Microinvasive carcinoma (T1mic) of the breast: clinicopathologic profile of 21 cases

Evaluation of the Efficacy of Postoperative Adjuvant Therapy for HER2-Positive Ductal Carcinoma in Situ with Microinvasion

A retrospective study on 90 eligible HER2+ ductal carcinoma in situ with microinvasion (DCIS-MI) patients was performed with a median follow-up time of 57 months. The baseline was consistent between the 4-cycle and 6-cycle chemotherapy groups. There were more patients with multiple foci of micrometastasis in the target therapy group in the two groups with or without target therapy (p < 0.01). Postoperative chemotherapy with a 4-cycle regimen can achieve the expected therapeutic effect in patients with HER2+ DCIS-MI, but the role of target therapy in HER2+ DCIS-MI patients has not been confirmed.

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.

Clinical significance of microinvasive breast cancer across the different subtypes and human epidermal growth factor receptor 2 expression levels

PURPOSE

The clinical behavior, prognosis, and management of microinvasive breast cancer (MiBC) is controversial. We aimed to clarify its significance across different subtypes and the role of human epidermal growth factor receptor 2 (HER2) expression in MiBC.

METHODS

We analyzed 1530 patients with T1mi (tumor size ≤ 0.1 cm), node-negative breast cancer who underwent breast conserving surgery or total mastectomy between 2001 and 2020 at the Asan Medical Center (AMC).

RESULTS

When divided into four subtypes, hormone receptor (HR)+/HER2-, HR+ /HER2+ , HR-/HER2+ , and HR-/HER2-, HR-/HER2+ had the highest prevalence rate of 38.5% in MiBC patients. In a median follow-up period of 74 months (0-271 months), 103 (6.7%) patients had recurrent tumor, and 95 (6.2%) had local recurrence. Disease-free survival (DFS) and local recurrence-free survival (LRFS) were worst in the HR-/HER2+ group. The five-year DFS for the HR-/HER2+ group was 92.2%, while it was 97.1% for the HR+/HER2- group (p = 0.024 The five-year LRFS for HER2- patients were better than that of HER2+ MiBC patients, which were 97.1 and 93.8%, respectively (p = 0.010). Univariate and multivariate Cox regression analyses showed that the HR-/HER2+ group had relatively higher risk of recurrence compared to the HR+/HER2- group (hazard ratio [HR] = 2.332, 95% confidence interval [CI] 1.412-3.852, p = 0.001 unadjusted; HR = 3.346, 95% CI 1.408-7.953, p = 0.006 adjusted).

CONCLUSION

HER2 overexpression was significantly associated with adverse clinicopathologic parameters and increased local recurrence risk in MiBC. Therefore, more understanding of the clinical behavior of HER2 in MiBC will enable tailoring of adjuvant therapy for these patients.

Long-term outcomes and effects of hypofractionated radiotherapy in microinvasive breast cancer: Analysis from a randomized trial

PURPOSE

The natural history of microinvasive (T1mi) breast cancer is uncertain. The objective was to evaluate long-term local and distant recurrence rates following breast conserving surgery (BCS) in a prospective cohort of patients with T1mi compared to T1a-2 disease who received whole breast irradiation (WBI) in the context of a randomized trial of hypofractionation.

METHODS

1234 patients with T1-2 N0 breast cancer were randomized to receive adjuvant WBI of 42.5Gy in 16 daily fractions, or 50Gy in 25 daily fractions after BCS. An analysis of patients with T1mi tumors compared with T1a-2 disease was performed. Kaplan-Meier estimates of local recurrence (LR), distant recurrence, and overall survival (OS) were compared using the log-rank test.

RESULTS

Median follow-up was 12 years. T1mi was found in 3% (n = 38) of patients. The 10-year LR rate was 22.6% in T1mi vs. 6.9% in T1a-2 breast cancer [hazard ratio (HR) = 3.73; 95% confidence interval (CI): 1.93, 7.19; p < 0.001]. The 10-year risk of distant recurrence was 5.1% for T1mi, and 12.1% for T1a-2 disease (HR = 0.56; 95% CI: 0.19, 1.84; p = 0.36). Ten-year OS was 91.5% in T1mi and 84.4% in T1a-2 disease, (HR = 0.48; 95% CI: 0.18, 1.30; p = 0.14). Rates of LR did not differ whether treated by hypofractionation or conventional fractionation (HR = 1.21; 95% CI: 0.35, 4.18; p = 0.77).

