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Adaptive replanning to account for lumpectomy cavity change in sequential boost after whole-breast irradiation. Int J Radiat Oncol Biol Phys 2014 Dec 01;90(5):1208-15

Date

12/03/2014

Pubmed ID

25442046

DOI

10.1016/j.ijrobp.2014.08.342

Scopus ID

2-s2.0-84920161259   7 Citations

Abstract

PURPOSE: To evaluate the efficiency of standard image-guided radiation therapy (IGRT) to account for lumpectomy cavity (LC) variation during whole-breast irradiation (WBI) and propose an adaptive strategy to improve dosimetry if IGRT fails to address the interfraction LC variations.

METHODS AND MATERIALS: Daily diagnostic-quality CT data acquired during IGRT in the boost stage using an in-room CT for 19 breast cancer patients treated with sequential boost after WBI in the prone position were retrospectively analyzed. Contours of the LC, treated breast, ipsilateral lung, and heart were generated by populating contours from planning CTs to boost fraction CTs using an auto-segmentation tool with manual editing. Three plans were generated on each fraction CT: (1) a repositioning plan by applying the original boost plan with the shift determined by IGRT; (2) an adaptive plan by modifying the original plan according to a fraction CT; and (3) a reoptimization plan by a full-scale optimization.

RESULTS: Significant variations were observed in LC. The change in LC volume at the first boost fraction ranged from a 70% decrease to a 50% increase of that on the planning CT. The adaptive and reoptimization plans were comparable. Compared with the repositioning plans, the adaptive plans led to an improvement in target coverage for an increased LC case (1 of 19, 7.5% increase in planning target volume evaluation volume V95%), and breast tissue sparing for an LC decrease larger than 35% (3 of 19, 7.5% decrease in breast evaluation volume V50%; P=.008).

CONCLUSION: Significant changes in LC shape and volume at the time of boost that deviate from the original plan for WBI with sequential boost can be addressed by adaptive replanning at the first boost fraction.

Author List

Chen X, Qiao Q, DeVries A, Li W, Currey A, Kelly T, Bergom C, Wilson JF, Li XA

Authors

Xiaojian Chen PhD Assistant Professor in the Radiation Oncology department at Medical College of Wisconsin
Adam Currey MD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin
Tracy R. Kelly MD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin
X Allen Li PhD Professor in the Radiation Oncology department at Medical College of Wisconsin
J Frank Wilson MD Professor Emeritus in the Radiation Oncology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Breast Neoplasms
Female
Heart
Humans
Lung
Mammography
Mastectomy, Segmental
Organ Size
Patient Positioning
Prone Position
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Image-Guided
Retrospective Studies
Time Factors
jenkins-FCD Prod-486 e3098984f26de787f5ecab75090d0a28e7f4f7c0