Validation of the PREDICT Prognostication Tool in US Patients With Breast Cancer.

BACKGROUND: PREDICT is an online prognostication tool derived from breast cancer registry information on approximately 6,000 women treated in the United Kingdom that estimates the postsurgical treatment benefit of surgery alone, chemotherapy, trastuzumab, endocrine therapy, and/or adjuvant bisphosphonates in early-stage breast cancer. Our aim was to validate the PREDICT algorithm in predicting 5- and 10-year overall survival (OS) probabilities using real-world outcomes among US patients with breast cancer. METHODS: A retrospective study was performed including women diagnosed with unilateral breast cancer in 2004 through 2012. Women with primary unilateral invasive breast cancer were included. Patients with bilateral or metastatic breast cancer, no breast surgery, or missing critical clinical information were excluded. Prognostic scores from PREDICT were calculated and external validity was approached by assessing statistical discrimination through area under time-dependent receiver-operator curves (AUC) and comparing the predicted survival to the observed OS in relevant subgroups. RESULTS: We included 708,652 women, with a median age of 58 years. Most patients were White (85.4%), non-Hispanic (88.4%), and diagnosed with estrogen receptor-positive breast cancer (79.6%). Approximately 50% of patients received adjuvant chemotherapy, 67% received adjuvant endocrine therapy, 60% underwent a partial mastectomy, and 59% had 1 to 5 axillary sentinel nodes removed. Median follow-up time was 97.7 months. The population's 5- and 10-year OS were 89.7% and 78.7%, respectively. Estimated 5- and 10-year median survival with PREDICT were 88.3% and 73.8%, and an AUC of 0.77 and 0.76, respectively. PREDICT performed most poorly in patients with high Charlson-Deyo comorbidity scores (2-3), where PREDICT overestimated OS. Sensitivity analysis by year of diagnosis and HER2 status showed similar results. CONCLUSIONS: In this prognostic study utilizing the National Cancer Database, the PREDICT tool accurately predicted 5- and 10-year OS in a contemporary and diverse population of US patients with nonmetastatic breast cancer.

Modeling the COVID Pandemic: Do Delays in Surgery Justify Using Stereotactic Radiation to Treat Low-Risk Early Stage Non-Small Cell Lung Cancer?

INTRODUCTION: It was suggested that stereotactic radiation (SBRT) is an "alternative if no surgical capacity is available" for non-small cell lung cancer (NSCLC) care during the COVID-19 pandemic. The purpose of this study was to compare the oncologic outcomes of delayed surgical resection and early SBRT among operable patients with early stage lung cancer. METHODS: The National Cancer Database was queried for patients with cT1aN0M0 NSCLC who underwent surgery or SBRT (2010-2016) with no comorbidity. Patients with any comorbidities or age >80 were excluded. The outcome of interest was overall survival. Delays in surgical care were modeled using different times from diagnosis to surgery. A 1:1 propensity match was performed and survival was analyzed using multivariable Cox regression. RESULTS: Of 6720 healthy cT1aN0M0 NSCLC patients, 6008 (89.4%) received surgery and 712 (10.6%) received SBRT. Among surgery patients, time to surgery >30 d was associated with inferior survival (HR > 1.4, P ≤ 0.013) compared with patients receiving surgery ≤14 d. Relative to SBRT, surgery demonstrated superior survival at all time points evaluated: 0-30 d, 31-60 d, 61-90 d, and >90 d (all P < 0.001). Among a propensity-matched cohort of 256 pairs of patients, delayed surgery (>90 d) remained association with better overall survival relative to early SBRT (5-year survival 76.9% versus 32.3%, HR = 0.266, P < 0.001). CONCLUSIONS: Although longer time to surgery is associated with inferior survival among surgery patients, delayed surgery is superior to early SBRT. Surgical resection should remain the standard of care to treat operable early stage lung cancer despite delays imposed by the COVID-19 pandemic.

Racial-ethnic variations in phyllodes tumors among a multicenter United States cohort.

BACKGROUND AND OBJECTIVES: Previous studies have identified racial-ethnic differences in the diagnostic patterns and recurrence outcomes of women with phyllodes tumors (PT). However, these studies are generally limited in size and generalizability. We therefore sought to explore racial-ethnic differences in age, tumor size, subtype, and recurrence in a large US cohort of women with PT. METHODS: We performed an 11-institution retrospective review of women with PT from 2007 to 2017. Differences in age at diagnosis, tumor size and subtype, and recurrence-free survival according to race-ethnicity. RESULTS: Women of non-White race or Hispanic ethnicity were younger at the time of diagnosis with phyllodes tumor. Non-Hispanic Other women had a larger proportion of malignant PT. There were no differences in recurrence-free survival in our cohort. CONCLUSIONS: Differences in age, tumor size, and subtype were small. Therefore, the workup of young women with breast masses and the treatment of women with PT should not differ according to race-ethnicity. These conclusions are supported by our finding that there were no differences in recurrence-free survival.

