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carcinoma breast RADIOTHERAPY TECHNIQUES

A comprehensive review

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carcinoma breast RADIOTHERAPY TECHNIQUES

  1. 1. RT TECHNIQUES IN CARCINOMA BREAST DR. NABEEL YAHIYA JUNIOR RESIDENT IN RADIATION ONCOLOGY KOTTAYAM MEDICAL COLLEGE
  2. 2. TOPICS COVERED  INDICATIONS OF RT  SIMULATION TECHNIQUES  PMRT AND BCS RT TECHNIQUES  NODAL IRRADITION AND INDICATIONS  MATCHING OF TANGENTS WITH NODAL FIELDS  CONTOURING GUIDE LINES  BOOST TECHNIQUES AFTER BCS  IMRT  APBI  TOXICITY
  3. 3. RADIOTHERAPY  Important tool in treatment of breast cancer  Aims – 1. To decrease chances of LR 2. Increase local control & hence increase survival
  4. 4. INDICATIONS OF RADIATION  PMRT  LABC  T3 T4 lesions  MARGIN POSITIVE  Node positive more than 4 VS 1-3  POST BCS
  5. 5. PMRT  Unfavorable characteristics such as  lymphovascular invasion  close or positive margins  extracapsular extension  less than 10 lymph nodes removed in the axillary dissection
  6. 6. SIMULATION
  7. 7. TREATMENT POSITION  supine position, with the arm abducted (90 degrees or greater).  Commercially available or custom made breast tilt boards with armrests that maintain the patient's daily position with the slope of the chest wall parallel to the table  often in combination with immobilization devices (e.g., alpha cradle, plastic molds)
  8. 8. BREAST BOARD
  9. 9.  ADVANTAGE  Allow comfortable arm up support  brings arms out of the way of lateral beams.  Positions patient so that the breast / sternum is horizontal -avoiding angulation of the collimator.  DISADVANTAGES  Possibility of skin reactions in the infra mammary folds  Access to CT scanners hampered
  10. 10. VAC-LOCK
  11. 11. Breast ring with valecro Alpha cradle
  12. 12.  For pendulous breast  Prone or lateral decubitus
  13. 13. LATERAL DECUBITUS
  14. 14. PRONE POSITION
  15. 15. TREATMENT VOLUME  POST BCS  The entire breast and chest wall are included in the irradiated volume  PMRT- entire ipsi lateral chest wall  PLUS OR MINUS  Nodal irradiation  Axillary  SCF  IMN
  16. 16. FIELDS  Medial & lateral tangential fields – cover chest wall or breast & lower axilla  Single ant field – covers supraclavicular & upper axilla
  17. 17. FIELD BORDERS
  18. 18. FOR TANGENTIAL FIELDS  Upper border – bottom of head of clavicle  Medial border – at or 1cm away from midline  Lateral border – 2-3cm beyond all palpable breast tissue – mid axillary line  Lower border – 2cm below infra mammary fold of opposite breast  Anterior - 1-2cm margin of light, above the highest point of breast.
  19. 19. FIELD BORDERS- TANGENTS
  20. 20. SIMULATION AND SETUP  At the CT/fluoroscopic simulator, the scar(s) and drain sites are identified with radiopaque wires  The four field borders are chosen and radiopaque wires are placed prior to simulation  The fluoroscopic simulator reveals the extent of respiratory motion, the cardiac silhouette, and lung volume
  21. 21. CONVENTIONAL SIMULATION  SSD or SAD
  22. 22.  Bring gantry to the antro-posterior position central axis kept in the medial field border,half b/w superior and infr borders  Rotate gantry to 50-60 degree  Length and width adjusted  Medial and lateral markers should cross the central crosswire  Simulation films taken for the medial tangent
  23. 23.  Gantry rotated 180 degree to get the lateral tangents  Again check if the markers are crossing the cross wires  Separation of the 2 tangential beams measured at central axis of the field  Treatment depth =1/2 the separation of the fields  Simulation film of the lateral field is taken  Ideally 2-3 cms of the lung field should be included in the field.
