Ductal Carcinoma In Situ Size Research Articles

Abstract PO4-17-05: Patterns of care: radiotherapy after breast conserving surgery and the use of endocrine therapy for screen-detected ductal carcinoma in situ (DCIS) in the UK

Abstract Background The use of adjuvant radiotherapy (RT) and endocrine therapy (ET) in the management of pure ductal carcinoma in situ (DCIS) remains controversial. We investigate how the use of adjuvant RT after breast conserving surgery (BCS) and use of adjuvant ET (in BCS and mastectomy patients) has changed over time. Methods A prospective cohort SQL database of 11,284 patients (the Sloane Project) diagnosed 2003-2012 with screen-detected DCIS in the UK was interrogated for use of adjuvant RT and ET over time and association with factors reported to be predictive of recurrence (patient age, DCIS nuclear grade, size, comedo necrosis, resection margins), as well as institution of surgery, travel time to radiotherapy facility, Index of Multiple Deprivation and outcome (provided by the National Disease Registration Service, NDRS). RT data by site were confirmed with more recent data from the National Audit of Breast Cancer in Older Patients (NABCOP), which looked at patterns of care and outcomes for women aged 70 years and over, compared with those aged 50-64 in England and Wales. Results Among the 7,949 women (70.6%) treated by BCS, post-operative adjuvant RT was given to 4,939 (62.1%); RT use after BCS increased over time (R2 =0.92; p< 0.01). RT use was associated with year of diagnosis (p < 0.01), younger age at diagnosis (p < 0.01), larger DCIS size (p < 0.01), presence of comedo necrosis (p < 0.01), higher nuclear grade (p < 0.01) and presence of microinvasion (p < 0.01). Adjusted analyses showed the most significant factor for RT after BCS was the surgery institution. Travel time to RT facility, Index of Multiple Deprivation and final radial margin were not associated with RT use. When compared with the more recent data from the NABCOP, a marked variation in radiotherapy use across hospitals remains. Ipsilateral recurrence rate varied significantly by hospital, with some of the difference associated with RT utilisation. ET was prescribed in 1313 women (12%), more often following BCS than mastectomy (p < 0.001), with significant variation by institution and a decline in the use of ET over time. Conclusion Marked geographic variation in the use of RT and ET after surgery for DCIS persists in the UK and is likely due to physician choice rather than other factors such as travel times to RT facilities. This is contributing to geographic variation in ipsilateral recurrence rates, suggesting the need for adoption of more authoritative guidelines to support clinical decision-making. Consistent national practice could provide auditable performance standards for adjuvant therapy of screen detected DCIS and contribute to more uniform patient care. Citation Format: Karen Clements, David Dodwell, Elinor Sawyer, Ramsey Cutress, Nisha Sharma, Abeer Shaaban, Alastair Thompson. Patterns of care: radiotherapy after breast conserving surgery and the use of endocrine therapy for screen-detected ductal carcinoma in situ (DCIS) in the UK [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-17-05.

Predictors of residual disease after breast conservation surgery for ductal carcinoma in situ: A retrospective study.

Breast-conserving therapy is the standard of care for ductal carcinoma in situ (DCIS). Debate on what constitutes a satisfactory margin persists. This study aimed to identify predictors of residual disease at re-excision. This is a population-based retrospective cohort study of women with DCIS who underwent a lumpectomy between 2007 and 2017 in Manitoba, with close (≤2 mm) or positive margins that led to re-excision. The DCIS re-excision rate was 29.3% for 1001 patients. 63.2% of patients were found to have residual disease on re-excision. On univariable analysis, the size, margin status, number of positive margins, type of second surgery, and Van Nuys Prognostic Index score were associated with residual disease on re-excision. The size of DCIS and the number of positive margins remained statistically significant on multivariable analysis. Re-excision should be rationalized by considering the predictors of residual disease in conjunction with other factors.

Lumpectomy without radiation for ductal carcinoma in situ of the breast: 20-year results from the ECOG-ACRIN E5194 study

We report the 20-year rate of ipsilateral breast event (IBE) for patients with ductal carcinoma in situ (DCIS) treated with lumpectomy without radiation on a non-randomized prospective clinical trial. Patients were enrolled in cohort 1: low- or intermediate-grade DCIS, size ≤ 2.5 cm (n = 561); or cohort 2: high-grade DCIS, size ≤ 1 cm (n = 104). The Kaplan–Meier method was used to estimate time-to-event distributions. Cox proportional hazard methods were used to estimate hazard ratios (HRs) and tests for significance for event times. 561 patients were enrolled in cohort 1 and 104 in cohort 2. After central pathology review, 26% in cohort 1 were recategorized as high-grade and 26% in cohort 2 as low- or intermediate-grade. Mean DCIS size was similar at 7.5 mm in cohort 1 and 7.8 mm in cohort 2. Surgical margin was ≥3 mm in 96% of patients, and about 30% received tamoxifen. Median follow-up was 19.2 years. There were 104 IBEs, of which 54 (52%) were invasive. The IBE and invasive IBE rates increased in both cohorts up to 15 years, then plateaued. The 20-year IBE rates were 17.8% for cohort 1 and 28.7% for cohort 2 (p = 0.005), respectively. Invasive IBE occurred in 9.8% and 15.1% (p = 0.09), respectively. On multivariable analysis, IBE risk increased with size and was higher in cohort 2, but grade and margin width were not significantly associated with IBE. For patients with DCIS treated with excision without radiation, the rate of IBE increased with size and assigned cohort mostly in the first 15 years.

