Test 4 Flashcards
One of the most common malignancies in males, older patients and slow-growing (watch and wait in older patients)
Surgery, RT, or hormonal manipulation; no chemo
Castration or hormonal castration
AP/PA and boots nodes
Immobilization: mid-abdomen to feet; knee sponge, rubber band, sandbags, register table, etc.
Prostate cancer
65% of prostate cancers occur in men over ___ years old
65
3 types of prostate RT
Prostate seeding with iodine or palladium for earlier state disease
EBRT: long treatments
IMRT and VMAT: 3D planning allows conformal dose
Combination of medical/hormonal (gonadotrophin-releasing hormone agonist) or surgical castration with an anti-androgen for the treatment of advanced prostate cancer
Maximal androgen blockade (MAB)
Luteinizing hormone-releasing hormone (LHRH, ex: leuprolide) and gonadotropin-releasing hormone (GnRH) receptor blockers
Hormonal castration
4 things prostate treatment depends on
Patient’s age
Stage/aggressiveness of disease
Underlying medical conditions and patient preference
Gleason score (GS)
2-10 grade of histology of prostate CA; most common morphology (1-5) + highest grade histology (1-5)
Gleason score (GS)
Lateral and posterior borders for prostate cancer
Lat: anterior to pubic symphysis
Post: spare rectum but allow coverage
Superior, inferior, and lateral borders for prostate cancer with LN involvement
Sup: mid-sacrum to L5
Inf: 2 cm inferior to prostate or BIT
Lat: 1.5-2 cm lateral to pelvic brim/bony pelvis
___ field box VMAT, ___-___ field IMRT for prostate
4, 6-7
Less than 35-40% of rectum receiving ___ Gy
60 Gy
Seminal vesicles _______ and _______ to prostate
Superior, posterior
Prostate ___ cm above urethra
1 cm
___ mm margin from GTV and PTV for prostate and ___ mm margin from PTV to block = ___ cm from GTV to block
6 mm
9 mm
1.5 cm
Prostate: ___ Gy in 38 days = ___ cGy per fraction
76 Gy
200 cGy
Early stage six field prostate and SV dose and total dose
Dose: 5940-6000 cGy
Total: 7000-7400 cGy
Prostate dose
LN involvement
Four field pelvis
4500 cGy
Prostate dose
LN involvement
Six field prostate and SV
5940 cGy
Prostate dose
LN involvement
Six field prostate only total
7200-7400 cGy
Prostate clinical trials: 7020 cGy at 270 cGy per fraction = ___ cGy at ___ cGy per fraction
8440 cGy at 200 cGy per fraction
Why are the prostate clinical trials effective?
Rad bio effect very similar; adding dose quicker, less doses/treatment time/patient doesn’t have to come in as much
2 forms of daily IGRT for prostate treatment
US not as common: sonory or iBeam
Gold fiducials
Triangulate marks on port film of prostate and make sure all three points are lined up, now used
Gold fiducials
Parallel opposed fields not used in IMRT because beams can’t face each other or algorithm will fight against itself to get dose to certain area
Optimization
If DVH tails off = _______
Hotspots
Want critical structures close to ___-axis and to fall off as rapidly as possible on DVH
Y-axis
Normal fractionated dose
180-200 cGy
Permanent implant takes ___-___ hours to place seeds through _______ and lasts ___-___ weeks
1-2 hours
Perineal
1-2
3 radioactive isotopes used in prostate treatments
Iodine-125
Palladium
Iridium
Palladium half-life and energy
T1/2: 17 days
E: 21 keV
Iodine-125 half-life and energy
T1/2: 59.6 days
E: 28 keV
___-___ prostate seeds; low dose range of ___ cGy, high dose range of ___-___ cGy
180-200 seeds
125 cGy
145-160 cGy
Which prostate seed source gets higher dose?
Iodine-125 has longer half-life and lower dose rate so it needs a higher dose
Which prostate seed source is used in larger volume implant?
