Breast Cancer
Radiation Oncology II
4412
History
Recorded 5000 years ago
Before 20th century-William Halstead
performed radical mastectomy
Today we use multidisciplinary
approach
Radiation therapy
Chemotherapy
Hormone therapy
Surgery
Epidemiology
Most common malignancy in women
Second major cause of death (lung
#1)
Men can get breast cancer
Risk Factors
Don’t have to have risk factors to get
breast cancer
Gender- women out number men
Age- older women/higher probability
Incidence rises steadily during the
reproductive years after age 30
Family history
Mothers/sisters/daughters doubles the
risk
According to the ACS:
Although smoking and breast cancer
does not have a direct link, smoking
increases the risk for other cancers and
affects the overall health of a person
Research does not show a link between
breast cancer and pollutants. Research
is ongoing
Diet has been inconclusive as a risk
factor for breast cancer. Diet and weight
are risk factors for other types of cancers
BRCA 1 and 2
The gene BRCA 1 & 2 is associated
with 5 to 8 out of 10 women have a
likelihood of developing breast cancer
We all have these genes
These genes become defective
BRCA1 is a human tumor suppressor
gene that produces a protein called
breast cancer type 1 susceptibility
protein.
Originally stood for Berkeley
California as this was where it was
first discovered in 1990.
This gene was later cloned in 1994 by
scientists at Myriad Genetics.
BRCA1 is expressed in the cells of
breast and other tissue
It helps repair damaged DNA or
destroys cells if DNA cannot be
repaired.
When BRCA1 becomes damaged,
damaged DNA is not repaired
properly and this increases the risks
for cancer.
Certain variations of the BRCA1 gene
lead to an increased risk for breast
cancer.
Researchers have identified hundreds
of mutations in the BRCA1 gene,
many of which are associated with an
increased risk of cancer.
Women with an abnormal BRCA1 or
BRCA2 gene have up to an 60% risk
of developing breast cancer by age
90
Increased risk of developing ovarian
cancer is about 55% for women with
BRCA1 mutations and about 25% for
women with BRCA2 mutations
Prognostic Indicators
1. Lymph node involvement
Most significant aspect of staging
2. Higher number of involved nodes
increases recurrence and decreases
survival
3. Usually 10 axillary nodes are evaluated
1.
1.
2.
3.
4.
<3 low risk
>4 high risk
>10 extremely poor prognosis
Involvement of internal mammary nodes,
lower survival
2. Tumor Extent
Lesions <0.5 cm= 5 year survival
>0.5 cm= 82% 5 year survival
3. Histology
1. Ductal carcinoma in situ
Most common non-invasive breast cancer
Non-invasive
Nearly all women can be cured
Ductal
Carcinoma in
Situ
2. Infiltrating ductal carcinoma
Most common invasive breast
cancer
Starts in the milk passage or duct
Invades fatty tissue of breast
Can spread
Infiltrating
Ductal
Carcinoma
3. Infiltrating (invasive) lobular
carcinoma
Starts in the milk glands or
lobules
Spreads
Usually found in 1 out of 10
cases
Infiltrating
Lobular
Carcinoma
Lobular carcinoma in situ
This increases the risk of cancer
later
Patient needs an exam 2-3 times
per year
Mammography every year
Lobular
Carcinoma in
Situ
Inflammatory carcinoma
Extremely poor prognosis
Breast tenderness
Breast enlargement
Peau d’orange appearance
Erythema
Warmth
Inflammatory Breast Cancer
Staging
Staging system is TNM
Patients are staged for:
The selection of proper treatment
Evaluation of treatment methods
Indicates prognosis
Two methods of staging:
1. clinical
Physical workup, operative findings, pathology
2. pathological
Microscopic assessment of the tumor margin
Diagnosis
Estrogen and progesterone receptor
status
Tissues are examined for the effects of
hormones on the cells
Indicates the potential response to
hormonal therapy
Receptor positive patients are more
likely to respond to hormonal therapy
Receptor positive tumors usually have a
better outcome
Survival (Prognosis)
Overall 5 year survival after first
diagnosis is approx. 96%
Regional spread 75%
Distant mets at time of diagnosis
20%
Patients can relapse up to 20 years or
more after treatment
Few options for treatment are
available after relapse
Anatomy
Lymphatic drainage
1. superficial
Drains the skin covering the breast
2. deep
Drains the internal breast tissues
Three groups of nodes in the breast:
1. axillary lymph nodes
Primary deep lymphatic drainage of the
breast
Between 10 & 38 lymph nodes are in each
axilla
2. internal lymph nodes
Located near the edge of the sternum
Embedded in the fat in the intercostal
spaces
Approx. 4 per side
3. supraclavicular nodes
Lymphatic drainage from the breast to the
supraclavicular nodes, liver and contralateral
internal mammary nodes
Sites of Origin
The breast is divided into quadrants
Upper outer
Upper inner
Lower outer
Lower inner
Most breast cancers will arise in the
upper outer quadrant- more breast
tissue
Multicentric describes tumors that
appear in several areas of the breast
Spread
Breast cancer tends to grow:
Locally
Involves the ducts and adjacent tissues
May spread to local and regional lymphatics
Involvement of axillary lymph nodes occurs
orderly and progressively
Recurrence
Local recurrence (in the breast)
Regional recurrence (lymphatics)
Distant metastatic sites
Axillary and internal mammary lymph
nodes are the most likely sites of
regional involvement of breast cancer.
