ductal carcinoma in situ ( dcis ) is a noninvasive cancer that can be an obligate precursor of invasive ductal carcinoma ( idc ) .   since the early 1990s , reported survival outcome for dcis is equivalent for breast conserving surgery ( bcs ) versus mastectomy     [ 1 , 2 ] . bcs is an oncoplastic procedure , in that its goal is to remove all dcis , including a circumferential margin of noncarcinomatous tissue , commensurate with preserving as much of the normal breast tissue and appearance as possible . while there is no consensus on a safe margin width in breast conservation therapy , margins may be categorized as positive if directly involved with cancer cells , as inadequate if less than 1 - 2  mm , and as negative if greater than 10  mm . multiple studies have shown that ipsilateral breast tumor recurrence ( ibtr ) is associated with positive margins in patients undergoing bcs     [ 46 ] . most recently , the early breast cancer trialists ' collaborative group concluded that the avoidance of four local recurrences would avoid breast cancer - related death     . thus , obtaining appropriate surgical margins is of paramount importance in determining long - term outcome . margin width is also one of four critical factors employed in the usc / van nuys prognostic index ( uvpni : age , lesion size , margin width , and pathologic classification ) as a means of appropriately stratifying patients with dcis into three separate treatment categories . the uvnpi identifies those patients who may be treated without radiation and those who may require mastectomy . while based on a prospective non - randomization of patients , the uvpni provides guidelines to improve patients ' prognostic indices with additional surgery that increases margin width . margin width is the only modifiable factor that may obviate the need for radiation and reduce the risk of recurrence .   in an attempt to minimize the need for re - operation and maintain anatomic accuracy , many surgeons now obtain  additional margins  ( bcs - am ) at the time of the initial surgery by shaving off a thin layer of tissue inside the surgical cavity in one or all of the six dimensions . the efficacy of this approach in preventing re - excision and ibtr for idc and dcis has been addressed in several studies     [ 914 ] . the added benefit of re - excising additional tissue at the time of initial surgery is the certainty of the location of the additional tissue in relation to the index cancer . the purpose of this paper is to compare bcs and bcs - am procedures with respect to rates of re - excision for dcis based on our institutional experience . institutional review board approval was obtained to query the department of pathology database for all patients who underwent surgical management for dcis from january 2004 to september 2008 , with all cases reviewed by a single pathologist ( b. singh ) . the reports were reviewed for demographic , surgical , and histopathologic data , as well as reoperations . a group of 405 patients were retrospectively identified using patient records as having undergone surgical management for dcis at our institution .   in 201 patients ( 50% ) , standard bcs was performed ( without removal of am ) ; in 151 patients ( 37% ) , bcs - am was performed ( figure 1 ) , the remaining 53 patients ( 13% ) underwent total mastectomy ( tm ) as their initial surgical management . however , the first four surgeons performed 86.6% of the surgical procedures in the study . since the other nine surgeons did not perform a minimum of 30 surgeries , have a minimum cell size of five for bcs and bcs - am surgeries , or perform a minimum of 10% of the surgeries in the total sample , we did not compare their surgical techniques . the four surgeons abstracted their patient charts for : ( 1 ) indications for surgery , including a palpable mass , calcifications , and mammographically or mri - detected lesions , ( 2 ) surgical technique : localization wire or bracket and ( 3 ) indications for re - excision : mass , residual calcifications , or residual dcis close to margins ( table 1(b ) ) . in general , sentinel axillary node dissection with or without formal axillary nodal dissection is not performed for cases of dcis , as it is presumed to be localized disease . for non - palpable lesions , a modified kopans hook wire localizes the lesion in 2 views ( including after a sonographic localization ) and is performed in the department of breast imaging by the radiologist .   