CONCLUSIONS

The risk of LR was considerably higher in patients with T1mi compared to T1a-2 tumors, but OS remained very good. Future research should evaluate the utility of wider local excision and boost radiation to optimize local control for microinvasive breast cancer.

A deep learning model for breast ductal carcinoma in situ classification in whole slide images

The pathological differential diagnosis between breast ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) is of pivotal importance for determining optimum cancer treatment(s) and clinical outcomes. Since conventional diagnosis by pathologists using microscopes is limited in terms of human resources, it is necessary to develop new techniques that can rapidly and accurately diagnose large numbers of histopathological specimens. Computational pathology tools which can assist pathologists in detecting and classifying DCIS and IDC from whole slide images (WSIs) would be of great benefit for routine pathological diagnosis. In this paper, we trained deep learning models capable of classifying biopsy and surgical histopathological WSIs into DCIS, IDC, and benign. We evaluated the models on two independent test sets (n= 1382, n= 548), achieving ROC areas under the curves (AUCs) up to 0.960 and 0.977 for DCIS and IDC, respectively.

Significance of HER2 in Microinvasive Breast Carcinoma

OBJECTIVES

We compared the clinicopathologic features, clinical management, and outcomes of human epidermal growth factor receptor 2 (HER2)-expressing and nonexpressing microinvasive breast carcinomas (MiBC) to explore the significance of HER2 in MiBC.

METHODS

Clinicopathologic and follow-up information of cases with final diagnosis of MiBC with known HER2 status between 2007 and 2019 were analyzed.

RESULTS

Nineteen (41.3%) HER2-positive (HER2+) and 27 (58.7%) HER2-negative (HER2-) MiBCs were identified. HER2 positivity was likely to be associated with high nuclear grade, presence of tumor-infiltrating lymphocytes, hormonal receptor negativity, and increased Ki-67 in both microinvasive and associated in situ carcinomas. Nodal metastases were found in 2 ER+/HER2- cases (5.3%). One HER2+ case was found to have isolated tumor cells in the axillary node. The majority of patients with HER2+ MiBCs (76.5%) did not receive HER2-targeted therapy. All patients with available follow-up were alive without recurrence or distant metastasis, with a median follow-up of 38 months.

CONCLUSIONS

Similar to the larger size of invasive breast carcinomas, HER2 positivity is associated with high-grade morphologic features in MiBCs. However, HER2 overexpression in MiBCs does not appear to be associated with nodal metastasis or worse outcome in our study cohort. The role of HER2-targeted therapy in this clinical setting merits additional study.

Impact of microinvasion on breast cancer mortality in women with ductal carcinoma in situ

BACKGROUND

Ductal carcinoma in situ (DCIS) is a neoplastic proliferation of epithelial cells which is confined within the basement membrane of the mammary ductal-lobular system. It is of interest to determine to what extent the potential to metastasize increases for DCIS patients when the basement membrane is breached (i.e. microinvasion is present).

METHODS

We retrieved the records of 525,395 women who had either first primary DCIS or small (≤ 2.0 cm) node-negative invasive breast cancer in the Surveillance, Epidemiology and End Results (SEER) registries database (1990-2013). For each patient, we extracted information on year of diagnosis, age at diagnosis, tumour size, tumour grade, oestrogen receptor status, use of radiotherapy, type of surgery, cause of death and follow-up time. We classified patients into four groups, according to the size of the invasive component of the primary tumour. We estimated the actuarial rate of breast cancer-specific mortality at ten and 20 years for women in each size category.

