B73
Inter-centre variability of left ventricular ejection fractions (LVEF) measured by multigated aquisition (MUGA) scan in early breast cancer patients for adjuvant trastuzumab therapy: potential impact on multi-centre studies and defining lower limit of normal
Maung Moe1, Wendy Phillips2, Caryl Lewis2, Carol Thomas2, Ann Barnes2
1Singleton Hospital, Swansea, UK, 2Withybush Hospital, Haverfordwest, UK
Aim
To evaluate the inter-centre variability in LVEF measurements by MUGA scan in early breast cancer patients receiving adjuvant trastuzumab therapy following adjuvant chemotherapy.
Method
Retrospective review of LVEFs and clinical histories of 62 consecutive patients, under the care of one oncologist, in two different hospitals (SGH vs. WGH) that use its own scanners, and statistical analysis with SPSS v16.
Results
SGH vs. WGH: 27 vs. 35 patients; total scans 101 vs. 92. There were no statistically significant differences in mean age (54.6 vs. 55), patients who had no (3.7% vs. 14.3%), 1 4 cycles (77.8% vs. 77.1%) or >4 cycles (18.5% vs. 8.6%) of anthracycline, history of hypertension (25.9% vs. 22.9%) and ACE inhibitors use (7.4% vs. 14.3%). Using independent samples t test there are statistically significant difference in means of scans per patient (3.7 vs. 2.6; p = 0.007), all LVEFs (51% vs. 64%; p = <0.0001), pre-trastuzumab LVEFs (55.7% vs. 65.8%; p = 0.001), lowest LVEFs (46.7% vs. 60.6%; p = <0.0001) and highest LVEFs (56.2% vs. 67.3%; p = <0.0001). There is significant difference in number of patients with LVEF <50% (59.3% vs. 11.4%; p = <0.0001) but not with LVEF <40% (22.2% vs. 8.6%; p = 0.13). Similar results are seen when the analysis was limited to patients with 4 cycles of anthracycline (19 vs. 20 patients) for LVEF <50% (57.9% vs. 15%; p = 0.005) and LVEF <40% (15.8% vs. 10%; p = 0.589). There were no statistically significant differences in means of maximum decrease from highest (10.7% vs. 11.2%) or pre-trastuzumab base line LVEF (10.1% vs. 8.2%).
Conclusion
LVEFs by MUGA may not be comparable between different centres. Serial MUGA scan should be done in the same centre to detect the real changes in LVEF. Lower limit of normal may be different among centres.
