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Rx planning and post rx care of radiation therapy patient

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Treatment planning, post care of a radiation therapy in head and neck cancer

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Rx planning and post rx care of radiation therapy patient

  1. 1. Vinay Pavan Kumar K 2nd year PG student AECS Maaruti College of Dental Sciences
  2. 2. Radiation therapy Introduction History General factors Treatment modalities Dose Dental management Implants in irradiated bone
  3. 3.  Early dental intervention is most important factor to prevent possibility of infection during Rx  Frequently, the patients are elderly, have poor oral hygiene, low economic status, receive limited dental care  Patient should be explained about the short term and long term side effects of the treatment
  4. 4. The use of high energy radiations from X-rays, gamma rays, neutrons and other sources to kill cancer cells and shrink the tumor
  5. 5. Era of discovery (1895 - 1920s)  Roots of RT were established  Atom and various electromagnetic particles, their therapeutic use  Lack of knowledge of the biological effects  As the era progressed, biologists began to understand the relationship between time and dose Slater J.M, From X-rays to Ion beams: A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  6. 6.  Regaud demonstrated that fractionated therapy; Coutard – External beam radiation therapy  Coolidge developed a practical X-ray tube, to deliver higher-energy X-rays (180–200 KV) to deeper tumors  Rutherford, 1919, the structure of atom  Two major divisions of radiation medicine – diagnosis and therapy Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  7. 7. Orthovoltage era (1920 – 1950s)  Treatment of deep tumors - Radium-based intracavitary and interstitial irradiation  A transitional period : Physical developments that led to supervoltage (approx. 500 KV–2MV) RT were being made Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  8. 8.  The first supervoltage X-ray tubes, built by Coolidge were the basis of the linear accelerator  Electron beam therapy became a practical and useful therapeutic option in 1940, when Kerst developed the betatron. The first machine produced 2 MeV electrons; later devices yielded up to 300 MeV Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  9. 9. Megavoltage era (1950 – 1985)  Tumors located in deep tissues - the development of cobalt teletherapy machines and megavoltage linear electron accelerators  Cobalt teletherapy was capable of producing beams equivalent to approximately 1.3 MeV X-rays  During this era, radiation medicine advanced as a discipline Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  10. 10. Era of intensity modulated X-ray therapy ( 1970s)  Background started in 1946, with Wilson claiming the use of protons in medical treatments  Wilson reasoned that protons, among the charged particles, offered the longest range for a given energy and were the simplest and most practical for medical use Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  11. 11. Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  12. 12.  Physical principles  Absorption of radiation by tissues  Biologic effects  Dosimetry  Radiation curves GENERAL FACTORS
  13. 13. Electromagnetic waves Photons Particulate Radiations Electron, proton, neutrons
  14. 14. Electromagnetic waves  Photoelectric effect  Compton effect  Pair production Particulate radiations
  15. 15.  DNA – Confined to intranuclear damage – most cell deaths  Water – Abundant compared to DNA
  16. 16.  Anoxia – 3x resistant to radiation  Cell cycle – Asynchronous  Radiation – Series v/s fractioned dose Reoxygenation Redistribution Repopulate Repair
  17. 17. Amount of energy absorbed by the tissues subjected to radiation (rads = 100ergs/gm)
  18. 18.  Isodose curves – Electromagnetic waves Particulate radiations Single beam Multiple beam
  19. 19. Single beam curve (photons) –  Dose decreases from surface to depth  Low energy X-rays – Surface receives highest dose  High energy X-rays – ‘Skin-sparing’ effect
  20. 20. Single beam curves (particulate radiations)  Homogeneous from surface to depth depending on the energy of beam
  21. 21.  Simulation  Maintain same position  Body molds, face masks, tattoos www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  22. 22.  After simulation, the exact area that will be treated, the total radiation dose, dose allowed for the normal tissues, and the safest angles (paths) for radiation delivery  150-200 cGy / fraction www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  23. 23.  The type of cancer  The size of the cancer  The cancer’s location in the body  Approximity to normal tissues www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  24. 24.  How far into the body the radiation needs to travel  The patient’s general health and medical history  Whether the patient will have other types of cancer treatment  Other factors, such as the patient’s age and other medical conditions www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  25. 25.  External beam radiation therapy  Internal beam radiation therapy  Systemic radiation therapy www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  26. 26.  Coutard  3D conformal RT (3D-CRT)  Delivered using Linear Accelerator (LINAC)  Sophisticated computer software and advanced treatment machines to deliver radiation precisely www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  27. 