RESULTS

We identified 161,394 women with pure DCIS, 13,489 women with microinvasive carcinoma (≤ 0.1 cm of invasion), 153,856 women with invasive cancer 0.2-1.0 cm in size and 196,656 women with invasive cancer 1.1-2.0 cm in size. The 20-year actuarial breast cancer-specific mortality rate was 3.8% for women with pure DCIS, was 6.9% for women with microinvasive carcinoma, was 6.8% for women with invasive cancer 0.2-1.0 cm in size and was 12.1% for women with invasive cancer 1.1-2.0 cm in size. The adjusted hazard ratio for death associated with microinvasive carcinoma (vs. pure DCIS) was 2.00 (95% CI 1.76-2.26; p < 0.0001).

CONCLUSIONS

In terms of prognosis, microinvasive cancer more closely resembles small invasive cancer 0.2-1.0 cm) than pure DCIS. For invasive cancers under 1.0 cm, size has little impact on mortality.

Pathways to clinical CLARITY: volumetric analysis of irregular, soft, and heterogeneous tissues in development and disease

Three-dimensional tissue-structural relationships are not well captured by typical thin-section histology, posing challenges for the study of tissue physiology and pathology. Moreover, while recent progress has been made with intact methods for clearing, labeling, and imaging whole organs such as the mature brain, these approaches are generally unsuitable for soft, irregular, and heterogeneous tissues that account for the vast majority of clinical samples and biopsies. Here we develop a biphasic hydrogel methodology, which along with automated analysis, provides for high-throughput quantitative volumetric interrogation of spatially-irregular and friable tissue structures. We validate and apply this approach in the examination of a variety of developing and diseased tissues, with specific focus on the dynamics of normal and pathological pancreatic innervation and development, including in clinical samples. Quantitative advantages of the intact-tissue approach were demonstrated compared to conventional thin-section histology, pointing to broad applications in both research and clinical settings.

Update on Immunohistochemical Analysis in Breast Lesions

CONTEXT

- The utility of immunohistochemistry (IHC) in breast lesions needs to be updated with exceptions among these lesions. Biomarker studies with IHC in triple-negative breast carcinoma may help develop targeted therapies for this aggressive breast cancer. The distinction of metastatic lung adenocarcinoma to the breast and invasive breast carcinoma has significant prognostic and therapeutic implications. The determination can be challenging because both primary tumors can express estrogen receptor and/or HER2 by IHC, creating a diagnostic dilemma.

OBJECTIVES

- To provide a practical update on the use of IHC markers in differential diagnoses in breast lesions, including benign, atypical, precancerous, and malignant tumors; to highlight recently published research findings on novel IHC markers in triple-negative breast carcinoma cases; and to reinforce the importance of IHC use as an ancillary tool in distinguishing metastatic lung adenocarcinoma to the breast from primary breast carcinoma using real case examples.

DATA SOURCES

- PubMed (US National Library of Medicine, Bethesda, Maryland) literature review and authors' research data and personal experiences were used in this review.

CONCLUSIONS

- Immunohistochemistry has an important role in making differential diagnoses in breast lesions in morphologically equivocal settings; recognizing IHC expression status in the exceptions among these lesions will aid in the correct diagnosis of challenging breast cases. Studies suggest that androgen receptor, p16, p53, GATA3, and PELP1 may have potential diagnostic, prognostic, and predictive value in triple-negative breast carcinoma cases; these findings may provide insight and a greater understanding of the tumor biology in triple-negative breast carcinomas. In distinguishing metastatic estrogen receptor-positive or HER2⁺ lung adenocarcinoma to the breast from primary breast carcinoma, napsin A, TTF-1, and GATA3 comprise a useful IHC panel.

Complexities and challenges in the pathologic assessment of size (T) of invasive breast carcinoma

Size (the "T" in the TNM System) of invasive breast carcinoma is a proven independent prognostic factor; however, its accurate determination can be challenging. The purpose of this review is to discuss the complexities inherent in determining "T"-including those encountered in the clinical measurement ("cT", ie, physical and radiologic assessment) as well as pathologic determination (pT) of invasive breast carcinomas. Pathologic estimation of tumor size, macroscopic, as well as microscopic, can be problematic due to the complexity of multiple situations, seeming confusion regarding staging guidelines, and interobserver variation in interpretation. Additional problematic scenarios in determination of "T" include those incurred in excisions performed after the performance of needle core biopsies, and in cases wherein there are multiple foci of invasive carcinoma, as well as in carcinomas status post-neoadjuvant chemotherapy. It can also be difficult to determine "T" in certain types of invasive carcinoma, particularly those of the lobular type. In this communication, some of the complexities and challenges in determing "T" are discussed, and modest suggestions are offered to assist in optimizing such assessments.

