The impact of the sequence of radiation and chemotherapy on local control after breast-conserving surgery.

PURPOSE

We conducted this study to evaluate the effects of delaying primary radiation after adjuvant chemotherapy on local control following breast-conserving surgery compared with radiation delivered immediately following surgery.

PATIENTS AND METHODS

This retrospective, nonrandomized study evaluated local control in 471 patients treated with breast-conserving surgery and radiation from 1980 through 1990. Three patient subsets were studied, identified by the sequence of radiation and adjuvant therapy if given. The three subgroups were: surgery, radiation, no chemohormonal therapy (332 patients; RT only); surgery, all chemotherapy, radiation (53 patients; chemo first); and surgery, chemotherapy, radiation, chemotherapy (86 patients; sandwich). Median follow-up times ranged from 53 months in the chemo first group to 77 months in the RT only group.

RESULTS

All three groups had similar local control rates at 3 and 5 years. At 36 months, the actuarial local control rate achieved by the RT only group was 98% (confidence interval: 95%-99%); by the chemo first group, 94% (CI: 82%-98%); and the sandwich group, 96% (CI: 89%-99%). At 60 months, the local control rate for the RT only group was 96% (CI: 93%-98%), the chemo first group, 86% (CI: 70%-94%) and the sandwich group 95% (CI: 87%-98%).

CONCLUSIONS

This report demonstrates no significant difference in the local recurrence rate following breast-conserving surgery and radiation therapy, whether radiation immediately followed the surgery or whether it was delayed by the administration of postsurgical adjuvant chemotherapy. These data differ from other reports, and suggest that this question remains open, requiring further follow-up that focuses not only on local control as an endpoint, but disease-free and overall survival as well.