Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Oct 22;8(6):465-469.
eCollection 2022 Dec 29.

Interobserver variability in gross tumor volume contouring in non-spine bone metastases

Carolina de la Pinta  1 , Raquel García LaTorre  2 , Alberto Martínez-Lorca  3 , Eva Fernández  1 , Raul Hernanz  1 , Mercedes Martín  1 , Jose A Domínguez  1 , Teresa Muñóz  1 , Elena Canales  2 , Carmen Vallejo  1 , Marina Alarza  1 , Asunción Hervás  1 , Manuel Garví  1 , Vanesa Pino  1 , Sonsoles Sancho  1
Affiliations

Interobserver variability in gross tumor volume contouring in non-spine bone metastases

Carolina de la Pinta et al. J Clin Transl Res. .

Abstract

Background and aim: The optimal imaging test for gross tumor volume (GTV) delineation in non-spine bone metastases has not been defined. The use of stereotactic body radiotherapy (SBRT) requires accurate target delineation. Magnetic resonance imaging (MRI) and/or 18fludesoxyglucose positron emission tomography (18FDG-PET) allow for better visualization of the extent of bone metastases and optimizes the accuracy of tumor delineation for stereotactic radiotherapy compared to computed tomography (CT) alone. We evaluated the interobserver agreement in GTV of non-spine bone metastases in a single center and compared MRI and/or 18FDG-PET and CT in GTV delineation.

Methods: Anonymous CT and MRI and/or 18FDG-PET obtained from 10 non-spine bone metastases were analyzed by six radiation oncologists at our center. Images acquired by CT and MRI and/or 18FDG-PET were used to delineate 10 GTVs of non-spine bone metastases in the pelvis, extremities, and skull. The cases showed different characteristics: blastic and lytic metastases, and different primary cancers (lung, breast, prostate, rectum, urothelial, and biliary). In both CT and MRI and/or 18FDG-PET, the GTV volumes were compared. The index of agreement was evaluated according to Landis and Koch protocol.

Results: The GTV volume as defined on MRI was in all cases larger or at least as large as the GTV volume on CT (P=0.25). The median GTV volume on MRI was 3.15 cc (0.027-70.64 cc) compared to 2.8 cc on CT (0.075-77.95 cc). Interobserver variance and standard deviation were lower in CT than MRI (576.3 vs. 722.2 and 24.0 vs. 26.9, respectively). The level of agreement was fair (kappa=0.36) between CT and MRI. The median GTV volume on 18FDG-PET in five patients was 5.8 cc (0.46-64.17 cc), compared to 4.1 cc on CT (0.99-54.2 cc) (P=0.236). Interobserver variance and standard deviation in CT, MRI, and 18FDG-PET were 576.3 versus 722.2 versus 730.5 and 24 versus 26.9 versus 27.0, respectively. The level of agreement was slight (kappa=0.08) between CT and 18FDG-PET.

Conclusions: Interobserver variance in non-spine bone metastases was equal when MRI and PET were compared to CT. CT was associated with the lowest variance and standard deviation. Compared to CT GTVs, the GTVs rendered from MRI images had fair agreement, while the GTVs rendered from 18FDG-PET had only slight agreement.

Relevance for patients: The delimitation of the treatment volume in non-spine bone metastases with SBRT is important for the results determining its efficacy. It is therefore essential to know the variability and to manage it to achieve the highest quality of treatment.

Keywords: contouring; gross tumor volume; non-spine bone metastases; stereotactic body radiotherapy; variability.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1. Patient with metastasis in calotte (CT and MRI sequences) (case number 7).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Potters L, Kavanagh B, Galvin JM, Hevezi JM, Janjan NA, Larson DA, et al. American society for therapeutic radiology and oncology (ASTRO) and American college of radiology (ACR) practice guideline for the perfomance of stereotactic body radiation therapy. Int J Radiat Oncol Biol Phys. 2010;76:326–32. - PubMed
    1. Garcia-Barros M, Paris F, Cordon-Cardo C, Lyden D, Rafii S, Haimovitz-Friedman A, et al. Tumor response to radiotherapy regulated by endothelial cell apoptosis. Science. 2003;300:1155–9. - PubMed
    1. Fuks Z, Kolesnick R. Engaging the vascular component of the tumor response. Cancer Cell. 2005;8:89–91. - PubMed
    1. Tree A, Khoo VS, Eeles RA, Ahmed M, Dearnaley DP, Hawkins MA, et al. Stereotactic body radiotherapy for oligometastases. Lancet Oncol. 2013;14:e28–37. - PubMed
    1. Videtic GM. The role of stereotactic radiotherapy in the treatment of oligometastases. Curr Oncol Rep. 2014;16:391. - PubMed

LinkOut - more resources