Re-evaluating the role of sentinel lymph node biopsy in microinvasive breast carcinoma

The role of sentinel lymph node biopsy in microinvasive breast carcinoma is unclear. We examined the incidence of lymph node metastasis in patients with microinvasive carcinoma who underwent surgery at our institution. Retrospective review of our pathology database was performed (1994-2012). Of 7000 patients surgically treated for invasive breast carcinoma, 99 (1%) were classified as microinvasive carcinoma. Axillary staging was performed in 81 patients (64, sentinel lymph node biopsy; 17, axillary lymph node excision). Seven cases (9%) showed isolated tumor/epithelial cells in sentinel nodes. Three of these seven cases showed reactive changes in lymph nodes, papillary lesions in the breast with or without displaced epithelial cells within biopsy site tract, or immunohistochemical (estrogen receptor, progesterone receptor, and HER2) discordance between the primary tumor in the breast and epithelial cells in the lymph node, consistent with iatrogenically transported epithelial cells rather than true metastasis. The remaining four cases included two cases, each with a single cytokeratin-positive cell in the subcapsular sinus detected by immunohistochemistry only, and two cases with isolated tumor cells singly and in small clusters (<20 cells per cross-section) by hematoxylin and eosin and immunohistochemistry. The exact nature of cytokeratin-positive cells in the former two cases could not be determined and might still have represented iatrogenically displaced cells. In the final analysis, only two cases (3%) had isolated tumor cells. Three of these four cases had additional axillary lymph nodes excised, which were all negative for tumor cells. At a median follow-up of 37 months (range 6-199 months), none of these patients had axillary recurrences. Our results show very low incidence of sentinel lymph node involvement (3%), only as isolated tumor cells, in microinvasive carcinoma patients. None of our cases showed micrometastases or macrometastasis. We recommend reassessment of the routine practice of sentinel lymph node biopsy in patients with microinvasive carcinoma.

A Brief Overview of the WHO Classification of Breast Tumors, 4th Edition, Focusing on Issues and Updates from the 3rd Edition

The WHO Classification of Tumors of the Breast, 4th edition, is an update to the 3rd edition that was published in 2003, and covers all neoplastic and preneoplastic lesions of the breast. Changes to the 4th edition include new aspects and changes to the terminology that reflect our present-day knowledge of these lesions. Definitions for histopathological diagnosis are complemented by a description of clinical features, epidemiology, macroscopy, genetics, and prognostic and predictive features. In this review of the WHO classification, we have focused on invasive carcinomas, precursor lesions, and some benign epithelial proliferations.

