Test 3 Flashcards by Courtney W

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Most common leukemia in kids; radiation therapy (RT), chemo, and bone marrow transplant (BMT)
Treatment of choice: BMT

Acute lymphoblastic leukemia (ALL)

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4 RT treatment techniques for ALL

Total body irradiation (TBI) used in combination with BMT to prevent rejection
CNS technique
Helmet field/whole brain prophylactic treatment to cover meninges
Testicular field: leukemia cells track to testicles (“sanctuary”)

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Testicular field dose

400 cGy in 1 fraction and TBI

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Cranial-spinal irradiation (CSI) helmet field (right and left laterals) and spinal fields treat CSF

CNS technique

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Most common leukemia per ACS; same in all ages, slight increase over 50
RT, chemo, and BMT (TBI)
Treatment of choice: BMT

Acute myeloid leukemia (AML)

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Was the most common leukemia in US for years, usually elderly patients that can live awhile with disease
Optimal treatment unknown; palliative RT for local masses and involved lymph node (LN) and/or spleen

Chronic lymphocytic leukemia (CLL)

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Associated with Philadelphia chromosome, middle age around 55
RT for spleen or TBI, chemo, and transplant
Treatment of choice: BMT

Chronic myeloid leukemia (CML)

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2 types of TBI’s

High dose

Low dose

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High dose TBI dose for transplant

1000 cGy in 1 treatment

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2 types of high dose TBI’s

Single

Fractionated

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Single and fractionated high dose TBI dose

Single: 550 cGy at 275 cGy a side and 400 cGy/min
Fractionated: 1225 cGy in 7 fractions, about 175 cGy per treatment

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Low dose TBI dose

5-15 cGy 2-5 times a week to 50-150 cGy, 10 cGy/min

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TBI lung dose less than _______ cGy; pneumonitis at _______ cGy

800 cGy

1400 cGy

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Chemo drug that gives same results as TBI

Methotrexate

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Half body treatment

Hemibody irradiation (HBI)

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Upper and lower doses for HBI and time between upper and lower treatment

Upper: 600 cGy (lower because of lungs)
Lower: 800 cGy
Time: 2-4 weeks between treatments

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Produces hormones under complex feedback-control mechanisms that affect various functions to meet ongoing metabolic needs and stresses of the organism; rare diseases

Endocrine system

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Master regulatory gland of the endocrine system

Pituitary gland

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Gland that regulates metabolism
Treatment: surgery, RT (EBRT and brachytherapy with iodine-131), and hormonal therapy; responsiveness dependent on histology

Thyroid cancer

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Thyroid dose

50-60 Gy in 7 weeks, 180-200 cGy per fraction

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Iodine-131 for anaplastic thyroid disease dose (radioresistant), activity, and 2 forms

Dose: high dose at 60 Gy
Activity: 50-100 mCi (don’t stay in hospital with less than 100 mCi)
2 forms: liquid and pill (traces to thyroid)

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Primary treatment goal: normalize pituitary hormonal function or relieve local compressive or destructive effects of the tumor; accomplished surgically, RT, medically, or in combination
Post-op RT controversial but can stop recurrence; RT for patients who don’t fit surgery medically or refuse
Protons (rapid fall-off), SRS, IMRT
Use 6-10 or more to get good dose coverage
SRS margin: 0.5-1 cm

Pituitary tumors

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IMRT for pituitary tumors 2 patient positions, fields, field size (FS), and margins

2 positions: tuck chin to avoid eyes; if patient can't tuck chin, do vertex, kick couch 90 degrees, and turn collimator Fields: 2 laterals and AP (dose pushes up towards an unopposed field; use wedge with heel to AP) FS: 5x5 or 6x6 cm Margins: 1.5 cm

Pituitary dose and dose for tumors 2 or more cm

Dose: 180-200 cGy per treatment, 4500-5400 cGy total dose range 2 cm or larger tumor: up to 5400 cGy

7 hormones secreted by the pituitary

``` Growth Prolactin Thyroid-stimulating Follicle-stimulating Luteinizing Melanocyte-stimulating Adrenocorticotropic ```

Hormone that controls body growth

Growth hormone

Hormone that initiates milk production

Prolactin

Hormone that controls thyroid gland

Thyroid-stimulating hormone

Hormone that stimulates egg and sperm production

Follicle-stimulating hormone

Hormone that stimulates other sexual and reproductive activity

Luteinizing hormone

Hormone that relates to skin pigmentation

Melanocyte-stimulating hormone

Hormone that influences the action of the adrenal cortex, stress response

Adrenocorticotropic hormone

2 cells of the pituitary gland

Acidophil | Basophils

Cell that secretes growth hormone and prolactin

Acidophil

Cells that secretes everything else

Basophils

Located anterior, superior and medial to kidneys; on superior pole of kidneys, surround outer part Surgery is treatment of choice; RT increases local control a little but is usually used as adjuvant to surgery or for palliation More common in left than right

Adrenal cortex tumors

Adrenal cortex tumor dose for inoperable patients and for adrenal mets

Inoperable: 50-60 Gy in 5-7 weeks; 1 large field at 40 Gy and smaller boost Mets: palliative 30-40 Gy in 2-3 weeks

Malignancies in thorax; most common in lung, pankos tumor in apex/high in lung Esophageal thymomas, germ cell tumors, mets, etc. All modalities together or alone; RT for LN's (PET) High doses, very good immobilization devices from head to mid-thigh with arms above head AP/PA fields and laterals if needed Patients with lung cancer require treatment of primary tumor, and hilar, mediastinal and supraclavicular LN's Treat AP/PA until cord tolerance reached then obliques and laterals; boost fields smaller Multiple field design variations due to volume (limit volume of structure receiving dose) and dose limitations to certain structures Shielding, MLC's, IMRT, VMAT, etc. Can monitor spinal cord dose; CT to define depth

Respiratory system disease

Tumor originating from epithelial cells of the thymus which plays an important role in kids' immunity Occurs in younger patients, surgery is treatment of choice RT when tumor unresectable; IMRT, VMAT, and tomotherapy offer conformal isodoses

Thymoma

3 routes of spread of respiratory system diseases

Direct Lymphatic Hematogenic through blood

Tumor reproduces and grows in size and mass, altered surface enzymes grow into surrounding structures; direct or local extension

Direct spread

Cancer cells enter LN system

Lymphatic spread

2 ways of lymphatic spread