in the resection of superficial lesions , an ellipse of skin is included , and , for deep lesions close to the chest wall , fascia is included . intraoperatively , at least a 1 cm rim of normal tissue in all directions is taken . the margins are marked accordingly with a long suture denoting the lateral margin and a short suture denoting the superior margin . a confirmatory digital specimen x - ray is taken in 2 views and the films are reviewed intraoperatively by the surgeon . the specimen the breast imager subsequently reviews the specimen film . at the discretion of the surgeon , they are oriented using a suture to mark the new true margin and secured to a telfa pad and sent to pathology as a fresh specimen . for palpable lesions , excisions are performed with estimated margins of at least 1  cm and suture tagged for orientation . when any margin is measured in the pathology laboratory on immediate inspection as closer than the desired 1  cm , an additional segment is excised from the excision bed at that site . nonpalpable lesions , including microcalcifications and/or biopsy clips , are excised with hook wire localization and specimen radiographic control to insure complete excision . the hook wire localizer provides additional orientation , and any margins estimated as close on specimen radiography , or by direct inspection for mass lesions or clips in the pathology laboratory , are treated by additional excision of the appropriate cavity margin sites . for a palpable mass , the lesion is excised with an approximate 1  cm margin of normal tissue , then the specimen is examined for adequacy of margins and oriented with sutures . additional margins are routinely excised , the extent of which is influenced by the original specimen . superior , medial , inferior , lateral , anterior , and posterior margins are excised , oriented with sutures to indicate new margin , and sent individually fresh to pathology . for radiologic - detected disease , following needle localization of a mass lesion , calcifications or a clip , if the lesion is superficial , an ellipse of overlying skin is removed ; the pectoralis fascia is usually taken as the deep margin . then , additional margins are routinely excised and sent to pathology , with the extent of excision based on inspection of the specimen and the specimen radiograph . if the radiologic abnormality is not included in the needle - localization specimen , or only partially included , the surgical site is first re - excised and the new specimen x - rayed . if this includes the lesion , routine margins are then sent as above . using a 10-blade scalpel , the segment of breast tissue containing the lesion ( palpable or area localized by a hook wire ) is excised with 1  cm margins of grossly uninvolved tissue and oriented with sutures . a babcock clamp and 10-blade scalpel are then used to obtain additional margins of at least 1  cm in the superior lateral , inferior medial , anterior , and posterior planes . for lesions subadjacent to the skin , deep lesions lying on the pectoralis major fascia are excised en bloc with the underlying fascia . a thin superficial layer of underlying muscle is obtained to augment the deep posterior surgical margin . the excision specimens were measured in three dimensions and oriented , and six aspects were inked with different colored inks that can withstand histological processing . the specimen was serially sectioned along the long axis , and biopsy site and clip , if present , were identified . additional margin specimens were measured in three dimensions and oriented with one suture identifying the true margin , which was typically inked black , with the opposite margin inked blue . volume of each specimen was calculated by multiplying the three dimensions of each specimen , noted on gross examination . the extent of dcis was reported as the number of slides with dcis and total number of slides for the case . if dcis was present > 10  mm from a margin , it was considered negative and this distance was not reported in the final pathology report . if dcis was < 10  mm from a margin , the closest distance to the margin was reported . microscopic examination of dcis included assessment of   morphologic subtype , nuclear grade , necrosis , multifocality , and calcifications . multifocality is defined as presence of dcis in a section prepared from more than one block of the specimen , which is the standard definition used by nsabp     . the volume of   dcis was assessed on microscopic examination as number of slides with dcis over the total number of slides . immunohistochemical stains for estrogen receptor ( er ) ( sp1 antibody , ventana ) and progesterone receptor status ( pr ) ( 1e2 , ventana ) were performed for all cases and reported as a percentage . the final pathology report included a summary of pathological variables , including the margin status and   biomarkers ( er and pr ) . patients who underwent bcs ( n = 201 ) , bcs - am ( n = 151 ) , or tm ( n = 53 ) for dcis between 2004 and 2008 at nyumc were compared by clinicopathological variables and were found to be similar in age , grade and size of dcis , necrosis , multifocality , calcifications , and er / pr status ( table 1(a ) ) . patients who underwent bcs - am instead of bcs had a 10% lower incidence of positive or < 1  mm margins ( p < .05 ) and a 24% higher incidence of widely negative margins ( > 10  mm ; p < .05 ) .   