Changes in breast cancer reports after pathology second opinion

Breast cancer pathology reports contain valuable information about the histologic diagnosis, prognostic factors and predictive indicators of therapeutic response. A second opinion may be requested by medical oncologists and surgeons, when a patient is referred from another institution for treatment. We report the experience with pathology second opinion in selected patients referred to the Breast Oncology Unit. 205 cases referred to the Breast Oncology Unit were selected for second opinion after clinical evaluation, between 2002 and 2012. The cases reviewed included 102 core needle biopsies, 88 surgical specimens from the breast and 18 lymphadenopathies, 14 from the axillary region. Pathology second opinion was based on a review of hematoxylin-eosin preparations, recuts of submitted paraffin blocks and written external pathology reports. Immunohistochemical studies for hormone receptors, HER2, myoepithelial cells, and other markers were performed in selected cases. A case was reclassified as showing major change when second opinion showed a potential for significant change in prognosis or treatment. Otherwise, it was considered to represent minor change or to be concordant. In 52 cases (25.4%), the pathology review showed changes. Thirty-three (16%) patients were reclassified for major changes and 19 (9.2%) as minor changes. In six patients, more than one major change was identified. The major discrepancies identified were related to the histologic classification (12 cases), the presence or absence of invasion in ductal carcinoma (15 cases), the results of hormone receptors (5 cases), and HER2 (7 cases). Major changes in histologic classification included two cases diagnosed as invasive ductal carcinoma and reclassified as benign, four cases with diagnosis of breast cancer reclassified as metastatic lung cancer, one case diagnosed as small cell carcinoma of lung metastatic in the breast, reclassified as primary carcinoma of the breast, and three cases with diagnosis of breast cancer in the axilla reclassified as primary cutaneous adnexal carcinomas (2) and metastatic melanoma (1), respectively. In two cases, the histologic type of the primary breast tumor was changed. Second opinion in breast pathology may uncover significant discrepancies that impact on patient management and prognosis. Major discrepancies are most frequently related to the assessment of the presence or absence of invasion in ductal carcinoma, the results of predictive makers of therapeutic response, and the differential diagnosis of breast cancer and nonmammary tumors in the breast, the axilla, and at distant sites.

Expression and role of fibroblast activation protein-alpha in microinvasive breast carcinoma

BACKGROUND

Diagnosis of ductal carcinoma in situ (DCIS) in breast cancer cases is challenging for pathologist due to a variety of in situ patterns and artefacts, which could be misinterpreted as stromal invasion. Microinvasion is detected by the presence of cytologically malignant cells outside the confines of the basement membrane and myoepithelium. When malignant cells invade the stroma, there is tissue remodeling induced by perturbed stromal-epithelial interactions. Carcinoma-associated fibroblasts (CAFs) are main cells in the microenvironment of the remodeled tumor-host interface. They are characterized by the expression of the specific fibroblast activation protein-alpha (FAP-α), and differ from that of normal fibroblasts exhibiting an immunophenotype of CD34. We hypothesized that staining for FAP-α may be helpful in determining whether DCIS has microinvasion.

METHODS

349 excised breast specimens were immunostained for smooth muscle actin SMA, CD34, FAP-α, and Calponin. Study material was divided into 5 groups: group 1: normal mammary tissues of healthy women after plastic surgery; group 2: usual ductal hyperplasia (UDH); group 3: DCIS without microinvasion on H & E stain; group 4: DCIS with microinvasion on H & E stain (DCIS-MI), and group 5: invasive ductal carcinoma (IDC). A comparative evaluation of the four immunostains was conducted.

RESULTS

Our results demonstrated that using FAP-α and Calponin adjunctively improved the sensitivity of pathological diagnosis of DCIS-MI by 11.29%, whereas the adjunctive use of FAP-α and Calponin improved the sensitivity of pathological diagnosis of DCIS by 13.6%.

CONCLUSIONS

This study provides the first evidence that immunostaining with FAP-α and Calponin can serve as a novel marker for pathologically diagnosing whether DCIS has microinvasion.

The incidence and predictor of lymph node metastasis for patients with T1mi breast cancer who underwent axillary dissection and breast irradiation: an institutional analysis

OBJECTIVE

This study was designed to evaluate the rate and the predictors of axillary lymph node metastasis in patients with T1mi breast cancer.

METHODS

We analyzed 62 cases of ductal carcinoma in situ with microinvasion, and the pathology records and treatment charts were retrospectively reviewed for information on the patient and tumor characteristics. All the included patients underwent breast conserving surgery and 48 patients underwent axillary lymph node dissection.

RESULTS

The incidence of axillary involvement was 8.3%. Comedo ductal carcinoma in situ (P = 0.031), histologic grade 3 (P = 0.025), the presence of necrosis (P = 0.007) and Van Nuys group 3 (P = 0.025) were significant predictors of axillary involvement on the statistical analysis. Axillary dissection was significantly associated with the occurrence of arm lymphedema (P = 0.030).

