A standard treatment for early-stage breast cancer is to remove the tumor via lumpectomy and then follow that with radiation therapy and the drug, tamoxifen. But a report presented at the 2010 annual meeting of the American Society of Clinical Oncology (ASCO) has called this approach into question. Researchers at Massachusetts General Hospital, Boston, studied women over the age of 70 who had estrogen receptor positive (ER+) tumors that were removed by lumpectomy. The subjects were randomly assigned to receive either tamoxifen alone or tamoxifen plus radiation therapy.
After more than 10 years, the women who received just the tamoxifen
fared about the same as those who also received radiation. Although
radiation resulted in fewer recurrences in the affected breast, the
chance of being free from distant metastases was 95% with tamoxifen
alone vs. 93% for tamoxifen plus radiation. The 10-year
breast-cancer-specific survival was 98% with tamoxifen alone vs. 96%
with radiation. The overall survival was 63% with tamoxifen alone vs.
61% with radiation added, i.e., it was slightly higher when women did
not receive radiation.
The authors themselves concluded that "the addition of radiation does not impact survival, distant disease free survival, breast cancer specific survival or breast conservation" (Hughes 2010).
The Web site Breastcancer.org states that "these results shouldn't be used to make treatment decisions for women younger than 70." Fair enough. But many readers are bound to wonder whether radiation is worthwhile for women under the age of 70. That wasn't addressed in this study. Radiation's main purpose after breast surgery is to prevent recurrences, and it does a pretty good job at that. However, its impact on survival is not as great as some people suppose. Even the authoritative Perez and Brady textbook refers to "the lack of survival benefit associated with breast irradiation…." Needless to say, a lot of questions remain about the actual survival benefit of radiation therapy, including some indications for which it is now commonly used.
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References:
Hughes KS, et al. Lumpectomy plus tamoxifen with or
without irradiation in women age 70 or older with early breast cancer.
2010 ASCO Annual Meeting. Oral Abstract Session, Breast Cancer -
Local-Regional and Adjuvant Therapy. J Clin Oncol 28:15s, 2010
(suppl; abstr 507)
Hughes KS, Schnaper LA, Berry D, et al. Lumpectomy plus
tamoxifen with or without irradiation in women 70 years of age or older
with early breast cancer. N. Engl. J. Med.
2004;351(10):971-977.
Perez, Carlos and Brady, Luther, eds. Principles
and Practice of Radiation Oncology, Philadelphia: LWW, 4th ed.,
2004, p. 1371.