with the widespread use of screening mammography , the incidence of dcis in the usa has exponentially increased over the past 30 years . in 1983 , 4800 cases were diagnosed , and in 2011 the incidence had increased to an estimated 57,650 cases . currently , in the usa approximately one quarter of breast cancers are noninvasive at diagnosis . the surgical treatment for ductal carcinoma in situ ( dcis ) includes breast conserving surgery ( bcs ) with or without adjuvant radiation therapy and mastectomy . for an increasing proportion of patients with dcis , breast conserving therapy nevertheless , there are approximately 30% patients in the united states who undergo mastectomy for a variety of reasons that include an inability to obtain clear margins after multiple excisions , the presence of diffuse microcalcifications suspicious for malignancy , brca mutation carriers , history of collagen vascular disease , and personal preference [ 25 ] . although no prospective randomized trials comparing mastectomy to breast conserving therapy have been completed , the mortality using either treatment is low and the 10-year survival exceeds 95% . local recurrence following mastectomy is not a common event with estimated recurrence rates in range of 1 - 2% [ 57 ] . the aim of this study was to identify the overall incidence of relapse and risk factors for local recurrence , and accordingly for whom adjuvant treatment including postmastectomy radiation therapy may be considered . in addition , this paper includes a review of the literature with a focus on local regional relapse with respect to surgical margins after mastectomy . this is an irb approved retrospective review of a prospectively maintained breast cancer database on patients treated at the cancer center at beth israel medical center and roosevelt hospital . between 1997 and 2010 , 969 patients with the diagnosis of dcis were identified in the database . among these 207 patients therefore , 211 breasts ( in 207 patients ) treated with mastectomy constitute the study group . patients with new diagnosis of dcis or concomitant dcis and lobular carcinoma in situ ( lcis ) were included . all clinical and histopathology characteristics were obtained from the database , cross - referenced with patient charts , and pathology reports were studied . the median age at diagnosis was 50 years ( ranging from 25 years to 88 years ) . in the majority of patients , the surgical procedures included mastectomy alone in 39 ( 18.5% ) cases and mastectomy with sentinel lymph node biopsy or axillary sampling in 172 ( 81.5% ) cases . nuclear grade 1 was noted in 22 patients , grade 2 in 97 patients , and grade 3 in 92 patients . resection margins were defined as clinically close and positive when dcis was noted 1  mm and was scored as negative in all other instances . among the study group 88.6% ( n = 187 ) had negative margins and 11.4% ( n = 24 ) had close or positive margins . 2 patients developed a local - regional recurrence at 8.2 years and 10.7 years after initial diagnosis . the recurrence had an invasive histology , and neither of these 2 patients had a skin sparing mastectomy . both these failures were among the group of mastectomies reported to have clinical close / positive margins . on further analysis , comparing the 187 patients with negative margins and 24 patients with close / positive margin status , there was a significant correlation with risk for local regional relapse ( p = 0.0125 , fisher 's exact test ) . following initial lumpectomy and reexcision that failed to yield clean margins , the patient underwent total mastectomy with sentinel lymph node biopsy . margin status confirmed dcis present at the anterior medial - superior margin , and within one millimeter of the anterior margin at the lower inner quadrant , and at the medial - inferior margin . she received no adjuvant therapies . in a 2007 , a follow - up patient who underwent genetic testing was diagnosed to be a brca mutation carrier . she was without evidence of disease and underwent prophylactic oopherectomy and contralateral mastectomy at the time . in 2010 , at a time interval of 8.2 years from initial diagnosis , she presented with a local recurrence at the superior lateral aspect of the reconstruction . at relapse , pathology confirmed dcis and invasive recurrence in an area where presumably breast tissue was left behind . in addition , metastases to 7 out of 9 axillary nodes with extracapsular extension were reported . following initial lumpectomy and reexcision that failed to yield clean margins , the patient underwent total mastectomy with sentinel lymph node biopsy . final pathology reported intermediate - grade dcis with associated comedo necrosis . margin status confirmed dcis present at the anterior medial - superior margin , and within one millimeter of the anterior margin at the lower inner quadrant , and at the medial - inferior margin . she received no adjuvant therapies . in a 2007 , a follow - up patient who underwent genetic testing was diagnosed to be a brca mutation carrier . she was without evidence of disease and underwent prophylactic oopherectomy and contralateral mastectomy at the time . in 2010 , at a time interval of 8.2 years from initial diagnosis , she presented with