Combining Radiation with Other Breast Cancer Treatments
A trio of recently published studies has provided further evidence that using radiation in combination with other breast cancer treatments can minimize the risk of recurrence and boost survival.
For example, a study presented at the recent annual meeting of the American Society of Clinical Oncology in New Orleans concluded that combining radiation with the hormonal treatment tamoxifen can significantly reduce the risk of breast cancer recurrence after surgery. The combination treatment was especially effective in women with early-stage disease who had no lymph-node involvement.
Dr. Norman Wolmark presented results from the cases of 1,009 women included in the National Adjuvant Breast and Bowel Project. He noted that women who received just tamoxifen alone after surgery had a risk of a new tumor developing in the same breast that was 6.8 times greater than women who received both tamoxifen plus radiation after surgery.
Conversely, women who had radiation alone (without tamoxifen) had a risk of recurrence in the same breast that was 3.9 times higher than women who had the combination treatment.
Furthermore, the risk of developing a new tumor in either breast was also greater if just hormone therapy or radiation were used by themselves, as compared with using both treatments in combination. The risk of recurrence in either breast was 4.4 times greater for women who had tamoxifen alone, and 2.3 times greater for women receiving radiation alone.
Wolmark suggested that radiation was apparently the key to local control of the cancer, as women who received radiation to the affected breast had a recurrence rate that was half that of women who received only tamoxifen.
But tamoxifen appeared to be the key to preventing recurrence in the opposite breast, he said. Women who received tamoxifen had a 1.2 percent risk of developing breast cancer in the opposite breast, compared to a 3.3 percent risk for those receiving radiation.
Wolmark cautioned that the study was restricted to women with small breast tumors that were less than one centimeter in diameter. Nonetheless, he said, the findings were significant enough to recommend the use of both therapies in combination as standard practice.
Radiation and Localized Surgery
A study by researchers at the University of California, Los Angeles has concluded that localized surgery plus radiation may be as effective as mastectomy in preventing local recurrence of ductal carcinoma in situ (DCIS) for some patients. However, this appears to be true only if the "surgical margins" after tumor removal are cancer free. In other words, the tissue that is removed around the tumor site appears to be free of cancer.
Writing in the journal Cancer, Dr. Elaine Weng and colleagues reported on 88 patients diagnosed with DCIS between 1985 and 1992. In 30 percent of the cases, the patients' tumors were treated with mastectomy, 27 percent had only localized surgery, and 43 percent had localized surgery plus radiation.
After a median follow-up period of 8.3 years, the researchers found that tumors recurred in 4 percent of the patients undergoing mastectomy, 25 percent of the patients undergoing localized surgery, and 13 percent of the patients undergoing localized surgery plus radiation therapy.
However, the recurrence rate for localized surgery plus radiation was only 3.4 percent among patients whose surgical margins were tumor free. This was equivalent to the rates for patients undergoing mastectomy.
Furthermore, the median time to recurrence was 21 months in patients who did not receive radiation, but up to 33 months in patients who had radiation therapy in addition to their surgery.
Radiation and Chemotherapy
Finally, a report published in the Journal of Clinical Oncology found that combining radiation with chemotherapy appears to prolong survival in breast cancer patients who have had surgery.
Lead author Dr. Timothy Whelan of the Hamilton Regional Cancer Center in Ontario, Canada, noted that earlier studies have shown that radiation can lower the risk of cancer recurrence, but few studies have defined its impact on breast cancer survival. To evaluate the survival benefit, Whelan and his colleagues reviewed 18 studies involving 6,000 women with breast cancer who underwent radiation therapy between 1973 and 1984.
Most of the women in these studies had a mastectomy to remove their breast cancer and then underwent chemotherapy. Afterward, some women also received radiation targeted at the chest and lymph nodes to kill any remaining cancer cells. Whelan's team compared women who underwent surgery and chemotherapy with those who had surgery and chemotherapy plus radiation.
They found that adding radiation therapy reduced the risk of cancer recurrence by almost a third (31 percent). Most of this benefit was due to a 75 percent reduction in the risk of cancer recurring in the breast, they noted. However, they also found that radiation not only helped prevent cancer from returning, but it also resulted in a 17 percent lower risk of dying.
The researchers cautioned, however, that treatments for breast cancer have changed dramatically since the studies they evaluated were conducted. Whelan said a new, large-scale study should be undertaken comparing radiation in combination with newer chemotherapy drugs, hormone-based therapies and lumpectomy.
Sources:
[Table of Contents] [Archived Issues / Search] [The Breast Center]