Association of DCIS size and margin status with risk of developing breast cancer post-treatment: multinational, pooled cohort study

ObjectiveTo examine the association between size and margin status of ductal carcinoma in situ (DCIS) and risk of developing ipsilateral invasive breast cancer and ipsilateral DCIS after treatment, and stage...

How Well Does Non-mass Enhancement Correlate With DCIS/Invasive Cancer?

Contiguous non-mass enhancement (NME) often coexists with a solid tumor component on MRI, but it can be challenging to predict whether NME represents invasive breast cancer, ductal carcinoma in situ (DCIS), benign disease, or biopsy site reaction. The purpose of this study was to determine the association between the size/extent of NME and the presence of invasive cancer and/or DCIS on final pathology. This was a single institution retrospective analysis of a prospectively maintained breast cancer registry (2010-2020). Female patients who underwent surgical resection were included if they had a diagnosis of invasive breast cancer (with or without DCIS) and had an MRI showing both a solid mass and contiguous NME. The size of NME on MRI was compared with the size of invasive cancer and/or DCIS on the final pathology. From a total of 3443 patients, 225 patients were included. 86.2% had invasive ductal carcinoma (IDC), and 12.0% had invasive lobular carcinoma 76.9% were ER+, 16.4% were HER2+, and 13.3% were triple negative breast cancer (TNBC). 18.7% received neoadjuvant chemotherapy (NCT) of whom 31% achieved a complete radiographic/pathologic response. Pearson correlation coefficients (r) between the size of NME and invasive cancer/DCIS showed a strong and positive correlation of MRI NME with DCIS on pathology in patients without NCT. Subgroup analysis showed the strongest correlations for NME and DCIS among non-white (r = .70) and HER2 + patients (r = .74) who did not receive NCT. Strong correlations between NME and DCIS were found for HER2 + disease and non-white patients, but only modest correlations were found for other patient/disease characteristics. These correlations may impact decisions in surgical approach.

Retrospective Cohort Study of Practical Applications of Paramagnetic Seed Localisation in Breast Carcinoma and Other Malignancies.

(1) Background: Paramagnetic seeds are a safe alternative for the wire-guided localisation of non-palpable breast lesions, but can also be applied for non-breast lesions. This study presents the experience with a paramagnetic seed, MagSeed® (Endomagnetics Ltd., Cambridge, UK, CE-registered and FDA-cleared), in an academic and non-academic breast centre. (2) Methods: Multicentre, retrospective analysis of 374 consecutive patients who underwent surgery after paramagnetic seed localisation (MSL) between 2018 and 2020. Indications for localisation included non-palpable breast lesions (n = 356), lymph nodes (n = 15) or soft tissue lesions (n = 3). The primary outcome was feasibility and the rate of positive section margins. The secondary outcome was predictive factors for positive section margins. (3) Results: The accurate excision of high-risk breast lesions, lymph nodes and soft tissue lesions was seen in 91.07% (n = 56). Positive section margins were observed in 7.86% (n = 25) after breast conserving surgery for invasive or ductal carcinoma in situ (DCIS) (n = 318). Invasive breast cancer associated with DCIS (p = 0.043) and the size of DCIS (p < 0.001) were significantly correlated with the positive section margins. (4) Conclusion: This study confirms the feasibility of MSL, as well as the higher risk for positive margins in cases of breast carcinoma with associated DCIS. Soft tissue lesions and lymph nodes associated with other malignancies, e.g., melanoma, can also be localised with paramagnetic seeds. This offers perspectives for future applications, such as the de-escalation of axillary treatment in breast cancer.

The presentation, management and outcome of patients with ductal carcinoma in situ (DCIS) with microinvasion (invasion ≤1 mm in size)—results from the UK Sloane Project

BackgroundThe diagnosis, management and prognosis of microinvasive breast carcinoma remain controversial.MethodsWe analysed the outcomes of patients with DCIS with and without microinvasion diagnosed between 2003 and 2012 within the Sloane project.ResultsMicroinvasion was recorded in 521 of 11,285 patients (4.6%), with considerable variation in reported incidence among screening units (0–25%). Microinvasion was associated with high-grade DCIS, larger DCIS size, comedo necrosis and solid, cribriform architecture (all P < 0.001). Microinvasion was more frequent in patients who underwent mastectomy compared with breast-conserving surgery (BCS) (6.9% vs 3.6%, P < 0.001), and in those undergoing axillary nodal surgery (60.4% vs 30.3%, P < 0.001) including the subset undergoing BCS (43.4% vs 8.5%, P < 0.001). Nodal metastasis rate was low and not statistically significant difference from the DCIS only group (P = 0.68). Following median follow-up of 110 months, 3% of patients had recurrent ipsilateral high-grade DCIS, and 4.2% developed invasive carcinoma. The subsequent ipsilateral invasion was of Grade 3 in 71.4% of patients with microinvasion vs 30.4% in DCIS without microinvasion (P = 0.02). Distant metastasis and breast cancer mortality were higher with microinvasion compared with DCIS only (1.2% vs 0.3%, P = 0.01 and 2.1% vs 0.8%; P = 0.005).ConclusionsThe higher breast cancer mortality with microinvasion indicates a more aggressive disease.