  24. 24. PARAMETERS MEASURED FROM SIMULATOR FILMS  Central lung distance [CLD]) - perpendicular distance from the posterior tangential field edge to the posterior part of the anterior chest wall at the center of the field  Maximum lung distance [MLD])- the maximum perpendicular distance from the posterior tangential field edge to the posterior part of the anterior chest wall  the length of lung as measured at the posterior tangential field edge on the simulator film
  25. 25. CENTRAL LUNG DISTANCE CLD (cm) % of lung irradiated 1.5 cm 6% 2.5 cm 16% 3.5 cm 26%
  26. 26. SAD TECHNIQUE
  27. 27.  Used in some institutions  Need breast bridge with that we can measure  1.The distance on straight line that separates medial and lateral entrance points  2.The Angle from horizontal that defines this connecting line  3.The width of field necessary to flash over surface of the breast  We also need angle that sternum makes relative to treatment table top
  28. 28. BREAST BRIDGE
  29. 29.  Either we can find S and D by entering these data in to a computer program  Or we can calculate manually by mathematical equation  D= sep/2.sinØ-AcosØ  S= sep/2.cosØ+AcosØ
  30. 30. INVERTED HOCKEY STICK TECHNIQUE
  31. 31. POST BCS Wedges or compensators – to achieve uniform dose distribution in breast Used in intact breast to produce minimal (10% or less) dose variation from base to apex
  32. 32. Higher dose to the apex without wedges
  33. 33. BOLUS  Increases dose to skin & scar after mastectomy  Cosmetic results may be inferior  Universal wax bolus used  Usually not used  May be used if skin involved
  34. 34. IRRADIATION OF REGIONAL LYMPHATICS
  35. 35. TREATMENT POLICY FOR REGIONAL NODES (PEREZ)
  36. 36. INDICATIONS OF SCF IRRADIATION  4 or more positive axillary nodes  1-3 positive lymph nodes- strongly recommended  Positive margin or T3/T4 lesion at physicians discretion
  37. 37. NCIC CTG MA.20 RESULTS  The study enrolled 1,832 women, most of whom (85%) had one to three positive lymph nodes  a smaller proportion of women (10%) who had high- risk, node-negative breast cancer.  All women had been treated with breast-conserving surgery and adjuvant chemotherapy or endocrine therapy  The participants were randomized to receive either WBI alone or WBI plus RNI
  38. 38.  a median follow up of 62 months  statistically significant benefits for the group receiving the added RNI therapy.  greater than 30 percent improvement in DFS (from 84 % VS 89.7 %)
  39. 39.  Standard tangential fields include the breast or chest wall  and anatomically may cover level I and some of level II (lower) axillary nodes  So to include upper II, III and SCF node separate anterior field has to be included
  40. 40. SCF  Single anterior field is used. Field borders –  Upper border : thyrocricoid groove  Medial border : extends to the pedicles of the vertebral bodies and follows the medial edge of the sternocleidomastoid muscle superiorly  Lateral border: lateral border is a vertical line at the level of the coracoid process, just medial to the humeral head  Lower border : matched with upper order of tangential fields
  41. 41. MATCHING SUPRACLAVICULAR & CHEST WALL FIELDS
  42. 42. Angulation By inferior angulation of the tangential fields. Half beam block technique Blocking the supraclav field’s inferior half, eliminating its divergence inferiorly . Hanging block technique Superior edge of tangential beam made vertical by vertical hanging block.
  43. 43. • Single isocentre technique: Isocentre placed at the junction of tangential and supraclavicular field • Inferior portion of field blocked for supraclavicular treatment and superior portion blocked for tangential field
  44. 44.  In the era when MLC was not available?  Need asymmetric collimator and breast board
  45. 45. SINGLE ISO CENTRIC TECHNIQUE
  46. 46. IMN IRRADIATION
  47. 47. INDICATION  Remain a controversial issue  more than 4 L.N  1-3 L.N with central and medial lesion  T3 T4 LESION and margin positive  SLN in IMN
  48. 48. EORTC 22922/10925 TRIAL  4,004 women with stage I, II, and III breast cancer with involved axillary lymph nodes and/or a medially located primary tumor  to IM-MS radiation (50 Gy in 25 fractions) or no IM-MS irradiation.  Three-fourths of women (76.2%) had breast-conserving surgery  55.6% had axillary lymph node involvement, and axillary radiation was given to 7.8% of women with IM-MS radiation and 6.8% without.
