Researchers from Europe, Japan and America compared 9,779 women with an average age of 64 from 566 study sites in Belgium, France, Germany, Greece, Japan, the Netherlands, the UK/Ireland and the USA.
"The primary aim of our five-year research study was to carry out an international randomised trial to evaluate the efficacy and safety of the breast cancer drug exemestane, alone or following tamoxifen" explains co-author Professor C J H van de Velde from Leiden University Medical Center in The Netherlands.
"However, because we had recruited a large number of patients, we decided that this also provided us with an invaluable opportunity to examine how different countries treat postmenopausal women with early breast cancer.
"The results of our study show wide international variations in the percentages of women who receive breast conserving surgery (BCS) rather than breast removal (mastectomy) and radiotherapy after surgery.
Key findings of the study included
- 58% per cent of the women had T1 tumours (less than 2cm), 37% had T2 tumours (2-5cm) and 5% had larger/more advanced (T3/T4) tumours.
- 47% of the women had axillary node-positive disease, where the cancer affects the lymph nodes.
- The highest percentage of node-negative disease was observed in the countries with the highest percentage of T1 tumours - the USA, France and Germany.
- In general, women with T1 tumours were more likely to receive BCS. However, despite the fact that T1 tumour rates were similar in the USA and France (74% and 76% respectively), 89% of T1 tumours were treated with BCS in France compared with only 55% in the USA.
- Women with T2 tumours were more likely to receive a mastectomy than BCS, but this varied widely between countries, from 42% in France to 69% in the USA.
- The overall mastectomy rate for all tumours was 44%, with the lowest rate in France (19%) and the highest rate in Greece (56%).
- BCS was highest in women aged between 50 and 70 and mastectomy rates were highest in women under 50.
- Despite international guidelines that radiotherapy should be part of breast-conserving therapy, France and Belgium were the only countries to report 100% treatment rates. The highest non-treatment rates were in Japan (where 14% of patients did not receive radiotherapy), the UK and Ireland (13%) and the USA (14%).
- 39% of women received radiotherapy after a mastectomy and 93% of women received radiotherapy after BCS treatment.
- Some 82% of patients underwent Axillary Lymph Node Dissection, ranging from 75% in the USA to 99% in the UK and Ireland.
"Our study showed that despite international consensus guidelines, there are wide global variations in the way postmenopausal women are treated for early breast cancer" concludes Professor van de Velde.
"We believe that there should be further efforts to ensure that women can all benefit from the most effective breast cancer treatment available, regardless of which country they live in."
The TEAM (Tamoxifen and Exemestane Adjuvant Multinational) trial covered nine countries: Belgium (414 women), France (1,230), Germany (1,471), Greece (207), Japan (184), The Netherlands (2,753), UK and Ireland (1,275) and USA (2,232).