Overuse of Axillary Surgery in Patients with Ductal Carcinoma In Situ: Opportunity for De-escalation.

Ductal carcinoma in situ (DCIS) is noninvasive breast cancer and therefore nodal staging is not routinely recommended. We evaluated the use of and factors associated with axillary surgery in DCIS in the National Cancer Database (NCDB). DCIS cases were identified from the NCDB 2012-2018. Use of axillary surgery was evaluated over time, and factors associated with axillary surgery were assessed for breast-conserving surgery (BCS) and mastectomy groups. We identified 178,762 patients, median age of 60 years. Majority of DCIS (87%) was ER-positive, and 14% low, 43% intermediate, and 44% high grade. Median DCIS size was 1.1 cm. BCS was performed in 72%, whereas 28% had mastectomy. Overall axillary surgery was performed in 38% and was higher in patients undergoing mastectomy compared with patients undergoing BCS (88% vs. 19%, p < 0.001). At axillary surgery, the vast majority (92%) had 1-5 nodes examined, whereas 8% had >5 nodes examined. Over time, axillary surgery decreased in BCS patients (21%in 2012 to17%in 2018, p < 0.001) but increased slightly in mastectomy patients (86% in 2012 to90%in 2018, p < 0.001). On multivariable analysis, factors significantly associated with axillary surgery were younger patient age, larger tumor size, higher grade, and ER-negative status. Factors associated with axillary surgery reflect higher risk disease for upstage to invasive cancer, indicating surgeon judgment. However, despite axillary surgery being overtreatment of DCIS, it is common in mastectomy and is performed for one in five patients undergoing BCS. This provides opportunity for improvement in breast cancer care delivery.

Preoperative Evaluation of Non-Mass-Like Enhancement on Magnetic Resonance Imaging for Measuring Tumor Extent and Affecting Surgical Margin Status in Breast Cancer Patients

Purpose: This study investigated the correlation between non-mass-like enhancement (NME) observed on preoperative breast magnetic resonance imaging (MRI) and the actual pathological size of breast cancer. We further examined the effect of NME on the positive resection margins during partial mastectomy.Methods: We retrospectively collected data from breast cancer patients who underwent surgery between January 2018 and September 2020. Patients were divided into two groups based on their MRI findings: NME and no-NME (mass-like lesion only) groups. The medical records, including MRI findings and clinicopathological information of patients, were collected retrospectively, and correlations with pathologic results were analyzed. Propensity score matching was applied to develop comparable cohorts of the NME group and no-NME group.Results: This study included a total of 317 patients, with 66 and 251 patients in the NME and no-NME groups, respectively. The mean pathologic size of invasive lesion was significantly smaller than the mean lesion size in the NME group (1.55±1.39 cm vs. 3.45±1.81 cm, p&lt;0.001). The mean pathologic size of ductal carcinoma in situ (DCIS) lesions was larger than that in the NME group but without statistical significance (3.91±2.67 cm vs. 3.50±1.79 cm, p=0.326). In the NME group, NME estimated DCIS size to within 1 cm in 20 patients (30.3%) and overestimated invasive lesion size by more than 1 cm in 31 patients (46.9%). NME (vs. no-NME; odds ratio [OR], 2.967; 95% confidence interval [CI], 0.878-10.025) showed a tendency to predict positive resection margins, but this was not statistically significant (p=0.080).Conclusion: NME findings on MRI showed a similar extent of DCIS lesions. NME findings on preoperative MRI should be considered an important factor for measuring the extent of tumors, especially in DCIS patients.

Macrophage density is an adverse prognosticator for ipsilateral recurrence in ductal carcinoma in situ

IntroductionThere is evidence that supports the association of dense tumor infiltrating lymphocyte (TILs) with an increased risk of ipsilateral recurrence in ductal carcinoma in situ (DCIS). However, the association of cellular composition of DCIS immune microenvironment with the histopathologic parameters and outcome is not well understood. MethodsWe queried our institutional database for patients with pure DCIS diagnosed between 2010 and 2019. Immunohistochemical studies for CD8, CD4, CD68, CD163, and FOXP3 were performed and evaluated in the DCIS microenvironment using tissue microarrays. Statistical methods included Fisher's exact test for categorical variables and the two-sample t-test or the Wilcoxon Rank-Sum test for continuous variables. ResultsThe analytic sample included 67 patients. Median age was 62 years (range = 53 to 66) and median follow up was 6.7 years (range = 5.3 to 7.8). Thirteen patients had ipsilateral recurrence. Of all the clinicopathologic variables, only the DCIS size and TIL density were significantly associated with recurrence (p = 0.023 and 0.006, respectively). After adjusting for age and TIL density, only high CD68 (>50) and high CD68/CD163 ratio (>0.46) correlated with ipsilateral recurrence (p = 0.026 and 0.013, respectively) and shorter time to recurrence [hazard ratio 4.87 (95% CI: 1.24–19, p = 0.023) and 10.32 (95% CI: 1.34–80, p = 0.025), respectively]. ConclusionsIn addition to DCIS size and TIL density, high CD68+ tumor-associated macrophages predict ipsilateral recurrence in DCIS. High CD68+ macrophage density and CD68/CD163 ratio also predict a shorter time to recurrence.

