Microinvasive breast cancer: pathological parameters, cancer subtypes distribution, and correlation with axillary lymph nodes invasion. Results of a large single-institution series

Characteristics and risk factors of axillary lymph node metastasis of microinvasive breast cancer

PURPOSE

To select patients who would benefit most from sentinel lymph node biopsy (SLNB) by investigating the characteristics and risk factors of axillary lymph node metastasis (ALNM) in microinvasive breast cancer (MIBC).

METHODS

This retrospective study included 1688 patients with MIBC who underwent breast surgery with axillary staging at the Asan Medical Center from 1995 to 2020.

RESULTS

Most patients underwent SLNB alone (83.5%). Seventy (4.1%) patients were node-positive, and the majority had positive lymph nodes < 10 mm, with micro-metastases occurring frequently (n = 37; 55%). Node-positive patients underwent total mastectomy and axillary lymph node dissection (ALND) more than breast-conserving surgery (BCS) and SLNB compared with node-negative patients (p < 0.001). In the multivariate analysis, independent predictors of ALNM included young age [odds ratio (OR) 0.959; 95% confidence interval (CI) 0.927-0.993; p = 0.019], ALND (OR 11.486; 95% CI 5.767-22.877; p < 0.001), number of lymph nodes harvested (≥ 5) (OR 3.184; 95% CI 1.555-6.522; p < 0.001), lymphovascular invasion (OR 6.831; 95% CI 2.386-19.557; p < 0.001), presence of multiple microinvasion foci (OR 2.771; 95% CI 1.329-5.779; p = 0.007), prominent lymph nodes in preoperative imaging (OR 2.675; 95% CI 1.362-5.253; p = 0.004), and hormone receptor positivity (OR 2.491; 95% CI 1.230-5.046; p = 0.011).

CONCLUSION

Low ALNM rate (4.1%) suggests that routine SLNB for patients with MIBC is unnecessary but can be valuable for patients with specific risk factors. Ongoing trials for omitting SLNB in early breast cancer, and further subanalyses focusing on rare populations with MIBC are necessary.

Meta-analysis on axillary lymph node metastasis rate in ductal carcinoma in situ with microinvasion

OBJECTIVE

To address the question of axillary lymph node staging in ductal carcinoma in situ with microinvasion (DCIS-MI), we retrospectively evaluated axillary lymph nodes metastasis (ALNM) rate in a cohort of postsurgical DCIS-MI patients. By analyzing these data, we aimed to generate clinically relevant insights to inform treatment decision-making for this patient population.

METHODS

A systematic search was conducted on PubMed, Web of Science, Embase, The Cochrane Library, CNKI, Wanfang Database, Wipe, and China Biomedical Literature Database to identify relevant publications in any language. All the analyses were performed using Stata 16.0 software.

RESULTS

Among the 28 studies involving 8279 patients, the pooled analysis revealed an ALNM rate of 8% (95% CI, 7% to 10%) in patients with DCIS-MI. Furthermore, the rates of axillary lymph node macrometastasis, micrometastasis, and ITC in patients with DCIS-MI were 2% (95% CI, 2% to 3%), 3% (95% CI, 2% to 4%), and 2% (95% CI, 1% to 3%), respectively. Moreover, 13 studies investigated the non-sentinel lymph node (Non-SLN) metastasis rate, encompassing a total of 1236 DCIS-MI cases. The pooled analysis identified a Non-SLN metastasis rate of 33% (95% CI, 14% to 55%) in patients with DCIS-MI.

CONCLUSION

The SLNB for patients with DCIS-MI is justifiable and could provide a novel therapeutic basis for systemic treatment decisions.