``` LN chain (LN to LN) Enters LN and gains access to blood/circulatory system ```

7 common mets side of respiratory system disease

``` Liver Adrenals Bone Brain Cervical LN's Kidneys Contralateral lung ```

Downfall to volumetric arc therapy (VMAT) versus IMRT for lung treatment

More lung treated with VMAT

When is lung disease treatment definitive or curative versus palliative?

Definitive or curative without extrathoracic spread, with = palliative

Why may cord dose be higher towards cephalic margin?

Thinner part

How did PET/4DCT change the treatment of lung cancer?

4D = time, tracks tumor motion; lead to more arc/IMRT treatments

AP/PA might miss part of lung tumor so do _________; _________ increase dose to both already compromised lungs, thicker part

Obliques; laterals

Difficulty breathing except in upright position, can't lay flat

Orthopnea

Dose for SVC syndrome oncologic emergency and time it takes to relieve symptoms

Dose: 250-400 cGy in 2-3 fractions (high) Time: relief from symptoms in 2-3 weeks but no long-term survival

2 reasons boost/shrinking fields are done

Decrease when tumor decreases in size | Reduce dose to OARs

Organ that has lower dose tolerance than what's needed to treat tumor

Critical structure

Spinal cord, heart, lung, and esophagus TD's

Spinal cord: 4500-4700 cGy Heart: 4000 cGy Lung: 1750 cGy Esophagus: 5500 cGy

When treating near heart, consider when ___% of heart receives ___-___ Gy; can see pericarditis and pancarditis

60% | 45-55 Gy

Inflammation of membrane surrounding heart

Pericarditis

Inflammation of entire heart

Pancarditis

Lung = pneumonitis; fibrosis greater than ___% volume exposure

40%

Volume of lung receiving 2000 cGy, want it at 20-30%

V20

Need SSD and thickness at point; lateral horns from flattering filter lead to high doses

Off-axis points

Percent of lung cancer cases that are large cell non-oat/non-small cell lung cancer (NSCLC)

88%

Palliative dose for NSCLC

45 Gy in 18 fractions

Right lung has ___ lobes, left has heart so ___ lobes

3, 2

Fields, dose, and 2 boost doses for NSCLC where surgery is not possible

AP/PA obliques up to 5000 cGy and 1 boost of 1000 cGy = 60 Gy in 6-7 weeks to tumor or regional LN's with positive disease 2nd boost to primary tumor of 500-1500 cGy = 65-7000 cGy total

Preoperative dose for NSCLC where surgery is possible (early T's, no nodes, M1-M2)

30 Gy in 10 fractions, no improvement in survival

Postoperative dose (initial and boost) for NSCLC where surgery is possible (early T's, no nodes, M1-M2)

60-66 Gy, 200 cGy per fraction | Initial dose of 5000 cGy with boost of 1000-1500 cGy to volume with disease = 60-66 Gy

2 sources for brachytherapy for postoperative for NSCLC; permanant interstitial catheter implants

HDR iridium | LDR iodine-125

20% of lung cancers; poor prognosis, more aggressive High mets rate, rapid proliferation results in a greater initial response to radiation Chemo and RT Prophylactic brain irradiation because it commonly metastasizes to brain

Small/oat cell lung cancer

Dose to primary tumor, residual tumor, and total dose per fraction for small/oat cell lung cancer

4000 cGy in 6 weeks to primary tumor and 1000 cGy to residual tumor = 45-60 Gy in 180-200 cGy per fraction

Thymoma dose per fraction and dose for positive margins

Dose: 45-50 Gy at 180-200 cGy per fraction | Positive margins: 54-60 Gy

Connection between two tubular structures by surgery or pathology, creates weakness

Anastomosis

Past _____ cGy to trachea, fistula can form

4500 cGy

Trachea dose, boost, and borders

50-60 Gy (over 60 Gy gives best results but can result in complications) Lower border at carina, initially give 4500 cGy at lower carina and a boost to 50-60 Gy

Tumors along chest wall; ex: recurrent breast cancer (tangents), connective tissue, etc. Size and location affect field arrangement; ex: electrons if superficial

Soft tissue tumors

Lymphoma dose

4500 cGy