  49. 49.  After a median follow up of 10 years, overall survival 1.6% in favour of IMN radiotherapy, p=0.054).  Disease free survival by 3% p=0.044  metastases-free survival by 3% (78% vs. 75%)
  50. 50.  If IMN is to be included in the treatment great care should be taken to minimize dose to heart and lungs  Usually ipsilateral IMN are treated
  51. 51. 1. Extension of tangential fields– by extending medial border – 3cm across midline or by using imaging techniques 2. Separate field – • Medial border – midline , matching with tangential field border • Lateral border – 5-6cm from midline • Superior border – abuts inferior border of supraclav field or at 1st ICS (superior border of head of clavicle) if only IMNs are to be treated • Inferior border – at xiphoid or higher if 1st three ICS covered
  52. 52. DEEP TANGENTS More normal tissue is being irradaited. (lung, heart and contralateral breast)
  53. 53.  Partial Wide tangent with block  Include only 1-3 ICS
  54. 54. Anterior field Oblique field
  55. 55.  The dose to the IMN field (45 to 50 Gy at 1.8 to 2 Gy per day) is calculated at a point 4 to 5 cm beneath  ideally based on CT scan localization  electrons in the range of 12 to 16 MeV are preferred
  56. 56. MATCHING THE TANGENTIAL BEAMS WITH INTERNAL MAMMARY FIELD
  57. 57. MATCHING OF IMN & TANGENTIAL FIELDS cold region if IM tangential matching overlies large amt of breast tissue Cold area negligible if thin breast tissue beneath match-line Lack of separate IM field - irradiation of Excessive lung vol
  58. 58. OBLIQUE ELECTRON FIELD MATCHING
  59. 59. POSTERIOR AXILLARY BOOST
  60. 60. POSTERIOR AXILLARY BOOST  There is considerable debate regarding the necessity of a posterior axillary boost.  The posterior axillary boost has been employed to supplement axillary dose  Usually 70-80% prescribed dose is recieved at mid axillary plain  Dose of 10-15 Gy is givven
  61. 61.  Superior border – splits the clavicle  Inferior border – Superior edge of chest wall portal  Medial border – To allow 1.5-2cm of lung on the portal film  Lateral border – medial border of humeral head
  62. 62. 3D CRT AND RTOG GUIDELINES
  63. 63. PLANNING CT  Take planning CT from hyoid to cover marked lower border  3mm cut will be ideal
  64. 64. DURING CT SIMULATION Post-BCS Post-Mastectomy
  65. 65. REGIONAL NODAL CONTOURING
  66. 66. SCF begins
  67. 67. Axillary level III begins
  68. 68. Axillary level II begins
  69. 69. Axillary level I begins
  70. 70. Axillary level I ends
  71. 71. IMC begins
  72. 72. IMC ends
  73. 73. DOSE  50 Gy in 25-28 fractions  42.5 in 16 fractions  40 Gy in 15 fractions  39 Gy in 13 fractions  PLUS BOOST OF 10-20 GY after BCS
  74. 74. ROLE OF IMRT IN BREAST CANCER
  75. 75. IMRT BREAST: WHY? (1) Better dose homogeneity for whole breast RT (2) Better coverage of tumor cavity (3) Feasibility of SIB (4) Decrease dose to the critical organs (5) Left sided tumors- decrease heart dose
  76. 76.  Reduces the hotspots specially in the superior and inframammary portions of the breast. Increases homogenity Manifests clinically into decrease in moist desqumation in these areas.