Selective Avoidance of Sentinel Lymph Node Biopsy After Neoadjuvant Chemotherapy in Human Epidermal Growth Factor 2-Positive/Triple-Negative Breast Cancer Patients With Excellent Response

PURPOSE

The Avoid Axillary Sentinel Lymph Node Biopsy After Neoadjuvant Chemotherapy (ASLAN) trial aims to demonstrate the oncologic safety of omitting axillary surgery in patients with excellent response after neoadjuvant chemotherapy (NACT) for early human epidermal growth factor 2 (HER2)-positive (+)/triple-negative breast cancer (TNBC) who have undergone breast-conserving surgery (BCS) and adjuvant radiotherapy. The ASLAN trial will provide crucial information that could change the procedure in highly selected patients undergoing axillary surgery after NACT.

METHODS

ASLAN is a prospective, multicenter, and single-arm surgical trial. The recruitment will be conducted among five tertiary care hospitals in the Republic of Korea. The total number of patients to be recruited will be 178, and we plan to complete patient enrollment by December 2023. The enrollment is considered among patients with HER2+ breast cancer (BC) or TNBC at clinical stage T1-3N0-1M0 who are expected to achieve breast pathological complete response (BpCR) based on a combination of radiologic imaging and physical examination after NACT. BCS was performed on eligible patients. After BCS, patients who showed BpCR were enrolled with the omission of sentinel lymph node biopsy (SLNB). The primary study endpoint upon completion of this trial is 5-year recurrence-free survival, and the secondary endpoints include the 5-year ipsilateral breast tumor recurrence interval, 5-year ipsilateral axillary recurrence interval, 5-year distant metastasis-free survival, 5-year BC-specific survival, 5-year overall survival, 5-year contralateral BC-free survival, re-operation rate according to breast biopsy after NACT, adverse events within 5 years, and quality of life.

DISCUSSION

Several clinical trials are currently underway to determine whether SLNB can be omitted after NACT in patients with HER2+ BC or TNBC that are expected to achieve pathologic complete response. The ASLAN trial is expected to provide valuable clues regarding the feasibility of omitting axillary surgery in highly selected patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04993625. Registered on August 6, 2021. Clinical Research Information Service Identifier: KCT0006371. Registered on July 22, 2021.

Clinicopathological characteristics, treatments, and prognosis of breast ductal carcinoma in situ with microinvasion: A narrative review

Background

Ductal carcinoma in situ with microinvasion (DCIS-MI) is defined as ductal carcinoma in situ (DCIS) with a microscopic invasive focus ≤1 mm in the longest diameter. The current literature is controversial concerning the clinical prognostic features and management of DCIS-MI. This narrative review described recently reported literature regarding the characteristics, treatment, and prognosis of it.

Methods

Searching PubMed for relevant articles covering the period of 1982 to 2021 using the following terms by MeSH and free-word: breast cancer, microinvasion, DCIS, DCIS-MI, and invasive ductal carcinoma (IDC).

Results

DCIS-MI tends to express more aggressive pathological features such as necrosis, HER2+, ER- or PR-, and high nuclear grade. The overall prognosis of DCIS-MI is typically good, however, some indicators such as young age, HR-, HER2+ and multimicroinvasive lesions, were associated with worse prognoses. And there are also conflicting results on the differences between the prognoses of DCIS-MI and DCIS or T1a-IDC. Postoperative chemotherapy and anti-HER2 therapy still have uncertain benefits and are more likely to be used to treat high-risk patients who are HR- orHER2+ to improve the prognosis.

Conclusion

DCIS-MI has more aggressive pathological features, which may suggest its biological behavior is worse than that of DCIS and similar to early IDC. Although the overall prognosis of DCIS-MI is good, when making decisions about adjuvant therapy clinicians need to give priority to the hormone receptor status, HER2 expression and axillary lymph node status of patients, because these may affect the prognosis and treatment response.

A clinical diagnostic test on the detection of sentinel lymph node metastasis in breast neoplasms using a 1-step RT-PCR

BACKGROUND

Currently, assessment of sentinel lymph node (SLN) requires cytology, hematoxylin-eosin (HE), and immunohistochemistry (IHC). However, routine pathological slides still suffer from certain sampling errors and have time limitations. This study sought to investigate the sensitivity and specificity of SLN detection by reverse transcription-polymerase chain reaction (RT-PCR), which quantifies the expression of mammaglobin and cytokeratin-19 genes to determine SLN status.

