Breast cancer: relapses reduced by a half with low-dose tamoxifen
Even at low dose (5 mg/day), tamoxifen can reducethe risk of developing relapses and new tumours in women who received a diagnosis of intraepithelial breast cancer by a half. This was shown in an Italian study conducted by Andrea De Censi, Director of the complex unit of medical oncology at Ospedali Galliera in Genoa, which was presented at the San Antonio Breast Cancer Symposium in Texas, the most important international congress on breast cancer.
Tamoxifen therapy at a dose of 20 mg/day for 5 years is commonly used to reduce the risk of relapses in women who underwent surgery for early stage breast cancer. However, at this dose, the use of this drug can induce important side effects, including an increased risk of menopause symptom onset – which sometimes leads to treatment discontinuation – or an increased risk of endometrial cancer.
“Our study, called TAM-01, shows that low-dose tamoxifene (5 mg/day for 3 years), reduces the risk of relapse by 50% and the risk of new tumours by 75% as compared to placebo” said Andrea De Censi. “This result overlaps the outcome obtained with the 20 mg dosage. Besides confirming the drug efficacy, the low-dose treatment results in a statistically significant reduction of serious adverse events, without increasing menopause symptoms such as hot flashes, vaginal dryness and pain during sexual intercourse”.
The randomized, Phase III study TAM-01 enrolled 500 women who had previously undergone surgery due to early stage breast cancer. Patients were divided into two groups and treated respectively with tamoxifen low dose or placebo for three years, in 14 Italian sites including the European Institute of Oncology. After more than 5 years since the beginning of treatment, 5.5% women treated with low-dose tamoxifen had a relapse as compared to 11.3% women treated with placebo, with a risk reduction of 52% in the former. No other statistically significant differences were observed between the two groups in terms of menopause symptom onset.
This important result was obtained thanks to support by AIRC-Italian Association for Cancer Research, the Italian Ministry of Health and LILT-Italian League for the Fight Against Cancer. As the next step, Professor De Censi aims at starting a new study for primary prevention in women with increased risk of breast cancer. “We trust that a 5 mg/day treatment with tamoxifen will show to be an opportunity for primary prevention in healthy women at high risk of developing breast cancer, including women with BRCA mutation, known as the Angelina Jolie gene” concluded De Censi.