a local recurrence at the superior lateral aspect of the reconstruction . at relapse , the patient underwent wide local excision and axillary lymph node dissection . pathology confirmed dcis and invasive recurrence in an area where presumably breast tissue was left behind . in addition , metastases to 7 out of 9 axillary nodes with extracapsular extension were reported . her follow - up history is significant for the diagnosis of an early - stage cervical cancer that was treated surgically . in 2010 , at an interval of 10.7 years from initial diagnosis , the patient presented with ipsilateral supraclavicular metastasis . there was no evidence of metastatic disease on the ipsilateral chest wall , and the contralateral breast exam was clinically unremarkable . pathology confirmed the recurrence to be consistent with breast primary and dissimilar from the cervix . the patient was treated with arimidex for 18 months and then switched to faslodex . at the january 2012 followup her follow - up history is significant for the diagnosis of an early - stage cervical cancer that was treated surgically . in 2010 , at an interval of 10.7 years from initial diagnosis , the patient presented with ipsilateral supraclavicular metastasis . there was no evidence of metastatic disease on the ipsilateral chest wall , and the contralateral breast exam was clinically unremarkable . pathology confirmed the recurrence to be consistent with breast primary and dissimilar from the cervix . the patient was treated with arimidex for 18 months and then switched to faslodex . at the january 2012 followup in this retrospective series , very few patients had skin sparing mastectomy and majority of the patients had total mastectomy with lymph node sampling . currently , however , skin sparing mastectomy is one of the most commonly used techniques . this requires meticulous surgical expertise that preserves skin viability with complete removal of breast parenchyma . the best outcomes are expected with thin skin flaps that reduce the risk for residual breast tissue left behind . the approach of removing pectoralis fascia also minimizes the risk for residual breast tissue and close / positive margins of resection . studies on patients treated with skin sparing mastectomy yield no increased incidence of local recurrence with this technique compared to conventional mastectomy [ 12 , 17 ] . the relapses seen after breast conserving therapy in dcis have a 50 - 50 chance for being either of in situ or invasive histology . however , relapses after mastectomy are mostly invasive as observed in this study and other published reports [ 13 , 16 ] . the incidence of local - regional relapse rate we observed is similar to other reports in the literature table 2 . studied 80 dcis patients treated by mastectomy and < 10  mm surgical margin . with a median followup of 61 months , they reported 7.5% ( 6/80 ) rate of local recurrence . further , it was observed that 5 of these 6 recurrences occurred among the 31 patients with margins 2  mm compared to 1/6 failures among the 49 patients with greater than 2  mm negative margin . the study by chan et al .   included 193 patients with dcis treated with mastectomy . , 59 patients were identified to have < 5  mm clear margin or positive margin . the study by chan et al .   reported an overall recurrence rate of 1.7% among the 59 patients with a < 5  mm or positive margin following mastectomy . one of 19 patients ( 5% ) with margin < 1  mm had local relapse . on further review by nuclear grade only , they reported 3.3% crude risk of local recurrence among 30 patients who had a high nuclear grade . the study included patients with microinvasive dcis and paget 's disease associated with dcis . with a mean follow - up time of 4.5 years , they observed a relapse rate of 1.1% . carlson et al .   completed a retrospective review of 223 patients who underwent skin sparing mastectomy for dcis . with a followup of 82.3 months , a relapse rate of 5.1% ( n = 11 ) was reported . among this group , on univariate analysis , they showed that high tumor grade significantly influenced local relapse but surgical margin status did not reach statistical significance . one of the 2 local relapses we observed was in a patient who 5 years subsequent to the initial diagnosis and treatment was diagnosed to be a mutation carrier . the retrospective design of the study precluded any systematic evaluation of risk for relapse based on presence of absence of brca mutations . further , both the relapses observed were among the group of 24 patients that had close / positive margins . although the association of margin status and relapse was statistically significant , we acknowledge that this observation is based on a relatively small sample size with short followup . in the literature , the final margin status is often associated with risk of local relapse [ 14 , 15 , 18 , 19 ] . this probably represents an incomplete excision of the initial tumor at the time of mastectomy suggesting undetected residual burden left behind . table 3 is a summary of published literature with a focus on the impact of unfavorable mastectomy margin . the average risk of relapse on the compiled data in table 3 is 6.4% and is higher than the baseline risk of 0.94% observed for all patients ( table 2 ) . remarkably , the absolute numbers of relapses among patients with close / positive margins who are at a higher risk for relapses remain in single digit range . based on these observations , one may conclude that not all positive / close margins will recur ; however , most recurrences observed will have a close / positive margin . kelley et al .   