METHODS

The RT-PCR detection of cycles threshold (CT) values has a direct relationship with the lymph node metastasis. This study prospectively collected 256 sentinel lymph nodes from 150 patients diagnosed with breast cancer between August and November 2017. In the detection of metastases in lymph nodes, molecular markers can be verified at the cell-level and tissue-level of tumor cells. In this study, IHC results were used as the gold standard for judging sentinel lymph node status.

RESULTS

(I) According to the established cell models, as the lymph nodes in tumor cells increase, RT-PCR CT values decrease. (II) 83 lymph nodes were first collected, and the interpretation criteria for the molecular detection results were determined based on the IHC results. (III) The statistical analysis showed that the sensitivity of the RT-PCR was 80.49% and the specificity was 91.55%. The positive predictive and negative predictive values were 64.71% and 96.06%, respectively. There was no significant difference between RT-PCR detection and IHC detection (P=0.076). Statistical chi-square analysis also showed that the difference between intraoperative freezing and immunohistochemistry was statistically significant (P=0.000). There was a statistically significant difference between intraoperative freezing and RT-PCR detection (P=0.000). RT-PCR detection is more sensitive than intraoperative frozen detection, and is closer to the results of immunohistochemistry.

CONCLUSIONS

RT-PCR had objective and rapid output advantages, and was proven to be true and reliable. RT-PCR detection can not only rapidly assess sentinel lymph node status in breast cancer patients during surgery, but its accuracy is also close to that of IHC. Correctly determine whether to perform axillary lymph node dissection and improve the survival rate of patients.

Regional Lymph Node Metastasis and Axillary Surgery of Microinvasive Breast Cancer: A Population-Based Study

Microinvasive breast cancer (MBC for short) is a rare entity with the decision of axillary surgery under debate in clinical practice. We aimed to unravel the lymph node metastasis (LNM) rate, axillary surgery, and prognosis of MBC based on 11,692 patients derived from the Surveillance Epidemiology and End Results (SEER) database between 2003 and 2015. In this retrospective study, 19.5% (2276/11,692) of patients received axillary lymph node dissection (ALND), 80.5% (9416/11,692) received non-ALND. In the total cohort, 10-year breast cancer-specific survival (BCSS) was 96.3%, and the LNM rate was 6.4% (754/11,692). Multivariate analyses showed that LNM had the strongest predictive weight (N3, HR 14.200, 95% CI 7.933−25.417; N2, HR 12.945, 95% CI 7.725−21.694; N1, HR 3.05, 95% CI 2.246−4.140, all p < 0.001). Kaplan−Meier analyses showed that ALND did not confer a survival benefit on 10-year BCS in patients with N0 (94.7% vs. 97.1%, p < 0.001) and in patients with 1−2 positive nodes (92.1% vs. 89.5%, p = 0.355), respectively, when compared to non-ALND. Our study demonstrated that the vast majority of MBC have a low LNM rate and excellent prognosis; patients with LNM showed poor prognosis. Assessment of lymph node status is necessary, and non-ALND surgery is required and sufficient for MBC with 0−2 positive nodes.

Breast ductal carcinoma in situ with micro-invasion versus ductal carcinoma in situ: a comparative analysis of clinicopathological and mammographic findings

AIM

To determine the differences in clinicopathological and mammographic findings between ductal carcinoma in situ (DCIS) and ductal carcinoma in situ with micro-invasion (DCIS-MI) and explore clinicopathological and mammographic factors associated with DCIS-MI.

