방사선의학 웹진

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Abstract
Purpose: Regional nodal irradiation (RNI) to the axilla and supraclavicular area presents distinct toxicities, such as lymphedema and shoulder stiffness, compared with whole-breast irradiation. There is insufficient evidence on the safety of dose-escalation in hypofractionated RNI. We aimed to evaluate and compare toxicity rates in patients with breast cancer who received hypofractionated RNI with and without dose-escalation.

Methods and materials: We retrospectively analyzed 381 patients with breast cancer treated with hypofractionated RNI between March 2015 and February 2017. Patients received either the standard-dose to the regional nodal area (43.2 Gy/16 fx; 48.7 Gy3.5 equivalent dose [EQD2], 2 Gy equivalent dose with α/β= 3.5 Gy) or dose-escalation with a median dose of 54.8 Gy3.5 EQD2 (range, 51.7-60.9 Gy3.5 EQD2), depending on clinical and pathologic nodal stage. Toxicity rates of lymphedema and shoulder stiffness were assessed, and statistical analyses were conducted to identify associated factors.

Results: The median follow-up time was 32.3 months (5.7-47.0 months). After radiation therapy, 71 (18.6%) patients developed lymphedema, and 48 (12.6%) developed shoulder stiffness. Patients who received dose-escalation exhibited significantly higher rates of lymphedema (32.1% vs 14.8%; odds ratio, 2.72, P = .0004) and shoulder stiffness (23.8% vs 9.4%; odds ratio, 2.01, P = .0205) compared with the standard-dose group. Moreover, dose-escalation showed a tendency to increase the severity of lymphedema and shoulder stiffness.

Conclusions: Patients who received dose-escalation in hypofractionated RNI face a higher risk of developing lymphedema and shoulder stiffness compared with those who received standard-dose hypofractionated RNI. Therefore, it is crucial to implement close and frequent monitoring for early detection, along with timely rehabilitation interventions for these patients.

Affiliations

Euidam Kim 1, Ji Sung Yoo 2, Yeon-Joo Kim 3, Jungnam Joo 4, Eun Sang Oh 5, Yoonsun Chung 1, Seung Hyun Chung 6, Tae Hyun Kim 5
1Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea.
2Department of Rehabilitation Medicine, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea. Electronic address: jsyoo@ncc.re.kr.
3Department of Radiation Oncology, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea. Electronic address: yjkim1785@ncc.re.kr.
4Office of Biostatistics Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
5Department of Radiation Oncology, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea.
6Department of Rehabilitation Medicine, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea.