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Palliative, Benign, Constraints > Constraints > Flashcards

Constraints Flashcards

1
Q

What is the usual CW constraint for peripheral lung SBRT lesions?

A

For 3 fx lung SBRT
- V30 < 30 cc

Caveats:
- May not always be possible for peripheral lesions
- Do not compromise target coverage
- ASTRO guidelines explicitly forbid from trimming PTV to meet this CW constraint
- CW tox (pain, etc) is usually amenable to conservative management

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2
Q

What is the threshold for CW dose before Gr ≥ 2 CW tox is observed in lung SBRT pts>

A
  • V30 Gy > 70 cc
    – V30Gy < 70 cc may be a more practical constraint for peripheral lung SBRT pts
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3
Q

What are the usual OAR constraints for lung SBRT?

A
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4
Q

What are the SRS Dmax constraints for the Optic nerve (ON)?

A

SRS constraints for ON:
- Dmax < 8 Gy
– Rare (~0%) risk of optic neuropathy
- Dmax < 12 Gy
– <10% risk of optic neuropathy

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5
Q

What are the NCCN dose constraints for the lungs for pts receiving CFRT for esophageal or gastric cancers?

A

Lung constraints for esophageal cancer CFRT?
- V40Gy ≤ 10%
- V30Gy ≤ 15%
- V20Gy ≤ 20%
- V10Gy ≤ 40%
- V5Gy ≤ 50%
- Dmean < 20 Gy

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6
Q

What are acceptable lung constraints for centrally located lesions undergoing 5 fx SBRT?

A
  • V20Gy < 10% (minor deviation < 15%)
  • D1500cc max 12.5 Gy
  • D1000cc max 13.5 Gy
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7
Q

What are the NCCN dose constraints for the spine for pts receiving CFRT for esophageal or gastric cancers?

A

Spine constraints for esophageal cancer CFRT:
- Dmax ≤ 45 Gy

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8
Q

What are the NCCN dose constraints for the bowel for pts receiving CFRT for esophageal or gastric cancers?

A

Bowel constraints for esophageal cancer CFRT:
- Dmax < 54 Gy
- V 45Gy < 195 cc

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9
Q

What are the NCCN heart dose constraints for pts receiving CFRT for esophageal or gastric cancers?

A

Heart constraints for esophageal cancer CFRT:
- V30Gy ≤ 30 % (20% preferred)
- Dmean < 30 Gy (26 Gy preferred)

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10
Q

What are the NCCN stomach dose constraints for pts receiving CFRT for esophageal or gastric cancers?

A

Stomach constraints for esophageal cancer CFRT:
- Dmean < 45 Gy
- Dmax < 54 Gy

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11
Q

What are the NCCN liver dose constraints for pts receiving CFRT for esophageal or gastric cancers?

A

Liver constraints for esophageal cancer CFRT:
- V30Gy ≤ 33%
- Dmean < 25 Gy

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12
Q

What are the NCCN kidney dose constraints for pts receiving CFRT for esophageal or gastric cancers?

A

Kidney constraints for esophageal cancer CFRT:
- V20Gy ≤ 33%
- Dmean <18 Gy
– Corresponds to a <5% risk of relevant kidney dysfunction

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13
Q

For liver SBRT, what are the allowed Dmean for the liver?

A

Liver constraints for Lung SBRT:
- 50 Gy in 5 fx:
– Dmean < 13 Gy
- 27.5 Gy in 5 fx:
– Dmean < 17 Gy

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14
Q

What is the % risk of developing symptomatic pneumonitis when using the lung dose constraint (V20Gy < 30%)?

A

< 20%

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15
Q

What are the dose constraints for the cochlea for CFRT?

A
  • Dmean ≤ 45 Gy (≤ 35, preferred)
    – < 30% risk of sensory-neural hearing loss
  • Dmean < 32 Gy
    – < 20% risk of grade 2+ tinnitus
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16
Q

What are the dose constraints for the cochlea for SRS?

A

Dmax < 9 Gy
Dmean < 3 Gy

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17
Q

What are the QUANTAC rectal dose constraints to keep grade ≥2 late rectal toxicity < 15% and grade ≥3 late rectal toxicity < 10%?

A

Rectal Dose Constraints:
- V50Gy < 50%
- V60Gy < 35%
- V65Gy < 25% (65+25=90)
- V70Gy < 20% (70+20=90)
- V75Gy < 15% (75+15=90)

Rule of 90s for the three highest constraints!
Also, related to bladder constraints:
- V75 < 25%; Subtract 10% for rectum (V75 < 15%)
- V70 < 35%; Subtract 15% for rectum (V70 < 20%)
- V65 < 50%; Subtract 25% for rectum (V65 < 25%)

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18
Q

What are the QUANTAC bladder dose constraints for CFRT?

A

Bladder Dose Constraints:
- V65Gy < 50%
- V70Gy < 35%
- V75Gy < 25%
- V85Gy < 15%

Memory Hook:
- Bladder:
– V75 < 25%; Subtract 10% for rectum (V75 < 15%)
– V70 < 35%; Subtract 15% for rectum (V70 < 20%)
– V65 < 50%; Subtract 25% for rectum (V65 < 25%)

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19
Q

What is the SRS brainstem constraint to keep the risk of necrosis or cranial neuropathy < 5%?