Iodine-125 has higher energy and can treat further out; used for larger disease
Iodine-125 typical dose, rate, and size
145 cGy rate of 7 cGy/hr and larger volume implant
Palladium dose and rate
125 cGy, 19 cGy/hr
4 bladder cancer treatments
Cystectomy for early stage disease, carcinoma in situ, etc.
RT for advanced disease or inoperable patients: 3 or 4 field
Intravesical chemo
Combination
Chemo instilled directly in bladder
Intravesical chemo
What is an example of intravesical chemo?
Bacillus calmette-guerin (BCG)
Combination bladder treatment: ___ Gy ___ weeks before partial or radical cystectomy
30 Gy, 2 weeks
Initial dose and dose with boost for bladder cancer being treated with RT alone
Initial: 45-50 Gy
Boost: 65-70 Gy
2 reasons the bladder is treated empty
Guarantee size
Smaller treatment field
AP/PA bladder fields superior, inferior, and lateral margins
Sup: L5-S1
Inf: BOF or more if bladder neck involved
Lat: 1.5-2 cm beyond pelvic brin
Lateral bladder fields anterior and posterior borders
Ant: 1 cm in front of bladder
Post: 2-3 cm posterior to tumor, exclude rectum
Helps reduce penis/urethra cancer in foreskin
Circumsicion
Penis/urethra cancer position
Opposed laterals in prone
Penis/urethra cancer initial, boost, and total dose
Initial: 55-60 Gy
Boost: 1000 cGy
Total: 65-70 Gy
5 LNs associated with penis cancer
External iliacs Obturator Presacral Inguinal Pelvic
Penis cancer with LN involvement dose for no gross enlargement and for palpable LNs
No: 50 Gy
Palpable: 70 Gy
Treatment of choice and treatment for inoperable kidney cancer
Choice: surgery
Inoperable: RT
Kidney cancer initial dose to upper abdomen, boost, and total dose
Initial: 5040 cGy
Boost: 540 cGy
Total: 5580 cGy
Kidney cancer energy because there’s a lot of tissue
10 MV or more
Kidney cancer fields
Equal or unevenly weighted fields
AP/PA and obliques
What is the dose limit to the contralateral kidney if one has been removed due to kidney cancer?
Under 15-18 Gy
What is the side effect from a nephrectomy or radiation nephrectomy?
Hypertension
3 structures kidney and ureter involvement treatment portals include
Entire renal fossa
Ureteral bed
Ipsilateral bladder trigone
Seminomas of the testis are considered _______
Radiosensitive
3 LNs associated with early seminomas of the testis
Periaortic
Ipsilateral renal hilar
Ipsilateral iliacs
Unilateral and bilateral testicular treatment field
Uni: hockey stick
Bi: inverted-Y
Clam/scrotal shield during testicular treatment for reproductivity decreases internal scatter which could be as high as ___% the total dose
10%
Initial dose, fractions, and boost for larger testicular masses
Initial: 20-2500 cGy
Fracts: 10-20 fractions
Boost: 1000 cGy to known mass
Length and lateral border for testicular seminoma cancer
Length: top of T10 to top of obturator foramen
Lat: aortic LNs visualized by CT and ipsilateral renal hilar LN about 10-13 cm wide or sides of transverse processes
Left sided testicular tumor field
Widened field at level of renal hilar LNs to include these LNs
5 breast cancer prognostic factors
LN status: number of axillary LNs involved with tumor very important aspect of staging; sentinel node biopsy and tangents to cover LNs
Tumor extent/size of primary tumor; larger tumor more likely involved with skin, chest wall, etc.
