Accelerated partial breast irradiation with interstitial brachytherapy as the sole modality of radiation for women with low risk early stage breast cancer
10661 Purpose: The aim of the study is to evaluate the safety and feasibility of radical brachytherapy for accelerated partial breast irradiation (APBI) and to study the outcome with respect to local control and survival. Materials and Methods: During May 2000 to December 2004, 115 women participated in the ongoing prospective study of APBI using interstitial brachytherapy as the sole modality of radiation for early breast cancer. Women with age > 40 years, single tumour up to 3 cm without diffuse microcalcification and clinically negative axilla were considered suitable. Brachytherapy was done either intraoperatively during the breast conserving surgery or postoperatively using 2–4 planes. Tumor bed demarcation was done with radiopaque clips placed during surgery, CT scans, ultrasonography and/or fluoroscopy. Cavity with 1cm margin was treated based on orthogonal pair of X rays to a dose of 34 Gy in 10 fractions over 1 week with twice daily fractionation using high dose rate iridium source. Results: Implant was done postoperatively in 35 patients while in remaining patients it was done intraoperatively. Implant procedure was tolerated well by all the patients. In 8 patients only 3 or 4 fractions of HDR Brachytherapy were delivered and this was followed by 45 Gy/25 # whole breast radiation therapy for following reasons: positive nodes (4), EIC positive (3) and poor implant coverage (1). At a median follow up of 23 months, the actuarial local control rate is 100%. Three year actuarial disease free survival is 93% while the overall survival is 100%. Complications included fat necrosis in 5 and wound gape in 4 patients. Cosmesis was good to excellent in 60% of the patients. Conclusion: In this ongoing prospective study, APBI using radical interstitial implant was well tolerated and appears to be safe and feasible in appropriately selected patients. Further follow up is needed for confirm the long term safety of the procedure. No significant financial relationships to disclose.