A

SRS Brainstem constraint
- Dmax < 12.5 Gy

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20
Q

What are the QUANTAC pharyngeal constrictor dose constraint to keep the risk of dysphagia or symptomatic aspiration < 20%?

A

Dmean < 50 Gy

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21
Q

What is the QUANTAC penile bulb dose constraint to keep the risk of ED < 35%?

A
  • Dmean to 95% < 50 Gy
  • D90 < 50 Gy
  • D70 < 70 Gy
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22
Q

Which sites in an adult human body harbor bone marrow and in what proportions?

A
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23
Q

What were the trachea/bronchus constraints on the RTOG 0813 dose-escalation trial for centrally located NSCLC?

A
  • V18 Gy < 4 cc
  • Dmax < 105% of Rx
  • decreases the risk of stenosis and fistula formation
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24
Q

What duodenal, stomach, small blowel constraints can be used for pancreas SBRT?

A
  • V15 < 9cc
  • V20 < 3cc
  • V33 < 1 cc
  • Dmax < 23 Gy
25
Q

What is the dose constraint for the brachial plexus for a 5 fx SBRT/SABR?

A

D3cc < 6 Gy per fx (30 Gy total)

26
Q

What are the usual esophageal constraints for pts undergoing CRT for NSCLC?

A
  • V60 < 17%
    – > 60 Gy has been reliably linked to esophagitis
  • Mean esophageal dose < 34 Gy (17 x 2)
27
Q

What is the constraint for the contralateral lung for pts w/ malignant pleural mesothelioma s/p extrapleural pneumonectomy f/b CHT undergoing RT?

A

Contralateral
- Dmean < 15 Gy
- D20 < 7%

28
Q

For pts undergoing def CRT for lung cancer, what is the contralateral lung constraint?

A
  • Lung V20 < 30%
    – Yields a <20% risk of sx pneumonitis
29
Q

What are the NCCN heart constraints for CFRT for lung cancer?

A
  • Heart:
    – Dmean < 20%
    – V50 < 25%
30
Q

What are the spinal cord, lung, and heart constraints for 45 Gy in 30 fx BID tx for SCLC?

A
  • Spinal cord Dmax < 42 Gy
  • (Lungs - PTV) V20 < 35%
  • Heart
    – D100% < 30%
    – D50% < 50%
31
Q

What are the spinal cord, lung, and heart constraints for 66 Gy in 33 fx BID tx for SCLC?

A
  • Spinal cord Dmax < 48 Gy
  • (Lungs - PTV) V20 < 35%
  • Heart
    – D100% < 30%
    – D50% < 50%
32
Q

What are common lung dose constraints for def CRT for esophageal cancers?

A
  • Lung
    – V40Gy ≤ 10%
    – V30Gy ≤ 15%
    – V20Gy ≤20%
    – V10Gy ≤40%
    – V05Gy ≤50%
    – Mean < 20 Gy
33
Q

What are common heart dose constraints for def CRT for esophageal cancers?

A
  • V30Gy ≤30% (closer to 20% preferred)
  • Mean < 30 Gy (closer to 26 Gy preferred =)
34
Q

What are common kidney dose constraints for def CRT for esophageal cancers?

A
  • V20Gy ≤33%
  • Mean < 18 Gy
35
Q

What are the common liver constraints for the def CRT for esophageal cancers?

A
  • V30Gy ≤33%
  • Mean < 25 Gy
36
Q

What are the dose constraints per the NRG GI006 trial for gastric cancer?

A
  • PTV V100% (50.4Gy) ≥ 95%
  • Heart V40 < 50%
  • V20 Gy of each kidney < 30%
  • Liver V30Gy < 30%
37
Q

What bowel constraint should be used for post-op cervical cancer cases?

38
Q

What are the normal tissue constraints per RTOG 0724 for post-op cervix?

A
  • Kidney: 2/3 of each kidney < 18 Gy
  • Spinal cord: 0.03 cc should receive > 45 Gy
  • Bowel (“bowel space” includes small bowel, colon, and sigmoid out to the edge of the peritoneum)
    – V40 Gy < 30%
  • Rectum: V45 Gy < 60%
  • Bladder: V45 Gy < 35%
39
Q

What are the recommended normal tissue dose constraints for OARs for brachytherapy?

A
  • ICRU bladder point, ICRU rectal point: ≤ 3.7 Gy x 5 fractions
  • D2cc bladder: ≤ 90 Gy EQD2 (80 preferred)
  • D2cc rectum: ≤ 75 Gy EQD2
  • D2cc sigmoid: ≤ 75 Gy EQD2
40
Q

Why is the duodenum especially vulnerable to RT compared to other parts of the small and large bowels?