Histology
Receptor status
Flow cytometry
Evaluate at least 10 axillary LNs; 3 or less positive LNs = low risk, 4 or more = high risk
Axillary LN dissection
5 year survival for breast lesions/tumors smaller than 0.5 cm, over 0.5 cm, less than 2 cm, and greater than 5 cm
< 0.5 cm = 99%
> 0.5 cm = 82%
< 2 cm = 91%
> 5 cm = 63%
3 breast cancer histologies
Infiltrating ductal most common
Lobular second most common
Peau d’orange/inflammatory: clinical diagnosis and poor prognosis
Receptor status most common in postmenopausal women, slow growing
Tamoxifen
Estrogen (ER) positive
3 receptors used for breast cancer
Estrogen (ER)
Progesterone (PR)
HER2 gene
Receptor status that indicates faster-growing breast cancer but responds better to treatment
HER2
Triple positive (ER, PR, and HER2) have _______ outcome
Better
Triple negative have _______ survival independent of age, race, stage, and grade
___ times more likely to die and increased risk of local failure because it behaves more aggressively and lacks non-targeted treatments
Worst, 3
2 breast cancer staging methods
Clinical
Pathological
Physical, operable, gross findings; LNs, breast, etc.
Clinical
Microscopic assessment of cell histology
Pathological
Breast cancers is a relative ______ disease process; distant mets sometimes occurs _______ after definitive treatment of the primary tumor
Slow, decades
3 routes of spread of breast cancer
Extension in breast, ipsilateral breast at risk; tangential treatments skimming beam covers entire breast tissue
Regional LN involvement: axillary, internal mammaries, etc.
Distant mets
5 sites of distant mets of breast cancer
LNs most common Bone Lung Liver Contralateral breast (0.5-1% risk)
Best breast cancer treatment method
Multimodality treatment of surgery, RT, and chemo
4 breast cancer surgeries
Radical mastectomy
Modified radical mastectomy
Lumpectomy
Breast reconstruction surgery: expanders
Remove both breasts, underlining chest pectoralis major and minor muscles, and axillary LNs; high morbidity
Radical mastectomy
Remove both breasts and axillary LNs; less morbidity and arm edema and more arm movement
Modified radical mastectomy
Remove breast tumor with margins and with axillary dissection or sentinel node biopsy
Lumpectomy
Whole body treatment to prevent growth of cancer, adjuvant
Systemic therapy
3 types of systemic therapy for breast cancer
Chemo before or after surgery or RT (usually before RT), single or combination
Endocrine therapy/hormonal treatment
HER-2 directed therapy
5 breast cancer chemo drugs
Cyclophosphamide 5FU Methotrexate Adriamycin/doxorubicin Vinblastine, mitoxantrone, and mitomycin C
2 breast cancer chemo combinations
CMF
AC
CMF
Cyclophosphamide
5FU
Methotrexate
AC
Doxorubicin
Cyclophosphamide
Deprive cancer cells of hormones they thrive on
Endocrine therapy/hormonal treatment
2 types of breast cancer endocrine therapy/hormonal treatments
Tamoxifen
Aromatase inhibitors
Targets HER-2, stops proliferation, and kills cells; best results with chemo
HER-2 directed therapy
Trastuzumab
Interferes with growth of cell
Trastuzumab
4 things breast treatment management depends on
Menopausal status
ER positive (better) or negative
Stage
Grade
Conservative RT (cure/prevent spread but preserve breast) high volume ___-___ weeks post-op
2-4 weeks
Energy range for breast RT
4 (very small breast) - 10 MV (large breast); increases with breast bridge size
Limited amount of lung treated during breast cancer RT, have to allow some portion to make sure entire breast is treated but at risk for pneumonitis
1-3.4 cm
2 reasons breasts are treated with tangentials
Skims chest wall so small margin of lung in field
Treats entire breast and LN chain
Postoperative breast RT in the past and today
Past: used to be prophylactic for LNs and seeding
Today: supraclavicular (SCV) field, IMRT (boost), etc.
Why is IMRT justified for the left breast?
Spares dose to heart
Why should the arm not be raised too much during breast treatment?
