Wednesday, January 21, 2004

Reported today in multiple outlets a synopsis of a study to be presented in the Journal of the National Cancer Institute. The full text may be found here (PDF). The authors conducted a meta-analysis of 15 randomized trials comparing results in patients who had received radiotherapy after breast conservation, versus surgery alone.

Two doctors evaluated the results of 15 international studies and found that women who omitted radiation therapy after surgery were dying at a rate 8.6 percent higher than women who had the radiation.

This with a three-fold increase of same-breast recurrence in the non-radiated group. This was independent of any systemic therapy given (previous studies had shown a decrease of same-breast recurrence in patients receiving systemic therapy). Relapse rates occurred 1.4-5.7 percent per year in the non-radiation group and 0.4 to 2.1 percent per year in the radiation arm. Patients with clear margins had increased survival with radiation.
As with any meta-analysis, the data should be takes with a grain of salt. The authors themselves point out that:

Although the effect of radiotherapy in reducing the risk of recurrence is undisputed, no statistically significant differences in overall survival in any individual trial.(emphasis mine)

The rationale for breast conservation over mastectomy has been that while the rate of in breast recurrence has been higher with breast conservation, the rate of overall survival is the same. This was examined in the NASBP B-06 trial in 1973. This data has held true for twenty years with results examined in the October 17, 2002 New England Journal of Medicine

The cumulative incidence of recurrent tumor in the ipsilateral breast was 14.3 percent in the women who underwent lumpectomy and breast irradiation, as compared with 39.2 percent in the women who underwent lumpectomy without irradiation (P<0.001). No significant differences were observed among the three groups of women with respect to disease-free survival, distant-disease–free survival, or overall survival.

The B-06 trial was restricted to tumors <4cm in diameter. In clinical practice that limit is expanded in women with larger breasts. Subareolar location of tumor is a relative contraindication as well. Because of their poor tolerance to radiation, women with vasculitis are not good candidates for conservation.

Radiation treatments require a large commitment on the part of the patient. Treatments last for six weeks, five days a week. Some patients have difficulty arranging reliable transportation to radiotherapy.

Hopefully with wider use of local radiation delivery systems such as the Mammosite or the Intrabeam can reduce the time and effort required to obtain good adjuvant therapy. Trials are ongoing.

My routine is to give the patient the option between the treatment modalities. I make the patients promise to undergo radiotherapy. I never make a patient commit to a choice their first visit, but have them come back with a family member to discuss things.

Despite the overwhelming evidence, many patients are not given the option of breast conservation.
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