MATERIALS AND METHODS

All DCIS patients with or without micro-invasion who underwent preoperative mammography at The Affiliated Hospital of Qingdao University from January 2016 through June 2020 were identified retrospectively. The correlations of clinicopathological findings with DCIS-MI were evaluated using univariate and multivariate binary logistic regression analyses. Imaging findings were compared between the groups by using the Pearson chi-square test.

RESULTS

A total of 445 DCIS lesions and 151 DCIS-MI lesions were included in the final analysis. Large extent (≥2.7 cm), high nuclear grade, comedo-type, negative progesterone receptor (PR), negative oestrogen receptor (ER), high Ki-67 and axillary lymph node metastasis were more frequently found in DCIS-MI than in DCIS (all p<0.05), and the first four of these were found to be independent predictors of DCIS-MI in the multivariate analysis (all p<0.05). Regarding imaging findings, compared to DCIS, DCIS-MI showed fewer occult lesions and more lesions with calcifications in mass, asymmetry, and architectural distortion (p=0.004). Grouped calcifications were usually associated with DCIS, while regional calcifications were commonly found in DCIS-MI (p<0.05).

CONCLUSION

Large extent, high nuclear grade, comedo-type and negative PR were found to be independent predictors of DCIS-MI. Lesions with calcifications and regional calcifications were more likely associated with DCIS-MI on mammography.

Axillary staging in ductal carcinoma in situ with microinvasion: A meta-analysis

INTRODUCTION

Ductal carcinoma in situ with microinvasion (DCISM); arguably a more aggressive subtype of DCIS, currently has variable recommendations governing its staging and management in the UK. As a result, there is ongoing controversy surrounding the most appropriate management of DCISM, in particular the need of axillary staging.

METHOD

A search was conducted on the databases MEDLINE and Embase using the keywords: breast, DCISM, microinvasion, "ductal carcinoma in situ with microinvasion", sentinel lymph node biopsy, SLNB, axillary staging was performed. 23 studies were selected for analysis. Primary outcome was the positivity of metastasis of lymph node; secondary outcome looked at characteristics of DCISM that may affect node positivity.

RESULTS

A total of 2959 patients were included. Significant heterogeneity was observed amongst the studies with regards to metastases (I² = 61%; P < 0.01). Lymph node macrometastases was estimated to be 2%. Significant subgroup difference was not observed between SLNB technique and lymph node macrometastases (Q = 0.74; p = 0.69). Statistical significance was observed between the focality of the DCISM and lymph node macrometastases (Q = 8.71; p = 0.033).

CONCLUSION

Although histologically more advanced than DCIS, DCISM is not linked with higher rates of clinically significant metastasis to axillary lymph nodes. Survival rates are very similar to those seen in cases of DCIS. Current evidence suggests that axillary staging in cases of DCISM will not change their overall management, thus may only be an unnecessary and inconvenient additional intervention considering the majority of DCISM diagnoses are made from post-operative pathology samples. A multidisciplinary team approach evaluating pre-operative clinical and histological information to tailor the management specific to individual cases of DCISM would be a preferred approach than routine axillary staging.

Breast ductal Carcinoma in situ associated with microinvasion induces immunological response and predicts ipsilateral invasive recurrence

Although microinvasion (Mi) is often thought to be an interim stage between ductal carcinoma in situ (DCIS) and established invasive ductal carcinoma, survival outcomes and biological behaviour of DCIS-Mi are still poorly understood. This study investigated the potential influence of Mi on disease-free survival (DFS) and assessed its correlations with clinicopathological parameters, prognosis, molecular, and immune markers. CD4, CD8, forkhead box P3 (FOXP3), CD68, CD163, programmed cell death protein 1 (PD-1), and its ligand (PD-L1) expression in pure DCIS and DCIS-Mi, from a cohort of 198 patients, were determined by immunohistochemistry. DFS, clinicopathological parameters, immune markers, and biomarker expression were correlated with presence of Mi. Twelve out of 198 DCIS cases were associated with Mi. DCIS-Mi was significantly linked with ipsilateral invasive recurrence (p = 0.032). Kaplan-Meier analysis revealed that DCIS-Mi had worse DFS for ipsilateral invasive recurrence (p = 0.011) and this was affirmed by multivariate Cox regression analysis (95% CI 1.181-9.010, HR = 3.262, p = 0.023). DCIS-Mi was associated with higher densities of immune infiltrates positive for CD4 (p = 0.037), FOXP3 (p = 0.037), CD163 (p = 0.01), and PD-L1 (p = 0.015). This study demonstrated that DCIS-Mi was correlated with high densities of immune infiltrates and predicted ipsilateral invasive recurrence.