Don’t want folds/bolus in infraclavicular area
Immobilization device that uses gravity to make the breast fall inferiorly
Slant/inversion boards
Breast ring/cup
Pro and con of treating breast in prone position
Pro: pulls breast away from chest wall and lung and makes breast more symmetric, decreasing lung and heart dose and hotspots
Con: harder on older patients and can’t be used when treating lymphatics
What kind of technique do breast treatments use?
3D isocentric SAD
2 things best for split beam breast technique
Asymmetric jaws
MLCs
What does the supine position for the breast need to improve dose homogeneity?
Compensating filter (wedge)
Initial breast dose with photons and total dose with boost of photons, electrons, or interstitial RT
Initial: 4500-5000 cGy
Total: 6000-6600 cGy
Superior breast border at the most cephalad of 5 points
First intercostal space
1-2 cm above superior portion of breast tissue
As far cephalad as possible without including arm
Superior extent of the palpable breast tissue
Over 2 cm cephalad to original location of mass
Inferior breast border
1-2 cm caudad to the inframammary fold
Medial breast border
At midline of patient as determined by palpation of suprasternal notch and xiphoid process
Why is it important to have the border midline during breast treatment?
In case other breast needs to be treated (radiation is cumulative)
Lateral breast border
Corresponding to midaxillary line including drain sites or incisions considered at risk, original tumor bed, and appropriate amount of lung margin
Cam be adjusted if more lung needs to be treated
Wedge scatter _______ dose to contralateral breast
Increases
If not using blocks during breast treatment, have to rotate collimator because of curve of chest wall
Trapezoidal effect
Dose _______ at junction point, want _______ dose to scar
Lower, high
Half beam blocking with hanging block, jaws at CA, etc. to prevent divergence
Supraclavicular field (SCV)
Typically have to _______ to get tangents in straight line and prevent divergence with inferior border of SCV field
Rotate couch
_______ and _______ for breast tangents and _______ for SCV
Couch and collimator rotation
Split beam
Superior, medial, lateral, and inferior borders for SCV field
Sup: 5 cm to suprasternal notch (SSN), avoid flash if possible to help reduce skin reaction
Med: midpoint of SSN
Lat: about 2-3 cm of the humeral head and block head
Inf: angle of Louis, just above the superior extent of palpable breast tissue, or over 2 cm superior to the original location of the mass in the breast
SCV medial and laterals angled ___-___ degrees to decrease exit dose to spinal cord
5-20°
Superior, medial, lateral, and inferior borders for posterior axillary boost (PAB) field
Sup: mid to upper clavicle
Med: 1 cm of lung
Lat: about 1-2 cm of humeral head which is blocked
Inf: angle of Louis, just above the superior extent of palpable breast tissue, or over 2 cm superior to the original location of the mass in the breast
SCV and PAB dose
5000-5040 cGy
Increase midaxillary dose to superior level
Patient flat on table
Special consideration for divergence of beam
Posterior axillary boost (PAB)
Small portion of patients have these LNs involved with breast cancer
If tangents deep, need separate field
5° move vertical
Internal mammary
Combination photon and electron IMRT breast treatment energy, dose, fractions, number of treatments, and total dose
Photon: 4-6 MV to 1440 cGy at 180 cGy per fraction in 8 treatments
e-: 12-14 MeV fields to 3060 cGy at 180 cGy per fraction in 17 treatments prevents anterior heart dose
Total: 4500 cGy
Intact breast initial and boost dose
Initial: 4500 cGy
Boost: 15-1600 cGy
Chest wall only (not concerned with cosmesis) initial and boost dose
Initial: 5000 cGy
Boost: 1000 cGy
Straight on
En face
Only treat involved portion of breast area with 1-2 cm margins in 1-2 weeks
Partial breast irradiation (PBI)
3 types of PBI
EBRT most common
Bachy balloon catheter two times a day 6 hours apart
Intraoperative
3 breast RT side effects
Telangiectasia
Hyperpigmentation
Fatigue
Spidery veins
Telangiectasia
Why are pediatric doses lower?
