Summary: Adding radiation therapy to tamoxifen after lumpectomy was associated with modestly lower risk ofr local and regional recurrence, but no survival advantage.
The Study: CALGB 9343 was a trial designed to evaluate lumpectomy plus tamoxifen with or without breast radiation therapy. Patients were at least 70 years old, had Stage I disease, and tumors that were hormone receptor positive. The trial was conducted from 1994 to 1999.
Results: At a median follow-up 12.6 years, the benefit of whole breast radiation therapy was statistically significant: At 10 years, 98% of patients who received tamoxifen plus radiation therapy were free from local-regional recurrences, compared with 90% of those who received only tamoxifen. However, mastectomy rates, distant metastases, overall survival, and risk of second primary cancers or death from other causes did not differ when comparing the two groups.
My Take: The current US National Comprehensive Cancer Network Guidelines state that radiation therapy after lumpectomy can be omitted in women 70 or older who have estrogen receptor-positive, node-negative breast cancers that are less than 2cm in size, and who receive adjuvant endocrine therapy. I agree, but I would offer radiation therapy to those women who want to optimize local control, who have few medical co-morbidities, and a high probability of surviving at least 10 years. And I would also in general be more aggressive with more advanced stage disease. I’m Dr. Michael Hunter, and I thank you for letting me share my thoughts.
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Reference: Hughes KS et al. Lumpectomy plus tamoxifen with or without irradiation in women age 70 years or older with early breast cancer: Long-term follow-up of CALGB 9343.J Clin Oncol 2013 Jul 1; 31:2382.