[Radioguided surgery for therapeutic excision of nonpalpable breast cancer]

Intratumoral injection of nanocolloid for lymphatic mapping enables therapeutic excision of clinically occult breast cancer with the aid of a gamma ray detection probe.

The aim of this study was to determine the success rate of radioguided tumor excision in addition to a guide wire and to identify factors predicting clear margins.

Sixty five consecutive patients with invasive occult breast cancer underwent radioguided tumor excision after intratumoral injection of 99 mTc-nanocolloid guided by ultrasound or stereotaxis. A localization wire was inserted; subsequently scintigraphy was performed (group 1). Results were compared with retrospective data from 67 consecutive patients who underwent therapeutic wire-directed excision alone (group 2). Factors predicting clear margin (>1 mm) were determined in a logistic regression model.

Adequate margins were obtained in 83 (group 1) and 64% (group 2; p = 0.014) respectively. The invasive component was performed in 4 and 14 patients, respectively. Factors predictive of clear margins were decreasing pathologic tumor diameter (p = 0.035), increasing weight of specimen (p = 0.046), absence of micro-calcifications (p = 0.004), and absence of carcinoma in situ component (p = 0.024). Radioguided excision was an independent predictor of complete excision of the invasive component (p = 0.012).

Application of radioguided surgery combined with wire localization seems to improve outcome of therapeutic excision of non-palpable invasive breast cancer compared to wire-directed excision alone.