Radiation Oncology: A Question-Based Review

APPENDIX

Normal Tissue Constraint Guidelines

The radiation dose constraints below are meant to serve as a guide only and may not be applicable to all clinical scenarios. Most doses are derived from randomized studies or consensus guidelines and we have attempted to provide the sources for these recommendations. Please refer to the individual pediatric chapters for dose constraints in the pediatric population as these can vary greatly from protocol to protocol and tend to be particularly site- and age-dependent.

What are the recommended dose constraints for the following organs and clinical scenarios?

ORGAN

CONSTRAINTS

CNS (1.8–2.0 Gy/fx)

 

Spinal cord

max 50 Gy (full cord cross-section); tolerance increases by 25% 6 mos after 1st course (for re-irradiation) (QUANTEC)

Brain

max 72 Gy (partial brain); avoid >2 Gy/fx or hyperfractionation (QUANTEC)

Chiasm/optic nerves

max 55 Gy (QUANTEC)

Brainstem

Entire brainstem <54 GyV59 Gy <1–10 cc (QUANTEC)

Eyes (globe)

Mean <35 Gy (RTOG 0225), max 54 Gy (RTOG 0615)

Lens

max 7 Gy (RTOG 0539)

Retina

max 50 Gy (RTOG 0539)

Lacrimal Gland

max 40 Gy (Parsons)

Inner ear/cochlea

mean ≤45 Gy (consider constraining to ≤35 Gy with concurrent cisplatin) (QUANTEC)

Pituitary gland

max 45 Gy (for panhypopituitarism, lower for GH deficiency) (Emami)

Cauda equina

Max 60 Gy (Emami)

CNS (single fraction)

 

Spinal cord

max 13 Gy (if 3 fxs, max 20 Gy) (QUANTEC)

CNS (single fraction)

 

Brain

V12 Gy <5–10 cc (QUANTEC)

Chiasm/optic nerves

max 10 Gy (QUANTEC)

Brainstem

max 12.5 Gy (QUANTEC)

Sacral plexus

V18 <0.035 cc, V14.4 <5 cc (RTOG 0631)

Cauda equina

V16 <0.035 cc, V14 <5 cc (RTOG 0631)

H&N (1.8–2.0 Gy/fx)

 

Parotid gland(s)

mean <25 Gy (both glands) or mean <20 Gy (1 gland) (QUANTEC)

Submandibular gland(s)

mean <35 Gy (QUANTEC)

Larynx

mean ≤44 GyV50 ≤27%, max 63–66 Gy (when risk of tumor involvement is limited) (QUANTEC)

TMJ/mandible

max 70 Gy (if not possible, then V75 <1 cc) (RTOG 0615)

Oral cavity

Nonoral cavity cancer: mean <30 Gy, avoid hot spots >60 Gy (RTOG 0920)

Oral cavity cancer: mean < 50 Gy, V55 <1 cc, max 65 Gy (RTOG 0920)

 

Esophagus (cervical)

V45 <33% (RTOG 0920)

Pharyngeal constrictors

Mean <50 Gy (QUANTEC)

Thyroid

V26 <20% (JHH)

Thoracic (1.8–2.0 Gy/fx)

 

Brachial plexus

max 66 Gy, V60 <5% (RTOG 0619)

Lung (combined lung for lung cancer treatment)

mean <20–23 Gy, V20 <30%–35% (QUANTEC)

Lung (ipsilateral lung for breast cancer treatment)

V25 <10% (JHH)

Single lung (after pneumonectomy)

V5 <60%, V20 <4–10%, MLD <8 Gy (QUANTEC)

Bronchial tree

max 80 Gy (QUANTEC)

Heart (lung cancer treatment)

Heart V45 <67%; V60 <33% (NCCN 2010)

Heart (breast cancer treatment)

V25 <10% (QUANTEC)

Esophagus

V50 <32% (Maguire), V60 <33% (Emami)

Thoracic (hypofractionation)

Total recommended cumulative dose by the number of fractions per NCCN 2010. Note: the max dose limits refer to volumes >0.035 cc (~3 mm3).

Spinal cord

1.    1 fraction: 14 Gy

2.    3 fractions: 18 Gy (6 Gy/fx)

3.    4 fractions: 26 Gy (6.5 Gy/fx)

4.    5 fractions: 30 Gy (6 Gy/fx)

Esophagus

1.    1 fraction: 15.4 Gy

2.    3 fractions: 30 Gy (10 Gy/fx)

3.    4 fractions: 30 Gy (7.5 Gy/fx)

4.    5 fractions: 32.5 Gy (6.5 Gy/fx)

Brachial plexus

1.    1 fraction: 17.5 Gy

2.    3 fractions: 21 Gy (7 Gy/fx)

3.    4 fractions: 27.2 Gy (6.8 Gy/fx)

4.    5 fractions: 30 Gy (6 Gy/fx)

