December 2008
Side-effects of Endocrine treatments may predict risk of breast cancer recurrence
A study has found that the occurrence of specific side-effects of endocrine treatment may provide a means to predict the likelihood of treatment success
Background
The Arimidex®, Tamoxifen, Alone or in Combination (ATAC) trial is one of the largest breast cancer studies conducted in postmenopausal patients with early breast cancer. The purpose of the ATAC trial was to compare the effectiveness of anastrozole and tamoxifen.
Anastrozole (Arimidex®) and tamoxifen are hormonal (or endocrine) therapies used in the treatment of hormone receptor-positive breast cancer. Side-effects of endocrine therapies can include vasomotor symptoms (eg. hot flushes) and joint symptoms including arthralgia (painful joints) and arthritis (inflamed joints).
Research findings
A retrospective analysis of women in the ATAC trial, treated with anastrozole or tamoxifen alone, was published in The Lancet Oncology this month1. This study focussed on whether the occurrence of specific side-effects of endocrine therapies can predict the likelihood of breast cancer recurrence.
Researchers analysed 3964 women in the ATAC trial who had hormone receptor-positive breast cancers, who started initial treatment with anastrozole or tamoxifen and who had not reported either vasomotor symptoms or joint symptoms at entry to the trial. Women who had reported newly developed vasomotor symptoms or joint symptoms at the first follow-up visit 3 months after starting treatment, were compared with women who did not report these symptoms. After median 100 months’ follow up, the women who had reported these symptoms at 3 months had lower subsequent breast cancer recurrence rates compared with the women who did not.
The researchers concluded that the appearance of new vasomotor or joint symptoms within the first 3 months of treatment may be a useful biomarker, suggesting a greater response to endocrine treatment compared to women without these symptoms.
National Breast and Ovarian Cancer Centre* comment
The question of whether the development of vasomotor and joint symptoms may serve as predictive markers for the efficacy of anastrozole or tamoxifen treatment is important to both clinicians and patients. Further studies are required, as suggested in the accompanying study editorial2, including comparison of outcomes between placebo and active-treatment groups to confirm the predictive value of these symptoms. This would have important implications for communication between health-care professionals and patients who report symptoms caused by endocrine therapies and may improve adherence to long-term endocrine therapy.
NBOCC* has developed clinical practice guidelines about the use of aromatase inhibitors as adjuvant endocrine therapy for women with hormone-receptor positive early breast cancer. An information booklet is also available to assist women with breast cancer in making decisions about the use of endocrine therapies.
Source
- Cuzick J, Sestak I, Cella, D & Fallowfied L. Treatment-emergent endocrine symptoms and the risk of breast cancer recurrence: a retrospective analysis of the ATAC trial.The Lancet Oncology 2008; 9(12): 1143-1148.
- Pritchard KI. Endocrine symptoms to predict risk of recurrence? The Lancet Oncology 2008 Dec; 9(12): 1117-9.