radiotherapy in early breast cancer
DESCRIPTION
gist of radiation therapy in early brast cancer; includes BCT, APBI, IORT.TRANSCRIPT
RADIOTHERAPY IN EARLY BREAST CANCER
Dr. T. SujitA M O ( Radiation Oncology )
Valavadi Narayanaswami Cancer Centre,
G.Kuppuswamy Naidu MemorialHospital,
Coimbatore - 641037,
Tamilnadu, India
March 2007
BCT Vs Mastectomy Trials
• NSABP B- 06
• EORTC 10853
• Institut Gustave-Roussy trial
• Danish Breast Cancer Group
• US National Cancer Institute study
Survival and tumor control rates with BCT similar to
Mastectomy
RT IN DCIS
• As part of BCT
• NSABP 17 and EORTC 10853 trials proved
that local recurrence was reduced with the
addition of RT to BCS ( 15% vs 31% )
• Obtaining a negative margin is very
important to prevent recurrences.
• Whole breast RT with a boost is the
standard radiotherapeutic management
RT IN EARLY INVASIVE BREAST CANCER – B C T
Post operative radiation delivered to the breast or
part of it with an aim to reduce recurrences.
Involves irradiating the entire breast by EBRT and
giving an additional boost to the tumor bed by
means of electrons, photons or brachytherapy.
Accelerated Partial Breast Irradiation completes
the entire course of RT in a period of 5 days using
brachytherapy.
WHOLE BREAST RT
• Treatment position – Supine with arm abducted; alpha cradle / breast board.
• Irradiated volume should include entire breast and chest wall.
• Field borders: – Upper : Head of clavicle– Lower : 2 cm below inframammary fold– Lateral : Mid axillary line– Medial : at or 1 cm over midline
WHOLE BREAST RT
• Energy : Usually 6 MV photons. In patients
with wide bridge separation ( > 22cm ) higher
energies are used.
• Dose : 46 – 50 Gy / 2 Gy per # / over 5 weeks
• Boost dose : 10 – 20 Gy depending on
excision margins.
RT BOOST TO TUMOR BED
• Rationale : Local recurrences tend to be
primarily in and around the primary tumor
site – boost risk of marginal recurrence.
• Given by either EBRT or Brachytherapy
• EBRT – photons or electrons
• Brachytherapy – LDR or HDR
Lyons Breast Cancer trial , EORTC ( Bartelink et al )
ACCELERATED PARTIAL BREAST IRRADIATION
Delivers an accelerated course of radiation
treatment to a small volume of breast tissue
in and around the primary tumor site.
RATIONALE OF APBI
~ Higher dose of RT can be given than by
conventional RT
~ Reduces overall treatment period
considerably
~ Patient convenience may increase
acceptance of radiation treatment after
breast-conservation surgery
METHODS OF DELIVERING RT
1. IOERT
2. BRACHYTHERAPY
~LDR
~HDR
IOERT
~ 1st studied by Abe ( University of Kyoto ) using Co 60
~ 1st IOERT using Linac – by Henschke & Goldson in 1976
~ Used IOERT mainly as a boost.
IOERT - EQUIPMENTS
~ Dedicated OT with Linac to avoid logistical incoveniences.
~ LINAC - 6 – 12 MeV energy sufficient
~ COLLIMATION / APPLICATOR SYSTEM:
lucite or aluminium applicators
conical / circular / rectangular / elliptical with
bevelled or unbevelled edges
~ “pancake” ionization chamber for dosimetry
~ patient monitoring facilities
PROCESS
PRE-OP ASSESSMENT – CT / MRI / USG
DETERMINATION OF TUMOR THICKNESS & BEAM ENERGY
GROSS DISEASE REMOVAL, TEMP. CLOSURE OF INCISION & TRANSPORT TO RT DEPT.
