BMC Cancer 2009, 9:254 http://www.biomedcentral.com/1471-2407/9/254 As with any proposed technique, no universal consensus has been reach on the efficacy of performing gross intra- operative examination of the BCS margins and selective immediate intraoperative re-excision of BCS margins that are thought to represent suspicious or compromised mar- gins. Although this assessment technique for surgical resection margins varies to some degree between reported series, it is primarily based upon the gross visual inspec- tion of the intact BCS specimen as well as gross visual inspection the cut surface of inked, non-fixed, sectioned BCS specimen at the time of BCS. In this regard, it is quite evident that one faction strongly favors its use [45] while another faction does not [46]. Fleming et al [45] have previously reported that "intraop- erative macroscopic margin assessment" is an effective technique for reducing the number of second operations in patients undergoing BCS for primary invasive breast cancer. They demonstrated that only 9.1% (20/220) of patients required a second operation when "intraopera- tive macroscopic margin assessment" was utilized as com- pared to 21.4% (47/220) of patients would have required a second operation if "intraoperative macroscopic margin assessment" had not been utilized. However, interest- ingly, in their study, only 19.8% (16/81) of patients that had macroscopically suspicious or compromised margins (as they defined as suspected tumor grossly/macroscopi- cally within 10 mm of any given gross/macroscopic mar- gin) at the time of the initial BCS surgery in which they then performed further selective immediate intraoperative re-excision of BCS margins actually had a final histologic- confirmed positive margin status on the original BCS specimen (as they defined as invasive carcinoma or DCIS at a distance of less than 5 mm from the microscopic mar- gin on permanent histopathology). In such series as Flem- ing et al [45], as well as others [33,45,52,54,79,80] that routinely advocate very wide microscopic margins of at least 5 mm on permanent histopathology to define a mar- gin status as negative, the utilization of our proposed nine standardized re-resection margins technique for the BCS resection bed cavity would have allowed those surgeon to consider far less extreme criteria for a negative margin sta- tus on the BCS specimen itself and may have provided them with more confidence that complete tumor excision had been successfully accomplished. In contract, Balch et al [46] have previously reported that "intraoperative gross examination" of surgical resection margins was not particularly useful for patients undergo- ing BCS for breast cancer. In their study, they reported that only 32.6% (46/141) of patients that had grossly suspi- cious or compromised margins (as they defined as sus- pected tumor grossly/macroscopically within 5 mm of any given gross/macroscopic margin) at the time of the initial BCS actually had final histologically positive mar- gins on the original BCS specimen (as they defined as invasive carcinoma or DCIS at a distance of within 2 mm from the microscopic margin on permanent histopathol- ogy). Additionally, they reported that "intraoperative gross examination" of surgical resection margins did not accurately reflect the margin status since 28.1% (18/64) of patients with final histologically positive margins (as they defined as invasive carcinoma or DCIS at a distance of within 2 mm from the microscopic margin on permanent histopathology) were initially thought to have grossly tumor-free margins (as they defined as no suspected tumor grossly/macroscopically within 5 mm of any given gross/macroscopic margin). Therefore, they recom- mended consideration of other potential techniques for intraoperative evaluation of surgical resection margins to attempt to reduce the need for a subsequent re-excision in patients undergoing BCS. For the assessment of surgical resection margins on the BCS specimen itself, it is pertinent for us to discuss and contrast the use of the "tangential shaved margins" tech- nique [9,55,59,81] versus that of the currently more widely accepted "perpendicular margins" technique (i.e., "radial margins" technique). In our series, the assessment of the surgical resection margins on the BCS specimen itself was performed by obtaining perpendicular sections along the entire long axis length of the BCS specimen, thus recognizably representing a rather limited sampling of the total margin surface of the BCS specimen. With the "perpendicular margins" technique on the BCS specimen itself, it is only when tumor cells are present at the inked edge of a particular perpendicular section being micro- scopically examined that the surgical resection margin is considered positive. The major advantage of this "perpen- dicular margins" method is that the relationship and accu- rate measurement of the distance between the tumor and the surgical resection margin surface of the BCS specimen itself can be microscopically evaluated. Alternatively, sur- gical resection margins on the BCS specimen can be assessed by utilizing the so called "tangential shaved mar- gins" technique [9,55,59,81]. In this method, the surface of the BCS specimen itself is either shaved [55,59,81] or peeled [9], and the resulting thin tissue sections are placed flat in cassettes for embedding, resulting in tangentially sectioned surfaces for microscopic margin assessment. With the "tangential shaved margins" technique, the pres- ence of any tumor cells within an examined section is grounds for interpretation as a positive surgical resection margin status. Because one is actually tangential section- ing into the periphery of the BCS specimen itself with the use of the "tangential shaved margins" technique, a meas- urement of the actual distance between the tumor and the surgical resection margin surface of the BCS specimen itself can not be accurately determined. Nevertheless, major advantage of this "tangential shaved margins" tech- Page 17 of 23 (page number not for citation purposes)