27.  Numerous tiny radiations – Collimators  Allows change in intensity – Modulation  Inverse treatment planning  Greater dose in areas required www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  28. 28.  Repeated imaging scans  Current condition of the patient  Accurate radiation treatment, allows reductions in the planned volume of tissue to be treated www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  29. 29.  Cyberknife  Radiation in fewer sessions  Small radiation fields and higher doses www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  30. 30.  Type of IMRT  CT imaging scanner + external beam RT  Both imaging and treatment www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  31. 31.  Brachytherapy  Radiation source placed in or on the body  Interstitial – Within the tumor  Intracavitatory – Within surgical or body cavity  Episcleral – Melanoma (eye)  Permanent – Low dose treatment  Temporary – Low or high dose treatment www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  32. 32.  Swallows or receives an injection of radioactive substance  Radioactive I, samarium, strontium, ibritumomab tiuxetan www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  33. 33.  External beam radiation therapy – One dose  Minimizes damages to the normal tissues  Exposing cancer cells at right stage of cell cycle www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  34. 34. Regaud – Fractionated therapy  Accelerated fractionation – Large daily or weekly dose  Hyperfractionation – Smaller fraction more than once a day  Hypofractionation – larger dose once a day or less often www.cancer.gov, National Cancer Institute, Radiation therapy for cancer
  35. 35. Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  36. 36. o Dental examination before radiation therapy and treatment plan o Dental management during radiation therapy o Dental management following radiation therapy
  37. 37.  Dental extractions  Minor surgical procedures  Pre – radiation prosthodontic care
  38. 38.  Dental awareness of the patient  Condition of the residual dentition  Urgency of treatment  Mode of therapy
  39. 39.  Radiation fields  Mandible vs Maxilla  Prognosis for tumour control
  40. 40. To ensure best results following extraction prior to radiation therapy -  Radical alveolectomy to ensure primary closure  Teeth should be removed in segments  Antibiotics should be administered during the healing period  Risk of bone necrosis due to dental extractions prior to radiation therapy was 12.7%
  41. 41. Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  42. 42.  Dentures  Avoid relining ill fitting dentures  Avoid soft temporary reline  Advised not to wear denture  Metallic crowns or fixed partial denture  Custom made soft plastic stent
  43. 43. o Mucositis o Xerostomia o Change in oral microflora o Loss of taste o Increased sensitivity to spicy food RADIATION EFFECTS OF ORAL CAVITY Short term effects
  44. 44. Long-term effects o Reduced bone healing – Osteoradionecrosis o Permanent loss of salivary function o Increased potential for dental caries o Increased susceptibility to infections – Candidiasis o Trismus
  45. 45. Mucositis  Earliest  2-3 week and subsides within 8-10 week  Slight erythema-desquamation-frank ulceration, pain and dsyphagia, weight loss  Severe cases may require stopping the therapy
  46. 46.  Maintaining good oral hygiene, frequent brushing  Oral mouth rinses - Combination of salt and sodium bicarbonates in water or dilute hydrogen peroxide
  47. 47. Loss of taste  Radiation to tongue and palate (5000 cGy)  1-2 week and returns to normal once treatment is completed  Damage to taste buds and microvili, disrupted innervation, lack of saliva Xerostomia and dental caries  60 rads  Decrease in salivary flow rates, increase in acidogenic bacteria  Prevention by daily use of topical fluoride Stannous and Sodium fluoride
  48. 48. Saliva substitutes and sialogogues  Most persistent morbidity is dry mouth  1 week and worsens with time  Sialogogues are used to stimulate salivary flow  Salivary substitutes Trismus and fibrosis  Shortly after radiation begins  May worsen by surgery prior to radiation  Primary treatment - excercising by using tongue blades, or bite openers
  49. 49.  Maintaining position of structures to be treated
  50. 50.  Removing structures from the radiation field  Positioning peroral cones
  51. 51.  Positioning dosimetric devices  Recontouring tissues to simplify dosimetry
  52. 52.  Positioning radioactive source
  53. 53. Only used with electron beam therapy
  54. 54. Mucositis and loss of taste  Subsides gradually  Heavy smokers or drinkers may experience longer delay in healing  Continue mouth rinses Xerostomia and dental caries  Salivary loss is permanent  Long term salivary substitutes and sailogogues  Fluoride application for tooth  Maintainence of oral hygiene
  55. 55. Candidiasis  Mainly because of xerostomia Trismus and fibrosis  Increase in severity with time  Only way to benefit is by regular exercising
  56. 56. Post radiation extractions  Greater risks of bone necrosis as high as 100% has been reported  Periodontally compromised and mobile tooth can be extracted with minimal risk  Localized periapical infection can be managed conservatively with anbibiotics avoiding the need for removal
