiation Sources & Dose Rates

3. Technique: The Afterloader System

1. Non-radioactive hollow applicators (metal or plastic tubes) are placed precisely into the tumour — guided by real-time ultrasound (prostate), CT (position verification), or MRI (superior soft-tissue definition, especially pelvis/prostate).
2. The patient is moved to a shielded room.
3. The afterloader remotely drives the ¹⁹²Ir source through the applicators.
4. The source dwells for seconds at 5-mm intervals, and controlled dwell-time variation sculpts the dose distribution.
5. Dosimetry = sum of contributions from each source dwell position (image-guided adaptive brachytherapy — IGABT).

"Patient setup and tumour motion are less relevant because the radiation sources move with the tumour and therefore retain their correct position." — Grainger & Allison's Diagnostic Radiology

4. Clinical Applications by Organ System

4.1 Prostate Cancer (most common)

• Permanent LDR ¹²⁵I seed implant or temporary HDR boost.
• Outpatient transperineal implant under real-time imaging.
• 5-year PSA relapse-free survival: 98% (PSA 0–4), 90% (PSA 4–10), 89% (PSA >10).
• Post-treatment biopsy negative in 80% of patients.
• Side effects: urinary frequency/urgency (most patients, resolving over months), retention risk in prior TURP patients, proctitis < 2%.
• Potency preservation rates appear superior to radical prostatectomy and EBRT. — Harrison's Principles of Internal Medicine 22E; Campbell-Walsh-Wein Urology

4.2 Gynaecological Cancers (cervix, endometrium)

• Local control 96–100%
• Vaginal relapse rate only 4–5%
• PORTEC-2 trial: vaginal brachytherapy = pelvic external beam RT in vaginal failure rates, with less bowel toxicity.

4.3 Penile Cancer

• Interstitial ¹⁹²Ir implant (temporary needle array) — organ-preserving alternative to surgery.
• 5-year disease-free survival 67–78%; penile preservation ~80%.
• Late effects: soft tissue ulceration (22%), meatal stenosis (30%) — dose/volume dependent. — Campbell-Walsh-Wein Urology

4.4 Endobronchial / Lung Cancer

• Catheter placed via flexible bronchoscopy, loaded with ¹⁹²Ir.
• Indications: endobronchial tumours, recurrent disease after max EBRT, palliation (cough, dyspnoea, haemoptysis), occult early central lung cancer, anastomotic granulation post-transplant.
• Contraindications: airway fistulas, tumour directly involving major vessels, high-grade endotracheal obstruction (risk of post-RT oedema → occlusion).
• Outcomes: improves cough 20–70%, dyspnoea 25–80%, haemoptysis 70–90%; no survival benefit vs. EBRT.
• Complications: massive haemoptysis (fatal in 5–10%), fistula, radiation bronchitis, airway stenosis. — Murray & Nadel's Textbook of Respiratory Medicine

4.5 Breast Cancer (APBI)

• Accelerated partial breast irradiation (APBI) using interstitial catheters or balloon applicator.
• Used post-lumpectomy in selected early-stage/DCIS patients.
• Meta-analysis (PMID 36914530): APBI an effective option in eligible DCIS patients.

4.6 Skin Cancer

• High-dose rate surface mould brachytherapy (e.g., 40 Gy over 5 days in twice-daily 4 Gy fractions for squamous cell carcinoma in situ). — Campbell-Walsh-Wein Urology; Dermatology 5e

5. Advantages vs. External Beam Radiotherapy (EBRT)

6. Physiotherapy in Brachytherapy — The Rehabilitation Interface

6.1 Pelvic Floor Physiotherapy (Gynaecological Brachytherapy)

• Radiation to the pelvis causes pelvic floor dysfunction: vaginismus, dyspareunia, fibrosis, incontinence.
• Vaginal dilator therapy (supervised by physiotherapist) is standard post-treatment to prevent vaginal stenosis.
• Pelvic floor physical therapy is recommended by the American Brachytherapy Society (2026 Working Group Report, PMID 41982027) for management of pelvic floor dysfunction and sexual health post-brachytherapy.
• A randomised clinical trial protocol (KYOCOL, PMID 40467316) is testing a physiotherapy-yoga educational intervention during uterovaginal brachytherapy (cervical cancer). Patients perform daily physiotherapist-supervised sessions during HDR brachytherapy hospitalisation to reduce stress, pain, and fatigue.

6.2 Physiotherapy-Yoga for Stress, Pain & Fatigue During UBT

• Population: Women undergoing uterovaginal brachytherapy for cervical cancer
• Intervention: Physiotherapist-supervised physiotherapy-yoga + patient education programme during bedrest hospitalisation, continued 15 days post-treatment
• Primary outcome: Perceived Stress Scale at 15 days post-UBT
• Rationale: UBT requires days of strict bedrest, inducing pain, anxiety, stress, reduced physical capacity — yoga/physiotherapy addresses all these simultaneously

6.3 Reflexology & Acupressure During Brachytherapy

• Foot reflexology + aromatherapy RCT (PMID 33855996): reduced anxiety and pain during brachytherapy for cervical cancer (Oncol Nurs Forum, 2021).
• Acupressure RCT (PMID 40679634, 2025): reduced anxiety, depression, and pain in gynecological cancer patients receiving brachytherapy.

6.4 Telerehabilitation Post-Gynaecological Radiation

• Educational telerehabilitation programme for pelvic floor dysfunction after gynaecological cancer treatment (PMID 38802934) — RCT protocol evaluating remote physiotherapy for patients post-brachytherapy.

6.5 Bladder & Bowel Rehabilitation (Prostate Brachytherapy)

• Urinary symptoms (frequency, urgency, retention) are the primary post-treatment complaint.
• Pelvic floor muscle training (PFMT) supports bladder control recovery.
• Radiation proctitis → bowel physiotherapy strategies (dietary, biofeedback).

6.6 Knowledge Gap: Physical Therapist Awareness

7. Key Recent PubMed Evidence

8. Summary

• Pelvic floor PT and vaginal dilator therapy are ABS-recommended post-gynaecological brachytherapy
• Physiotherapy-yoga during hospitalisation for UBT reduces pain, stress, and physical deconditioning
• Acupressure and reflexology provide procedural anxiety/pain relief
• Telerehabilitation extends access to pelvic floor PT post-treatment
• Bladder/bowel rehabilitation supports recovery after prostate brachytherapy