Reoperation rate of ductal carcinoma in situ: impact of tomosynthesis (3D) and spot magnification.

Surgical planning depends on precise preoperative assessment of the radiological extent of ductal carcinoma in situ (DCIS). Despite different modalities used, reoperation rates for DCIS due to involved margins are high. To evaluate the impact of additional imaging views (spot magnification, tomosynthesis) on surgical reoperation rate of DCIS. The retrospective single institute study includes 157 patients with biopsy-proven pure DCIS seen on mammogram as microcalcifications and treated with breast-conserving surgery. Patients have been divided into three groups according to additional imaging performed: spot magnification, tomosynthesis, and none. All breast images (mammograms, spot magnification, tomosynthesis) were reviewed and the maximum extent of pathological microcalcifications was recorded. Radiological size was compared to final histopathological size. Reoperation rate due to inadequate margins was recorded. Reoperation rates (25%) due to inadequate margins were as follows: spot (18%), tomosynthesis (27%), none (31%); P = 0.488. Spot magnification, tomosynthesis, and digital zoom of full-field digital mammography predicted similarly the final histopathological size. Reoperation group had a significantly greater preoperative radiological median size (26 mm vs. 20 mm; P = 0.014) as well as median size of disease on final histopathological report (29 mm vs. 14 mm; P < 0.001). Discrepancy between radiological and final histopathological size became greater with increasing DCIS extent. The main factors for reoperations are DCIS size and discordance between radiological and histopathological sizes. The use of additional imaging views (spot magnification, tomosynthesis) did not reduce reoperation rate.

Abstract P3-18-11: Meeting the challenge of successful one-stage lumpectomy for DCIS

Abstract Introduction: Positive lumpectomy margins are associated with an increased risk for ipsilateral tumor recurrence, and necessitate additional procedures to achieve acceptable margins. Re-excision rates are higher in patients with ductal carcinoma in situ (DCIS) versus those with invasive carcinoma. The purpose of this study was to investigate the clinicopathologic characteristics, surgical techniques, and other outcomes associated with re-excision over time following primary breast conserving surgery for DCIS. Methods: Our institutional Breast Cancer Database was queried for patients treated with lumpectomy as the primary procedure for pure DCIS from 2010-2021. Cases of microinvasive disease were excluded. The primary endpoint was the rate of re-excision following lumpectomy. Variables of interest included patient demographics and clinicopathologic characteristics. As a secondary analysis, adjusted odds ratios for the association of MarginProbe® with re-excisions were calculated using a multivariable logistic regression model controlling for age, tumor size, breast density and DCIS subtype. Individual comparisons of continuous variables were based on t-tests, group proportions compared with one-way ANOVA, and categorical variables compared using Chi Square tests. Results: Out of a total of 695 patients in our cohort, 221 (32%) had re-excisions. There was a statistically significant 2% decline per year in the number of re-excisions (p=0.005). Patients who underwent re-excision had larger size of DCIS (2.37 cm vs 1.37 cm, p&amp;lt;0.001). Papillary-type DCIS was associated with an increased rate of re-excision surgery (Table 1). Prior to the introduction of the MarginProbe® for intraoperative margin assessment in 2014, approximately 42% of patients with DCIS underwent re-excisions. This decreased to 24.9% in the post-2013 time frame (p=0.02). In an unadjusted estimate for the odds ratio for association, patients who underwent lumpectomy with MarginProbe® were 81% less likely to require re-excision (OR = 0.19, 95% CI = 0.12, 0.31, p&amp;lt;0.0001). In a logistic regression model controlling for potential confounders with re-excision as the dependent variable and MarginProbe® as the primary explanatory variable, patients for whom the MarginProbe® was used were 66% less likely to require re-excision when controlling for age, tumor size, menopausal status, breast density, and pathology (OR = 0.34, 95% CI 0.16, 0.69). Of patients who required re-excision, 20% went on to mastectomies as their second procedure. After each unsuccessful re-excision, a larger proportion of patients converted to mastectomy. In total, 26% of patients who had unsuccessful primary surgery went on to mastectomies. Of patients who proceeded to mastectomy as their second procedures, 13% were found to carry BRCA1 or 2 mutations. Conclusions: In our study of patients diagnosed with pure DCIS and treated with primary breast conserving surgery, larger size of DCIS and papillary subtype were associated with an increased rate of re-excision procedures. A proportion of patients with unsuccessful primary lumpectomies required multiple procedures to complete their surgical treatment and 26% went on to mastectomy. Patients whose primary procedures included intraoperative margin assessment with the MarginProbe® were significantly less likely to require re-excision. Intraoperative margin assessment is an important tool that can support breast conserving surgery in the challenging population of patients with DCIS. Table 1.Clinicopathologic CharacteristicsVariableNo Re-excision (n=313)Re-Excision (n=100)P-ValueAge; mean (SD)61.48 (12.01)58.04 (13.39)0.016Age of Menopause; mean (SD)50.22 (5.18)48.13 (5.45)0.004Size of DCIS; mean (SD)1.37 (1.25)2.37 (2.00)&amp;lt;0.001Breast Density (%)0.149N/A6 (1.9)2 (2.0)Entirely Fatty10 (3.2)3 (3.0)Extremely Dense19 (6.1)13 (13.0)Heterogeneously Dense165 (52.7)42 (42.0)Scattered Fibroglandular113 (36.1)40 (4.0)DCIS SubtypePapillary93 (29.7)48 (48.0)0.001Cribiform206 (65.8)69 (69.0)0.641Solid190 (60.7)60 (60.0)0.994Comedo54 (17.3)25 (25.0)0.117Surgical Margins (%)&amp;lt;0.001Close (&amp;gt;0 and &amp;lt;1mm)3 (1.0)60 (60.0)Negative (≥1 mm)310 (99.0)13 (13.0)Positive (≤0 mm)0 (0.0)27 (27.0) Citation Format: Joshua A Feinberg, Charles DiMaggio, Nakisa Pourkey, Jennifer Chun Kim, Jenny Goodgal, Amber Guth, Deborah Axelrod, Freya Schnabel. Meeting the challenge of successful one-stage lumpectomy for DCIS [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-11.