Adjuvant trastuzumab with or without chemotherapy in stage 1 pT1N0 HER2+ breast cancer: a National Cancer Database analysis.

PURPOSE: Approximately 20% of all breast cancers (BC) are HER2 amplified. In the APT trial, weekly paclitaxel/trastuzumab in node negative HER2+ BC with tumors < 3 cm was associated with a 7-year invasive disease-free survival of 93%. However, this was in the context of a non-randomized trial, and for pT1N0 HER2+ BC it remains unclear whether HER2 monotherapy would provide similar clinical outcomes to chemo-HER2 therapy. We hypothesized that adjuvant chemo-HER2 therapy would be associated with a modestly improved overall survival compared to HER2 monotherapy in patients with tumors < 2 cm. METHODS: In the National Cancer Database (2004-2017), patients with a primary diagnosis of pT1N0M0 HER2+ BC, were separated into two groups: (i) HER2 monotherapy, i.e., trastuzumab, and (ii) chemo-HER2 therapy. A 3:1 propensity match was performed to balance patient selection bias between the two different cohorts. Long-term overall survival (OS) was compared between both groups. RESULTS: A total of 23,281 patients met the criteria. 22,268 (96.7%) received chemo-HER2 therapy and 1013 (4.4%) received HER2 monotherapy. Propensity match identified 1995 patients who received chemo-HER2 therapy, and 666 who received HER2 monotherapy. After matching, adjuvant chemo-HER2 therapy was associated with a modest survival advantage over HER2 monotherapy (5-year OS 94.1% vs. 90.6%, P = 0.041). CONCLUSIONS: Even though there is a modest OS advantage favoring adjuvant chemo-HER2 therapy in patients with pT1N0 HER2+ BC, HER2 monotherapy was associated with 5-year OS > 90%. Therefore, in select patients who have contraindications for cytotoxic chemotherapy, or decline adjuvant chemotherapy altogether, adjuvant trastuzumab monotherapy appears to be a reasonable alternative.

Guideline-Consistent Treatment for Inflammatory Breast Cancer Provides Associated Survival Benefit Independent of Age.

BACKGROUND: Guideline-consistent treatment (GCT) for inflammatory breast cancer (IBC) includes neoadjuvant chemotherapy (NAC), modified radical mastectomy (MRM), and radiation. We hypothesized that younger patients more frequently receive GCT, resulting in survival differences. METHODS: Using the National Cancer Database (2004-2018), female patients with unilateral IBC (by histology code and clinical stage T4d) were stratified by age (< 50, 50-65, > 65 years). Factors associated with NAC, MRM, radiation, and "GCT" (defined as all three treatments) were identified using multivariable logistic regression. Multivariable Cox proportional hazards regression identified predictors of overall survival. RESULTS: Of 3278 IBC patients, 30% were younger than 50 years, 44% were 50-65 years of age, and 26% were older than 65 years. The youngest group comprised the greatest proportion of non-White patients ([35%] vs. [29%] age 50-65 years and [23%] age > 65 years, p < 0.001) and was most often treated at academic facilities ([33%] vs. [28%] age 50-65 years; and [23%] age > 65, p < 0.001). Patients older than 65 years received NAC, MRM, and radiation less frequently, and only 35% underwent GCT (vs. [57%] age 50-65 years and [52%] age < 50 years; p < 0.001). On multivariable logistic regression, age older than 65 years independently predicted omission of NAC (odds ratio [OR], 0.36), MRM (OR, 0.56), and radiation (OR, 0.56) (all p < 0.001), and patients older than 65 years also were less likely to undergo GCT than patients 50-65 years of age (OR, 0.65; p = 0.001). GCT was associated with superior overall survival in all three age groups ([hazard ratio {HR}, 0.61] age < 50 years, [HR, 0.62] age 50-65 years, [HR, 0.53] age > 65 years; all p < 0.001). CONCLUSION: Advanced age alone should not limit receipt of GCT for IBC. Multimodal care should be performed for IBC patients of all ages to improve oncologic outcomes for this aggressive breast cancer subtype.

