SECTOR RESECTION WITH OR WITHOUT POSTOPERATIVE RADIOTHERAPY FOR STAGE-I BREAST-CANCER - 5-YEAR RESULTS OF A RANDOMIZED TRIAL

Background: The effectiveness of routine postoperative irradiation fol lowing breast-conserving treatment of breast cancer has not previously been assessed in randomized clinical trials that have taken place in settings where mammography has been a major pathway to diagnosis or th at have followed patients treated surgically by sector resection. Purp ose: The aim of this study was to determine if treatment of stage I br east cancer by strictly standardized surgical technique with meticulou s confirmation of a complete excision can reduce the local recurrence rate to an acceptable level without routine adjuvant radiotherapy. Met hods: In this trial conducted in Sweden, 381 women with stage I breast cancer were surgically treated by sector resection plus axillary diss ection; then 184 women were randomly selected to receive postoperative radiotherapy to the breast (XRT group), and 197 women received no fur ther treatment (non-XRT group). Patient accrual started in October 198 1 and ended in September 1988. Criteria for eligibility were a unifoca l cancer 20 mm or less in diameter (visible on mammogram) and radical excision and no histopathologic signs of axillary metastases. Results: After median follow-up times of 65 and 63 months, the 5-year local re currence rate was 2.3% (95% confidence interval CI = 0.1%-4.3%) in t he XRT group and 18.4% (95% CI = 12.5%-24.2%) in the non-XRT group, re spectively. The life-table curves were significantly different (P = .0 001). The two treatment groups did not differ in overall survival: For the XRT group, the value was 91.0% (95% CI = 86.4%-95.4%); for the no n-XRT group, it was 90.3% (95% CI = 85.8%-94.8%). The same was true fo r survival free from regional and distant recurrence: XRT group, 90.0% (95% CI = 85.3%-94.5%); non-XRT group, 87.1% (95% CI = 82.3%-92.0%). The rate of local recurrences was significantly higher in patients tre ated more recently (P. = 003). Conclusions: Sector resection plus radi otherapy to the breast very effectively achieves local tumor control. Surgery alone results in similar survival prospects, but the probabili ty of local recurrence approaches 20% at 5 years. Implications: The in crease in recurrence rate observed over time suggests that surgical te chnique and patient selection should be improved. The benefits of redu ced cost and patient inconvenience that would result from the eliminat ion of postoperative radiotherapy must be carefully weighed against th e disadvantages of local recurrence. Longer term follow-up must be don e to estimate the risk of cancer recurrence in these women 10 and 15 y ears later, and methods must be developed to identify those women who have a higher risk of recurrence. Finally, economic analyses of this a nd similar trials are needed to give empirical underpinnings for optim al use of radiotherapy.