Effect of Margin Status on Local Recurrence After Breast Conservation and Radiation Therapy for Ductal Carcinoma In Situ

Abstract

Surgical margins negative for DCIS should be obtained after BCS for DCIS. A margin threshold of 2 mm seems to be as good as a larger margin when BCS for DCIS is combined with RT.

Prognostic markers and long-term outcomes in ductal carcinoma in situ of the breast treated with excision alone

“…This underscores the necessity for accurate size measurement of DCIS. Cao et al 21 showed that larger tumors were more likely to have positive lumpectomy margins, and Dunne et al 22 showed the significance of margin status on local recurrence.…”

Therapeutic analysis of Intrabeam‐based intraoperative radiation therapy in the treatment of unicentric breast cancer lesions utilizing a spherical target volume model

“…A study by Silverstein et al21 had demonstrated that the likelihood of local recurrence in patients that were not treated with adjuvant radiotherapy decreased as tumor‐free surgical margin increased. Another study by Dunne et al demonstrated that a 2 mm margin was superior to a margin less than 2 mm, but there was no significant difference seen with a greater than 5 mm margin 22. Other studies have made similar conclusions 22.…”

“…Another study by Dunne et al demonstrated that a 2 mm margin was superior to a margin less than 2 mm, but there was no significant difference seen with a greater than 5 mm margin 22. Other studies have made similar conclusions 22. These studies have also shown that ductal carcinoma in situ (DCIS) is almost always unicentric, the lesions seen in clinic are often large, and they present locally and lack stromal invasion and distant metastases.…”

“…Also, a uniform cancer cell distribution seems unlikely given the clinical findings that the recurrence rate decreased with an increase in surgical margins and drastically declined at 2 mm margin 21, 22. In addition, a half‐Gaussian distribution is simple and it also follows the IB‐IORT dose fall‐off, therefore it is speculated that the cancer cell killing and normal tissue sparing would benefit from the IB‐IORT dose fall off with this pattern, since the region with the largest cancer cell burden will get the largest dose for intensive killing.…”

Local and Systemic Outcomes in DCIS Based on Tumor and Patient Characteristics: The Radiation Oncologist's Perspective

“…At present, young age per se should not be a contraindication for BCT, especially because it is unknown whether these patients have a superior long-term prognosis if treated by mastectomy. Local recurrences followingboth skin sparing and simple-mastectomy after DCIS are reported and also seem to occur particularly in younger women (12,13).Numerous studies have shown an increased risk of local recurrence when DCIS was excised with doubtful or involved margins (2,6,7,14,15). Various thresholds have been reported as a safe margin status, from "the inked margin not being involved with DCIS," to ≥1, 2, 3, or 5 mm, or even ≥1 cm.…”