[HTML][HTML] Hormone replacement therapy after breast cancer: 10 year follow up of the Stockholm randomised trial

M Fahlén, T Fornander, H Johansson… - European journal of …, 2013 - Elsevier
M Fahlén, T Fornander, H Johansson, U Johansson, LE Rutqvist, N Wilking, E von Schoultz
European journal of cancer, 2013Elsevier
BACKGROUND: The management of hormonal deficiency symptoms in breast cancer
survivors is an unsolved problem. While hormone replacement therapy (HRT) may increase
the risk of breast cancer in healthy women, its effects on recurrence is unclear.
Observational studies have suggested decreased recurrence rates from HRT. The few
clinical trials in this field have all been closed preterm. METHODS: The Stockholm trial was
started in 1997 and designed to minimise the dose of progestogen in the HRT arm. Disease …
BACKGROUND
The management of hormonal deficiency symptoms in breast cancer survivors is an unsolved problem. While hormone replacement therapy (HRT) may increase the risk of breast cancer in healthy women, its effects on recurrence is unclear. Observational studies have suggested decreased recurrence rates from HRT. The few clinical trials in this field have all been closed preterm.
METHODS
The Stockholm trial was started in 1997 and designed to minimise the dose of progestogen in the HRT arm. Disease-free women with a history of breast cancer were randomised to HRT (n=188) or no HRT (n=190). The trial was stopped in 2003 when another Swedish study (HABITS, the Hormonal Replacement After Breast Cancer – Is it Safe?) reported increased recurrence. However the Stockholm material showed no excess risk after 4years of follow-up. A long term follow-up has now been performed.
FINDINGS
After 10.8years of follow-up, there was no difference in new breast cancer events: 60 in the HRT group versus 48 among controls (hazard ratio (HR)=1.3; 95% confidence interval (CI)=0.9–1.9). Among women on HRT, 11 had local recurrence and 12 distant metastases versus 15 and 12 for the controls. There were 14 contra-lateral breast cancers in the HRT group and four in the control group (HR=3.6; 95% CI=1.2–10.9; p=0.013). No differences in mortality or new primary malignancies were found.
INTERPRETATION
The number of new events did not differ significantly between groups, in contrast to previous reports. The increased recurrence in HABITS has been attributed to higher progestogen exposure. As both trials were prematurely closed, data do not allow firm conclusions. Both studies found no increased mortality from breast cancer or other causes from HRT. Current guidelines typically consider HRT contraindicated in breast cancer survivors. Findings suggest that, in some women symptom relief may outweigh the potential risks of HRT.
Elsevier