melanoma/sarcoma part II

treatment options for sarcoma

surgery

chemo

radiation (external beam or brachytherapy)

what is the most common site for a sarcoma

what is the most common metastastic site for a sarcoma

sarcoma simulation (4)

supine

vac lok for immobilization

head first or feet first

other devices such as clam shells or leg supporters can be used

sarcoma simulation head first or feet first depends on

tumor location

sarcoma contouring-what does the physician contour and why

tumor, tumor bed, for purpose of block creation

sarcoma contouring for dosimetry (2)

no specific contours created by dosimetry

be mindful of the body location being treated-are there critical structures nearby, if so contour them

sarcoma beams used

parallel opposed beams (AP/PA or obliques)

sarcoma field arrangement field borders

usually 2 cm radially

5-7 cm superiorly/inferiorly

for the sarcoma field arrangement, some of the normal tissue surrounding the treatment area is spared to

prevent lymphedema

beam modifiers used for sarcoma field arrangement

MLC

wedges

SNS/FNF

sarcoma beam energy and why

6 MV or 18 MV depending on tumor location and patient thickness

sarcoma prescription pre-op

5000 cGy in 25 Fx

sarcoma prescription post-op

6000 cGy in 30 Fx

Primary: 5000 cGy in 25 Fx

Boost-1000 cGy in 5 Fx

what is required for sarcoma for cure

surgery

no surgery no cure

which radiation scheme is recommended for sarcoma

pre-op

sarcoma fields

can use a primary and boost technique

sarcoma plan evaluation (3)

field should be well covered by 100% of the dose

normalization range: 95-105%

acceptable hot spot: small 107%

when should the external for sarcoma be deleted

whenever the uninvolved leg's external contour meets the treated leg's external contour

during patient treatment of sarcoma, what should be noted about the uninvolved leg

the uninvolved leg must be moved out of the path of the beams

how should the issues be adressesed with sarcoma planning

document for the therapist and go to the treatment machine on day one to confirm set up

order of most common to least common skin cancers

basal cell carcinoma most common

then squamous cell carcinoma

melanoma is the least common skin cancer

basal cell carcinoma vs melanoma growth and metastasis

basal cell grows slowly and rarely metastasizes

melanoma is malignant

where does melanoma most commonly metastasize to

axillary lymph nodes

what is the most common cause of skin cancer

UV radiation exposure (from the sun)

what is the treatment option of choice for skin cancer

surgery to remove the tumor

what are some side effects of radiation treatment for skin cancers

erythema

Dry desquamation (shedding of the top layer of skin)

moist desquamation (shedding of several skin layers)

melanoma simulation (5)

vac lok

head in supine

wedged knees

akimbo

solder wire

what does akimbo mean and why

in melanoma treatment, the arm is moved away from the body to prevent the self bolusing of skin folds that leads to desquamation

what does solder wire do for melanoma

it indicates the field outline

how do skin folds cause a self bolusing effect

the skin fold adds extra layers of skin that moves d-max closer to the skin surface

what should be noted about melanoma couch placement

female patients are placed on an incline, debaja, or breast board so that the breast is placed away from the field

don't place couch on the breast board

what critical structure may be adjacent to the axilla fields (melanoma)-5

lung

humeral head

brachial plexus

heart

spinal cord

which beam modifiers will we use for melanoma

FIF

melanoma and original disease site

the axilla may not be the disease site but melanoma commonly metastasizes to the axillary lymph nodes

hypofractionation is used with melanoma treatments due to the fact that melanoma is

radioresistant

beam energy for practicing melanoma

18x

calc pt placement for melanoma/sarcoma

avoid surgical clips

cross hairs can never be in surgical clips

how far can mlcs travel from the jaw

14.5 cm

beam modifiers we are using for melanoma

FIF and wedges

max dose for melanom

<30 Gy

is it acceptable to have a max dose greater than 30 Gy on the treatment couch or the immobilization device but not in the patient

yes

melanoma fields should be covered by

2700 cGy

melanoma-clinically significant hot spots should be

homogenous and evenly distributed

where should 30 Gy hotspots not be left in melanoma and why

underarm area

skin folds can cause a self bolus effect

the physician wants to increase the skin dose of a patient with melanoma, what three options can we employ (3)

lower energy

electron fields

bolus

what skin disorder is treated with multiple electron fields and what is this disorder

mycosis fungoides- T cell lymphoma

what is the most common site of sarcoma

extremity

what is the most common metastatic site for sarcoma

lung

what is the purpose of a leg supporter for sarcoma

it removes the unaffected limb out of the beam path

sarcoma sim-HFS or FFS

HFS-tumor is on upper extremity

FFS-tumor is on lower leg/ankle

FFS positioning

whatever is left is left and same for right

the fields for what are so large and why (3)

sarcoma

not just treating the tumor but also the muscle

sarcoma spreads along the path of muscle

treating subclincal disease, tumor, and tumor bed

why are wedges used for sarcoma

due to the lack of tissue in the limbs

in which position are the wedges directed for sarcoma

heel directed to less thick side

toe directed to more thick side

what is the difference between a physical wedge and dynamic wedge

a dynamic wedge uses moving jaw and changing dose rates to produce the dose distributions

which radiation scheme is reccomended for sarcoma and why 4

pre-op

1. no treatment delay

2. smaller surgical field/less aggressive surgery

3. less chance of seeding with a normal tumor

4.fewer LT complications (lymphedema, fibrosis, loss of ROM)

what does pre-op do to the sarcoma tumor

it shrinks the tumor

what is the benefit of using 18x for FIFs

mixed energies allows you to cool the plan

why should the jaw be closed when doing FIFs

mlc leakage can occur between the leaves

max hs for sarcoma

113-114%

hotspot distribution for sarcoma

small 107

107 and 105 should be homogenous and even distributed

after sim the physician has decides he wants to treat sarcoma with laterals, what issues are we facing with planning and TM and how do we correct them?

remove the opposed leg out of the external

place the uninvolved leg in a supporter to remove it from the treatment field (confirm at the machine)

the patient has a superficial tumor, and the physician does not want to use parallel opposed field, what can you do? (4)

AP and Lat beam

mix photons and electrons (all AP)

1 proton field

3-4 fields on iMRT