  57. 57.  Regaud,1922  “when bone in the radiation field was exposed for atleast 2 months in the absence of local neoplastic disease” - Beumer  “an area greater than 1 cm of exposed bone in a field of irradiation that had failed to show any evidence of healing for atleast 6 months” - Marx
  58. 58.  The reported incidence of ORN of the mandible varies widely, ranging from 2-39 per cent  Trauma, exposure of radiated bone, infection  Hypovascular, hypocellular and hypoxic conditions of the bone  Type of radiation treatment, dosage, tissue volume
  59. 59. ORN Stage I 30 Dive of HBO Healing Non responder 10 Dive of HBO Stage II Non responder Stage III Local surgical debridement Wound dehiscence Nonresponder to stage II Healing 10 Dive of HBO Total of 30 Dive of HBO Surgical resection 10 Dive of HBO Patient pain free Reconstruction surgery Stage IIIR
  60. 60.  Three types of ORN – Type 1 –  Radiation therapy within 21 days of tooth extraction Type 2 –  Induced by trauma  It generally occurs 3-6 months after radiation therapy Type 3 –  Spontaneously 6 months to 2 years after radiation therapy  Associated with higher radiation doses, brachytherapy (Cronje, 1998) Hyperbaric oxygen therapy for prophylactic treatment after head and neck radiation to prevent osteoradionecrosis of the mandible, Group health - A clinical review
  61. 61. Radiation Irreversible cell damage Tissue breakdown Hypocellularity Osteoblasts death – direct RT damage ORN Vascular damage Endarteritis obliterans Thrombosis of vessels Gradual ischemia Damage to bone tissue Loss of reparative and synthetic function Lyons A, Ghazali N, Osteoradionecrosis of the jaws:Current understanding of its pathophysiology and treatment, Brit J Oral Maxillofac Surg, 2008;46:653-660
  62. 62.  Conservative measures  Hyperbaric oxygen (HBO)  PENTO or PENTOCLO  Surgical Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  63. 63. The HBO treatment –  20 sessions each at 2.4 ATA for 90 minutes, followed by a 30 minute ascent back to one ATA. This is known technically as a 14/90/30 cycle  Followed by surgery and then 10 further 14/90/30 sessions Vudiniabola S et al, Hyperbaric oxygen in the prevention of osteoradionecrosis of the jaw, Aust Dent J, 1999;44(4):243-247
  64. 64.  Increases diffusion distance of oxygen in tissue of the compromised vascular beds  Improves the wound environment, resists infection, and enhances wound repair Lin YC et al, Scientific rationale of hyperbaric oxygen therapy for osteoradionecrosis of the jaw, Clin Dent J, 2005;24(1):1-14
  65. 65. Lin YC et al, Scientific rationale of hyperbaric oxygen therapy for osteoradionecrosis of the jaw, Clin Dent J, 2005;24(1):1-14
  66. 66.  Enhance the killing ability of leucocytes to stimulate fibroblast growth  Increase collagen formation - promotes growth of capillaries  Toxic to aerobic and anaerobic bacteria, and inhibits bacterial toxin formation
  67. 67. Vudiniabola S et al, Hyperbaric oxygen in the prevention of osteoradionecrosis of the jaw, Aust Dent J, 1999;44(4):243-247
  68. 68.  PENtoxifylline – Improves peripheral vasculature  400 mg b.i.d  TOchopherol (Vit.E) – Anticoagulant, scavangers  1000 IU (600 and 400 IU) Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  69. 69.  Often candidates for new dentures  To prevent trauma due to dentures – 6 months  Social status  Conventional techniques to be followed  Border extension should be carefully evaluated
  70. 70.  Systematic review and meta-analysis was done to evaluate the failure rate of dental implants placed in irradiated bone between 6 and 12 months and after 12 months from the cessation of radiotherapy  Placement of dental implants between 6 and 12 months post radiotherapy was associated with a 34% higher risk of failure  Placing implants in bone within a period shorter than 12 months after radiotherapy may result in a higher risk of failure Claudy M P et al, Time interval after radiotherapy and dental implant failure:Systematic review of observational studies and meta analysis, Clin Imp Dent Rel Res, 2013:1-10
  71. 71. Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  72. 72. References o Taylor T D , Clinical Maxillofacial Prosthetics, 1st edition, 2000, Quintessence publications, Illionis, pp 37 – 52 o Beumer J, Curtis TA, Firtell D N, Maxillofacial Rehabilitation : Prosthodontic and Surgical Considerations, 3rd edition, 1996, Mosby, St. Louis, pp 23-78 o Slater J.M, From X-rays to Ion beams:A short history of radiation therapy, Biological and Medical Physics, pp:3-18
  73. 73. o www.cancer.gov, National Cancer Institute, Radiation therapy for cancer o Marx R E, A New Concept in the Treatment of Osteoradionecrosis, J Oral Maxillofac Surg, 1983; 41:351-35 o Lyons A, Ghazali N, Osteoradionecrosis of the jaws:Current understanding of its pathophysiology and treatment, Brit J Oral Maxillofac Surg, 2008;46:653- 660 o Kelly J A, Beumer J, Dental management of irradiated patients, ppt
  74. 74.  Hyperbaric oxygen therapy for prophylactic treatment after head and neck radiation to prevent osteoradionecrosis of the mandible, Group health - A clinical review  Vudiniabola S et al, Hyperbaric oxygen in the prevention of osteoradionecrosis of the jaw, Aust Dent J, 1999;44(4):243-247  Lin YC et al, Scientific rationale of hyperbaric oxygen therapy for osteoradionecrosis of the jaw, Clin Dent J, 2005;24(1):1-14

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