Whole breast radiotherapy in the lateral decubitus position: a dosimetric and clinical solution to decrease the doses to the organs at risk (OAR).

Abstract

PURPOSE:

To evaluate whole breast 3D-conformal radiotherapy (RT) delivered in the lateral decubitus position (isocentric lateral decubitus [ILD]) and to report the acute toxicity of a series of consecutive patients treated with ILD.

MATERIALS AND METHODS:

From January to December 2010, 56 consecutive patients with large breasts and early-stage breast cancer treated by breast conserving surgery underwent 3D-conformal whole breast RT in the lateral decubitus position. A dose of 50 Gy in 25 fractions via two opposed isocentric beams was prescribed to whole breast, with or without a 16 Gy photon tumor bed boost. Dosimetry of all patients was reviewed, and the acute toxicity of treatment, evaluated weekly using the NCI CTC v3.0 scale, was analyzed.

RESULTS:

Median age was 57 years (range: 33-71). 85% of patients had a breast circumference of at least 95 cm and 80% had at least a C cup size. Average breast volume was 991 cm(3) (range: 225-2791 cm(3)). Median dose to the breast was 50 Gy, while median dose to the tumor bed was 16 Gy. Grade 1, 2 and 3 dermatitis developed in 37.5%, 58.9% and 1.8% of patients, respectively. From a dosimetric point of view, doses to the ipsilateral lung were extremely low: average V(1Gy), V(2Gy) and V(5Gy) were 26.6%, 9.3% and 0.7%, respectively. Average mean lung dose was 0.96 Gy. For the 26 patients with left-sided tumors, heart doses were also extremely low: average V(1Gy), V(2Gy) and V(5Gy) were 58.8%, 14.2% and 0.7%, respectively. Average mean heart dose was 1.35 Gy.

CONCLUSION:

Whole breast radiotherapy in the lateral decubitus position for patients with large breasts and early-stage breast cancer provides an excellent dosimetric profile, with low doses to the heart and ipsilateral lung. It is also very well tolerated, with a good acute toxicity profile.

• Authors: Youlia M Kirova, Tarek Hijal, Francois Campana, Nathalie Fournier-Bidoz, Anne Stilhart, Rémi Dendale, Alain Fourquet
• Journal: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology (Radiother Oncol) Vol. 110 Issue 3 Pg. 477-81 (Mar 2014) ISSN: 1879-0887 [Electronic] Ireland
• PMID: 24342456 (Publication Type: Journal Article)
• Copyright: Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Topics

• Adult
• Aged
• Breast (radiation effects)
• Breast Neoplasms (radiotherapy)
• Female
• Humans
• Middle Aged
• Organs at Risk
• Patient Positioning
• Radiotherapy Dosage
• Radiotherapy, Conformal (adverse effects)