examined the use of the usc / van nuys prognostic index ( usc / vnpi ) , a histopathologic scoring system for dcis patients that takes into account tumor size , nuclear grade , necrosis , margin width , and patient age . they observed that mastectomy patients with a high usc / vnpi score may be at increased risk for local recurrence reporting overall local relapse rate of 3% at a mean follow - up time of 83 months . the probability of recurrence among patients scored between 1012 was 9.6% compared to 0% for those scoring 49 at 12 years . the authors suggested that utilization of a clear margin on segmental excision serves as a surrogate for extensive dcis . in this series , the average tumor extent of the 11 patients experiencing recurrence is 5.6  cm and all had multifocal disease . although the authors report a correlation between their calculated usc / vnpi scores and recurrence , it is worth noting that the margin data used in the scores referred to premastectomy margins , that is , margins that were obtained after excision or biopsy but before mastectomy . the investigators might have arrived at different conclusions had the usc / van nuys prognostic index used the final mastectomy margins . more likely it is the final margin status of the mastectomy sample that would impact local recurrence . this study reported on the largest number of postmastectomy recurrences to date and included a review of 10 chest wall relapses . among these 10 patients , the common risk factors included young age , as well as multiquadrant dcis , suggesting probability of residual breast tissue left behind after mastectomy . the patients in this study had their primary cancers treated at different institutions ; therefore , this study cited a number of limitations , including lack of a comparison group , absence of data on mastectomy margins , and differences in standards of treatment among different institutions . among the 10 recurrences observed , 9 were successfully salvaged with excision and radiation therapy at the time of relapse . the high salvage rate with surgery and radiation therapy suggests that delayed approach to pmrt for patients thought to have higher than baseline risk may be reasonable . with this approach , the routine application of pmrt with its attended late side effects can be avoided .   in summary , the risk of relapse is low and there is evidence that salvage therapy including surgery and rt is highly effective [ 20 , 21 ] . the rare local relapse after mastectomy limits our ability to acquire substantial evidence on the risk factors for relapse in dcis . the low statistical power , to some extent , explains the lack of a clear consensus on this subject . postmastectomy studies on dcis that have tried to evaluate the impact of margin status have drawn conclusions based on very small numbers and through retrospective studies with inherent biases . therefore , in clinical practice , the application of pmrt remains limited to an individualized risk determined at the discretion of the treating physicians . such individualized assessment should include surgical technique used , extent of margin involvement , dcis grade , and extent of tumor . future research exploring the risk of relapse based on presence or absence of brca mutations and potential contribution of molecular breast cancer biomarkers including oncotype dx , hoxb-13 , and others yet to be defined may guide the individual risk categorization for local relapse and accordingly the role for adjuvant therapies .
background . dcis treated by mastectomy ensures high local control rates . 
 there is limited data on risk for relapse and lack of clear indication for adjuvant radiation therapy ( rt ) . 
 we report a retrospective review on a population of dcis patients treated with mastectomy . the objective was to identify the overall incidence of relapse , risk factors for local recurrence , and accordingly for whom 
 adjuvant postmastectomy rt may be considered . methods . 
 this is an irb - approved retrospective study on a prospective breast cancer database . from 1997 to 2007 
 , we identified 969 patients with diagnoses of dcis , among them 211 breasts in 207 patients were treated with mastectomy and comprise the study group . 
 results . with a median followup of 55 months ( 4.6 years ) 
 the 10-year relapse - free survival is 97% . 
 two of 211 breasts ( 0.9% ) treated with mastectomy developed a local - regional recurrence . both the relapses were among patients defined as having < 1  mm final mastectomy margin . conclusions . 
 the rare local relapse after mastectomy limits our ability to reliably identify risk factors for relapse . 
 the consideration for postmastectomy rt should be based on an individualized risk evaluating surgical technique used , presence of brca mutation , grade and extent of tumor , and proximity of lesion to the margin of resection .