Long-term review of a breast conservation series and patterns of care over 18 years.

Background: Multiple randomized trials of breast conservation compared with mastectomy in early breast cancer have validated equivalence of survival. Overwhelmingly the standard management of breast conservation includes surgical removal of the tumour, axillary dissection, postoperative breast irradiation, and adjuvant systemic therapy as appropriate. The outcomes are reviewed of 832 women with early breast cancer treated by local resection and irradiation at Royal Prince Alfred Hospital over an 18 year period, with particular emphasis on the changing patterns of practice.

Methods: Between September 1978 and May 1996, 832 women with early stage breast cancer were treated with conservative surgery and radiation therapy. The changes in patient, tumour and treatment factors were analysed over this time period. The outcomes of local recurrence and survival were recorded. Trends in patterns of these variables were evaluated by dividing the 18 years accrual period into three consecutive periods (1978-1983, n = 28; 1984-1990, n = 392; 1991-1996, n = 412).

Results: At a median follow up of 76 months, the 5 and 10 year actuarial local recurrence rates were 4% and 6%, respectively. Half of the local recurrences were at the primary site. Young age, extensive intraduct carcinoma, oestrogen receptor (ER) status and extranodal spread were predictive of local recurrence on multivariate analysis. The 5 and 10 year overall survival rates were 88% and 73%, respectively. Actuarial 5 year local recurrence (4%, 6%, 2%) and survival (96%, 88%, 92%) rates varied little across the three time intervals. There was an increase in median age from 46 to 56 years over the accrual period, with no change in median primary tumour size (1.5 cm). There were significant histopathological improvements in reporting margin status and ER status. Surgically, the median number of axillary lymph nodes retrieved (14) did not alter significantly. With respect to adjuvant therapies, irradiation of lymph nodes regions decreased over time. The proportion of patients receiving adjuvant hormones or chemotherapy increased significantly (18%, 35%, 54%).

Conclusions: The low local recurrence rate and high survival are consistent with published literature for early breast cancer. Changes in practice during the accrual period included improvements in histopathological reporting, a reduction in irradiation of lymph node regions, and an increase in the use of systemic therapy. These changes parallel international recommendations regarding the optimal management of early breast cancer.