  77. 77.  With IMRT - better conformation of dose to target tissues, increased sparing of normal tissues , limiting dose to lungs & heart  Studies have shown – 50% reduction in cardiac mortality rate  %age of ipsilateral lung volume receiving >20% of isocentre dose can be decreased to 3.4%
  78. 78. ISSUES WITH IMRT  Breast is a mobile organ (organ motion effects)  ACTIVE Breathing Control (ABC) costly apparatus required  Geometric uncertainties as per patients and lumpectomy cavity position  Uncertainties regarding surgical clips displacement / lumpectomy cavity
  79. 79. Adapted from Larry Marks, Duke TO AVOID THIS
  80. 80. BE CAREFULL DOCTOR SPARED MY HEART AND LUNG BUT HE ALSO SPARED TUMOR
  81. 81. POST BCS  Technique similar to PMRT  BUT  Boost is needed
  82. 82.  The need for a boost to the tumor bed following lumpectomy and whole breast radiation remains an area of debate  RATIONALE  65% to 80% of breast recurrences after conservation surgery and irradiation occur around the primary tumor site  The Lyon Breast Cancer Trial  Bartelink et al. reported the results of the EORTC trial
  83. 83. RANDOMIZED BOOST TRIALS
  84. 84.  LR were lesser with boost  Most studies boost of 10-16 Gy  Patients 40 years of age or younger benefited most
  85. 85.  Indications – high risk pts with – 1. Young age – most important prognostic factor for LR, recommended for pts<50yrs 2. Surgical margins - +ve or close margins not re-excised 3. Extensive intraductal component (EIC) 4. Tumor size >4cm (T2) 5. Lymphovascular emboli 6. High grade
  86. 86. LOCALIZATION OF LUMPECTOMY CAVITY  Pre-op clinical finding , pictures  Imaging- mammogram,usg,MRI  Per-op finding  HPR  Surgical clips  Post op imaging with USG,CT or MRI
  87. 87. Use of mammography in defining the boost target localisation in breast conserving treatment
  88. 88. BOOST TECHNIQUES  Electrons  Interstitial brachytherapy  EBRT
  89. 89. ELECTRON BOOST
  90. 90. BOOST-ELECTRONS  Appropriate energy selected to allow 85 -90% isodose line to encompass target volume & decrease dose to the lung.  Clinical set up - post lumpectomy volume or scar on skin +3 cm in all directions.  Energy – 9-16 MeV  Dose – 10-16 Gy
  91. 91.  Advantage over implant:  no need for anesthesia, admission, uncomfortable insertion of 10 -20 needles  relative ease in setup, outpatient setting, lower cost  decreased time demands on the physician  excellent results compared with 192Ir implants  Complications – skin reactions – telengiectasia
  92. 92. INTERSTITIAL BOOST
  93. 93. INTERSTITIAL IMPLANT  Women with large breasts & deep seated tumors (>4cm below skin)  Surgical clips to localize & define every extension of cavity – 6 clips suffice –med , lat , sup , inf , cephalad , caudal  Higher dose can be delivered more easily at depth with implant  Source used – Ir192 by LDR or HDR
  94. 94.  Timing of implant – intraoperative – pre-planned , accurate localization , single anaesthesia , catheters placed more accurately in tumor bed  Post EBRT
  95. 95. A. Defining the implantation isocentre and definitive needle entrance and exit points at the skin for a breast implant. Reconstruction boost target isocentre from mammography, by simulator, or CT. The indicated entrance points are too close to the target volume (A) B. Inclination of the implantation equator plane away from the target to avoid an overlap of the boost PTV and needle exit points at the skin
  96. 96. (C). Indication of new entrance and exit points, further away from the boost CTV, to avoid skin teleangiectases . (D)Occurrence of severe teleangiectasic ‘stars’ at skin entrance or exit points if rules for implementation are not followed Why this planning so important. With a delivered dose of 50 Gy , chances of late teleangiectasia may occur in 30% of cases Vessels may have already received 20–40 Gy from the breast irradiation. Therefore, there is usually only a small dose amount left in skin vessel tolerance for teleangiectasia
  97. 97. ANAESTHESIA  Breast implants can easily be carried out under L.A. and premedication with 2.5–5 mg midazolam given 15–30 min before the implantation.(GA, <0.5%)  The patient is placed in supine position with the homolateral arm in 90° abduction.  After the design of implant geometry and localisation of entrance and exit points of the needles, the skin is infiltrated at each point with 0.5–1 ml 1% lidocaine.  Retroareolar region is painful (1-5 ml extra infiltrate in that area)
  98. 98. DESIGN OF THE IMPLANT GEOMETRY  Needles are implanted parallel and equidistance from each other.  In most cases inserted in a mediolateral direction.  In very medially or laterally located tumor sites, needles should be implanted in a craniocaudal direction .to enable separate target area from skin points.  In some rare cases, the upper outer quadrant has to be implanted with needles orientated in a 45° angle to avoid overlap of source positions and skin
  99. 99.  2 planes of needles are usually needed to cover the PTV.  A single plane may be sufficient in case of a target thickness of less than 12 mm.  Three planes are required in a large breast where the targeted breast tissue between pectoral fascia and skin is thicker than 30 mm.  15-25 needles spaced 15–20 mm are usually required.
