MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed

  • Noora Al-Hammadi National Center for Cancer Care and Research Hamad Medical Corporation
  • Palmira Caparrotti National Center for Cancer Care and Research Hamad Medical Corporation
  • Saju Divakar National Center for Cancer Care and Research Hamad Medical Corporation
  • Mohamed Riyas National Center for Cancer Care and Research Hamad Medical Corporation
  • Suparna Chandramouli National Center for Cancer Care and Research Hamad Medical Corporation
  • Rabih Hammoud National Center for Cancer Care and Research Hamad Medical Corporation
  • Jillian Hayes National Center for Cancer Care and Research Hamad Medical Corporation
  • Maeve Mc Garry National Center for Cancer Care and Research Hamad Medical Corporation
  • Satheesh Paloor National Center for Cancer Care and Research Hamad Medical Corporation
  • Primoz Petric National Center for Cancer Care and Research Hamad Medical Corporation

Abstract

Introduction: Omitting the placement of clips inside tumour bed during breast cancer surgery poses a challenge during delineation of lumpectomy cavity clinical target volume (CTVLC). We aimed to quantify inter-observer variation and accuracy for CT- and MRI-based segmentation of CTVLC in patients without clips.

Materials and methods: CT- and MRI-simulator images of 12 patients, treated by breast conserving surgery and radiotherapy, were included in this study. Five radiation oncologists recorded the Cavity Visualization Score (CVS) and delineated CTVLC on both modalities. Expert-consensus (EC) contours were delineated by a senior radiation oncologist, respecting opinions of all observers. Inter-observer volumetric variation and generalized conformity index (CIgen) were calculated. Deviations from EC contour were quantified by the accuracy index (AI) and inter-delineation distances (IDD).

Results: Mean CVS was 3.88 +/- 0.99 and 3.05 +/- 1.07 for MRI and CT, respectively (p=0.001). Mean volumes of CTVLC were similar: 154 +/- 26 cm3 on CT and 152 +/- 19 cm3 on MRI. Mean CIgen and AI were superior for MRI when compared with CT (CIgen: 0.74 +/- 0.07 vs. 0.67 +/- 0.12, p=0.007; AI: 0.81 +/- 0.04 vs. 0.76 +/- 0.07; p=0.004). CIgen and AI increased with increasing CVS.  Mean IDD was 3 mm +/- 1.5 mm and 3.6 mm +/- 2.3 mm for MRI and CT, respectively (p=0.017).

Conclusions: When compared with CT, MRI improved visualization of post-lumpectomy changes, reduced the inter-observer variation and improved the accuracy of CTVLC contouring in patients without clips in the tumour bed.

Author Biographies

Noora Al-Hammadi, National Center for Cancer Care and Research Hamad Medical Corporation
Senior Consultant radiation oncologist, Department of Radiation Oncology
Palmira Caparrotti, National Center for Cancer Care and Research Hamad Medical Corporation
Consultant radiation oncologist, Department of Radiation Oncology
Saju Divakar, National Center for Cancer Care and Research Hamad Medical Corporation
Consultant radiation oncologist, Department of Radiation Oncology
Mohamed Riyas, National Center for Cancer Care and Research Hamad Medical Corporation
Consultant radiation oncologist, Department of Radiation Oncology
Suparna Chandramouli, National Center for Cancer Care and Research Hamad Medical Corporation
Radiation oncologist, Department of Radiation Oncology
Rabih Hammoud, National Center for Cancer Care and Research Hamad Medical Corporation
Medical physicist, Department of Radiation Oncology
Jillian Hayes, National Center for Cancer Care and Research Hamad Medical Corporation
Radiation therapist, Department of Radiation Oncology
Maeve Mc Garry, National Center for Cancer Care and Research Hamad Medical Corporation
Radiation therapist, Department of Radiation Oncology
Satheesh Paloor, National Center for Cancer Care and Research Hamad Medical Corporation
Medical physicist, Department of Radiation Oncology
Primoz Petric, National Center for Cancer Care and Research Hamad Medical Corporation
Senior consultant radiation oncologist, Department of Radiation Oncology
Published
2017-06-07
How to Cite
Al-Hammadi, N., Caparrotti, P., Divakar, S., Riyas, M., Chandramouli, S., Hammoud, R., Hayes, J., Mc Garry, M., Paloor, S., & Petric, P. (2017). MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed. Radiology and Oncology, 51(2). Retrieved from https://radioloncol.com/index.php/ro/article/view/2735
Section
Clinical oncology