Individual Positioning: A Comparative Study of Adjuvant Breast Radiotherapy in the Prone Versus Supine Position

Journal Article · Tue Sep 01 04:00:00 EDT 2009 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2008.10.045· OSTI ID:21281998

Varga, Zoltan; Hideghety, Katalin; Mezo, Tamas; Nikolenyi, Aliz; Thurzo, Laszlo ^[1]; Kahan, Zsuzsanna ^[1]

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1. Department of Oncotherapy, University of Szeged, Szeged (Hungary)

Purpose: To study breast radiotherapy in the prone vs. supine positions through dosimetry and clinical implementation. Methods and Materials: Conformal radiotherapy plans in 61 patients requiring only breast irradiation were developed for both the prone and supine positions. After evaluation of the of the first 20 plan pairs, the patients were irradiated in the prone or supine position in a randomized fashion. These cases were analyzed for repositioning accuracy and skin reactions related to treatment position and patient characteristics. Results: The planning target volume covered with 47.5-53.5 Gy in the prone vs. the supine position was 85.1% {+-} 4.2% vs. 89.2 {+-} 2.2%, respectively (p < 0.0001). Radiation exposure of the ipsilateral lung, expressed in terms of the mean lung dose and the V{sub 20Gy}, was dramatically lower in the prone vs. supine position (p < 0.0001), but the doses to the heart did not differ. There was no difference in the need to correct positioning during radiotherapy, but the extent of displacement was significantly higher in the prone vs. supine position (p = 0.021). The repositioning accuracy in the prone position exhibited an improvement over time and did not depend on any patient-related parameters. Significantly more radiodermatitis of Grade 1-2 developed following prone vs. supine irradiation (p = 0.025). Conclusions: Conformal breast radiotherapy is feasible in the prone position. Its primary advantage is the substantially lower radiation dose to the ipsilateral lung. The higher dose inhomogeneity and increased rate of Grade 1-2 skin toxicity, however, may be of concern.

• OSTI ID: 21281998
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 75; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
DOSIMETRY
HEART
IMPLEMENTATION
IRRADIATION
LUNGS
MAMMARY GLANDS
NEOPLASMS
PATIENTS
PLANNING
POSITIONING
RADIATION DOSES
RADIODERMATITIS
RADIOTHERAPY
SKIN
TOXICITY