[The effect of local control on overall survival after the breast-conserving therapy of breast carcinoma].
BACKGROUND: The impact of local control on survival in breast carcinoma has been controversially discussed depending upon the specific view of disease as being systemic from the initial onset or locally confined with spread sequentially from the primary tumor to the regional lymph nodes and then to distant sites. Results of recent studies provide a good example of why controversy persists over the benefit of local control on survival. PATIENTS AND METHODS. There are 4 recently updated randomised trials that compare conservation surgery alone or with radiation: Milan III (follow-up 3.5 years), Canada (follow-up 5 years), Uppsala/Orebro (follow-up 5 years), and NSABP-B06 (follow-up 10 to 12 years). In addition, the reanalysis of NSABP-B06-protocol reported by the EMMES Corporation has become available. Of further importance is the meta-analysis of Levitt et al. , which has used special statistical tools, the BAYESIAN-technique.
RESULTS: All 4 trials report statistically significant increased local control and improved survival for the irradiated patients. Based on p-values and confidence intervals, survival was statistically improved in long-term follow-up of the NSABP-B06 trial, but not in the other trials, probably because of small sample sizes and short follow-up. At 10 years, the overall survival rates for the NSABP-B06 were 65 +/- 2.1% and 71 +/- 2.0% for lumpectomy alone or with radiation respectively (p = 0.04), the distant-disease-free survival 55 +/- 2.3% vs. 62 +/- 2.2% (p = 0.03), and the disease-free survival 48 +/- 2.2% vs. 56 +/- 2.2% (p < 0.01). Within the Bayesian framework, the expected advantage in 10 year survival was 6% (the mean of NSABP-B06 10 year survival) with an 83% probability that the 10-year-survival difference ranges between 2% and 10%.
CONCLUSIONS: The careful analysis of these randomized trials comparing lumpectomy with or without radiation clearly indicate an improvement in overall survival for the irradiated patients which is associated with increased local control. Combination of this survival trend with the reduced psychological and economic costs associated with local recurrence provides excellent arguments for radiation therapy as the standard treatment concept in breast conservation therapy.