Inter-observer variation in delineation of the heart and left anterior descending coronary artery in radiotherapy for breast cancer: A multi-centre study from Denmark and the UK

doi:10.1016/j.radonc.2013.06.025

Radiotherapy and Oncology

Volume 108, Issue 2, August 2013, Pages 254-258

https://doi.org/10.1016/j.radonc.2013.06.025 Get rights and content

Abstract

Background and purpose

To determine the extent of inter-observer variation in delineation of the heart and left anterior descending coronary artery (LADCA) and its impact on estimated doses.

Methods and materials

Nine observers from five centres delineated the heart and LADCA on fifteen patients receiving left breast radiotherapy. The delineations were carried out twice, first without guidelines and then with a set of common guidelines.

Results

For the heart, most spatial variation in delineation was near the base of the heart whereas for the LADCA most variation was in its length at the apex of the heart. Common guidelines reduced the spatial variation for the heart and the length of the LAD, but increased the variation in the anterior–posterior/right–left plane. The coefficients of variation (CV) in the estimated doses to the heart were: mean dose 7.5% without and 3.6% with guidelines, maximum dose 8.7% without and 4.0% with guidelines. The CVs in the estimated doses to the LADCA were: mean dose 27% without and 29% with guidelines, maximum dose 39% without and 31% with guidelines.

Conclusions

For the heart, there was little inter-observer variation in the estimated dose, especially when guidelines were used. In contrast, for the LADCA there was substantial variation in the estimated dose, which was not reduced with guidelines.

Section snippets

Patients

Fifteen patients were selected at random from women who received adjuvant radiotherapy to the conserved left breast at the Odense University Hospital in 2010. The patients were scanned on a Phillips Bigbore with voxel size 0.9866 × 0.9866 × 3 mm. Contrast was not used, as it was not clinical practice in any of the participating centres. Each patient received radiotherapy according to the 2010 guidelines from the Danish Breast Cancer Cooperative Group (DBCG) (http://www.dbcg.dk). The field

Results

Volume, similarity indices, CV of estimated doses and estimated doses derived both without and with guidelines are shown in Table 1.

Mean similarity indices were higher for all patients in heart delineations performed with guidelines, see Supplementary Fig. A.4, indicating a higher spatial overlap in delineations. For the heart delineations, the largest inter-observer spatial distance variation was at the base of the heart (see Fig. 2a). For some patients notable variation was also present at

Discussion

In radiotherapy planning, the need for adequate coverage of the breast is balanced against the need to avoid irradiating the heart. The heart is often the dose-limiting organ at risk for left-tangential breast cancer radiotherapy. Although some inter-observer variation is inevitable in delineating the heart, reasonable consistency between observers is required to enable appropriate treatment guidelines to be formulated and followed. This study has assessed the extent of such variation for nine

Conclusions

Heart delineations were subject to major inter-observer variation at the base of the heart. However, for left sided radiotherapy the heart is exposed in a region with low inter-observer variation, and the estimated dose was therefore only subject to modest inter-observer variation. The use of common guidelines significantly reduced the variation in heart delineations. The guidelines reduced the inter-observer variation in LADCA delineations in the CC-direction but increased the variation in the

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Cardiac dosimetry in breast cancerInter-observer variation in delineation of the heart and left anterior descending coronary artery in radiotherapy for breast cancer: A multi-centre study from Denmark and the UK

Abstract

Background and purpose

Methods and materials

Results

Conclusions

Section snippets

Patients

Results

Discussion

Conclusions

Int J Radiat Oncol Biol Phys

Lancet Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Radiother Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Mortality from cardiovascular disease more than 10 years after radiotherapy for breast cancer: nationwide cohort study of 90,000 swedish women

BMJ

Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials

Lancet

Increased cardiovascular mortality more than fifteen years after radiotherapy for breast cancer: a population-based study

BMC Cancer

Cardiac dosimetry in breast cancer
Inter-observer variation in delineation of the heart and left anterior descending coronary artery in radiotherapy for breast cancer: A multi-centre study from Denmark and the UK