Is it ductal carcinoma in situ with microinvasion or "Ductogenesis"? The role of myoepithelial cell markers

Mammary myoepithelial cells have been under-recognized for many years since they were considered less important in breast cancer tumorigenesis compared to luminal epithelial cells. However, in recent years with advances in genomics, cell biology, and research in breast cancer microenvironment, more emphasis has been placed on better understanding of the role that myoepithelial cells play in breast cancer progression. As the result, it has been recognized that the presence or absence of myoepithelial cells play a critical role in the assessment of tumor invasion in diagnostic breast pathology. In addition, advances in screening mammography and breast imaging has resulted in increased detection of ductal carcinoma in situ and consequently more diagnosis of ductal carcinoma in situ with microinvasion. In the present review, we discuss the characteristics of myoepithelial cells, their genomic markers and their role in the accurate diagnosis of ductal carcinoma in situ with microinvasion. We also share our experience with reporting of various morphologic features of ductal carcinoma in situ that may mimic microinvasion and introduce the term of ductogenesis.

Role of Sentinel Lymph Node Biopsy in Microinvasive Breast Cancer

BACKGROUND

Microinvasive ductal carcinoma (DCISM), defined as DCIS with a focus of invasive carcinoma ≤ 1 mm, can be managed similarly to pure DCIS; however, management of the axilla in DCISM has been a subject of debate. Reports in the literature differ on the utility and necessity of sentinel lymph node biopsy (SLNB) for DCISM. The aim of the present study was to identify risk factors for nodal disease in patients with DCISM, which can help develop a selective approach to SLNB in this patient population.

METHODS

The National Cancer Database was used to select patients with DCISM (pT1mi), diagnosed from 2012 to 2015, who underwent SLNB. Multivariable regression analysis was performed to determine associations between sentinel lymph node metastasis and relevant clinical variables.

RESULTS

Our cohort comprised of 2609 patients with pT1mi who underwent SLNB. Of these, 76 (2.9%) were found to have sentinel lymph node metastases on final pathology. Low/intermediate grade tumors were associated with decreased SLN metastasis (OR 0.50, CI 0.28-0.92). Age and receptor status of the tumor did not have a clear association in predicting SLN metastases.

CONCLUSIONS

The rate of sentinel node metastases in DCISM is low at only 2.9% in this national study. Tumor grade was identified as influencing the risk of SLN metastases. This information can factor into shared decision-making for SLNB in patients with DCISM.

The Role of Sentinel Lymph Node Biopsy in Patients With B5c Breast Cancer Diagnosis

BACKGROUND/AIM

The histopathological assessment of the B5c category may sometimes be hampered by simple artifacts that may lead to over- or underestimation of that particular breast cancer so that its management is still controversial, especially with regard to the decision to proceed immediately to sentinel lymph node (SLN) biopsy. Hence, a retrospective study was performed in 174 patients undergoing breast-conserving surgery with a preoperative diagnosis of B5c in order to assess the usefulness of axillary node staging by means of SLN biopsy.

PATIENTS AND METHODS

Pre- and post-operative parameters including imaging data, histology of the primary tumor and SLN biopsy, biological prognostic factors, type of operation, and adjuvant regimens were computed.

