1. RT TECHNIQUES IN
CARCINOMA BREAST
DR. NABEEL YAHIYA
JUNIOR RESIDENT IN RADIATION ONCOLOGY
KOTTAYAM MEDICAL COLLEGE
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. RADIOTHERAPY
Important tool in treatment of breast cancer
Aims –
1. To decrease chances of LR
2. Increase local control & hence increase survival
4. INDICATIONS OF RADIATION
PMRT
LABC
T3 T4 lesions
MARGIN POSITIVE
Node positive more than 4 VS 1-3
POST BCS
5. PMRT
Unfavorable characteristics such as
lymphovascular invasion
close or positive margins
extracapsular extension
less than 10 lymph nodes removed in the axillary
dissection
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)
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
17. 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
18. FIELDS
Medial & lateral tangential fields – cover chest wall or
breast & lower axilla
Single ant field – covers supraclavicular & upper axilla
20. 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.
22. 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
25. 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
26. 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.
27. 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
31. 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
34. 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
36. 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
38. 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
41. 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
42. 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
43. 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 %)
44. 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
45. 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
50. 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.
51. • 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
52. In the era when MLC was not available?
Need asymmetric collimator and breast board
56. 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
57.
58. 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.
59. 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%)
60. 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
61. 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
65. 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
67. 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
70. 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
71. 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
88. 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
89. 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.
90.
91. 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%
92. 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
96. 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
99. LR were lesser with boost
Most studies boost of 10-16 Gy
Patients 40 years of age or younger benefited most
100. 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
101. 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
102. Use of mammography in defining
the boost target localisation in
breast conserving treatment
105. 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
106. 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
108. 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
109. Timing of implant – intraoperative – pre-planned ,
accurate localization , single anaesthesia , catheters
placed more accurately in tumor bed
Post EBRT
110. 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
111. (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
112. 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)
113. 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
114.
115. 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.
116. 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.
117. Total number of
catheters based on
size of the seroma
cavity
15 and 25 catheters
Connected to HDR
118.
119.
120. 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
121.
122.
123. 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
124. 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
125. 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
126.
127.
128. TECHNIQUES FOR PBI
Interstitial brachytherapy with HDR or LDR
Intracavitary brachytherapy with Mammosite
Intraoperative electron beam therapy
3D conformal radiation therapy
129. MULTICATHETER INTERSTITIAL TECHNIQUES
Experience is greatest with the multicatheter
interstitial technique
it was initially developed as a boost technique
following whole breast irradiation
130. 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
131. 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
132. 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.
133. 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
137. 5th Int. Meeting ISIORT Madrid, June 2008
OTHER INTRACATARY CATHETER.
SAVI
ClearPath™
Contura
138. 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
139. 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
142. 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
144. 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
145. 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
146. 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.
147. 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
148. 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
149. 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
150. 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%)
152. “ 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