Neoadjuvant Endocrine Therapy as an Alternative to Neoadjuvant Chemotherapy Among Hormone Receptor-Positive Breast Cancer Patients: Pathologic and Surgical Outcomes.

BACKGROUND: Neoadjuvant chemotherapy (NCT) is considered more effective in downstaging hormone receptor-positive (HR+) breast cancer than neoadjuvant endocrine therapy (NET), particularly in node-positive disease. This study compared breast and axillary response and survival after NCT and NET in HR+ breast cancer. METHODS: Based on American College of Surgeons Oncology Group (ACOSOG) Z1031 criteria, women age 50 years or older with cT2-4 HR+ breast cancer who underwent NET or NCT and surgery were identified in the National Cancer Database 2010-2016. Chi-square and logistic regression analysis determined differences between the NCT and NET groups and therapy response, including downstaging and pathologic complete response (pCR, ypT0/is and ypN0). RESULTS: Of 19,829 patients, 14,025 (70.7%) received NCT and 5804 (29.3%) received NET. The NET patients were older (mean age, 68.9 vs. 60.3; P < 0.001) and had greater comorbidity (1+ Charlson-Deyo score, 21% vs. 16%; P < 0.001). Therapy achieved T downstaging (any) for 58% of the patients with NCT versus 40.5% of the patients with NET, and in-breast pCR was achieved for 9.3% of the NCT versus 1.3% of the NET patients (P < 0.001). Approximately half of the mastectomy procedures could have been potentially avoided for the patients with in-breast pCR (53.6% of the NCT and 43.8% of the NET patients). For the cN+ patients, N downstaging (any) was 29% for the NCT patients versus 18.3% for the NET patients (P < 0.001), and nodal pCR was achieved for 20.3% of the NCT versus 13.5% of the NET patients (P < 0.001). Among those with nodal pCR, axillary lymph node dissection (ALND) still was performed for 56% of the patients after NCT and 45% of the patients after NET. CONCLUSIONS: Although the response rates after NCT were higher, NET achieved both T and N downstaging and pCR. Neoadjuvant endocrine therapy can be used to de-escalate surgery for patients who cannot tolerate NCT or when chemotherapy may not be effective based on genomic testing.

Despite Equivalent Outcomes, Men Receive Neoadjuvant Chemotherapy Less Often Than Women for Lymph Node-Positive Breast Cancer.

BACKGROUND: Neoadjuvant chemotherapy (NAC) downstages breast cancer and provides prognostic information. Males with breast cancer are known to receive less treatment overall and have poorer outcomes relative to females. We hypothesized that males would be less likely to receive NAC. PATIENTS AND METHODS: Patients with a primary diagnosis of cN1-3 breast cancer were identified in the National Cancer Database (2004-2016). Multivariable logistic regression determined the association between NAC utilization and sex, and the relationship between sex and NAC response, controlling for demographic and tumor factors. Overall survival was analyzed using a multivariable Cox model. RESULTS: In total, 196,027 patients (194,010 females, 2017 males) met inclusion criteria. A significantly greater proportion of males underwent mastectomy (80% vs. 60%, P < 0.001), and axillary lymph node dissection (76% vs. 74%, P = 0.022). Overall fewer men received chemotherapy than women (73% vs. 84%, P < 0.001); men also received NAC at a significantly lower rate (26% men vs. 45% women, P < 0.001). After accounting for demographic and oncologic factors including hormone receptor (HR) subtype, females remained more likely to undergo NAC (OR 1.84, P < 0.001). On multivariable analysis, sex was not associated with pathologic response or overall survival after NAC. CONCLUSIONS: Although oncologic outcomes after NAC were similar, males with node-positive breast cancer received less NAC and more aggressive surgery than females. These data suggest men achieve outcomes comparable to women with cN1-3 disease, and NAC should be used in appropriate male patients to downstage the breast and axilla.

Hospital System Adoption of Magnetic Seeds for Wireless Breast and Lymph Node Localization.

