Abstract
Aim To correlate residual double strand breaks (DSB) 24 h after 4 Gy test doses to skin in vivo and to lymphocytes in vitro with adverse effects of earlier breast radiotherapy (RT). Patients and methods Patients given whole breast RT ≥5 years earlier were identified on the basis of moderate/marked or minimal/no adverse effects despite the absence ('RT-Sensitive', RT-S) or presence ('RT-Resistant', RT-R) of variables predisposing to late adverse effects. Residual DSB were quantified in skin 24 h after a 4 Gy test dose in 20 RT-S and 15 RT-R patients. Residual DSB were quantified in lymphocytes irradiated with 4 Gy in vitro in 30/35 patients. Results Mean foci per dermal fibroblast were 3.29 (RT-S) vs 2.80 (RT-R) (p = 0.137); 3.28 (RT-S) vs 2.60 (RT-R) in endothelium (p = 0.158); 2.50 (RT-S) vs 2.41 (RT-R) in suprabasal keratinocytes (p = 0.633); 2.70 (RT-S) vs 2.35 (RT-R) in basal epidermis (p = 0.419); 12.1 (RT-S) vs 10.3 (RT-R) in lymphocytes (p = 0.0052). Conclusions Residual DSB in skin following a 4 Gy dose were not significantly associated with risk of late adverse effects of breast radiotherapy, although exploratory analyses suggested an association in severely affected individuals. By contrast, a significant association was detected based on the in vitro response of lymphocytes.
Original language | English |
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Pages (from-to) | 244-249 |
Number of pages | 6 |
Journal | Radiotherapy and Oncology |
Volume | 119 |
Issue number | 2 |
DOIs | |
Publication status | Published - May 1 2016 |
Funding
The study was supported by The Royal Marsden Hospital Charity , Grant No. 06048 . The funder was not involved in any aspects of the research. The Royal Marsden Hospital Charity is gratefully acknowledged for financial support. We acknowledge NHS funding to the NIHR Biomedical Research Centre at The Royal Marsden and the ICR and to the Centre for Research in Health Protection at Public Health England. Dr Melvin Chua is kindly supported by the National Medical Research Council Singapore Transition Award ( NMRC/TA/0030/2014 ).
Keywords
- Breast cancer
- DNA damage response
- Late adverse effects
- Radiotherapy
ASJC Scopus subject areas
- Hematology
- Oncology
- Radiology Nuclear Medicine and imaging