RE-OPENING OF INCISION, APPLICATOR PLACEMENT & TREATMENT
FINAL CLOSURE OF WOUND IN OT
IORT - BREAST
DOSE : 10 – 20 Gy IN A SINGLE FRACTION
TOTAL PROCEDURE: 30 – 45 min
TREATMENT TIME : 2 – 4 min
EBRT ( IF REQUIRED ) – AFTER 4-6 WEEKS
Single 21 Gy fraction is equivalent to 60 Gy / 30 #
( Veronesi et al )
HDR BT
~ Implants
~ Can reach areas inaccesible by electron
applicators
~ Can be used to treat deep seated tumors
~ Logistical advantage - portable
HDR BT IN APBI
( As sole modality of radiation )
~Criteria: ( ABS RECOMMENDATIONS )
T1,T2 < 3 cm
N0
Post lumpectomy with ALND
~Two plane or volume implant
~Catheters 1 – 1.5 cm apart
~Min. distance of 1- 2 cm from skin
~Dose prescription should cover 2 cm of excision margins
~DOSE : HDR – 32 Gy in 8 # -
2 # daily 6 hrs apart over 4 days
LDR – 45 – 50 Gy over 4 days
~No significant difference in results of HDR Vs LDR
HDR BT AS BOOST
~ Following 45 – 50 Gy of EBRT
~ Dose : 10 – 20 Gy
~ Can be treated within 6 hrs of surgery
~ Vicini et al : I 125 permanent implants
MAMMOSITE
~Device consists of a catheter with an inflatable balloon at one end.
~The other end can be connected to a HDR remote afterloading
machine.
~The balloon is inflated with saline to fill the lumpectomy cavity.
~Catheter is preferably inserted at the time of surgery.
~CT films are taken for dosimetric planning purposes
~DOSE:
As sole modality : 34 Gy / 10 # over 5 days,
2 # per day 6 hrs apart
As boost : 14 – 16 Gy in 4 # over 2 days,
2 # per day 6 hrs apart
MAMMOSITE DEMO
Patient.wmv
IOERT Vs HDR IORT
IOERT HDR IORTBetter dose homogeneity: < 10% variation from surface to depth
> 100 % variation
Total procedure time: 30-45 min 45 – 120 min
Faster treatment time : 2-4 min 5 – 30 min
Higher dose at depth ( 2 cm ) Lower dose at depth
Large tumor beds can be treated Not suitable
Difficult to use in certain anatomic locations
Can be use in inaccessible sites
Standard applicators for all patients Custom made applicators for different anatomic locations
Logistical problems Portable, but requires shielding
TREATMENT RESULTS ARE EQUAL WITH REGARD TO LOCAL CONTROL, SURVIVAL AND COSMESIS.
Is APBI a standard treatment?
APBI utilising either IOERT or HDR achieves good local
control and cosmesis.
Reduced treatment time translates into better patient compliance for RT.
However,
There are no randomised studies comparing APBI with conventional BCT.
APBI alone, without the use of systemic therapy is less effective than conventional whole breast RT.
RT TO THE AXILLA
• 20 – 40 % of patients with clinically negative nodes have
pathologically +ve nodes
• 20 % of patients with palpable nodes have histologically –
ve nodes.
• Axilla & SCF should be irradiated if > 4 nodes are +ve
( ASCO recommendation )
• Tumor size > 3 cm is also an indication for axillary RT
• Clinically & pathologically negative nodes – to irradiate or
not?– No benefit for supplementary irradiation after axillary dissection
yielding negative nodes or 1-3 positive nodes.
I M N ?
• IMN are not routinely treated.
– Failure at IMN is rare
– Majority of patients at risk receive adjuvant
chemotherapy
3D CRT & IMRT
• Overcomes the problem of dose
inhomogeneties seen with conventional RT
• Reduces the volume of lung receiving
radiation.
• Reduces volume of heart receiving RT
Anthracyclines
FACTORS INFLUENCING COSMESIS
• Surgical factors : Extent of resection, Orientation and length of scar, Closure or not of the tylectomy cavity, separate or continuous axilla-tylectomy scars, extent of axillary dissection.
• Radiation therapy factors: Whole breast RT dose, Dose gradient within the breast tissue, Type and dose of boost, Beam energy, Volume treated, Concurrent use of chemo.
• Host factors : Size and shape of breasts, Compliance with care and hygiene, Intrinsic sensitivity to radiation, concurrent medical illnesses.
SEQUELAE OF THERAPY
• Arm or breast edema, breast fibrosis,
radiation pneumonitis, rib fractures, mastitis,
myositis, brachial plexus dysfunction,
diastolic cardiac dysfunction.
Thank you