BACKGROUND: As an alternative to traditional wire localization, an inducible magnetic seed system can be used to identify and remove nonpalpable breast lesions and axillary lymph nodes intraoperatively. We report the largest single-institution experience of magnetic seed placement for operative localization to date, including feasibility and short-term outcomes. METHODS: Patients who underwent placement of a magnetic seed in the breast or lymph node were identified from July 2017 to March 2019. Imaging findings, core needle biopsy, surgical pathology results, and type of surgery were collected. Outcomes included procedural complications, magnetic seed and biopsy clip retrieval rates, and need for additional surgery. RESULTS: A total of 842 magnetic seeds were placed by nine radiologists in 673 patients and retrieved by six surgeons at six operative locations. The majority of breast lesions were malignant (395/659, 59.9%); 136 seeds were placed for lymph node localization. The overall magnetic seed retrieval rate was 98.6%, whereas the biopsy clip retrieval rate was 90.9%. Only six patients (0.7%) experienced a complication from magnetic seed placement. Reexcision was performed in 15.2% of patients with breast cancer; 9.6% of benign/high risk lesions were upgraded to malignancy at surgical excision. CONCLUSIONS: The magnetic seed technique is safe, effective, and accurate for localization of breast lesions and lymph nodes, and importantly uncouples surgery from the localization procedure. The high magnetic seed retrieval rate and low reexcision rate may reflect the accuracy of magnetic marker placement as a "second chance" localization procedure, especially in cases with biopsy clip migration.

Limited Reporting of Histopathologic Details in a Multi-Institutional Academic Cohort of Phyllodes Tumors: Time for Standardization.

BACKGROUND: Phyllodes tumors are rare fibroepithelial neoplasms that are classified by tiered histopathologic features. While there are protocols for the reporting of cancer specimens, no standardized reporting protocol exists for phyllodes. METHODS: We performed an 11-institution contemporary review of phyllodes tumors. Granular histopathologic details were recorded, including the features specifically considered for phyllodes grade classification. RESULTS: Of 550 patients, median tumor size was 3.0 cm, 68.9% (n = 379) of tumors were benign, 19.6% (n = 108) were borderline, and 10.5% (n = 58) were malignant. All cases reported the final tumor size and grade classification. Complete pathologic reporting of all histopathologic features was present in 15.3% (n = 84) of cases, while an additional 35.6% (n = 196) were missing only one or two features in the report. Individual details regarding the degree of stromal cellularity was not reported in 53.5% (n = 294) of cases, degree of stromal atypia in 58.0% (n = 319) of cases, presence of stromal overgrowth in 56.2% (n = 309) of cases, stromal cell mitoses in 37.5% (n = 206) of cases, and tumor border in 54.2% (n = 298) of cases. The final margin status (negative vs. positive) was omitted in only 0.9% of cases, and the final negative margin width was specifically reported in 73.8% of cases. Reporting of details was similar across all sites. CONCLUSION: In this academic cohort of phyllodes tumors, one or more histopathologic features were frequently omitted from the pathology report. While all features were considered by the pathologist for grading, this limited reporting reflects a lack of reporting consensus. We recommend that standardized reporting in the form of a synoptic-style cancer protocol be implemented for phyllodes tumors, similar to other rare tumors.

Germline Genetic Mutations in a Multi-center Contemporary Cohort of 550 Phyllodes Tumors: An Opportunity for Expanded Multi-gene Panel Testing.

BACKGROUND: A paucity of data exists regarding inherited mutations associated with phyllodes tumors (PT); however, some are reported (TP53, BRCA1, and RB1). A PT diagnosis does not meet NCCN criteria for testing, including within Li-Fraumeni Syndrome (TP53). We sought to determine the prevalence of mutations associated with PT. METHODS: We performed an 11-institution review of contemporary (2007-2017) PT practice. We recorded multigenerational family history and personal history of genetic testing. We identified patients meeting NCCN criteria for genetic evaluation. Logistic regression estimated the association of select covariates with likelihood of undergoing genetic testing. RESULTS: Of 550 PT patients, 59.8% (n = 329) had a close family history of cancer, and 34.0% (n = 112) had ≥ 3 family members affected. Only 6.2% (n = 34) underwent genetic testing, 38.2% (n = 13) of whom had only BRCA1/BRCA2 tested. Of 34 patients tested, 8.8% had a deleterious mutation (1 BRCA1, 2 TP53), and 5.9% had a BRCA2 VUS. Of women who had TP53 testing (N = 21), 9.5% had a mutation. Selection for testing was not associated with age (odds ratio [OR] 1.01, p = 0.55) or PT size (p = 0.12) but was associated with grade (malignant vs. benign: OR 9.17, 95% CI 3.97-21.18) and meeting NCCN criteria (OR 3.43, 95% confidence interval 1.70-6.94). Notably, an additional 86 (15.6%) patients met NCCN criteria but had no genetic testing. CONCLUSIONS: Very few women with PT undergo germline testing; however, in those selected for testing, a deleterious mutation was identified in ~ 10%. Multigene testing of a PT cohort would present an opportunity to discover the true incidence of germline mutations in PT patients.