Abstract P3-12-36: The diagnosis and prognosis of ductal carcinoma in situ (DCIS) with microinvasion - Results from the United Kingdom Sloane project

Abstract Background/objectives The natural history of microinvasive carcinoma of the breast (one or more foci of invasion of 1mm or less) and its optimal management remain controversial. We analysed the frequency and outcome of patients with DCIS plus microinvasion within a large prospective cohort of screen-detected DCIS. Methods Patients with screen-detected DCIS diagnosed between 2003 and 2012 with or without microinvasion in the final surgical specimen were identified from the UK Sloane Project database. Comprehensive imaging, surgical, pathology, oncology and subsequent outcome data were collected with a median follow-up of 9 years. Results Among 11285 DCIS patients diagnosed in the UK, microinvasion was reported in 521 (4.6%). The frequency of reported microinvasion varied considerably among screening units (0-25%) but overall decreased from 7% in 2003/04 to 3% in 2011/12.As reported elsewhere, microinvasion was significantly associated with high grade DCIS (5.9% of 7182 cases) compared to 2.9% of intermediate grade and &amp;lt;1% of low grade DCIS (p&amp;lt;0.001, Chi square test). Microinvasion was associated with larger DCIS size (p&amp;lt;0.001) 2.2% of DCIS &amp;lt;10mm, 3.9% of DCIS 10-20mm, 5.8% of DCIS 20-30mm, 5.2% of DCIS 30-40mm and 8.0% of DCIS &amp;gt;40mm had microinvasive foci reported. Microinvasion was also associated with the presence of comedo necrosis (p&amp;lt;0.001), and solid (p&amp;lt;0.001), cribriform (p&amp;lt;0.001) or flat (p=0.03) DCIS architecture.Microinvasion was identified more frequently in patients who underwent mastectomy (6.9%) than in those who had breast conserving surgery (BCS) (3.6%; p&amp;lt;0.001). Axillary nodal surgery was more commonly performed for microinvasion (60.4% compared to 30.3%) including for patients undergoing BCS (43.4% vs 8.5% of all patients with BCS; p&amp;lt;0.001). The rate of nodal metastasis was, however, low and not statistically significantly different between those with and without microinvasion (0.4% and 0.1% respectively, p=0.27).Patients with microinvasion who underwent BCS were also more likely to receive radiotherapy (p&amp;lt;0.001). There was no significant association between the presence or absence of microinvasion with margin status or width. Subsequent events data for England showed that microinvasion was associated with a low rate of ipsilateral subsequent events, with 2.3% of patients having recurrent DCIS and 4.2% developing invasive carcinoma. This was not statistically significantly different from DCIS without microinvasion. All subsequent ipsilateral DCIS events in patients with microinvasion were of high grade. The majority (71.4%) of subsequent ipsilateral invasive carcinomas were of grade 3 compared with only 30.4% of grade 3 carcinomas in patients with DCIS without microinvasion (p=0.02). Breast cancer mortality was significantly higher in women whose tumours showed microinvasion (2.1%) compared with those without it (0.8%; p=0.005). Conclusions Microinvasion was most commonly identified within high-grade DCIS and in larger DCIS lesions, and was associated with comedo necrosis. Its pathological reporting decreased over a 10-year period, but there was significant variation between departments, which requires further evaluation. Patients with DCIS plus microinvasion were more likely to have undergone mastectomy, axillary node surgery and to receive radiotherapy after BCS. Microinvasive breast carcinoma was associated with a low rate of subsequent in situ/invasive events and had a good prognosis but, nevertheless, a higher breast cancer mortality than DCIS without microinvasion. Citation Format: Abeer M Shaaban, Bridget Hilton, Karen Clements, David Dodwell, Nisha Sharma, Cliona Kirwan, Elinor Sawyer, Anthony Maxwell, Matthew Wallis, Hilary Stobart, Senthurun Mylvaganam, Janet.Litherland Litherland, Samantha Brace-Mcdonnell, Joanne Dulson-Cox, Olive Kearins, Elena Provenzano, Sarah Pinder, Alastair Thompson. The diagnosis and prognosis of ductal carcinoma in situ (DCIS) with microinvasion - Results from the United Kingdom Sloane project [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-36.

