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1. ENDOBRONCHIAL BRACHYTHERAPY Dr.Tinku Joseph MD, DM, FCCP Consultant Pulmonologist AIMS, Kochi Lecture given at Hospital Serdang, Malaysia 2. Contents Overview Technique Types Indications Complications 3. Endobronchial Brachytherapy (EBBT) Placement of a radioactive source within or in close proximity to a malignancy in order to provide high doses of radiation in close proximity to the tumor. Palliative therapy Recently-: need for this technique has declined. 4. Goal-: Reduction in tumor size so that airway symptoms can be relieved. Compared with (EBRT), EBBT - local radiation is provided to the lesion (spares other tissues). Technique 5. 1. Selection of patients 2. Planning phase 3. FOB/Rigid with or without MV support 4. Placement of Radioactive source (Ir-192) 5. Fluroscopy 6. HDR/LDR given Technique 6. Technique (step 1) 7. Technique (step 2) 8. Technique (step 3) 9. Technique (step 4) 10. 1 2 11. Radiation Type Dose rate of brachytherapy depends upon the energy and rate of decay of the radionuclide used. Commonly used-: Iridium192 • According to dose rate 1) High dose rate (HDR)- - >12 Gy/Hr 2) Medium dose rate (MDR) - 2-12 Gy/Hr 3)Low dose rate (LDR) - - 0.4 -2 Gy/Hr 4)Ultra low dose rate (ULDR)- -0.01-0.3 Gy/Hr 12. ISOTOPES USED IN BRACHYTHERAPY can be embedded in Surface Applicator- placed directly on surface of tumor eg. Hard palate, skin, ocular Intracavitory- inserted into specially designed apparatus that is placed into body cavity eg. Gynec.malign, nasopharynx Intraluminal- Various organs with lumen (Oesophagus, endobronchial, biliary etc.) Interstitial- Directly through tissues encompassing tumor Intravascular- coronaries, peripheral art. internal mammary etc. 13. 10 to 12 Gray (Gy)/hour, Total dose - ranging from 5 to 40 Gy, Dose per session (fraction) varying from 3 to 10 Gy. Treated every 1-2 weeks (takes few mins) HDR/LDR: Treatment times are shorter outpatient procedure. Increase procedure efficiency, Reduce treatment cost. Simpler and safer therapy. Radiation Type- HDR 14. Radiation Type- LDR Delivers less than 2 Gy/hour Total dose of 1500 to 5000 Gy, Given over a few days (usually up to three days) Disadvantages: Manual manipulation of the radionuclide 30 to 70 hours of continuous treatment, Cumbersome radiation protection measures Catheter has to be left in place for the few days of administration. 15. Inpatient procedure Catheter displacement More costly than HDR EBBT Largely fallen out of favor. Radiation Type- LDR 16. Indications 1. palliative treatment of large obstructing central airway tumors (NSCLC). 2. Metastatic airway tumors. 3. Early NSCLC that is limited to the airway. 4. Benign tracheal stenosis 17. Palliation of central obstructing airway tumors Palliation of obstructive symptoms caused by large central airway tumors that are not amenable to surgical resection and/orEBRT. Patients cannot tolerate or fail other local ablative therapies (Nd:YAG laser, APC, or cryotherapy). 18. Types of cancer that are responsive to EBBT Biopsy proven NSCLC Early NSCLC localized to the airway. Positive resection margins or a stump Recurrence following surgery. Extrathoracic malignancy metastatic to lung Small cell carcinoma/carcinoid (no response) Palliation of central obstructing airway tumors 19. EBBT - patient or tumor criteria 20. Acute life threatening symptoms of airway obstruction First-: local ablative therapies or EBRT Followed by EBBT • Efficacy: Subjective and objective improvement following EBBT (20 to 100 % of patients). No survival benefit associated with EBBT or EBBT in combination with chemotherapy. EBBT + Coventional methods (beneficial) Palliation of central obstructing airway tumors 21. Hemoptysis improve most readily (90% response rate) Cough and dyspnea may improve less reliably, (underlying conditions such as COPD or radiation fibrosis). Responses in tumor size and the degree of airway obstruction are most commonly evaluated by chest radiography and bronchoscopy. 70 % of patients have greater than 50% improvement in patency that persists for at least six months. Palliation of central obstructing airway tumors 22. Benign airway stenosis Recurrent tracheal stenosis Following repeated attempts at dilation and stenting, HDR EBBT (eg, a single 3 to 10Gray [Gy] dose of Iridium192) is beneficial. Prevents formation of granulation tissue and reduce the recurrence rate of restenosis. Role in post TB stenosis ??? 23. Contraindications- Absolute 1) presence of fistulas between bronchi and other structures. (EBBT increases the risk of viscus rupture and fatal hemorrhage) 2) Presence of high grade airway obstruction. Try other modalities first use of brachytherapy will not immediately shrink tumor size (maximal effect is after three weeks) may result in postradiation tissue edema and complete airway obstruction. 24. Moribund patients. Other absolute contraindications to bronchoscopy in general. Contraindications- Absolute 25. 1. Lesions in close proximity to large vessels 2. Malignant involvement of the major arteries 3. Significant destruction of the bronchial wall 4. Mediastinal invasion Contraindications- Relative High risk of fistula formation and fatal hemorrhage 26. Complications <5%. Range (5-40%) Early (hours to days) or late (days to weeks). Early: Infrequent Usually due to bronchoscopy or catheter insertion. Hemoptysis Catheter displacement Early complications of bronchoscopy 27. Late: Radiation bronchitis Airway stenosis. Massive hemoptysis Fistula formation Complications 28. Conclusions (EBBT) Placement of a radioactive source within or in close proximity to a malignancy in order to provide high doses of radiation close to the tumor. EBBT is a good palliative treatment for endoluminal neoplasms of the lungs, either alone or in combination with other procedures. 29. Used in benign airway stenosis. HDR/LDR EBBT Bronchoscopy guided procedure. Combined with EBRT/APC/Nd YAG (better results) Good tolerance and low complication rate. Conclusions
