Side effects indicate breast cancer treatment success

31 Oct 2008

Toxicity of breast cancer treatment can be a marker of its success

The occurrence of hot flushes, cold and night sweats (vasomotor symptoms), and joint symptoms in breast cancer patients receiving endocrine treatment can indicate a reduced chance of cancer recurrence and thus act as a marker for treatment success.

These are the conclusions of an Article published in the December edition of The Lancet Oncology, written by Professor Jack Cuzick, Cancer Research UK and Queen Mary School of Medicine and Dentistry, London, UK, and colleagues.

During endocrine treatment for breast cancer, the occurrence of the above symptoms, related to oestrogen depletion or oestrogen blockage, could indicate success of the treatment. In this study, women with hormone-receptor-positive tumours who reported these symptoms at the first follow-up visit in the ATAC* trial (which assessed tamoxifen or anastrozole for adjuvant therapy of post-menopausal breast cancer) were compared with women without these symptoms to see if there was a relationship between the symptoms and recurrence.

The researchers found that 37.5% of eligible women reported newly emergent vasomotor symptoms at the 3-month follow-up visit. These women had lower recurrence than those who did not report new vasomotor symptoms, with the 9-year recurrence rate reduced from 23% in women without symptoms to 18% in those with them. A greater decrease in breast cancer recurrence was seen for the 31.4% of eligible women who reported new joint symptoms at the 3-month follow-up visit compared with women not reporting these symptoms — from 23% to 14%. These differences were seen with both tamoxifen and anastrozole; patients receiving anastrozole had lower recurrence rates than those receiving tamoxifen, both among women with and without symptoms.

The authors conclude: “The appearance of new vasomotor symptoms or joint symptoms within the first 3 months is a useful biomarker, suggesting a greater response to endocrine treatment compared with women without these symptoms. Awareness of the relation between early treatment-emergent symptoms and beneficial response to therapy might be useful when reassuring patients who present with them, and might help to improve long-term treatment adherence when symptoms cannot be alleviated.”