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Left‐sided breast cancer loco‐regional radiotherapy with deep inspiration breath‐hold: Does volumetric‐modulated arc radiotherapy reduce heart dose further compared with tangential intensity‐modulated radiotherapy?
Author(s) -
Pham Trang T,
Ward Rachel,
Latty Drew,
Owen Catherine,
Gebski Val,
Chojnowski Jacek,
Kelly Christopher,
Ahern Verity,
Tiver Kenneth,
Stuart Kirsty,
Wang Wei
Publication year - 2016
Publication title -
journal of medical imaging and radiation oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 43
eISSN - 1754-9485
pISSN - 1754-9477
DOI - 10.1111/1754-9485.12459
Subject(s) - medicine , radiation therapy , nuclear medicine , left breast , breast cancer , cancer , radiology
Left‐sided breast cancer radiotherapy has been associated with an increase in cardiac mortality. This study investigated the potential heart‐sparing effect of volumetric‐modulated arc radiotherapy ( VMAT ). We compared VMAT to tangential intensity‐modulated radiotherapy (t‐ IMRT ) in the loco‐regional treatment of left‐sided breast cancer, including internal mammary nodal irradiation, based on deep inspiration breath‐hold ( DIBH ) and free‐breathing ( FB ). Methods Radiotherapy for 15 patients was re‐planned. Four plans were compared: t‐ IMRT ‐ DIBH ; VMAT ‐ DIBH ; t‐ IMRT ‐ FB ; VMAT ‐ FB . Prescribed dose was 50 Gy in 25 fractions. T‐ IMRT plans were generated using tangentially orientated fields. VMAT plans were generated using two partial arcs (average arc 190°). Results Mean heart dose ( MHD ) was 5 ± 2.4 Gy, 5.7 ± 1.4 Gy, 9.7 ± 3.3 Gy and 8.1 ± 2.0 Gy for t‐ IMRT ‐ DIBH , VMAT ‐ DIBH , IMRT ‐ FB and VMAT ‐ FB respectively. The difference in MHD between IMRT ‐ DIBH and VMAT ‐ DIBH was not significant ( P = 0.14). VMAT ‐ DIBH significantly spared the volume of heart irradiated to doses of 20 Gy and above ( p < 0.05), however, resulted in a significantly higher V5 Gy ( P < 0.001), compared to t‐ IMRT ‐ DIBH . VMAT ‐ DIBH resulted in higher combined lung mean (11 ± 0.8 Gy vs. 8.8 ± 1.1 Gy, P < 0.001) and higher contralateral breast mean dose (5 ± 1 Gy vs. 1.6 ± 1.2 Gy, P < 0.001) compared with t‐ IMRT ‐ DIBH . Conclusions On average, there was no significant difference in MHD between VMAT ‐ DIBH and t‐ IMRT ‐ DIBH . However, VMAT ‐ DIBH was found to benefit a select group of patients. For patients in whom the MHD was >6.3 Gy with t‐ IMRT ‐ DIBH , the use of VMAT ‐ DIBH resulted in a benefit in reducing the MHD .