accordingly , rates for re - excision were significantly ( p < .0001 ) lower in the bcs - am cohort compared to the bcs alone ( bcs - am : 40% , bcs : 64% ) . residual dcis in re - excision specimens was also significantly lower ( p < .05 ) when am was obtained ( bcs - am : 22% , bcs : 32% ) . residual dcis was found in roughly half of the re - excisions for the bcs group ( 50% ) compared to the bcs - am group ( 54% ) , which is statistically significant ( p < 005 ) . seven variables ( necrosis , multifocality , calcification , er , pr , total volume , bcs , or bcs - am ) and their cross - products with bcs / bcs - am ( six more variables ) were analyzed to see which could be used to predict the response variable , the probability that re - excision surgery will need to be performed ( table 2(a ) ) . the optimal model ( p  .0001 ) for this response variable was found by comparing a series of reduced multivariate logistical regressions using g test statistics and log likelihoods . after completing this analysis , the optimal model to predict the probability of the occurrence of a re - excision surgery contained four significant predictors : bcs / bcs - am ( p  .0001 ) , multifocality ( p = .0002 ) , total volume ( p = .0284 ) , and er ( p = .0382 ) ( these p values come from the parameter estimates in the optimal reduced model ) ( table 2(b ) ) . the variables necrosis ( p = .5300 ) , calcification ( p = .8007 ) , and pr ( p = .9952 ) were found to be insignificant predictors and were , therefore , not in the optimal model ( these p values come from the parameter estimates in the original full model ) . for both the bcs and the bcs - am cohorts , volume of tissue excised is inversely correlated to the rate of re - excision ( table 3 ) .   in the bcs group , patients with and without re - excision had total volumes of 77.8  cm and 100.3  cm , respectively , ( p = .067 ) . patients who underwent bcs - am with and without re - excision had total volumes of 98.7  cm and 127.2  cm , respectively , ( p = .281 ) . the volume of additional margins with and without re - excision was 28.9  cm and 26.3  cm , respectively ( p = .44 ) . the volume of excision for all patients who did not undergo re - excision was 114.96  cm and those who did was 79.6  cm . using a two sample t - test , a significant difference in total volume was found when comparing bcs and bcs - am surgery ( p = .0003 ) . furthermore , when comparing surgery type with respect to re - excision rates using a series of two - sample t - tests , a significant difference in volume size was found between bcs surgery that required re - excision surgery and bcs - am that did not require re - excision surgery ( p  .0001 ) .   a subset analysis of patients with positive or close margins ( < 1  mm ) only found the volume of excision specimen not statistically significant ( p = .713 ) . the patients were stratified by margin status , regardless of the procedure performed , to examine the relationship between negative margins and total volume ( table 4 ) . the five margin size categories ' total volumes were compared using a series of two - sample t - tests .   a significant difference in total volume was observed when comparing positive margins with all the other margin sizes . in this analysis , widely negative margins ( > 10  mm ) correlated with the highest average total excision volume ( 130.4  cm ) and positive margin status correlated with the lowest ( 61.2  cm ) average total excision volume . width of margin , represented by five different groupings ( positive , 1 - 2  mm , 35  mm , 69  mm , negative ) , and total excisional volume were linearly related ( r = 0.931 ) . individual surgeons were also compared to determine if variation in surgical techniques ( bcs and bcs - am ) was a significant variable for rate of re - excision . nine surgeons did not perform a minimum of 30 surgeries , have a minimum cell size of 5 for bcs and bcs - am surgeries , or perform a minimum of 10% of the surgeries in the total sample . to keep the statistical power of the anova and the chi - squared test high ( 1- > 0.8 ) , the surgeons ' techniques were compared by individual re - excision surgery rates relative to three major variables : type of surgery ( bcs / bcs - am ) , total volume , and margin size . the rate of re - excision surgery after bcs ( p = .141355 ) and bcs - am ( p = .186487 ) was compared using the chi - squared test and no significant difference was demonstrated among the surgeons ( table 5(a ) ) . for specimens that required a re - excision , the specimen volumes for each surgeon were compared using a one - way analysis of variance test , and no significant difference was found between the surgeons ( p value of f statistics = .156 ) ( table 5(b ) ) . individual surgeon 's rate of re - excision surgery was compared by margin size ( table 5(c ) ) . each surgeon was compared to the three other surgeons using chi - squared tests or f statistics from an anova , and no significant difference was found . in this study , we evaluated the efficacy of simultaneous additional margin excision at the time of initial bcs in reducing the rate of surgical re - excision . our data show that bcs - am , compared to bcs , had a 10% lower incidence of positive or < 1  mm margins ( p < .05 ) and a 24% higher incidence of widely negative margins ( > 10  mm ; p < .05 ) . accordingly , rates for re - excision were significantly ( p < .0001 ) lower in the bcs - am cohort than the bcs alone ( bcs - am : 40% , bcs : 64% ) . statistical analysis revealed multifocality ( p = .0002 ) , total volume ( p = .0284 ) , and er ( p = .0382 ) to be significant predictors of re - excision in our population .   