Tumor bed-to-skin distance using accelerated partial-breast irradiation with the strut-adjusted volume implant device

Abstract

PurposeBecause of the risk of skin toxicity with single dwell position, single-lumen brachytherapy devices are sometimes contraindicated for tumor cavities 5–7mm from the skin surface. We discuss the use of multicatheter device to treat patients with tumor bed-to-skin distances <7mm. Methods and MaterialsWe treated 117 patients with accelerated partial-breast irradiation brachytherapy: 77 single-lumen and 40 multicatheter devices. A subset of 12 patients treated with SAVI® had bed-to-skin spacing <7mm. All patients had Tis-2N0 ductal carcinoma with negative margins. A total dose of 34.0Gy in 10 fractions was delivered twice daily. Planning target volume was created using computed tomography–based three-dimensional planning with a 1.0-cm expansion of the lumpectomy cavity. Skin dose was measured dosimetrically, with skin constraints <125% of the prescription. Toxicities were graded, and patients were assessed at various intervals. ResultsOf the patients treated with the multicatheter device, 0% (0/12) had their device pulled. At 2 weeks after treatment, fewer than 50% of the patients had skin toxicities of Grades 1–2, all of which resolved by 6 months. The cosmetic outcome was good to excellent at followup. ConclusionsMulticatheter devices permit well-tolerated accelerated partial-breast irradiation in patients with tumor cavities near the skin surface for which the single-lumen device may not be appropriate.