RESULTS

Invasive carcinoma and carcinoma in situ were diagnosed in 46 (26.5%) and 128 patients (73.5%), respectively. Preoperative tumor size was significantly related to post-operative diagnosis of invasive carcinoma (p=0.020), retaining its predictive value at logistic regression analysis (p=0.046). Post-operative predictive factors of invasion were represented by tumor stage (p=0.008) and grading (p=0.008).

CONCLUSION

B5c preoperative diagnosis in patients undergoing breast conservative surgery would suggest an immediate wide local excision avoiding any further preoperative histologic assessment. Conversely, one-stage SLN biopsy might be suggested for patients eligible to mastectomy, similar to patients with carcinoma in situ, although its impact on the therapeutic and prognostic assessment seems negligible.

A Nomogram to Predict Factors Associated with Lymph Node Metastasis in Ductal Carcinoma In Situ with Microinvasion

INTRODUCTION

Ductal carcinoma in situ (DCIS) with foci of invasion measuring ≤ 1 mm (DCISM), represents < 1% of all invasive breast cancers. Sentinel lymph node biopsy (SLNB) has been a standard component of surgery for patients with invasive carcinoma or extensive DCIS. We hypothesize that selective performance of SLNB may be appropriate given the low incidence of sentinel node (SN) metastasis for DCISM. We investigated the clinicopathologic predictors for SN positivity in DCISM, to identify which patients might benefit from SLNB.

METHODS

A retrospective review of the National Cancer Database was performed for cases from 2012 to 2015. Clinical and tumor characteristics, including SN results, were evaluated, and Pearson's Chi square tests and logistic regression were performed.

RESULTS

Of 7803 patients with DCISM, 306 (4%) had at least one positive SN. Patients with positive SNs were younger, more often of Black race, had higher-grade histology and larger tumor size, and were more likely to have lymphovascular invasion (LVI; all p < 0.001). In an adjusted model, the presence of LVI was associated with the highest odds ratio (OR) for node positivity (OR 8.80, 95% confidence interval 4.56-16.96).

CONCLUSIONS

Among women with DCISM, only 4% had a positive SN. Node positivity was associated with more extensive and higher-grade DCIS, and the presence of LVI was strongly correlated with node positivity. Our data suggest that LVI is the most important factor in determining which patients with DCISM will benefit from SN biopsy.

Molecular profiling of microinvasive breast cancer microenvironment progression

Background

Tumors develop by progression through a series of stages. Every cell of the tumor microenvironment is constantly changing in the flow of the cancer progression. It has become clear in recent years that stroma is essential for tumor maintenance and growth. Here, we aimed to give a chronological order of gene expression changes given in the dynamical framework of microinvasive breast cancer microenvironment.

Methods

RNA-seq was performed on seven microinvasive breast cancers. For each of them we microdissected seven different portions of the tumor, four related to the breast epithelium and three to the stroma. Breast epithelium was chronologically subdivided in normal breast epithelium (NBE), carcinoma in situ (CIS), emerging invasive fingers (EIF) and invasive breast cancer (IBC). For each of the breast epithelium subdivisions we collected the adjacent stroma (S): S-NBE, S-EIF and S-IBC.

Results

The overall differentially expressed genes (DEGs) in all the compartments were analysed and evaluated to understand the pathways involved in tumor progression. Then we analysed the DEGs of the epithelial and stromal portions in comparison with the normal portions. We observed that the stromal cells are necessary for the development and the maintenance of the tumor, especially in tumor progression. Moreover the most important genes involved in the main metabolic pathways were analysed and the communications within the different cell compartments were highlighted.

Conclusions

As a future perspective, a deeply study of the identified key genes, particularly in the stromal cells, will be crucial to develop an anticancer therapy that is undergoing a conversion from a cancer cell-centric strategy to a stroma-centric strategy, more genomically stable.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1936-x) contains supplementary material, which is available to authorized users.

Is Sentinel Lymph Node Biopsy Required for a Core Biopsy Diagnosis of Ductal Carcinoma In Situ with Microinvasion?

