Cardiac toxicity following left sided adjuvant radiotherapy for breast cancer is well described although not common. The risk is well publicised and perception of risk may alter both hospital presentation rates and investigations. The aim of this study was to identify cardiac related hospital presentation after adjuvant radiotherapy for early breast cancer and assess whether there were differences based on laterality.
This retrospective analysis included 396 patients treated with adjuvant radiotherapy within a single large regional centre between 2009-11. Patients with DCIS and neoadjuvant treatment were excluded as were patients who recurred. During the study period 80% of the regional population was served by a single public hospital and emergency department (ED) and these admission and ED records were analysed for all patients through to October 2015.
Median follow up was 54 months and the median age was 60. Tumours were left sided (L) in 204 patients and right sided (R) in192 with no difference based on postcode, insurance cover or other factors that might influence hospital of presentation. There were 3 ED admissions for myocardial infarction (1 L, 3 R) for a crude incidence of 1%, with a further 18 patients presenting with unspecified chest pain (9 L vs. 9 R) and 7 other cardiac related ED presentations (3 L vs. 4 R). Serum troponin levels were checked at some stage in 42 patients (19 L vs. 23 R). Ten patients were admitted under the cardiology team (3 L vs. 7 R) with a range of diagnoses. No differences were statistically significant.
Laterality of adjuvant radiotherapy for breast cancer does not appear to influence subsequent rates of ED presentation, cardiac related admission or troponin testing. Although presentation rates are likely incomplete assuming a proportion of patients presented elsewhere, laterality did not appear a significant factor in this.