in this study , total excision volume correlated with margin width regardless of procedure and variation in surgical technique and was inversely correlated with re - excision rate for both bcs and bcs - am . in cases of re - excision , the total volume of tissue excised with bcs - am is higher than that with bcs , and the dataset is limited in this regard . , our analyses emphasize the importance of total excision volume in successful bcs procedures and validate bcs - am as an effective means of retaining anatomical accuracy and reducing the incidence of a second re - excision procedure . the major concern in the management of patients in our setting was the need for subsequent excision where margin widths were neither widely negative ( > 10  mm ) nor definitively positive ( < 1  mm ) . the decision to re - excise in these cases was the presence of dcis in the vicinity of the margin for all four surgeons and was performed without exception for margins < 1  mm .   despite a generally uniform approach to the bcs and bcs - am technique at our institution , we recognize that surgeon variability is a potential confounder in our study .   to address this , we compared the four major surgeons involved in our case cohort ( representing 87% of cases ) and found they were not statistically different with respect to our outcome measures . taking additional margins provides a technical benefit to the pathologist . additional margins provide more accurate spatial orientation of the surgical specimen compared to inking by a pathologist , as the in situ anatomy is at variance from the   excision specimen . there are also instances in which inked specimen margins provide false negative data that an additional margin would in effect correct .   a recent study by povoski et al . found that half of their additional margin specimens that were positive for carcinoma ( 13/24 ) had a negative excision specimen . we also , however , noted the reverse effect in our study , as did cao et al .     , in which a re - excision performed for a positive margin was negative in a number of cases . some possible explanations for this include small residual tumor volume , tissue necrosis at the new margin , or tissue friability as a result of processing . interestingly , rizzo et al . did not find additional margin sampling to be significantly burdensome or costly to pathologists . additional margins should represent entire aspects of the excision cavity ; however , currently , there is no reproducible and effective method to ascertain spatial accuracy of additional margins . the inclusion criteria ( indication for surgery , e.g. , palpable mass , non - palpable mass , calcifications , mammographic , sonographic , or mri lesion ) were not controlled for . in addition , our study does not provide long - term followup and outcome ; thus , we can not comment on how bcs and bcs - am compare with respect to disease - free survival . shaving additional margins for excision of invasive and noninvasive carcinoma has already been shown to be effective in reducing re - excision rates and reducing margin positivity for early stage breast cancer     [ 9 , 1115 ]   cao and colleagues      retrospectively examined 126 patients with either dcis ( n = 23 ) or idc ( n = 103 ) , all of whom underwent bcs - am surgery that was similar in methodology to our series ( figure 1 ) .   among their patients , 103 had excisional specimens with histologically positive margins ; yet , of these patients , only 52 ( 50.5% ) had detectable carcinoma present on the additional margins . the investigators identified two pathological features , namely ,  large tumor size  and  presence of a dcis component  as significantly correlated with histologically positive lumpectomy margins ( in which carcinoma is < 2  mm from surface ) . by examining the pathology from both the original lumpectomy margins and the additional margins , they determined that 59% of margins were histologically negative as a direct result of removing additional margins . a study by janes and colleagues   found   similar efficacy in the surgical approach , linking   systemic superior and inferior cavity shavings ( ssics ) to reduction in   close margins and re - excision rates . ssics is a technique identical in principle to the  additional margins  approach employed in our study . the first ( n = 106 ) was a group with idc or dcis who underwent bcs , followed by pathological examination of the specimen . if margins were deemed < 10  mm , then additional margins were removed as needed .   