BACKGROUND

Among patients with a core biopsy diagnosis of ductal carcinoma in situ (DCIS), approximately 10% have microinvasion (DCISM), which, like DCIS, is subject to upstaging by surgical excision, but for which the rates of T and N upstaging are unknown, as is the role of sentinel lymph node biopsy (SLNB), since current studies of SLNB for DCISM are based on the final pathologic report, not the core needle biopsy. In this study, we identified the rates of T and N upstaging following surgical excision in patients with a suspected versus definite core needle biopsy diagnosis of DCISM.

METHODS

Overall, 369 consecutive patients (2007-2017) with a core biopsy diagnosis of suspected versus definite DCISM and surgical excision were stratified by extent of DCISM on core biopsy: suspicious focus, single focus, multiple foci/single biopsy, and multiple foci/multiple biopsies. Within strata, we identified clinicopathologic features associated with T and N upstaging.

RESULTS

Across core biopsy strata, there were no clear differences in imaging characteristics or median invasive tumor size (0.2 cm). Among 105 patients with a core biopsy suspicious for DCISM versus 264 with definite DCISM, 28% and 37%, respectively, were upstaged to at least pT1a, but only 1% and 6%, respectively, to pN1.

CONCLUSIONS

Although 28% of patients with suspected DCISM on core biopsy were surgically upstaged to invasive cancer, the frequency of pN1 SLN metastasis (1%) was comparable with that of DCIS, and was insufficient to recommend SLNB at initial surgery. SLNB remains reasonable for patients with definite DCISM on core biopsy.

Sentinel lymph node biopsy in microinvasive ductal carcinoma in situ

BACKGROUND

Microinvasive breast cancer is an uncommon pathological entity. Owing to the rarity of this condition, its surgical axillary management and overall prognosis remain controversial.

METHODS

A database was analysed to identify patients with microinvasive ductal carcinoma in situ (DCIS) who had surgery for invasive breast cancer at the European Institute of Oncology, Milan, between 1998 and 2010. Women who had undergone axillary staging by sentinel lymph node biopsy were included in the study.

RESULTS

Of 257 women with microinvasive breast cancer who underwent sentinel lymph node biopsy (SLNB), 226 (87·9 per cent) had negative sentinel lymph nodes (SLNs) and 31 had metastatic SLNs. Twelve patients had isolated tumour cells (ITCs), 14 had micrometastases and five had macrometastases in sentinel nodes. Axillary lymph node dissection was performed in 16 of the 31 patients with positive SLNs. After a median follow-up of 11 years, only one regional first event was observed in the 15 patients with positive SLNs who did not undergo axillary lymph node dissection. There were no regional first events in the 16 patients with positive SLNs who had axillary dissection.

CONCLUSION

Good disease-free and overall survival were found in women with positive SLNs and microinvasive DCIS. This study is in line with studies showing that SLNB in microinvasive DCIS may not be useful, and supports the evidence that less surgery can provide the same level of overall survival with better quality of life.

Sentinel lymph node biopsy in patients affected by breast ductal carcinoma in situ with and without microinvasion: Retrospective observational study

With the introduction of an organized mammographic screening, the incidence of ductal carcinoma in situ (DCIS) has experienced an important increase. Our experience with sentinel lymph node biopsy (SLNB) among patients with DCIS is reviewed.We collected retrospective data on patients operated on their breasts for DCIS (pTis), DCIS with microinvasion (DCISM) (pT1mi) and invasive ductal carcinoma (IDC) sized ≤2 cm (pT1) between January 2002 and June 2016, focusing on the result of SLNB.543 DCIS, 84 DCISM, and 2111 IDC were included. In cases of DCIS and DCISM, SLNB resulted micrometastatic respectively in 1.7% and 6.0% of cases and macrometastatic respectively in 0.9% and 3.6% of cases. 5-year disease-free survival and overall survival in DCISM and IDC were similar, while significantly longer in DCIS. 5-year local recurrence rate of DCIS and DCISM were respectively 2.5% and 7.9%, and their 5-year distant recurrence rate respectively 0% and 4%. IDC, tumor grading ≥2 and lymph node (LN) macrometastasis were significant predictors for decreased overall survival. Significant predictors for distant metastases were DCISM, IDC, macroscopic nodal metastasis, and tumor grading ≥2. Predictors for the microinvasive component in DCIS were tumor multifocality/multicentricity, grading ≥2, ITCs and micrometastases.Our study suggests that despite its rarity, sentinel node metastasis may also occur in case of DCIS, which in most cases are micrometastases. Even in the absence of an evident invasive component, microinvasion should always be suspected in these cases, and their management should be the same as for IDC.