  100. 100.  Reference needle is first implanted at the posterior (deepest) side into the centre of the PTV.  For definitive positioning, the needle should pass about 5 mm behind the internal scar.  The other needles of the posterior plane are then implanted parallel to the first one.
  101. 101.  Total number of catheters based on size of the seroma cavity  15 and 25 catheters Connected to HDR
  102. 102.  Boost can also be given by 3DCRT or IMRT  CTV for boost will be-tumor bed with 1.5 cm margin OR more if margins are close or positive  PTV = CTV + 5mm
  103. 103. DOSE & FRACTIONATION  Boost RT to tumor bed  Electron 10-16Gy in 5-8fractions  Photon 10-16Gy in 5-8Fractions  Brachytherapy  LDR – 15-20Gy  HDR – 12-16Gy in 3-4 Fractions
  104. 104. APBI  RT is a must for decreasing IBTR  Traditional WBRT need 5-6 week  Many fail to receive it  Accelerated partial breast irradiation solve this problem by completing treatment in 5 days  THE CURRENT STANDARD OF CARE OF WOMEN AFTER BCS IS WBRT
  105. 105.  Technique may vary  Radiation delivery to a smaller volume of breast tissue around lumpectomy site  Few large fraction during shorter duration  Rationale – majority of relapse at or near lumpectomy site  Lower probability of microscopic disease with increasing distance  RCT data is lacking
  106. 106. TECHNIQUES FOR PBI  Interstitial brachytherapy with HDR or LDR  Intracavitary brachytherapy with Mammosite  Intraoperative electron beam therapy  3D conformal radiation therapy
  107. 107. MULTICATHETER INTERSTITIAL TECHNIQUES  Experience is greatest with the multicatheter interstitial technique  it was initially developed as a boost technique following whole breast irradiation
  108. 108. ADVANTAGES OVER EBRT  EBRT  6 weeks (30 fractions)  Homogeneous dose  Logistical problem for patients  Difficult for frail, elderly, or chronically ill patients  Interferes with schedule of working women  Some BCT candidates will opt for mastectomy  5 days (10 fractions)  Dose is higher to tissue at greatest risk for sub- clinical malignant cells  Reduction in skin, cardiac and lung dose  Ideal for patients who live far from RT Center  Convenient  May increase number of women treated with BCT
  109. 109. DISADVANTAGES  EBRT  Noninvasive  Can cover nodal regions  Treats multi-centric carcinoma  Low complication rate  Linear accelerators widely available  Most radiation oncologists experienced  Invasive  Not useful for treatment of nodal basins  May miss tumor foci in other quadrants  Low, but definite risk of infection and/or fat necrosis  Requires special skills for performing; in placing catheters and dosimetry
  110. 110. MAMMOSITE  has been widely embraced due to its simplicity  less dependence on user experience  technique employs a single balloon catheter introduced into the lumpectomy site either at the time of lumpectomy or percutaneously after the procedure.
