carcinoma breast RADIOTHERAPY TECHNIQUES

RT TECHNIQUES IN
CARCINOMA BREAST
DR. NABEEL YAHIYA
JUNIOR RESIDENT IN RADIATION ONCOLOGY
KOTTAYAM MEDICAL COLLEGE

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

RADIOTHERAPY
 Important tool in treatment of breast cancer
 Aims –
1. To decrease chances of LR
2. Increase local control & hence increase survival

INDICATIONS OF RADIATION
 PMRT
 LABC
 T3 T4 lesions
 MARGIN POSITIVE
 Node positive more than 4 VS 1-3
 POST BCS

PMRT
 Unfavorable characteristics such as
 lymphovascular invasion
 close or positive margins
 extracapsular extension
 less than 10 lymph nodes removed in the axillary
dissection

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)

 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

Breast ring with
valecro Alpha cradle

 For pendulous breast
 Prone or lateral decubitus

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

FIELDS
 Medial & lateral tangential fields – cover chest wall or
breast & lower axilla
 Single ant field – covers supraclavicular & upper axilla

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.

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

CONVENTIONAL SIMULATION
 SSD or SAD

 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

 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.

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

CENTRAL LUNG DISTANCE
CLD (cm) % of lung
irradiated
1.5 cm 6%
2.5 cm 16%
3.5 cm 26%

 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

 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

INVERTED HOCKEY STICK TECHNIQUE

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

Higher dose to
the apex without
wedges

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

IRRADIATION OF REGIONAL
LYMPHATICS

TREATMENT POLICY FOR REGIONAL NODES
(PEREZ)

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

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

 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 %)

 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

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

MATCHING SUPRACLAVICULAR & CHEST
WALL FIELDS

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.

• 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

 In the era when MLC was not available?
 Need asymmetric collimator and breast board

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

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.

 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%)

 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

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

DEEP TANGENTS
More normal tissue is being irradaited. (lung, heart and
contralateral breast)

 Partial Wide tangent
with block
 Include only 1-3 ICS

 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

MATCHING THE TANGENTIAL BEAMS
WITH INTERNAL MAMMARY FIELD

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

OBLIQUE ELECTRON FIELD MATCHING

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

 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

PLANNING CT
 Take planning CT from
hyoid to cover marked
lower border
 3mm cut will be ideal

DURING CT SIMULATION
Post-BCS
Post-Mastectomy

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

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

 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.

 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%

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

Adapted from Larry Marks, Duke
TO AVOID THIS

BE CAREFULL
DOCTOR
SPARED MY
HEART AND
LUNG BUT HE
ALSO SPARED
TUMOR

POST BCS
 Technique similar to PMRT
 BUT
 Boost is needed

 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

 LR were lesser with boost
 Most studies boost of 10-16 Gy
 Patients 40 years of age or younger benefited most

 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

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

Use of mammography in defining
the boost target localisation in
breast conserving treatment

BOOST TECHNIQUES
 Electrons
 Interstitial brachytherapy
 EBRT

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

 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

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

 Timing of implant – intraoperative – pre-planned ,
accurate localization , single anaesthesia , catheters
placed more accurately in tumor bed
 Post EBRT

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

(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

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)

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

 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.

 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.

 Total number of
catheters based on
size of the seroma
cavity
 15 and 25 catheters
Connected to HDR

 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

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

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

 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

TECHNIQUES FOR PBI
 Interstitial brachytherapy with HDR or LDR
 Intracavitary brachytherapy with Mammosite
 Intraoperative electron beam therapy
 3D conformal radiation therapy

MULTICATHETER INTERSTITIAL TECHNIQUES
 Experience is greatest with the multicatheter
interstitial technique
 it was initially developed as a boost technique
following whole breast irradiation

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

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

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.

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

Six-prescription point,
multiple dwell
position technique
(RUSH technique.)
Harper et al 2005

5th Int. Meeting ISIORT Madrid, June 2008
OTHER INTRACATARY CATHETER.
SAVI
ClearPath™
Contura

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

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

PBI: 3D-CRT Beam Arrangement
3.85 Gy BID x 10 fractions

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

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

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

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.

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

 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

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

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%)

CARDIAC COMPLICATIONS
 Risk Factors
Left sided tmrs
Anthracycline
Fraction size >2Gy

“ 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

carcinoma breast RADIOTHERAPY TECHNIQUES

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carcinoma breast RADIOTHERAPY TECHNIQUES