Factors affecting outcome of patients with impalpable breast cancer detected by breast screening.

Factors affecting completeness of excision and outcome, whether conservation or mastectomy, in 152 patients with localized impalpable breast cancer undergoing therapeutic needle-guided wide local excision were assessed by univariate and multivariate analyses using multiple logistic regression. Independent factors related to completeness of excision at the first operation were operator experience (P = 0.0001), and size of the lesion (P = 0.005). Factors related to outcome were operator experience (P = 0.0003), more experienced operators having a higher rate of breast conservation, and tumour size (P = 0.0001), larger lesions being more likely to be treated by mastectomy. Patients initially operated on by the two most experienced surgeons were more than four times less likely to undergo mastectomy than those whose initial wide local excision was performed by a less experienced surgeon.