Breast conservation therapy without capsular contracture in young augmented women using interstitial brachytherapy

To describe a breast-conserving technique using interstitial brachytherapy after lumpectomy and axillary nodal sampling in selected women who are diagnosed with breast cancer in the presence of augmentation mammoplasty.

Over the past 20 years, we have developed and improved a technique of "pinch view" image-guided catheter insertion that avoids implant puncture. Selection criteria include: 1) women of any age with either subpectoral or retroglandular, augmentation implants (silicone or saline) who were diagnosed with stages Tis, T1, T2, N0, or N1 breast cancer; 2) any pathologic subtype of malignant breast cancer was accepted; 3) microscopic tumor extent ≤ 3 cm; 4) axillary node negative or metastasis to 1 to 3 nodes without extracapsular extension; and 5) surgical margins clear by the NSABP "no ink on tumor" definition. More than 250 women have been successfully treated. Patients were treated with high dose rate Iridium-192 brachytherapy to 34 Gy in 10 or 32 Gy in 8 twice daily fractions. The target volume was the surgical cavity edge with 1.5 to 2 cm margin using 3-D treatment planning systems.

The implant technique as currently employed is described. There have been no implant ruptures, and the Planning Treatment Volume (PTV-eval) exhibited at least 90% coverage by the 90% isodose line in the vast majority of cases. Dose Homogeneity Index exceeded 70% in most cases. The maximum skin dose was below the prescription dose in every case. Other than some patients with pre-existing capsular contracture, less than 5% experience new capsular contracture after interstitial brachytherapy.

A technique of reliable and reproducible accelerated partial breast irradiation is described that minimizes the risk of capsular contracture by avoiding circumferential dose to the foreign body in the breast.