Dose-volume effects of breast cancer radiation therapy on the risk of second oesophageal cancer

Exposure of the oesophagus in breast cancer radiotherapy: A systematic review of oesophagus doses published 2010–2020

“…These doses may be used to estimate average risks from different regimens by combining them with a published dose-response relationship in which the excess relative risk of oesophageal cancer increased by 7.1% per Gy for both median and mean oesophagus dose [8]. In our dose review, partial breast or breast/chest wall radiotherapy usually delivered mean oesophagus dose of <2.0 Gy.…”

“…The future lifetime risk of oesophageal cancer for women aged 60 in the general population is about 0.2% in the USA and 0.7% in the UK [32]. If women receive typical breast cancer nodal radiotherapy with 11.4 Gy oesophagus dose, then this risk may be approximately doubled [8]. Smoking increases the risk of oesophageal cancer, and the ratio of the age-specific mortality rates for women in the UK who currently smoke, compared to that for women who have never smoked is about three [33].…”

“…Randomised trials have identified heart disease, lung cancer and oesophageal cancer as the main diseases where breast cancer radiotherapy can increase the mortality risk [6]. The radiationrelated risks of these diseases depend on the incidental doses received by the heart, lungs and oesophagus respectively [6][7][8].…”

“…For heart disease and lung cancer, both dose-response relationships and systematic reviews of heart and lung doses from modern regimens are available [6][7][8][9][10]. These can be used to estimate the proportional risks of heart disease and lung cancer from modern breast cancer regimens.…”

“…For oesophageal cancer, a number of observational studies have shown increased oesophageal cancer risk after radiotherapy [11][12][13][14]. A dose-response relationship based on 252 women who developed oesophageal cancer after breast cancer radiotherapy suggests that the risk of oesophageal cancer increases by 7.1% per Gy (95% confidence interval 1.9-20.6) median oesophagus dose [8]. However, at present no systematic reviews of oesophageal dose from modern breast cancer radiotherapy have been conducted.…”