Risk factors for lymph node metastasis and the impact of adjuvant chemotherapy on ductal carcinoma in situ with microinvasion: a population-based study

BACKGROUND

Ductal carcinoma in situ with microinvasion (DCISM) represents ~1% of all breast cancer cases. Risk factors for lymph node (LN) metastasis and appropriate adjuvant therapy for DCISM are still widely debated.

METHODS

We retrieved DCISM data from the National Cancer Institute's Surveillance, Epidemiology, and End Results registry database (1998-2013). Chi-squared tests and logistic regression models were applied to investigate the potential risks of LN metastasis. Univariate and multivariate Cox proportional hazards regressions were performed to estimate the prognostic factors of DCISM. Survival outcomes were estimated using the Kaplan-Meier method. A 1:1 propensity score matching was used to minimize potential bias.

RESULTS

Overall, 6,219 patients with DCISM met our inclusion criteria. Younger age and higher grade disease were identified as risk factors for LN metastasis. In the multivariable analysis, LN metastasis and chemotherapy were prognostic factors for worse overall survival and breast cancer-specific survival. Furthermore, propensity score matching and subgroup analysis showed that chemotherapy may not be effective for DCISM patients.

CONCLUSION

Younger patients with high-grade disease tend to have LN involved in DCISM. Adjuvant chemotherapy might not be necessary for patients with DCISM.

Microinvasive Carcinoma versus Ductal Carcinoma In Situ: A Comparison of Clinicopathological Features and Clinical Outcomes

PURPOSE

Although microinvasive carcinoma is distinct from ductal carcinoma in situ (DCIS), the clinical significance of microinvasion in DCIS remains elusive. The purpose of this study is to evaluate the clinicopathological features and clinical outcomes of microinvasive carcinoma compared with pure DCIS.

METHODS

We assessed 613 cases of DCIS and microinvasive carcinoma that were consecutively resected from 2003 to 2014 and analyzed clinicopathological variables, expression of standard biomarkers such as the estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), p53, and Ki-67, and tumor recurrence.

RESULTS

Among the 613 cases, 136 (22.2%) were classified as microinvasive carcinoma. Microinvasive carcinoma was significantly associated with DCIS with a large extent, high nuclear grade, necrosis, and comedotype architectural pattern. ER and PR expressions were dominantly observed in pure DCIS, whereas positive HER2 status, p53 overexpression, and high Ki-67 proliferation indices were more frequently observed in microinvasive carcinoma. Lymph node metastasis was found in only four cases of microinvasive carcinoma with multifocal microinvasion. In the multivariate analysis, DCIS with a large extent, comedo-type architectural pattern, and negative ER status were found to be independent predictors of microinvasion. During follow-up, 12 patients had ipsilateral breast recurrence, and no differences in recurrence rates were observed between patients with DCIS and those with microinvasive carcinoma. The triple-negative subtype was the only factor that was associated with tumor recurrence.

CONCLUSION

Microinvasive carcinomas are distinct from DCIS in terms of clinicopathological features and biomarker expressions but are similar to DCIS in terms of clinical outcomes. Our results suggest that microinvasive carcinoma can be treated and followed up as pure DCIS.