The impact of surgical management on outcome from breast cancer
This thesis aimed to determine the causes of the better survival of women treated for breast cancer by specialist surgeons. Two separate studies were performed. Firstly, a geographically defined database of pathology and mortality data from 1980-88 was updated to 1996. Secondly, a retrospective cohort study was performed of 2762 (94% of total) case-records of women diagnosed during 1986 to 1991. Women treated by specialists, even in the screening time-period, had a long-term survival advantage. Inadequate compared to adequate treatment was associated with double the risk of recurrence independent of other factors. The case-mix for non-specialists was more often unknown. Specialists were more exact in the treatment given: a preoperative diagnosis and mammography were obtained twice as frequently; staging was more selective; breast conserving surgery was performed with equal frequency, but when performed by non-specialists was inadequate twice as frequently and was four times more likely to be due to more than one error. Non-specialists omitted axillary staging three times more often and inadequately treated the axilla ten times more often. Overall, inadequate loco-regional treatment was twice as likely if treated by a non-specialist. Specialists prescribed chemotherapy twice as often, but the prescription of systemic therapy to those at highest risk was the same. The loco-regional recurrence for non-specialists was twice that of specialists after accounting for pathology and treatment. Specialists had a 26% lower risk of death after allowing for demographic, prognostic and treatment variables. This was negated if adequacy of treatment was included as an independent variable. There was poor correlation between caseload and adequacy of treatment. Adequacy of loco-regional treatment correlated with death from breast cancer.