Abstract P5-15-09: A new method for marking the lumpectomy cavity during oncoplastic surgery and breast conservation

Abstract

Abstract Background: Oncoplastic surgery has dramatically improved patient outcomes following breast conservation, however, most patients require adjuvant radiation therapy following surgery. Adjuvant radiation is essential in order to decrease local recurrence rates, yet marking and identifying the exact location of the tumor bed that requires radiation remains challenging. This is particularly true when oncoplastic surgery is used to bring local tissue flaps into the area in order to reconstruct the defect created by surgical excision. Many surgeons currently place clips at various positions within the cavity in order to help define the target area. Alternatively, if no clips are placed, postoperative tissue changes visible on CT scan are used to determine the target location. Unfortunately, both of these current methods are imprecise and can be misleading for radiation treatment planning resulting in over or under estimation of the planned treatment volume. Given the shortcomings of current methods for targeting the lumpectomy cavity, we evaluated the utility of a new 3-dimensional bioabsorbable tissue marker as a more standardized approach. Methods and Materials: 40 patients with Stage I or II breast cancer were implanted with the BioZorb™ tissue marker (Portola Valley, CA) during partial mastectomy. All patients had pre-operative staging to insure they were appropriate candidates for breast conservation. Following excision of the tumor, a BioZorb tissue marker was sutured into the cavity. In some cases, oncoplastic techniques (including mobilization of glandular flaps) were used to reconstruct the defect from the partial mastectomy. The flaps were sutured through and around the BioZorb. In other cases, the walls of the lumpectomy cavity and the overlying tissue flaps were sutured to the BioZorb as a structural element. In all cases, the margins of the excision site were approximated to the edges or through the center of the tissue marker. Results: The surgical marker was easily inserted in all cases, and was clearly visualized with clinical imaging in all patients. Insertion did not interfere with surgical techniques, nor did it preclude concomitant surgical procedures such as wire localization, sentinel lymph node biopsy and/or breast reconstruction with oncoplastic techniques. Radiation treatment planning was easier and more precise based upon the visibility of the bioabsorbable and permanent components of the marker. The marker decreased boost volume significantly, and was particularly useful for radiation planning when there was no remaining seroma cavity at the surgical site. Conclusions: This novel 3-D bioabsorbable tissue marker reliably marked the area of surgical excision in a standardized fashion. Both the bioabsorbable and permanent clips within the marker are useful for radiation treatment planning and clinical follow-up of the surgical site. The marker was particularly useful in defining the surgical area when oncoplastic techniques were used to close the surgical cavity, and/or when no remaining seroma was present. This new method of marking the cavity allows for marked improvement in radiation treatment planning and may facilitate the use of advanced techniques in radiation delivery as well. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-15-09.