Intensity-modulated radiotherapy using two static ports of tomotherapy for breast cancer after conservative surgery: dosimetric comparison with other treatment methods and 3-year clinical results.
This study investigated the differences in dose-volume parameters for the breast and normal tissues during TomoDirectTM (TD) intensity-modulated radiation therapy (IMRT), TD-3D conformal radiotherapy (3DCRT) and 3DCRT plans, all using two beams, and analyzed treatment outcomes of two-beam TD-IMRT for breast cancer after breast-conserving surgery. Between August 2011 and January 2015, 152 patients were treated using two-beam TD-IMRT with 50 Gy/25 fractions. Among them, 20 patients with left-sided breast cancer were randomly chosen, and two-beam TD-IMRT, TD-3DCRT and 3DCRT plans were created for each patient. The homogeneity and conformity indices and various dose-volume parameters for the planning target volume and OARs were evaluated. Clinical outcomes were evaluated at 3 years. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 4.0. TD-IMRT and TD-3DCRT showed better whole-breast coverage than 3DCRT (P < 0.001). Most of the mean values of dosimetric endpoints for OARs were better in TD-IMRT than in TD-3DCRT and 3DCRT. Overall survival rates were 97.7% and local control rates were 99.1% at 3 years. Regional control and distant metastasis control rates at 3 years were 98.6% and 96.8%, respectively. Twenty-four of the 152 patients had Grade 2 or higher acute radiation dermatitis. Four patients (4/146 = 2.7%) had Grade 2 radiation pneumonitis. There were no late adverse events of Grade 2 or higher. Two-beam TD-IMRT appeared to yield better dose distribution for whole-breast external-beam radiation therapy than TD-3DCRT and two-beam 3DCRT. The treatment appeared to provide low skin toxicity and acceptable tumor control.
Radiation Therapy Center, Fukui Saiseikai Hospital, 7-1, Funabashi, Wadanaka-cho, Fukui 918-8503, Japan.|Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Aiko
A
Nagai
Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Yuta
Y
Shibamoto
Radiation Therapy Center, Fukui Saiseikai Hospital, 7-1, Funabashi, Wadanaka-cho, Fukui 918-8503, Japan.
Masanori
M
Yoshida
Department of Radiological Technology, Fukui Saiseikai Hospital, 7-1, Funabashi, Wadanaka-cho, Fukui 918-8503, Japan.
Koji
K
Inoda
Radiation Therapy Center, Fukui Saiseikai Hospital, 7-1, Funabashi, Wadanaka-cho, Fukui 918-8503, Japan.
Yuzo
Y
Kikuchi
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D015203:Reproducibility of Results; D016896:Treatment Outcome
Tomo-Direct; breast cancer; intensity-modulated radiation therapy; static tomotherapy; tomotherapy