Patterns and determinants of surgical management of screen detected breast cancer in the South-East Netherlands

Introduction: Patients with screen detected breast cancer tend to have small, non-palpable tumours with favourable characteristics for breast conserving surgery (BCS). The aims of this study were to analyse patterns in surgical management in patients with screen detected breast cancer and to determine factors predictive of the need for a re-operation after BCS (re-excision or secondary mastectomy). Methods: Patient data were retrieved from the population based Eindhoven Cancer Registry, which covers 14 hospitals in de south of the Netherlands. Data of patients aged 50-74 years, diagnosed with operable, invasive, non-metastasised, T1 or T2 tumours in the period from 1999 to 2005 were linked to the patients recorded by the Dutch Breast Screening Organisation to identify the screen-detected cancers. Results: A total of 5657 patients were diagnosed with early stage invasive breast cancer. In 2822 of the 5657 patients (50%) breast cancer was detected by screening. Eighty percent of the screen-detected breast cancers was smaller than 2 cm. Of all 2822 patients with screen-detected cancer 82% underwent primary BCS. From 1999 until 2006 the percentage of re-excisions after this primary BCS decreased from 14% to 8% and the percentage of secondary mastectomies decreased from 23% to 8%. Primary BCS rates ranged from 64% to 93% between the 14 hospitals. Multivariable analyses showed that tumour size >2 cm, lobular histology, axillary nodal tumour involvement and poor differentiation of the tumour were associated with a statistically significant increase in the risk of re-operation after BCS. Conclusion: The need for a second operation after breast conserving surgery in patients with screen-detected breast cancer has decreased significantly in the southern Netherlands since 1999. However, considerable variation in surgical approach and re-operation rate between hospitals was observed.