[ROQs] Constraints Flashcards by Muneeb Khan

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

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

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

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What are the usual OAR constraints for lung SBRT?

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

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

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

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

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

V20Gy < 10% (minor deviation < 15%)
D1500cc max 12.5 Gy
D1000cc max 13.5 Gy

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

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

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

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

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

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

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

Stomach constraints for esophageal cancer CFRT:
- D_mean < 45 Gy
- D_max < 54 Gy

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

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

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

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

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

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

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

< 20%

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What are the dose constraints for the cochlea for CFRT?

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

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What are the dose constraints for the cochlea for SRS?

D_max < 9 Gy
D_mean < 3 Gy

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

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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What are the QUANTAC bladder dose constraints for CFRT?

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

SRS Brainstem constraint
- D_max < 12.5 Gy

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

D_mean < 50 Gy

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

D_mean to 95% < 50 Gy
D90 < 50 Gy
D70 < 70 Gy

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

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

V18 Gy < 4 cc
D_max < 105% of Rx
decreases the risk of stenosis and fistula formation

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

V15 < 9cc
V20 < 3cc
V33 < 1 cc
Dmax < 23 Gy

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

D3cc < 6 Gy per fx (30 Gy total)

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

- V60 < 17% -- > 60 Gy has been reliably linked to esophagitis - Mean esophageal dose < 34 Gy (17 x 2)

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

Contralateral - D_mean < 15 Gy - D20 < 7%

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

- Lung V20 < 30% -- Yields a <20% risk of sx pneumonitis

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

- Heart: -- D_mean < 20% -- V50 < 25%

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

- Spinal cord D_max < 42 Gy - (Lungs - PTV) V20 < 35% - Heart -- D100% < 30% -- D50% < 50%

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

- Spinal cord D_max < 48 Gy - (Lungs - PTV) V20 < 35% - Heart -- D100% < 30% -- D50% < 50%

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

- Lung -- V40Gy ≤ 10% -- V30Gy ≤ 15% -- V20Gy ≤20% -- V10Gy ≤40% -- V05Gy ≤50% -- Mean < 20 Gy

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

- V30Gy ≤30% (closer to 20% preferred) - Mean < 30 Gy (closer to 26 Gy preferred =)

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

- V20Gy ≤33% - Mean < 18 Gy

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

- V30Gy ≤33% - Mean < 25 Gy

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

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

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

V40 < 30%

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

- 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%

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

- 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

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

- 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

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

- Risk of ON: -- < 55 Gy → < 3% -- 55-60 Gy → 3-7% -- > 60 Gy → 7-20%

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

< 7%

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

- Dose and risk of RM -- D_max 50 Gy → 0.2% -- D_max 60 Gy → 6% -- D_max 69 Gy → 50%.

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

- Lung Constraints for CFRT -- V20Gy to ≤ 30-35% -- D_mean ≤ 20-23 Gy - Corresponds to a risk of symptomatic pneumonitis to ≤ 20%

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

- CFRT: -- D_max <52Gy -- V50Gy< 10%. - 28 fx regimen -- D_max <52Gy -- V46.5Gy<2cc. - 20fx regimen -- D_max < 40Gy -- V37Gy < 90cc -- V33Gy < 130cc

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

- SRS: D_max ≤ 14 Gy -- Risk of serviceable hearing loss ≤ 25% - DFRT: D_mean ≤ 45 -- Risk of serviceable hearing loss ≤ 30%

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

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

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

D_max < 2-5 Gy

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

- HA-WBRT constraints for the hippocampus -- D100% ≤ 9 Gy -- D_max ≤ 16 Gy

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

- D_max ≤ 60 Gy → <3% risk of RN - D_max ≤ 72 Gy → 5% risk of RN - D_max ≤ 90 Gy → 10% risk of RN

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

- 1 fx: D_max ≤ 14 Gy - 3 fx: D_max ≤ 20 Gy - 5 fx: D_max ≤ 30 Gy

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

- 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)

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

- D_max ≤ 54 Gy - D1-10cc ≤ 59 Gy - corresponds to <5% 5 risk of neuropathy

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

- D_max < 10 Gy -- Risk of ON < 5%

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

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

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

- D_mean < 24 Gy -- risk of ≥ gr 3 esophagitis 5-20%

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

- time to distant mets: ~ 5 yrs - time to PCSM: ~ 10 yr

What are the SRS constraints for the cauda equina?

- D0.03cc < 16 Gy - D5cc < 14