Heart/Pericardium

1.    1 fraction: 22 Gy

2.    3 fractions: 30 Gy (10 Gy/fx)

3.    4 fractions: 34 Gy (8.5 Gy/fx)

4.    5 fractions: 35 Gy (7 Gy/fx)

Great vessels

1.    1 fraction: 37 Gy

2.    3 fractions: 39 Gy (13 Gy/fx)

3.    4 fractions: 49 Gy (12.25 Gy/fx)

4.    5 fractions: 55 Gy (11 Gy/fx)

Trachea/Large Bronchus

1.    1 fraction: 20.2 Gy

2.    3 fractions: 30 Gy (10 Gy/fx)

3.    4 fractions: 34.8 Gy (8.7 Gy/fx)

4.    5 fractions: 40 Gy (8 Gy/fx)

Rib

1.    1 fraction: 30 Gy

2.    3 fractions: 30 Gy (10 Gy/fx)

3.    4 fractions: 32 Gy (7.8 Gy/fx)

4.    5 fractions: 32.5 Gy (6.5 Gy/fx)

Skin

1.    1 fraction: 26 Gy

2.    3 fractions: 30 Gy (10 Gy/fx)

3.    4 fractions: 36 Gy (9 Gy/fx)

4.    5 fractions: 40 Gy (8 Gy/fx)

Stomach

1.    1 fraction: 12.4 Gy

2.    3 fractions: 27 Gy (9 Gy/fx)

3.    4 fractions: 30 Gy (7.5 Gy/fx)

4.    5 fractions: 35 Gy (7 Gy/fx)

GI (1.8–2.0 Gy/fx)

 

Stomach

TD 5/5 whole stomach: 45 Gy (QUANTEC)

Small bowel

V45 <195 cc (QUANTEC)

Liver (metastatic disease)

mean liver <32 Gy (liver = normal liver minus gross disease)(QUANTEC)

Liver (primary liver cancer)

mean liver <28 Gy (liver = normal liver minus gross disease) (QUANTEC)

Colon

45 Gy, max dose 55 Gy (Emami)

Kidney (bilateral)

mean <18 Gy, V28 <20%, V23 Gy <30%, V20 <32%, V12 <55%. If mean kidney dose to 1 kidney > 18 Gy, then constrain remaining kidney to V6 <30%. (QUANTEC)

GI (single fraction)

Dose constraints per RTOG 0631

Duodenum

V16 <0.035 cc, V11.2 <5 cc

Kidney (Cortex)

V8.4 <200 cc

Kidney (Hilum)

V10.6 <66%

Colon

V14.3 <20 cc, V18.4 <0.035 cc

Jejunum/Ileum

V15.4 <0.035 cc, V11.9 <5 cc

Stomach

V16 <0.035 cc, V11.2 <10 cc

Rectum

V18.4 <0.035 cc, V14.3 <20 cc

GU (1.8-2.0 Gy/fx)

 

Femoral heads

V50 <5% (RTOG GU Consensus)

Rectum

V75 <15%, V70 <20%, V65 <25%, V60 <35%, V50 <50% (QUANTEC)

Bladder

V80 <15%, V75 <25%, V70 <35%, V65 <50% (QUANTEC)

Testis

V3 <50% (RTOG 0630)

Penile bulb

Mean dose to 95% of the volume <50 Gy. D70 ≤70 Gy, D50 ≤50 Gy (QUANTEC 2010)

GU (LDR prostate brachytherapy)

 

Urethra

Volume of urethra receiving 150% of prescribed dose (Ur150) <30% (JHH)

Rectum

Volume of rectum receiving 100% of prescribed dose (RV100) <0.5 cc (JHH)

GYN

 

Bladder point (cervical brachytherapy)

Max 80 Gy (LDR equivalent dose) (ABS 2000)

Rectal point (cervical brachytherapy)

Max 75 Gy (LDR equivalent dose) (ABS 2000)

Proximal vagina (mucosa) (cervical brachytherapy)

Max 120 Gy (LDR equivalent dose) (Hintz)

Distal vagina (mucosa) (cervical brachytherapy)

Max 98 Gy (LDR equivalent dose) (Hintz)

SourcesABS 2000: American Brachytherapy Society consensus statement for HDR brachytherapy for cervical cancer (Nag S, et al., IJROBP, 2000); Emami: Emami et al., IJROBP 31:5, 1995Hintz: Hintz BL, et al., IJROBP, 1980JHH: clinical practice at Johns Hopkins Hospital; Maguire: Maguire PD, Sibley GS, Zhou SM, et al: Clinical and dosimetric predictors of radiation-induced esophageal toxicity. IJROBP 45:97–103, 1999NCCN 2010www.nccn.org; Parsons: Parsons JT, et al., Oncology, 2006QUANTEC (Quantitative Analyses of Normal Tissue Effects in the Clinic): IJROBP, 76 (2), Suppl, Mar 1, 2010RTOG protocols: www.rtog.orgRTOG

 


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