Hiral Shah, Presenter: Nothing to Disclose

Rupak K. Das PhD, Abstract Co-Author: Nothing to Disclose

Scott Patrick Tannehill MD, Abstract Co-Author: Nothing to Disclose

Heath Odau, Abstract Co-Author: Nothing to Disclose

Rakesh R. Patel MD, Abstract Co-Author: Nothing to Disclose

Purpose/Objective: High dose rate (HDR) interstitial accelerated partial breast irradiation (APBI) as the sole radiation modality following breast conserving surgery has been utilized at several institutions for select patients with early stage invasive breast cancer. We present our clinical outcomes, technical details, and dosimetry with HDR interstitial APBI for patients with DCIS. Materials/Methods: From 5/2001 to 1/2004, 29 pts with DCIS underwent HDR interstitial APBI at our institution. Selection criteria included lesions < 3 cm pathologic size, negative margins, and negative post-lumpectomy mammography. Catheter placement was performed via a prone, template- guided technique in 16 patients and via a supine, ultrasound-guided technique in 13 patients. Target volume was the surgical cavity with a 2 cm margin. CT-based dosimetry with catheter reconstruction and geometric optimization allowed selection of a prescription isodose line that was ≧ 85% of the mean central dose. The plan was adjusted manually to optimize target volume coverage while minimizing potential hot spots. In 5/2002, we implemented CT-based 3-D treatment planning allowing more accurate target delineation, improved geometric coverage of the target volume, and dosimetric verification. The volume of breast receiving 100% and 150% (Vol 100%, Vol 150%) of the prescribed dose was determined from dose volume histograms. The dose homogeneity index and percent target volume receiving 100% of the prescription dose was determined for quality assurance. All patients were treated with fractionated HDR brachytherapy delivered in the supine position (32-34 Gy/8-10 bid fractions). Acute toxicity was assessed based on RTOG criteria. Results: CT-based treatment planning allowed improved visualization of the lumpectomy cavity and normal structures. Patient and tumor characteristics, dosimetric details, and clinical outcomes are summarized in the table below. All patients tolerated therapy without any major toxicity or delays in completion of treatment. There has not been a single local or distant failure. Conclusions: To date, this represents the largest report in the literature of HDR interstitial APBI in the management of DCIS following breast conserving surgery. In our experience, the treatment is technically feasible, well-tolerated, and is associated with minimal toxicity with good to excellent cosmesis. There have been no ipsilateral breast recurrences thus far; however, additional follow-up will be required to determine the long-term efficacy in this cohort.

Shah, H, Das, R, Tannehill, S, Odau, H, Patel, R, High-Dose Rate Interstitial Accelerated Partial Breast Irradiation Following Lumpectomy for DCIS.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4418024.html