Local Control Following Single-Dose Intraoperative Radiotherapy Prior to Surgical Excision of Early-Stage Breast Cancer
Multiple partial breast radiotherapy techniques are available. We have previously presented the technical details of our procedure of delivering partial breast irradiation with a single fraction of intraoperative radiotherapy (IORT) targeting the tumor in situ prior to partial mastectomy. This study details our completed, single-institution trial.
Materials and Methods
An IRB-approved, DSMB-monitored phase II trial was performed with the following inclusion criteria: women age ≥48, ultrasound-visible invasive ductal cancers <3 cm, clinically negative axillary nodes. IORT was delivered using mobile electron irradiator, at least a 1.5-cm radial and 1-cm deep margin; patients received 15 Gy and immediately underwent partial mastectomy. Ipsilateral breast recurrence was classified as true/marginal, elsewhere in the breast or nodal basin. Kaplan-Meier methods were used to estimate survival functions and exact 95% confidence intervals are reported.
Between 2003 and 2007, 71 women underwent IORT (median follow-up: 3.5 years). For patients with tumor-involved or close margins, additional therapy was required: 7 patients, total mastectomy; 11, whole breast radiation. Four women experienced invasive ipsilateral breast failures (1 new primary, 3 margin recurrences) for a 3-year local control rate of 49 of 53 (94.8%; 95% confidence interval 92.4% [95% CI] 84.2–98.3%), actuarial three-year in breast recurrence was 8% (95% CI 2–18%), and breast cancer-specific survival was 100%.
Intraoperative radiotherapy delivered to an in situ tumor is feasible, but our local control rate at 3.5 years is concerning. Possible changes to this technique to improve local control rates include better preoperative imaging (MRI), routine intraoperative ultrasound, and improved IORT delivery (larger cone, increased dose).
- 16.Kimple RJ, Klauber-DeMore N, Kuzmiak CM, Pavic D, Lian J, Livasy CA, et al. Cosmetic outcomes for accelerated partial breast irradiation prior to surgical excision of early stage breast cancer using single dose intraoperative radiotherapy. Int J Radiat Oncol Biol Phys. 2010 [Epub ahead of print].Google Scholar
- 21.Smith TE, Lee D, Turner BC, Carter D, Haffty BG. True recurrence vs. new primary ipsilateral breast tumor relapse: an analysis of clinical and pathologic differences and their implications in natural history, prognoses, and therapeutic management. Int J Radiat Oncol Biol Phys. 2000;48:1281–9.PubMedCrossRefGoogle Scholar
- 24.Wazer DE, Kaufman S, Cuttino L, DiPetrillo T, Arthur DW. Accelerated partial breast irradiation: an analysis of variables associated with late toxicity and long-term cosmetic outcome after high-dose-rate interstitial brachytherapy. Int J Radiat Oncol Biol Phys. 2006;64:489–95.PubMedCrossRefGoogle Scholar
- 27.Holmes DR, Baum M, Joseph D. The TARGIT trial: targeted intraoperative radiation therapy versus conventional postoperative whole-breast radiotherapy after breast-conserving surgery for the management of early-stage invasive breast cancer (a trial update). Am J Surg. 2007;194:507–10.PubMedCrossRefGoogle Scholar
- 29.Reitsamer R, Peintinger F, Kopp M, Menzel C, Kogelnik HD, Sedlmayer F. Local recurrence rates in breast cancer patients treated with intraoperative electron-boost radiotherapy versus postoperative external-beam electron-boost irradiation. A sequential intervention study. Strahlenther Onkol. 2004;180:38–44.PubMedCrossRefGoogle Scholar