Distant metastasis
Bone
Brain
Liver
Lung
Eyes
Ovaries
Adrenal and pituitary glands
Detection
With early detection breast cancer is
one of the most curable malignant
diseases.
Three step health program:
1. monthly self exam- begin in the
early 20’s
2. Annual clinical exam- 20’s & 30’s
every 3 years, beginning 40
yrs/age, every year
3. Routine mammogram- as
recommended by established
guidelines- right now it is every year
for women 40 and older
Most breast changes are benign
Approx. 20% of all masses will be
malignant
Most common sign will be a painless
lump, usually hard with uneven edges
BUT
Some can be tender, soft and round
Other Detection Methods
Ultrasound- used in addition to
mammography- distinguished
between cystic and solid masses
Thermography- produces an image of
the temperature of the overlying skin
of the breast. The tumor produces
heat
PET
Bone scan- mets
MRI used for women with silicone breast
implants, extremely dense tissue or
changes in breast tissue secondary to
radiation therapy
CT- used for mets
Ductogram (galactogram) fine plastic tube
is placed into the opening of the duct at the
nipple. Dye is injected to show masses in
the duct with x-ray. Fluid can be withdrawn
for pathology.
Monthly Self Exam
Step One
Step Two and Three
Step Four
Step Five
Biopsy
A biopsy is the only way to know for sure
that there is cancer
Fine needle biopsy- small gauge needle is
placed into the breast tissue mass. Blood and
suspicious tissue is evacuated out and placed
on slides.
Core needle biopsy- partial removal of breast
mass
Excisional biopsy (lumpectomy) removal of the
entire mass with or without a portion of
surrounding normal tissue.
Pathology
Two basic methods are used for
obtaining pathological information:
1. gross examination- records the
dimensions of the specimen, the size of
the tumor, and tumor’s relationship to
the excisional margin
2. microscopic examination- examines
the specimen under the microscope for
tumor histology
Biopsy samples look for hormone
receptors
–ER positive- Estrogen
–PR positive- Progesterone
–These will respond to
hormonal therapy which leads
to a better prognosis
TREATMENT
1. Surgery
Radical mastectomy
Removal of the breast with overlying skin
Removal of the axillary lymph nodes
Removal of the pectoralis major and minor
muscles
Modified radical mastectomy
Removal of the breast with overlying skin
Removal of some or all of the axillary lymph
nodes
Pectoralis minor muscle might be removed
Pectoralis major muscle is left intact
Lumpectomy
Removal of the tumor with a margin of
normal appearing tissue
Lymph nodes are sampled through a
separate axillary incision
Axillary dissection
Removal of a sample of axillary lymph
nodes on the side of the affected breast
(staging)
Lumpectomy
Skin Sparing Mastectomy
Modified Radical Mastectomy
Total (Simple) Mastectomy
Radical Mastectomy
2. Chemotherapy(Systemic Drug
Therapy)
Used to destroy, prevent or delay tumor
spread to distant sites in the body.