  111. 111. Mammosite® Breast Brachytherapy Applicator • Simplified brachytherapy method for PBI • Dual lumen single catheter with expandable balloon at end • Balloon expands to fill the lumpectomy cavity • Radiation dose prescribed to 1 cm beyond balloon surface • Uses 192Ir (HDR) as the source • FDA approval May 2002 MammoSite PBI
  112. 112. MAMMOSITE CATHETER
  113. 113. Six-prescription point, multiple dwell position technique (RUSH technique.) Harper et al 2005
  114. 114. 5th Int. Meeting ISIORT Madrid, June 2008 OTHER INTRACATARY CATHETER. SAVI ClearPath™ Contura
  115. 115. EXTERNAL BEAM CONFORMAL RADIATION  it is the one that is most widely employed in the ongoing randomized trial  due to the fact that it is totally noninvasive and delivers a homogenous dose distribution
  116. 116. EBRT  generally employs multiple conformal fields  although plans as simple as two opposing small conformal fields may be adequate.  Challenges with this technique include daily positioning of the target  movement with breathing  delivery of higher doses to surrounding normal breast tissue than with the brachytherapy
  117. 117. PBI: 3D-CRT Target definition
  118. 118. PBI: 3D-CRT Beam Arrangement 3.85 Gy BID x 10 fractions
  119. 119. INTRA OPERATIVE ACCELERATED PARTIAL BREAST IRRADIATION  The radiation is delivered in a single intraoperative dose to the lumpectomy site at the time of surgery  Using intraoperative electrons or intraoperative photons
  120. 120. LINEAR ACCELERATOR ELECTRON
  121. 121. TARGETED IORT  Intra Op. X-ray (50 Kv)  High dose rate  Spherical radiation field  Dose to applicator surface  Single dose  Minimum shielding  Low energy X-rays have a higher Relative Biological Effectiveness  Time: 15 to 25 minutes
  122. 122. Drawing A shows breast and lumpectomy cavity (Star) after removal of breast cancer. Drawing B shows Intrabeam Photon Radiosurgery System and Applicator (Arrow) positioned within the lumpectomy cavity. Bright red area shows portion of breast targeted for radiotherapy
  123. 123. INTRABEAM APPLICATORS  Spherical Applicator Set Ranges from 1.5 to 5.0 cm diameters are available.  Ideally used in intracavitary applications to “fill” the tumor bed, which ensures an equal and spherical dose distribution to the surrounding tissue.
  124. 124. PARTIAL BREAST IRRADIATION TECHNIQUES Interstitial Brachyther. Intracavitary Brachyther Intraop. RT 3D Conformal RT Dose 34 Gy in 10 fr In 5 days 34Gy in 10 fr In 5 days 20-21Gy in single fraction 38 Gy in 10 fr. In 5 days Target 1.5 cm margin around WLE cavity 1cm around WLE cavity Visual by surgeon and radonc perop 2.5cm margin around WLE cavity Pros Many dwell positions for Irreg. cavity Ease of placement and planning Single dose Spares skin Fits with standard RT machines Cons Operator dependent High cost Fewer dwell positions RT before path known Specialised centres only Larger fields (respiration) and more normal tissue
  125. 125.  Whole breast needs to be treated till long term results of partial breast radiation is known  Boost radiation is always necessary-Electron boost, photon boost and brachytherapy boost give equally good results
  126. 126. COMPLICATIONS Lymphedema, breast edema, breast fibrosis, painful mastitis or myositis cardiac toxicity decreased arm mobility brachial plexopathy radiation pneumonitis rib fractures second neoplasms soft tissue necrosis
  127. 127. LYMPHEDEMA  Determinants Extent of Axillary Dissection Axillary RT Body Mass Index  Incidence Full Axill Dissection + RT – 25-30% Level 1/11 Dissection + RT – 6% axillary surgery and irradiation (33.7%) irradiation alone (26%) axillary dissection only (7.2%)
  128. 128. CARDIAC COMPLICATIONS  Risk Factors Left sided tmrs Anthracycline Fraction size >2Gy
  129. 129. “ Serious toxicity from PMRT in most circumstances is not sufficient to outweigh its likely benefits for the groups in whom it is recommended when current radiotherapy techniques are used”. ASCO
  130. 130. THANK YOU

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