The purpose of the CALGB 9343 study was to determine whether there is a benefit to adjuvant radiation therapy after breast-conserving therapy for a population of older women with small ER-positive breast cancers who will be treated with adjuvant endocrine therapy for 5 years.
Women over the age of 70 years with early ER-positive invasive breast cancer (tumor measuring no more than 2 cm) and clinically negative axillae were enrolled between 1994 and 1999. A total of 636 participants with stage I breast cancer who were all treated with lumpectomy (auxiliary exploration was left to the discretion of the treating surgeon) were randomly assigned to receive tamoxifen plus radiation therapy or tamoxifen alone. Primary endpoints were time to local or regional recurrence, frequency of mastectomy, breast cancer-specific survival, time to distant metastasis, and overall survival.
After a median follow-up of 12.6 years, investigators found no significant differences in time to mastectomy, time to distant recurrence, breast cancer-specific survival, or overall survival. At 10 years, 98% of patients who received dual-modality therapy were free from loco regional recurrence as compared with 90% in the group treated with tamoxifen alone. In the group that received tamoxifen alone, 42 of 319 women relapsed, compared with 23 of 317 in the group that received tamoxifen plus radiation therapy. More women in the tamoxifen group had local and regional relapses and were treated with surgery or radiation at the time of relapse. There was no significant difference in the number of distant relapses between the 2 treatment groups.
After long-term follow-up, there remains a benefit in terms of reduction of local recurrence for patients receiving tamoxifen plus radiation therapy. This does not translate into a survival advantage, however, and does not affect the rate of distant metastases. These findings allow physicians and patients a legitimate option to minimize treatment at the time of breast cancer diagnosis
Viewpoint
CALGB 9343 is a now a mature study and confirms the earlier findings[1] that endocrine therapy alone after breast conservation is a reasonable option for women over the age of 70 with small, node-negative, ER-positive tumors. Hughes and colleagues' study has influenced treatment guidelines and ought to be discussed with patients who would have met the entry criteria for this randomized controlled trial.[2] The study results do not reassure us of the safety of this minimalist approach for women with biologically aggressive tumors such as those with concomitant over expression of HER2. In an accompanying editorial by Smith and Buchholz,[3] we are reminded of the importance of considering other pertinent factors, such as the patient's life expectancy, co morbid illnesses, and tumor-specific criteria (e.g., grade, presence of lymph vascular invasion, and margin assessment).
As we reflect on the implications of this landmark study on practice, we need to consider the likelihood of whether an individual patient will actually adhere to a recommendation for lengthy endocrine treatment (the Hughes study assumes that women will take 5 years of tamoxifen), which is associated with cost and side effects. Another consideration is that we now have newer, more convenient strategies to deliver radiation using abbreviated and "personalized" schedules than were available when the Hughes study began, and these options make it easier for older women to bear radiation therapy. For women 70 years of age who are fit and have a life expectancy of 10 years or more, an appropriate approach may be an abbreviated schedule of radiation and adjuvant endocrine therapy. Clearly, we now have more breast cancer treatment options for older patients, and our challenge is to apply the available evidence wisely to best meet the needs of each individual patient.
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Southlake Oncology is a well-established, reputable medical oncology colon & breast cancer treatment center in north Texas. They also offer nutritional evaluations, a cancer support/education center for patients and family members, and an onsite American Cancer Society resource office. They are dedicated in providing the metroplex with convenient, state-of-the art cancer treatment technology in a professional yet comforting environment.
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