Radiotherapy of Breast Cancer in Laterally Tilted Prone vs. Supine Position: What about the Internal Mammary Chain?

Journal of Personalized Medicine

Tanja Hinsche¹  Mirko Nitsche¹  Robert Michael Hermann¹  Ulrich Martin Carl¹  Mathias Sonnhoff¹  Lilli Geworski²  Hans Christiansen³  Jan-Niklas Becker³  Alexander Kaltenborn⁴  Nils Temme⁵ 

[1] Center for Radiotherapy and Radiooncology Bremen and Westerstede, 26655 Westerstede, Germany;Department for Radiation Protection, Hannover Medical School, 30625 Hannover, Germany;Department of Radiotherapy and Special Oncology, Hannover Medical School, 30625 Hannover, Germany;Department of Trauma and Orthopaedic Surgery, Section for Plastic Reconstructive and Hand Surgery, Federal Armed Forces Hospital Westerstede, 26655 Westerstede, Germany;Radiologie Munchen, 80333 Muenchen, Germany;

关键词: radiotherapy;    breast cancer;    prone position;    supine position;    internal mammary chain;    parasternal region;   

DOI  :  10.3390/jpm12040653

来源: DOAJ

【 摘 要 】

Background: In the multimodal breast-conserving curative therapy of some high-risk breast cancer patients, extended external beam radiotherapy (EBRT) not only to the breast but also to the supraclavicular fossa and the internal mammary chain (parasternal region (PSR)) is indicated. We report a dosimetric study on the EBRT of the breast (“B”) and the breast including PSR (“B + PSR”), comparing the supine and the laterally tilted prone patient positions in free breathing. Methods: The planning CT scans of 20 left- and 20 right-sided patients were analyzed. EBRT plans were calculated with 3D conformal EBRT (3D) and with intensity-modulated EBRT (IMRT) for “B” and “B + PSR” in the prone and supine positions. The mean and threshold doses were computed. The quality of EBRT plans was compared with an overall plan assessment factor (OPAF), comprising three subfactors, homogeneity, conformity, and radiogenic exposure of OAR. Results: In the EBRT of “B”, prone positioning significantly reduced the exposure of the OARs “heart” and “ipsilateral lung” and “lymphatic regions”. The OPAF was significantly better in the prone position, regardless of the planning technique or the treated breast side. In the EBRT of “B + PSR”, supine positioning significantly reduced the OAR “heart” exposure but increased the dose to the OARs “ipsilateral lung” and “lymphatic regions”. There were no significant differences for the OPAF, independent of the irradiated breast side. Only the IMRT planning technique increased the chance of a comparatively good EBRT plan. Conclusion: Free breathing prone positioning significantly improves plan quality in the EBRT of the breast but not in the EBRT of the breast + PSR.

【 授权许可】

Unknown