in the second group , patients underwent ssics initially . the group receiving ssics had a reduced rate of close margin ( 18/106 versus 8/111 or 17% versus 7% ) and a reduced rate of re - excision . several other retrospective analyses are notable as well . in a separate retrospective study , huston et al .      divided a group of 171 patients with idc / dcis into three subdivisions , based on number of additional margins obtained ( 46 , 13 , and 0 ) , and compared their respective rates of re - excision . re - excision was performed if any margin was found to contain carcinoma within 2  mm of its border edge . they found that the group with 46 margins had a reoperative rate of 17.7% compared with 32.5% and 38.7% for the other two , respectively . interestingly , the three groups also had different volumes , correlating with the reoperative rates , as was the case in our data ( 129.19  cm , 46.04  cm , and 37.44  cm , resp . ) in another analysis of 125 dcis and idc lumpectomy specimens , jacobson et al . report that by taking additional margins re - excision was avoided in 49% of their patients for whom it otherwise would have been necessary     . rizzo and colleagues reported 320 patients who underwent bcs ( n = 199 ) or bcs - am ( n = 121 ) for either dcis or idc and observed an increase in negative margins ( 85.1% from 57.2% ) and a decrease in re - excisions with additional margins . this study did not find the effect to be significant for dcis when it was analyzed separately .   as discussed above , prior reports suggest that excising additional margins reduces both positive margin status and rate of re - excision for idc and idc with a dcis component . our data suggest that this effect is also true for cases of pure dcis and that the approach is successful because of higher overall excision volumes . the importance of this finding is highlighted by the published literature linking volume of excision to rates of recurrence . a report by vicini et al . reviewed 146 patients who received bcs for dcis and used a multivariate analysis to identify factors associated with reduced local recurrence . similarly , hwang et al . found that elderly patients with dcis seen at their institution were more likely to have large volume excisions as compared to younger patients . they propose this as one possible reason for lower recurrence rates in the elderly group     . surgeons may be more reluctant to excise larger volumes of tissue in younger patients with dcis because of potential cosmetic deformity . our studies found multifocality to be strongly associated with re - excision in agreement with the national surgical adjuvant breast and bowel project ( nsabp b-17 ) , in which multifocality was predictive of positive margins     . dcis is generally not a palpable lesion , making multiple foci more challenging to identify during surgery , even with wire - guided radiological assistance . these multiple foci may represent an artifact of pathological processing , where a three - dimensional disease process is visualized in a two - dimensional format . multiple foci of dcis in the same quadrant probably represent the same genetic profile , as has been demonstrated for invasive carcinoma     . our data suggest that excising additional margins for dcis increases the total average excision volume and decreases the incidence of re - excision .
purpose . 
 the purpose of this study was to compare the surgical and pathological variables which impact rate of re - excision following breast conserving therapy ( bcs ) with or without concurrent additional margin excision ( am ) . 
 methods . 
 the pathology database was queried for all patients with dcis from january 2004 to september 2008 . 
 pathologic assessment included volume of excision , subtype , size , distance from margin , grade , necrosis , multifocality , calcifications , and er / pr status . results . 
 405 cases were identified and 201 underwent bcs , 151-bcs - am , and 53-mastectomy . among the 201 bcs patients , 190 underwent re - excision for close or involved margins . 
 129 of these were treated with bcs and 61 with bcs - am ( p < .0001 ) . the incidence of residual dcis in the re - excision specimens was 32% ( n = 65 ) for bcs and 22% ( n = 33 ) for bcs - am ( p < .05 ) . 
 for both the bcs and the bcs - am cohorts , volume of tissue excised is inversely correlated to the rate of re - excision ( p = .0284 ) . 
 multifocality ( p = .0002 ) and er status ( p = .0382 ) were also significant predictors for rate of re - excision and variation in surgical technique was insignificant . 
 conclusions . 
 the rate of positive margins , re - excision , and residual disease was significantly higher in patients with lower volume of excision . 
 the performance of concurrent additional margin excision increases the efficacy of bcs for dcis .