While women younger than 70 years of age with invasive breast cancer should probably still receive radiotherapy plus tamoxifen following lumpectomy, those over age 70 who receive lumpectomy early, estrogen-receptor-positive breast tumors can probably get by with just tamoxifen.
In a large, randomized trial involving 769 women 50 and older with breast tumors of 5 cm or less that were removed by lumpectomy, the 5-year local relapse rate was 7.7% for those receiving tamoxifen alone after surgery and 0.6% for the women receiving tamoxifen plus local irradiation. A subgroup analysis indicated a benefit for women with T1, receptor-positive tumors of no more than 2 cm in diameter; 8-year rates of local relapse were 15.2% for women receiving tamoxifen alone versus 3.6% for women receiving tamoxifen plus radiation. The authors found no significant differences in the rates of distant relapse or in overall survival.
But a second trial that included 636 women 70 years of age or older with clinical stage I, estrogen-receptor-positive tumors that were removed by lumpectomy came to a somewhat different conclusion. The women receiving tamoxifen alone after surgery had a 5-year local relapse rate of 4%, while those receiving tamoxifen plus local irradiation had a rate of 1%. There were no significant differences between the two groups with regard to rates of mastectomy, distant metastases, or 5-year rates of survival (86% for the tamoxifen group vs. 87% for the tamoxifen plus radiation group).
Fyles AW, McCready DR, Manchul LA, et al. Tamoxifen with or without breast irradiation in women 50 years of age or older with early breast cancer. N Engl J Med. 2004;351:963-970.
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;351:971-977.
Smith IE, Ross GM. Breast radiotherapy after lumpectomy-no longer always necessary. N Engl J Med. 2004;351:1021-1023.