Min, Myo

Roos, Daniel

Keating, Elly

Penniment, Michael

Carruthers, Scott

Zanchetta, Lydia

Wong, Karen

Shakeshaft, John

Baxi, Siddhartha

2014-06-01

The aims of the study were to evaluate interobserver variability in contouring the brachial plexus (BP) using the Radiation Therapy Oncology Group (RTOG)-approved protocol and to analyse BP dosimetries. Seven outliners independently contoured the BPs of 15 consecutive patients. Interobserver variability was reviewed qualitatively (visually by using planning axial computed-tomography images and anteroposterior digitally reconstructed radiographs) and quantitatively (by volumetric and statistical analyses). Dose-volume histograms of BPs were calculated and compared. We found significant interobserver variability among outliners in both qualitative and quantitative analyses. These were most pronounced for the T1 nerve roots on visual inspection and for the BP volume on statistical analysis. The BP volumes were smaller than those described in the RTOG atlas paper, with a mean volume of 20.8 cc (range 11-40.7 cc) compared with 33 ± 4 cc (25.1-39.4 cc). The average values of mean dose, maximum dose, V60Gy, V66Gy and V70Gy for patients treated with conventional radiotherapy and IMRT were 42.2 Gy versus 44.8 Gy, 64.5 Gy versus 68.5 Gy, 6.1% versus 7.6%, 2.9% versus 2.4% and 0.6% versus 0.3%, respectively. This is the first independent external evaluation of the published protocol. We have identified several issues, including significant interobserver variation. Although radiation oncologists should contour BPs to avoid dose dumping, especially when using IMRT, the RTOG atlas should be used with caution. Because BPs are largely radiologically occult on CT, we propose the term brachial-plexus regions (BPRs) to represent regions where BPs are likely to be present. Consequently, BPRs should in principle be contoured generously.

Alan Walker Cancer Centre, Royal Darwin Hospital, Darwin, Northern Territory, Australia; Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia, Australia..

J Med Imaging Radiat Oncol . 2014;58(3):360-8. doi: 10.1111/1754-9485.12175. Epub 2014 Apr 9.

https://pubmed.ncbi.nlm.nih.gov/24716652/?otool=iaurydwlib

https://hdl.handle.net/10137/5600

Radiation Therapy Oncology Group protocol

brachial plexus

head and neck cancer

intensity-modulated radiotherapy

radiation-induced brachial plexopathy

Aged

Aged, 80 and over

Anatomic Landmarks

Brachial Plexus

Female

Head and Neck Neoplasms

History, Ancient

Humans

Male

Medical Oncology

Middle Aged

Observer Variation

Organ Sparing Treatments

Practice Guidelines as Topic

Radionuclide Imaging

Radiotherapy, Image-Guided

Reproducibility of Results

Sensitivity and Specificity

Tomography, X-Ray Computed

External evaluation of the Radiation Therapy Oncology Group brachial plexus contouring protocol: several issues identified.

Journal Article

Publication