J J Krawczyk1, B Engel. 1. Department of Radiation Oncology, Allan Blair Cancer Centre, Regina, Saskatchewan, Canada.
Abstract
PURPOSE: To evaluate the role of surgical clips in the planning of tangential beams in patients undergoing breast conserving surgery and adjuvant radiotherapy. METHODS AND MATERIALS: Between September 1996 and April 1998, 25 consecutive female patients with ductal carcinoma in situ, Stage I and II cancer of the breast, underwent lumpectomy with the excision cavity marked by the surgical clips. Subsequently, tangential fields were planned using clinical and radiologic information obtained during simulation without the clips position being visible. RESULTS: When measured from the center of the deepest clip to the posterior field border of the tangential fields in 6/25 patients (24%) the distance was less than 2 cm, with the closest being only 0.5 cm. Respective measurements for the distal end of the clip and the posterior border were: 9/25 patients (36%); less than 2 cm, with the closest distance of 0.3 cm. There was a positive correlation between the distance from the scar to the palpable breast border and the distance between the deepest clip and the posterior border of the tangential beams. CONCLUSION: The lumpectomy scar is often a poor indicator of the excision cavity as demarcated by surgical clips. Without the clips, part of the cavity may be underdosed by the tangential radiation beams. This is more likely for the cavities located close to the lateral or medial border of the breast tissue.
PURPOSE: To evaluate the role of surgical clips in the planning of tangential beams in patients undergoing breast conserving surgery and adjuvant radiotherapy. METHODS AND MATERIALS: Between September 1996 and April 1998, 25 consecutive female patients with ductal carcinoma in situ, Stage I and II cancer of the breast, underwent lumpectomy with the excision cavity marked by the surgical clips. Subsequently, tangential fields were planned using clinical and radiologic information obtained during simulation without the clips position being visible. RESULTS: When measured from the center of the deepest clip to the posterior field border of the tangential fields in 6/25 patients (24%) the distance was less than 2 cm, with the closest being only 0.5 cm. Respective measurements for the distal end of the clip and the posterior border were: 9/25 patients (36%); less than 2 cm, with the closest distance of 0.3 cm. There was a positive correlation between the distance from the scar to the palpable breast border and the distance between the deepest clip and the posterior border of the tangential beams. CONCLUSION: The lumpectomy scar is often a poor indicator of the excision cavity as demarcated by surgical clips. Without the clips, part of the cavity may be underdosed by the tangential radiation beams. This is more likely for the cavities located close to the lateral or medial border of the breast tissue.