Impact of SSO-ASTRO Margin Guidelines on Re-excision Rate in Breast-conserving Surgery: A Single-center Experience

Breast-conserving surgery (BCS) has been historically linked with a high rate of re-excision. To address this issue, the Society of Surgical Oncology (SSO) and the American Society for Radiation Oncology (ASTRO) developed consensus guidelines in 2014 to standardize practices and improve clinical outcomes for BCS patients. In our tertiary cancer care hospital, we assessed the impact of these guidelines on the re-excision rate following BCS.

We conducted a retrospective study on breast cancer patients who underwent BCS at the Shaukat Khanum Memorial Cancer Hospital and Research Centre in Lahore, Pakistan. The study compared the re-excision rate before the implementation of the SSO-ASTRO consensus guidelines (November 2015-July 2017) and after the implementation (January 2018-August 2019). Margins were considered positive if "ink on tumor" was present and negative if "no ink on tumor" was present. Fisher's exact test or Chi-square test was used to compare the re-excision rates between the pre- and post-guideline periods.

A total of 919 patients were identified, with 533 from the pre-guideline period and 386 from the post-guideline period. Of the 919 patients, 31 with ductal carcinoma in situ (DCIS) were excluded from the re-excision analysis because the guidelines were not implemented on the DCIS. Furthermore, the overall rate of re-excision in our data was 4.3%. The re-excision rate decreased from 71.1% to 28.9% (P ≤ 0.05) following the adoption of the guidelines. We observed a statistically significant decrease in the re-excision rate after implementing the SSO-ASTRO guidelines.

Implementation of the SSO-ASTRO margin guidelines led to a notable decrease in the overall re-excision rate in our data set. These findings suggest that continued adherence to the guidelines may lead to a further reduction in the re-excision rate in the future.