ABSTRACT
BACKGROUND: Needle localization of a marking clip is required to guide accurate removal of many breast lesions. When the clip is not visualized on specimen radiography, concerns regarding the completeness of cancer removal and long-term outcomes arise. Using a large cohort of women undergoing breast conservation, we examined the magnitude of the problem and the outcome of women with a missing clip. METHODS: We conducted a case-control study including all women undergoing mammographic wire-guided localization between 2013 and 2018 with a specimen radiograph showing a missing clip. The control group included women with successful removal of the clip(s). Data included demographics, cancer and treatment characteristics, and outcome. The groups were compared in regard to margin status, repeat surgery, and recurrence rates. RESULTS: The research group included 43 women [5% of the cohort; 95% confidence interval (CI) 3.9-7.2] with a missing clip. Positive margins were comparable (7, 17% of cases; 29, 15% of 196 cases in the control group; p = 0.96). Eleven women (33%) had a residual clip visualized on post-operative mammography; in four cases, a percutaneous biopsy of the clip was successful, all with no residual tumor. There was no significant difference in re-excision rates (14% vs. 8%, p = 0.23) or in local or distant recurrence. CONCLUSIONS: In the majority of women with a missing clip, the clip is not visualized on post-operative mammography. Those with a residual clip can be managed with percutaneous biopsy as long as the lesion was removed with clear margins, with comparable outcomes as women in whom the clip is visualized on specimen radiograph.