Longer lifespan
2 types of pediatric astrocytomas
Low grade
High grade
3 reasons RT is used for pediatric brain tumors
Inaccessible tumor
Recurrence
Post-op residue/positive margins
Pediatric low grade astrocytoma margin and dose
Margin: 1.5-2 cm around lesion
Dose: 50-55 Gy
3 pediatric high grade astrocytomas from least to most aggressive
Anaplastic
Primitive neuroectodermal tumor (PNET)
Glioblastoma multiforme (GBM)
6 pediatric brain tumors
Optic gliomas: low grade astrocytomas Benign tumors of CNS Medulloblastomas Ependymomas Germ cell tumors Brain stem gliomas
25% of childhood brain tumors
Medulloblastomas
Pediatric brain tumors that arise from ventricle lining
Ependymomas
Tumor of retina most common in 6 months to 4 years old
Chemo
Retinoblastoma
Layer at back of eyeball
Retina
Retinoblastoma treatment with hanging block for AP and lateral fields for inoperable patients, blocks lens and gives sharp beam edge
Suction cup to displace lobe and spare anterior portion of eye
IMRT to restrict dose
Hanging block technique
Retinoblastoma dose and dose per fraction
40-50 Gy at 180-200 cGy per fraction
Iodine-125 eye plaque stitched in eye dose in one week and cure
Dose: 30-40 Gy
Over 80% cure
Small round blue cells from neural crest, most common extracranial cancer in infancy
Most common site: adrenals of fetus, chest, pelvis, neck, etc.
Patients usually newborns to 24 months, median age of diagnosis = 17 months
Very aggressive and poor survival
Can be cured by surgery alone if caught early
Neuroblastoma
Group of embryonic cells during formation of neural tube
Neural crest
2 sites of neuroblastoma mets
Abdomen
Liver
Neuroblastoma dose to tumor bed post-op and -chemo and palliative dose
Dose: 20-30 Gy
Palliative: 1000 cGy
Newborns can receive about _____ cGy without problems
500 cGy
What is a side effect of neuroblastoma RT?
Bone and soft tissue decreased growth
Malignant embryonic cancer of kidney
Wilms’ tumor
Average age of wilms’ tumor presentation
3-4 years old
Wilms tumor dose to positive margin and dose to large tumors that rupture and spill into abdominal cavity
Pos: 20 Gy
Rupture: 3000 cGy to whole abdomen (great side effects)
3 risks when treating wilms’ tumor with RT
Scoliosis
Soft tissue atrophy
Bone growth defects
Main treatment of wilms’ tumor
Nephrectomy of affected kidney
Arise in mesenchyme anywhere in body
Soft tissue sarcoma (STS)
Connective tissue
Mesenchyme
Pediatric soft tissue sarcoma margin and dose
Margin: 1 cm
Dose: 36-5040 cGy
About 40% of pediatric STS’s; arise in H&N, genitourinary region, extremities, and truck
75% occur before age of 10
Amputation and pelvic exenteration
Rhabdomyosarcomas
2 rhabdomyosarcoma sites that have better prognosis and 1 that has worst prognosis
Better: orbit and genitourinary
Worst: alveolar (extremities and trunk)
Pediatric germ cell tumor dose
20-25 Gy
Usually fatal pediatric tumor; surgery treatment of chouce
Liver tumor
Most common childhood cancer overall
TBI and possible CNS prophylactic treatments
Acute lymphoblastic leukemia (ALL)
Pediatric disease of immune system that can cause lytic lesions
Langerhans cell histiocytosis (histiocytosis X syndromes)
Involved field pediatric hodgkin’s dose after chemo to reduce recurrence
1500-2500 cGy
Childhood tumor commonly developed in males
Nasopharynx
Childhood nasopharynx tumor dose that helps control relapse and positive margins
3000 cGy
Overgrowth of scar tissue more common in young women and African Americans; sharp pain, itchiness, and poor cosmesis
Keloids
Keloid dose
900-1200 cGy in 3 fractions 24-48 hours post-op