Abstract P1-22-06: A longitudinal cohort study of outcomes in 311 women with unresected ductal carcinoma in situ detected through the English breast screening programme

Abstract Background The variable natural history of ductal carcinoma in situ (DCIS) is poorly understood. The aim of this retrospective cohort study was to determine the outcomes of women who were diagnosed through the English National Health Service Breast Screening Programme (NHS BSP) and had no surgery for screen-detected DCIS. Method English NHS BSP databases were searched for women diagnosed with DCIS without invasive cancer on needle biopsy between 1 April 2001 and 31 March 2018 inclusive, who had no record of surgery within 6 months of diagnosis. These were cross-referenced with cancer registry data for further treatment, event information and mortality records. Details of potentially eligible women were sent to the relevant breast screening units for verification and for completion of data forms detailing clinical, radiological and pathological findings, non-surgical treatment, subsequent clinical course and outcomes. Results Data for 311 eligible women (median age 62 years) were included, with median follow-up (primary DCIS diagnosis to either surgery, development of invasive disease, death or last known to be alive) of 4.1 years (range 0.5 to 17.4 years). The median age at diagnosis was 64 years (range 47 to 90 years). Sixty (19%) women developed invasive breast cancer, 56 ipsilateral and 4 contralateral. Twenty-two women (7%) underwent surgery for DCIS (&amp;gt;6 months after diagnosis) and 86 (28%) died of other causes. Women with high or intermediate grade DCIS were significantly more likely to develop ipsilateral invasive breast cancer (iIBC) than those with low grade DCIS. 28/123 (23%) with high grade DCIS, 21/105 (20%) with intermediate grade DCIS, 5/76 (7%) with low grade DCIS and 2/7 (29%) with an unknown grade of DCIS developed iIBC. Ipsilateral invasion risk increased approximately linearly with time for at least 10 years. Women who developed iIBC were significantly younger than those who did not. This was driven primarily by a strong association among those with high grade DCIS. There was no significant difference in age between those with intermediate and low grade DCIS respectively who did or did not develop iIBC. The median baseline size of DCIS in women who developed iIBC was higher than in women who did not develop iIBC, both overall and in each of the three grade categories (median sizes - high grade 38 mm vs 29 mm, p=0.19; intermediate grade 35 mm vs 18 mm, p=0.31; low grade 18 mm vs 15 mm, p=0.38). This reached statistical significance for all grades combined: 37 mm (range 3-95) v 20 mm (range 3-200), p=0.02. Of the 262 women with a known microinvasion status, 8/25 (32%) with definite or possible microinvasion were subsequently diagnosed with ipsilateral invasive cancer compared to 38/237 (16%) without microinvasion (p=0.027). There was no significant association on univariable analysis between risk of iIBC and microcalcification as the predominant radiological feature (iIBC and microcalcification 47/258 vs iIBC and other radiological feature 7/46; p=0.83), the presence of histological necrosis (iIBC and necrosis, 14/89 vs iIBC and no necrosis, 31/157; p=0.49) or the use of ET (iIBC and ET 11/67 vs iIBC and no ET 45/244; p=0.86). Of the 51 invasive cancers that developed with a known grade, 46 (90%) were grade 2 or 3. Conclusion The findings suggest that women diagnosed with high or intermediate grade DCIS and those with microinvasion should continue to be offered surgery. For those with low grade DCIS there is a need for shared decision-making in the choice of surgery or active surveillance based on a discussion of the risks and benefits of the options as currently understood, and in the light of the low reproducibility of DCIS grading. Citation Format: Karen Clements, Anthony Maxwell, Bridget Hilton, Matthew Wallis, Cliona Kirwan, Hilary Stobart, Elena Provenzano, Nisha Sharma, Janet Litherland, Abeer Shaaban, David Dodwell, Joanne Dulson-Cox, Elinor Sawyer, Senthurun Mylvaganam, Olive Kearins, Samantha Brace-McDonnell, Sarah Pinder, Alastair Thompson. A longitudinal cohort study of outcomes in 311 women with unresected ductal carcinoma in situ detected through the English breast screening programme [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-22-06.

