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