Risk of Contralateral Breast Cancer in Women with Ductal Carcinoma In Situ Associated with Synchronous Ipsilateral Lobular Carcinoma In Situ.

BACKGROUND: Lobular carcinoma in situ (LCIS) is a risk factor for breast cancer, but the effect of LCIS found in association with ductal carcinoma in situ (DCIS) is unknown. In this study, we compared contralateral breast cancer (CBC) and ipsilateral breast tumor recurrence (IBTR) rates among women with DCIS with or without synchronous ipsilateral LCIS treated with breast-conserving surgery (BCS). METHODS: DCIS patients undergoing BCS from 2000 to 2011 with a contralateral breast at risk were stratified by the presence or absence of synchronous ipsilateral LCIS with the index DCIS (DCIS + LCIS vs. DCIS). Those with contralateral, bilateral, or prior ipsilateral LCIS were excluded. Associations of patient, tumor, and treatment factors with CBC and IBTR were evaluated. RESULTS: Of 1888 patients identified, 1475 (78%) had DCIS and 413 (22%) had DCIS + LCIS. At median follow-up of 7.2 (range 0-17) years, 307 patients had a subsequent first breast event; 207 IBTR and 100 CBC. The 10-year cumulative incidence of IBTR was similar in both groups: 15.0% vs. 14.2% (log-rank, p = 0.8) for DCIS + LCIS vs. DCIS, respectively. The 10-year cumulative incidence of CBC was greater in the DCIS + LCIS group: 10.9% vs. 6.1% for DCIS (log-rank, p < 0.001). After adjustment for other factors, CBC risk remained higher in DCIS + LCIS compared with DCIS (hazard ratio 2.06, 95% confidence interval 1.36-3.11, p = 0.001); there was no significant difference in IBTR risk. CONCLUSIONS: Compared with DCIS alone, DCIS + LCIS is associated with similar IBTR risk but double the risk of CBC. This finding should inform treatment decisions, in particular regarding endocrine therapy for risk reduction.

Impact of Breast Center Accreditation on Compliance with Breast Quality Performance Measures at Commission on Cancer-Accredited Centers.

PURPOSE: This study was designed to determine whether accreditation by the National Accreditation Program for Breast Centers (NAPBC) is associated with improved performance on six breast quality measures pertaining to adjuvant treatment, needle/core biopsy, and breast conservation therapy rates at Commission on Cancer (CoC) centers. METHODS: National Cancer Database 2015 data were retrospectively reviewed to compare patients treated at CoC centers with and without NAPBC accreditation for compliance on six breast cancer quality measures. Mixed effects modeling determined performance on the quality measures adjusting for patient, tumor, and facility factors. RESULTS: Of 1308 CoC facilities, 484 (37%) were NAPBC-accredited and 111,547 patients (48%) were treated at NAPBC centers. More than 80% of patients treated at both NAPBC and non-NAPBC centers received care in compliance with breast quality measures. NAPBC centers achieved significantly higher performance on four of the five quality measures than non-NAPBC centers at the patient level and on five of six measures at the facility level. For two measures, needle/core biopsy before surgical treatment of breast cancer and breast conservation therapy rate of 50%, NAPBC centers were twice as likely as non-NAPBC centers to perform at the level expected by the CoC (respectively odds ratio [OR] 1.96, 95% confidence interval [CI] 1.85-2.08, p < 0.0001; and OR 2.05, 95% CI 1.94-2.15, p < 0.0001). CONCLUSIONS: While NAPBC accreditation at CoC centers is associated with higher performance on breast quality measures, the majority of patients at all centers receive guideline-concordant care. Future studies will determine whether higher performance translates into improved oncologic and patient-reported outcomes.

Contralateral Breast Cancer Risk in Women with Ductal Carcinoma In Situ: Is it High Enough to Justify Bilateral Mastectomy?