A
  • Duodenum is relatively immobile, leading to consistent exposure to RT doses
  • Most of the duodenum is retroperitoneal, lying in close proximity to the PA nodes
41
Q

Per QUANTEC, what is the risk of optic neuropathy (ON) w/ Dmax < 55, 55-60, and > 60 Gy?

A
  • Risk of ON:
    – < 55 Gy → < 3%
    – 55-60 Gy → 3-7%
    – > 60 Gy → 7-20%
42
Q

Per QUANTEC, what is the risk of gastric ulceration with D100 < 45 Gy?

43
Q

Per QUANTEC, what is the risk of radiation myelitis (RM) w/ spinal cord Dmax 50 Gy?

A
  • Dose and risk of RM
    – Dmax 50 Gy → 0.2%
    – Dmax 60 Gy → 6%
    – Dmax 69 Gy → 50%.
44
Q

Per QUANTEC, what are the dose constraints and the corresponding risk of pneumonitis for lungs using CFRT

A
  • Lung Constraints for CFRT
    – V20Gy to ≤ 30-35%
    – Dmean ≤ 20-23 Gy
  • Corresponds to a risk of symptomatic pneumonitis to ≤ 20%
45
Q

What are the bowel constraints for CFRT and moderately hypofractionated RT for prostate cancer?

A
  • CFRT:
    – Dmax <52Gy
    – V50Gy< 10%.
  • 28 fx regimen
    – Dmax <52Gy
    – V46.5Gy<2cc.
  • 20fx regimen
    – Dmax < 40Gy
    – V37Gy < 90cc
    – V33Gy < 130cc
46
Q

What are the cochlea constraints and the corresponding risk of serviceable hearing loss for SRS and CFRT for acoustic neuroma?

A
  • SRS: Dmax ≤ 14 Gy
    – Risk of serviceable hearing loss ≤ 25%
  • DFRT: Dmean ≤ 45
    – Risk of serviceable hearing loss ≤ 30%
47
Q

What are the constraints for the liver and the corresponding risk of radiation-induced liver disease (RILD) when treating intrahepatic cholangiocarcinoma?

A
  • Dmean 30-32 Gy → < 5% RILD (excludes cirrhosis)
  • Dmean 28 Gy → < 5% RILD in Child-Pugh A / HCC per QUANTEC
  • Dmean 42 Gy → ~50% risk of RILD
48
Q

What are the usual dose constraints for cardiac implantable devices (CIED)?

A

Dmax < 2-5 Gy

49
Q

What are the dose constraints for the b/l hippocampis when tx w/ HA-WBRT?

A
  • HA-WBRT constraints for the hippocampus
    – D100% ≤ 9 Gy
    – Dmax ≤ 16 Gy
50
Q

Per QUANTEC, what are the Dmax constraints and the corresponding risk of radionecrosis (RN)?

A
  • Dmax ≤ 60 Gy → <3% risk of RN
  • Dmax ≤ 72 Gy → 5% risk of RN
  • Dmax ≤ 90 Gy → 10% risk of RN
51
Q

What are the spinal cord constraints for single, three, and five fx SRS/SRT?

A
  • 1 fx: Dmax ≤ 14 Gy
  • 3 fx: Dmax ≤ 20 Gy
  • 5 fx: Dmax ≤ 30 Gy
52
Q

For CFRT, what are the dose constraints for spinal cord, optic chiasm, optic nerves, and brainstem?

A
  • Optic Chiasm and Nerves
    – Desired D0.03cc ≤ 54Gy (acceptable ≤ 60 Gy)
  • Brainstem
    – Desired D0.03cc ≤ 54Gy (acceptable ≤ 60 Gy)
  • Spinal Cord
    – Desired DO.03cc ≤ 45Gy (acceptable ≤ 50 Gy)
53
Q

For CFRT, what are the dose constraints for the brainstem?

A
  • Dmax ≤ 54 Gy
  • D1-10cc ≤ 59 Gy
  • corresponds to <5% 5 risk of neuropathy
54
Q

What are the optic pathway constraints for a single fx SRS?

A
  • Dmax < 10 Gy
    – Risk of ON < 5%
55
Q

Per QUANTEC, what are the usual dose constraints for the parotid gland and the corresponding risk of gland dysfunction?

A
  • b/l parotid Dmean < 25 Gy
  • < 20% risk of long-term parotid gland function reduced to 25% of the pre-RT level
  • b/l parotid Dmean < 39 Gy
  • < 20% risk of long-term parotid gland function reduced to 50% of the pre-RT level
  • Single parotid Dmean < 20 Gy
56
Q

For CFRT, what is the usual dose constraint for the esophagus and the associated risk of ≥ Gr 3 esophagitis?

A
  • Dmean < 24 Gy
    – risk of ≥ gr 3 esophagitis 5-20%
57
Q

After biochemical failure, how long does it take for bone metastases to develop and the pt to die?

A
  • time to distant mets: ~ 5 yrs
  • time to PCSM: ~ 10 yr
58
Q

What are the SRS constraints for the cauda equina?

A
  • D0.03cc < 16 Gy
  • D5cc < 14

Palliative, Benign, Constraints (3 decks)

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