Used alone or in combinations
Examples:
Cyclophosphamide (C)
5-fluorouracil (F)
Methotrexate (M)
Adriamycin (doxorubicin) (A)
Vinblastine
Mitoxantrone
Mitomycin C
Tamoxifen
Chemotherapy cont’d
Endocrine therapy
Deprives cancer cells of the hormones
needed for growth
3. Radiation Therapy
There are as many techniques for breast
irradiation as there are radiation
oncology centers!
Breast set-ups are technically
challenging
Have to have straightforward,
reproducible techniques
Positioning and immobilization
Patient’s affected arm must be mobile
before sim and treatments are begun
Patient’s affected arm must be immobile
for day to day set ups
Patient disrobes from waist up
Clothes, sheets, other articles can keep
patient from laying flat and straight on the
treatment table
Body must be straight (in the sagittal
plane)
Stand at head of table and look straight
down patient’s body. Use the sagittal
laser to help.
Body must be level from side to side
Levelers (tattoo or marks) on patient’s
side help
Patient’s contralateral arm should rest
on the table top with palm down
If patient’s hand is on abdomen or grasping
a belt, this can result in distortion of the
thoracic anatomy.
Will cause rotation and/or displacement of
the uninvolved breast in the treatment field
The patient’s involved arm is raised and
supported far enough in a cephalad
direction
Avoids treating upper arm
Can help reduce or eliminate skin folds in the
axilla and supraclavicular areas
When treating breast or chest wallpatient’s head should be straight
When treating peripheral lymphatics- head
will be turned
Feet held together- keeps patient from
crossing feet and rotating the lower
abdomen
Patient’s with large and/or pendulous
breasts often have breast tissue displaced
up into the infra clavicular area
Patients with large or pendulous
breasts can be placed on a slant
board
Helps to keep the head and thorax
elevated relative to their pelvis and
lower extremities
Keeps breast tissue in a more normal
location
Helps to alleviate the problem of deep
skin folds in the supraclavicular area
Different Radiation Techniques
BREAST TANGENTS
Wedges are used for dose homogeneity
Bolus is not usually recommended to intact
breast- skin is not at risk for recurrence
Usually 4680-5040 cGy 180/200 per fraction
Tumor bed boosted to a total of 6000-6600 cGy
SUPRACLAVICULAR- 4680 cGy 180/fraction
PAB- can be added to bring midline axillary
dose to 4680 cGy
Intact Breast or Chest Wall
Women who require only breast or chest wall
irradiation are treated with tangential (glancing)
fields
This maximizes coverage of the tissues at risk
Minimizes the radiation dose to underlying
structures, primarily heart and lung
Usually use lower energies
Feet are directed away from the collimator to
correct for geometrical distortion of the radiation
beam
Isocentric technique is preferred
Supraclavicular field
Portal is angled 10-15 degrees to
prevent exposure of the spinal cord and
esophagus
The supraclavicular field is planned
before the tangential fields.
This field is used with patients who
usually have 4 or more positive axillary
nodes or extracapsular extension
Posterior Axillary Boost field (PAB)
Usually used to increase the mid-axillary
dose to the prescribed level
The dose from the anterior
supraclavicular field may be insufficient
Setup parallel opposed to the
supraclavicular field
Uses the identical inferior margin,
preserving the vertical straight edge
Internal mammary lymph nodes
Small percent of patients may be at risk
for internal mammary node involvement
Electron beam treatment is used
Treats the nodes but gives a high skin
dose
Breast boost
To the tumor bed after completion of
tangential irradiation
Delivered with electrons or implant
The location and length of scar does not
accurately reflect the position and size of
the tumor bed
Clips placed on tumor bed at the time of
surgery can help with localization
Skin Reactions
Skin folds tend to intensify skin
reactions, bolus effect
Keep area clean and dry
Avoid sun exposure to affected area
Use cornstarch
Do not shave under affected arm
Discourage use of lotions, creams,
deodorants, powders in treatment areas,
may contain perfumes, alcohol or metals
Use soft and loose fitting clothing
Avoid hot water bottles, ice packs, heating
pads in area of treatment
Cornstarch should not be used with moist
desquamation, can cause fungal growth
and wound infection
Skin doses
30 Gy erythema, dryness
40 Gy dry desquamation, flaking of skin,
especially in skin folds
50 Gy moist desquamation, complete
break down of skin. Patient may need to
take a break from treatment for some
healing of the skin.
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