Predictive value of ductal carcinoma in situ with invasive breast cancer in core needle biopsies for final pathologic size of intraductal elements

Preoperative evaluations of the size of ductal carcinoma in situ (DCIS) extension in invasive breast cancer (IBC) are problematic and markers of the actual size of DCIS remain elusive. This study aimed to quantify DCIS on core needle biopsy (CNB) and investigated its association with degree of DCIS extension on paired resection specimens, instead of with presence or absence of an extensive intraductal component or margin status as in earlier studies. This series examined 150 IBCs diagnosed from paired CNB and resection specimens. The DCIS/invasion ratio was calculated using the sum of each element size from CNB. In resection specimens, cases in which the greatest dimension of DCIS extension was longer than the greatest dimension of invasive size were defined as extended DCIS (Ext-DCIS). DCIS/invasion ratio level correlated positively with the degree of Ext-DCIS (P = 0.003). Using receiver operating characteristic curve analysis, setting cases with the subgroup of DCIS extension with greatest dimension > 2.5 times that of the invasive size in the resection specimen (Ext-DCIS > 2.5) as the positive class provided the best discrimination ability for DCIS/invasion ratio (0.375). In multivariate analysis, DCIS/invasion ratio > 0.375 was significantly associated with Ext-DCIS > 2.5 (P = 0.033). In conclusion, DCIS/invasion ratio > 0.375 in CNB was identified as a predictor of Ext-DCIS > 2.5 in resection specimens, suggesting that an approach combining DCIS/invasion ratio from CNB with preoperative staging may better predict the extent of DCIS and facilitate better surgical planning.

Biological features of ductal carcinoma in situ: clinical role and basis for treatment individualization

Ductal carcinoma in situ (DCIS) is an extremely heterogeneous disease in terms of clinical manifestations, morphological changes, and expression of biomarkers, which determine the risk of subsequent development of an invasive breast cancer (BC). Diagnosis and treatment of DCIS prevents the development of invasive tumors (which reduces the potential risk of death from BC); however, the prognostic value of local treatment depends on the biological characteristics of its. The tumor grade, presence of comedonecrosis and expression of estrogen receptors are the key prognostic factors in DCIS for the treatment tactics and prognosis. The clinical symptoms of DCIS are very scarce, the most of tumors is diagnosed by screening mammography; the typical sign of DCIS is malignant microcalcifications or changes of breast architectonic. The sensitivity of mammography, ultrasound and MRI directly depend on the biological characteristics of DCIS. Surgical treatment (breast-conserving surgery or mastectomy) significantly reduces the risk of BC death in women with DCIS G2/G3, and radiotherapy after breast-conserving surgery reduce the risk of local recurrence of non-invasive and invasive BC. The choice of the local treatment (breast-conserving surgery radiation therapy vs mastectomy) depend on such factors as: tumor size, localization, clear margins, and biological characteristics of DCIS. In contrast to invasive cancers, the negative margin in DCIS is more than 2 mm from the tumor. Regional lymph node involvement in DCIS occurs in less than 1% of cases; however, microinvasion is found in analyze the surgical specimen in 15% of patients, which raises the question about regional staging. Risk factors for microinvasion in DCIS are age less than 55 years, tumor lesion size more than 4.0 cm, DCIS grade G3, and tumor palpability. Adjuvant endocrine therapy with tamoxifen significantly reduces the 10-year risk of invasive recurrence by 51%, the risk of contralateral BC by 50% and the risk of death by 40%, but only for hormone-positive DCIS. HER2 overexpression is found in DCIS significantly often (up to 40% of cases) than in invasive BC, HER2+ status correlates with DCIS high grade G3, the presence of comedonecrosis and with increased risk of relapse (both non-invasive and invasive) but is not a reason for anti-HER2 therapy. DCIS low risk and DCIS high risk have not only different morphological characteristics, but also different models of biological behavior, which must be considered in the different choice of treatment tactics.

Measurements using mammography and ultrasonography underestimate the size of high-volume ductal carcinoma in situ

BackgroundSurgical decisions for ductal carcinoma in situ (DCIS) are based on lesion sizes. This study aims to determine the accuracy of pre-operative imaging in estimating the size of DCIS. MethodsThis was a retrospective review of clinicopathologic data of patients treated for DCIS with breast conserving surgery (BCS) between 2012 and 2018. Mammographic and sonographic lesion sizes were compared with final pathology sizes. ResultsFor the 152 lesions visible on mammography, mean size on imaging was significantly smaller when compared to final pathology (2.3 vs. 3.6 cm, p < 0.001). The mean difference of 1.3 cm was a significant underestimation with a correlation coefficient of 0.367 (p < 0.001). For 48 sonographically visible lesions, the radiologic size was significantly smaller than pathologic size (1.7 vs. 4.1 cm, p < 0.001), but the degree of underestimation was not significantly correlated (p = 0.379). ConclusionDCIS size was significantly underestimated by imaging. This must be taken into consideration during surgical planning.

Impact of Cavity Shave Margins on Margin Status in Patients with Pure Ductal Carcinoma In Situ

We examined the impact of cavity shave margins (CSMs) on margin status in patients with pure ductal carcinoma in situ (DCIS) undergoing partial mastectomy (PM). One hundred and nine patients from 2 multicenter, randomized controlled trials were identified with pure DCIS (no invasive cancer). Surgeons performed their best PM, with specimen radiography and resection of selective margins per surgeon discretion. Patients were then randomized to have CSM resected or not. A positive margin was defined as <2 mm from ink. Median patient age was 63 years; median size of DCIS was 1.20 cm; 43.6% of patients had high-grade DCIS; and 58 (53.2%) patients were randomized to take CSM. The "shave" and "no-shave" groups were well-matched for age, race, ethnicity, palpability, grade, and size of DCIS. Although 33 (56.9%) of the patients in the shave group had a positive margin before randomization, only 12 (20.7%) had a positive margin after randomization to CSM (p<0.001). In the no-shave group, 17 patients (33.3%) had a positive margin. Controlling for size and grade of DCIS, taking CSM resulted in a nearly 65% reduction in the positive-margin rate (odds ratio 0.366; 95% CI, 0.136 to 0.981; p= 0.046). Size of DCIS remained an independent predictor of positive margins in the model (odds ratio 1.646; 95% CI, 1.227 to 2.209; p= 0.001). CSM reduces positive-margin rates in patients with pure DCIS, and can be a practical solution for DCIS patients who tend to have a high rate of margin positivity.

