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A newly published study by British researchers finds that women who are diagnosed with
an early form of breast cancer called ductal carcinoma in situ
(DCIS) may be less likely to experience a recurrence of their disease if they are
treated with radiation after breast cancer surgery,
rather than with the drug tamoxifen. In the study, women
who were treated with radiation were 60% less likely to have their cancer return after
treatment, versus a reduction in risk of only 10% for the women who were treated with
tamoxifen. Though there has been controversy as to whether women with early-stage breast
cancer need more aggressive treatments, such as radiation, the results of this study
suggest that women who receive radiation after surgery fare better than those who receive
drug therapy alone.
DCIS is the most common type of non-invasive breast cancer, in which the cancer cells
are confined to milk ducts in the breast and have not spread into the fatty breast tissue
or to any other part of the body (such as the lymph nodes). When treated properly with
surgery, either lumpectomy or mastectomy, the chances of
surviving DCIS are nearly 100%. However, many women with DCIS do experience a recurrence
of the disease at a later point.
Tamoxifen is a drug used to help treat or prevent breast cancer and to help reduce the
risk that breast cancer will return after treatment. Many women with DCIS are treated with
tamoxifen. Radiation therapy is also commonly used after a lumpectomy to also help reduce
the risk of a cancer recurrence.
To compare the effectiveness of tamoxifen and radiation therapy in women diagnosed with
DCIS, Professor Jack Cuzick and researchers from the British charity Cancer Research UK
analyzed results from an ongoing study of 1,700 women from the United Kingdom, Australia
and New Zealand who have been studied since 1990.
The results of the study found that the risk of developing breast cancer in the same
breast after treatment was significantly lower among the DCIS patients treated with
radiation therapy alone (after surgery), compared with those who were treated with
tamoxifen. Radiation therapy also reduced the risk of a cancer recurrence in women with
invasive breast cancer—cancer which has spread beyond the breast ducts.
"It is clear that radiotherapy is needed for the majority of women with DCIS.
Tamoxifen should be limited to women who have estrogen sensitive cancers," said
Professor Jack Cuzick, in a Cancer Research UK news release. "Treatment is given
after complete local excision, which is also known as lumpectomy. The main difference for
women is that radiotherapy involves an intensive course of treatment for five weeks
whereas tamoxifen is given as a pill for five years."
Both radiation therapy and tamoxifen are associated with some side effects. The most
common side effects of radiation include fatigue, breast swelling, and a temporary
sunburn-like appearance of the breast. Side effects of tamoxifen include hot flashes and
vaginal dryness. Tamoxifen is also associated with some rare but potentially serious
problems, including an increased risk of endometrial cancer (cancer of the uterine
lining), stroke, and blood clots.
The researchers did emphasize that tamoxifen may still be needed for women with
estrogen-sensitive breast cancers. Tamoxifen works by blocking estrogen from reaching
breast cancer cells, thereby starving these cells. The drug is effective only in women
whose cancers have estrogen receptors (approximately 80% of breast cancers). In addition,
most physicians recommend radiation therapy for the majority of women who are treated with
lumpectomy.
Additional Resources and References
- The report, "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," is published in the July 12, 2003 issue of The Lancet, http://www.thelancet.com/
- The July 10, 2003 Cancer Research UK news release, "Radiotherapy beats tamoxifen
for treating pre-invasive breast cancer," is available at http://www.cancerresearchuk.org/
- To learn more about DCIS, please visit http://www.imaginis.com/breasthealth/dcis.asp
- To learn more about radiation therapy, please visit http://www.imaginis.com/breasthealth/radio_bctreatment.asp
- To learn more about tamoxifen, please visit http://www.imaginis.com/breasthealth/tamoxifen.asp
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