> Table 44: Tamoxifen in the treatment of ductal carcinoma in situ (DCIS)
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Introduction: Results from one randomized controlled trial showed that adding tamoxifen to the treatment of ductal carcinoma in situ (DCIS) can lower the risk of invasive and non-invasive breast cancer, both in the same breast and in the opposite breast, in women who have lumpectomy plus radiation [1]. Preliminary results from this study suggest that this benefit may be limited to women with estrogen-receptor positive tumors [2]. A second randomized controlled trial found that while tamoxifen did not lower the risk of invasive breast cancer, it did lower this risk of recurrence of DCIS both in the same breast and in the opposite breast [3].
Study selection criteria: Large randomized controlled trials.
Table Note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.
Study
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Study Population (number of participants)
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Follow-up (years)
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Absolute Risk of Invasive Breast Cancer (number of cases per 1,000 women)
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Relative Risk of Invasive Breast Cancer in Women Taking Tamoxifen Compared to Women Not Taking Tamoxifen, RR (95% CI)
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Among Women Not Taking Tamoxifen
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Among Women Taking Tamoxifen
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Randomized Controlled Trials
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National Surgical Adjuvant Breast and Bowel Project, Protocol B-24 [1]
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1,804 women with DCIS treated with lumpectomy plus radiation
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12
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16 per
1,000
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8.8 per
1,000
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0.55 (0.38-0.79)
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UK Coordinating Committee on Cancer Research [3]
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1,576 women with DCIS treated with lumpectomy either with or without radiation
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4.4
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*
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*
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1.11 (0.76-1.63)†
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* Absolute risk not provided. However, 4% of women not taking tamoxifen got invasive cancer vs. 6% of women taking tamoxifen (this difference was not statistically significant).
† While tamoxifen did not reduce the risk of invasive breast cancer, it did reduce the risk of recurrence of DCIS (0.68 (0.49-0.96)).
References
1. Fisher B, Land S, Mamounas E, et al. Prevention of invasive breast cancer in women with ductal carcinoma in situ: an update of the National Surgical Adjuvant Breast and Bowel Project Experience. Seminars in Oncology. 28(4):400-418, 2001.
2. Allred D, Bryant J, Land S, et al. Estrogen receptor expression as a predictive marker of the effectiveness of tamoxifen in the treatment of DCIS: Finding from NSABP Protocol B-24. 25th Annual San Antonio Breast Cancer Symposium (Abstract 30), 2002.
3. Houghton J, George WD, Cuzick J, et al. for the UK Coordinating Committee on Cancer Research (UKCCCR) Ductal Carcinoma in situ (DCIS) Working Party on behalf of DCIS Trialists in the UK, Australia, and New Zealand. Radiotherapy and tamoxifen in women with completely excised ductal carcinoma in situ of the breast in the UK, Australia, and New Zealand: randomised controlled trial. Lancet. 362(9378):95-102, 2003.
Updated 09/12/09