A Single institution's randomized double-armed prospective study of lumpectomy margins with adjunctive use of the MarginProbe in nonpalpable breast cancers.

Breast conservation surgery (BCS) aims to excise all cancerous tissue while minimizing the amount of healthy breast tissue removed. Up to 30% of patients undergoing BCS require a second operation for re-excision to obtain negative margins. Previous studies reported a lower re-excision rate with intraoperative use of the MarginProbe device (Dune Medical Devices). This device utilizes radiofrequency spectroscopy to detect differences between cancerous and normal tissue. From July 2009 to January 2010, our institution enrolled 46 patients electing for BCS in a prospective double-arm randomized controlled trial and had a significantly lower re-excision rate than that reported in the multicenter trial. Intraoperatively, after performing conventional lumpectomy with excision of any additional shavings deemed necessary based on palpation and visual inspection alone, patients were then randomized. In the device arm, the surgeon used the MarginProbe to interrogate the lumpectomy specimen, taking additional shavings from the cavity surfaces corresponding to the parts of the specimen read as positive by the device. In the control arm, only standard intraoperative assessments were performed. All specimens were evaluated by pathologists who were blinded to the study arm. In this population, 72% had invasive ductal carcinoma (IDC), 20% had ductal carcinoma in situ (DCIS), and 8% had invasive lobular carcinoma (ILC). Average age was 64years old. The average size of the specimen was 5.6cm, the average volume was 37.8cm3 , and the average weight was 32.7g. The mean size of DCIS was 1.4cm. For invasive specimens, 32 were T1 and 7 were T2. Prior to randomization, 43 patients were thought to have positive or close margins and therefore underwent additional shavings. Twenty-three patients were randomized to the device arm and 23 to the control arm. In the device arm, 14 (60%) patients had IDC, 7 (30%) had DCIS, and 2 (8%) had ILC, vs the control arm where 19 (82%) patients had IDC, 2 (8%) had DCIS, and 2 (8%) had ILC. Eight (35%) patients in the control group vs 1 (4%) in the device group underwent re-excision for margin involvement (P<.05). The use of the MarginProbe device at our institution significantly improved the ability of our surgeons to obtain clear margins during initial BCS. Our results show a lower re-excision rate (4%) than those published in the multicenter trial (19.8%). We postulate that in the face of more patients having DCIS in our device group (30%), our surgeons responded by taking thicker shavings when the MarginProbe device reported margin involvement during the initial lumpectomy, resulting in greater success achieving clear final margins on the shaved tissue and a significantly lower re-excision rate than previously reported with the MarginProbe device.

Adoption of SSO-ASTRO Margin Guidelines for Ductal Carcinoma in Situ: What Is the Impact on Use of Additional Surgery?

Historically, more than one-third of patients with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS) underwent additional surgery. The SSO-ASTRO guidelines advise 2mm margins for patients with DCIS having BCS and whole-breast radiation (WBRT). Here we examine guideline impact on additional surgery and factors associated with re-excision. Patients treated with BCS for pure DCIS from August 2015 to January 2018 were identified. Guidelines were adopted on September 1, 2016, and all patients had separately submitted cavity-shave margins. Clinicopathologic characteristics, margin status, and rates of additional surgery were examined. Among 650 patients with DCIS who attempted BCS, 50 (8%) converted to mastectomy. Of 600 who had BCS as final surgery, 336 (56%) received WBRT and comprised our study group. One hundred twenty-eight (38%) were treated pre-guideline and 208 (62%) were treated post-guideline. Characteristics and margin status were similar between groups. The re-excision rate was 38% pre-guideline adoption and 29% post-guideline adoption (p = 0.09), with 91% having only one re-excision. Re-excision for ≥ 2mm margins was uncommon (6% pre-guideline vs. 5% post-guideline). On multivariate analysis, younger age (OR 0.97, 95% CI 0.94-0.99, p = 0.02) and larger DCIS size (OR 1.43, 95% CI 1.2-1.8, p < 0.001) were predictive of re-excision; guideline era was not. Younger age (OR 0.93, 95% CI 0.9-0.97, p < 0.001) and larger size (OR 1.64, 95% CI 1.3-2.1, p < 0.001) were predictive of conversion to mastectomy, but residual tumor burden was low. The SSO-ASTRO guidelines did not significantly change re-excision rates for DCIS in our practice, likely since re-excision for margins ≥ 2mm was uncommon even prior to guideline adoption, dissimilar to historically observed variations in surgeon practices. Younger age and larger DCIS size were associated with additional surgery.