Cuzick J et al. (2008) Treatment-emergent endocrine symptoms and the risk of breast cancer recurrence: a retrospective analysis of the ATAC trial. Lancet Oncol 9: 1143–1148

In women with breast cancer vasomotor and joint symptoms are common adverse effects of endocrine treatment. Some studies have indicated that the development of vasomotor symptoms is associated with reduced breast cancer recurrence compared with women who lack these symptoms. No data have been reported on the association between joint symptoms and breast cancer recurrence.

Cuzick and coauthors performed a retrospective analysis of the Arimidex, Tamoxifen Alone or in Combination (ATAC) double-blind, randomized study to investigate whether vasomotor symptoms or joint symptoms were related to treatment efficacy. More women treated with tamoxifen experienced vasomotor symptoms compared with those who received anastrozole, whereas more patients in the anastrozole group reported joint symptoms. In total, 1,486 of 3,964 (37.5%) women who reported new vasomotor symptoms at 3-months' follow up had reduced breast cancer recurrence compared with those who did not report either of these symptoms (P=0.04). A larger, significant, 40% decrease in subsequent breast cancer recurrence for women who reported joint symptoms at 3-months' follow-up was seen compared with those without endocrine symptoms at that time (P<0.0001). The effect sizes were similar in patients treated with tamoxifen and anastrozole, and the effect of anastrozole remained superior to tamoxifen in all groups.

The authors conclude that new vasomotor or joint symptoms after 3 months of endocrine treatment could be a biomarker for response to endocrine therapy.