BACKGROUND: Women with ductal carcinoma in situ (DCIS) are increasingly choosing bilateral mastectomy. We sought to quantify rates of contralateral breast cancer (CBC) and ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery (BCS) for DCIS, and to compare risk factors for CBC and IBTR. METHODS: From 1978 to 2011, DCIS patients undergoing BCS with a contralateral breast at risk were identified from a prospectively maintained database. The association of clinicopathologic and treatment factors with CBC and IBTR were evaluated using Kaplan-Meier analysis, multivariable Cox regression, and competing risk regression (CRR). RESULTS: Of 2759 patients identified, 151 developed CBC and 344 developed IBTR. Five- and 10-year Kaplan-Meier CBC rates were 3.2 and 6.4%. Overall, 10-year IBTR rates were 2.5-fold higher than CBC rates, and, without radiation, 4-fold higher. On CRR, 5- and 10-year rates were 2.9 and 5.8% for CBC, and 7.8 and 14.5% for IBTR. CBC risk and invasive CBC risk were not significantly associated with age, family history, presentation, nuclear grade, year of surgery, or radiation. By multivariable Cox regression, endocrine therapy was associated with lower CBC risk (hazard ratio 0.57, p = 0.03). Ten-year risk of subsequent CBC in the subset of patients who developed IBTR was similar to the cohort as a whole (8.1 vs. 6.4%). CONCLUSIONS: CBC rates were low across all groups, including those who experienced IBTR. CBC was not associated with factors that increase IBTR risk. While factors associated with IBTR risk are important in decision making regarding management of the index DCIS, they are not an indication for contralateral prophylactic mastectomy.

Fine-Scale Genetic Structure and Reproductive Biology of the Blueberry Pathogen Monilinia vaccinii-corymbosi.

The fungus Monilinia vaccinii-corymbosi, a pathogen of Vaccinium spp., requires asexual and sexual spore production to complete its life cycle. A recent study found population structuring of M. vaccinii-corymbosi over a broad spatial scale in the United States. In this study, we examined fine-scale genetic structuring, temporal dynamics, and reproductive biology within a 125-by-132-m blueberry plot from 2010 to 2012. In total, 395 isolates of M. vaccinii-corymbosi were sampled from infected shoots and fruit to examine their multilocus haplotype (MLH) using microsatellite markers. The MLH of 190 single-ascospore isolates from 21 apothecia was also determined. Little to no genetic differentiation and unrestricted gene flow were detected among four sampled time points and between infected tissue types. Discriminant analysis of principal components suggested genetic structuring within the field, with at least K = 3 genetically distinct clusters maintained over four sampled time points. Single-ascospore progeny from eight apothecia had identical MLH and at least two distinct MLH were detected from 13 apothecia. Tests for linkage disequilibrium suggested that genetically diverse ascospore progeny were the product of recombination. This study supports the idea that the fine-scale dynamics of M. vaccinii-corymbosi may be complex, with genetic structuring, inbreeding, and outcrossing detected in the study area.

Utilization of Axillary Surgery for Patients With Ductal Carcinoma In Situ: A Report From the National Cancer Data Base.

BACKGROUND: This study evaluated the use of axillary surgery (AS), including sentinel lymph node biopsy (SLNB), for patients with ductal carcinoma in situ (DCIS) and the factors associated with its use. To determine whether utilization of SLNB is appropriate, predictors of SLNB performance were compared with factors predictive of tumor upstaging. METHODS: The National Cancer Data Base was utilized to identify patients with American Joint Committee on Cancer (AJCC) clinical stage 0 breast cancer treated from 2004 to 2013. DCIS with microinvasion was excluded. Chi square tests and logistic regression were used to examine patient, tumor, and facility features associated with SLNB and tumor upstaging. RESULTS: Of the 218,945 total patients, 155,093 (70.8 %) underwent lumpectomy, and 63,852 (29.2 %) underwent mastectomy. SLNB was performed for 19.0 % of lumpectomy patients and 63.5 % of mastectomy patients. Multivariate analysis for 2012-2013 demonstrated that estrogen receptor (ER)-negative and grade 3 tumors were more likely to be treated with SLNB in both groups. Tumor size was significant only for the lumpectomy patients who underwent one operation. Further, 22.8 % of lumpectomy patients and 18.7 % of mastectomy patients who underwent AS were upstaged compared with 1.8 % of lumpectomy and 3.6 % of mastectomy patients who did not undergo AS. Tumor upstaging was predicted by ER-negative status (odds ratio [OR] 2.99; 95 % confidence interval [CI] 2.76-3.24) but not by higher grade or larger tumor size. CONCLUSIONS: Use of SLNB for DCIS is high with mastectomy, and nearly one fifth of the lumpectomy patients underwent SLNB. However, the performance of AS was strongly associated with the likelihood of upstaging in both groups, suggesting that surgical judgment plays an important role in this decision.