CONCLUSIONS

A significant rate of axillary metastases occurred in the patients with T1mi breast carcinoma in this study. The comedo subtype of ductal carcinoma in situ, a high histologic grade, the presence of necrosis and the Van Nuys group 3 were significant predictors of axillary lymph node metastasis in patients with T1mi breast cancer. Thus, the patients with T1mi breast disease are indicated to a careful evaluation of axillary lymph node metastasis, if they have the earlier-mentioned unfavorable factors.

Microinvasive breast cancer and the role of sentinel node biopsy: an institutional experience and review of the literature

Ductal carcinoma in situ with microinvasion (DCISM) is a distinct clinicopathologic entity. Its true metastatic potential has been unclear, due in part to historical differences in the definition of microinvasion. The role of routine axillary staging for DCISM is controversial, given the reportedly low incidence of axillary metastases. We describe our institutional experience with DCISM, and define the role of axillary staging. A retrospective analysis was made of patients with DCISM. Forty-four patients underwent axillary staging (24 axillary lymph node dissection [ALND], 22 sentinel node biopsy [SNB]). Macrometastatic disease was present in three patients (7%), and two patients had isolated tumor cells (itc) in the sentinel node. Patients with axillary metastases tended to be younger. Comedonecrosis, nuclear grade, multifocal microinvasion or presentation as a clinical mass was not associated with a higher rate of axillary metastases. In this series, 7% of patients had macrometastatic disease, and two patients (5%) had itc only. Axillary staging is indicated, and SNB is appropriate for the identification of axillary metastatic disease.

Cancer canalaire in situ du sein avec micro-invasion. Place du ganglion sentinelle

OBJECTIVES

To investigate the role of sentinel lymph node biopsy for microinvasive ductal carcinoma in situ of the breast.

PATIENTS AND METHODS

From January 2001 to January 2006, lymphatic mapping was performed using radiocolloid and/or blue dye technique. Full axillary lymph node dissection was accomplished systematically in 10 instances at the beginning of the study, and furthermore when the sentinel node was involved (macrometastatic or micrometastatic disease).

RESULTS

Identification rate was 98% (40/41), the unsuccessful procedure occurred after incisional biopsy for diagnosis. The number of sentinel nodes removed was 2 in average (1-5). Sentinel node involvement was found in 10% of cases (4/40): 1 sentinel node macrometastasis pN1, 2 sentinel node micrometastases determined by hematoxylin and eosin staining pN1 (mi), 1 sentinel node micrometastasis detected only by immunohistochemical staining pN0 (mi).

DISCUSSION AND CONCLUSION

Sentinel lymph node sampling should not be currently applied for management of every ductal carcinoma in situ of the breast but a selective utilization is proposed in documented high risk subset of patients according to clinical, mammographic, and histologic features obtained by percutaneous biopsies. Ductal carcinoma in situ (DCIS) with proved or suspected microinvasion could be scheduled for sentinel node procedure a fortiori in cases undergoing mastectomy because of extensive DCIS before the occurrence of disturbances of lymphatic drainage induced by surgical breast dissection.

Cancers canalaires in situ du sein avec micro-invasion

OBJECTIVE

Specify the role of axillary lymph node removal in micro-invasive in situ duct carcinomas (DCIS-MI) of the breast with a series of 107 consecutive cases.

METHODS

Single-centre, retrospective, anatomoclinical study with application of the European guidelines adopting as pathological definition the presence of areas of micro-invasion not exceeding 1mm. Axillary lymph node dissection was systematically complete and was preceded by the search for the sentinel node in 10 patients using the isotope method.

RESULTS

Lymph node invasion was revealed in 8 cases in the global population (7.5%). All the cases except one exhibited typical deleterious histological features: comedo architectural sub-type, high nuclear grade, and size of the lesion>3 cm. The lymph node invasion was of 18.5% in the sub-group of high-grade micro-invasive comedo-carcinomas measuring more than 3 cm.

CONCLUSION

Contrary to those exhibiting pure DCIS, DCIS-MI patients require surgical exploration of the armpit, the most appropriate modalities of which are currently debated: classical axillary lymph node dissection or search for the sentinel lymph node; the selective lymphadenectomy procedure is not yet a consensually validated technique.

Ductal carcinoma in situ, complexities and challenges

The incidence of ductal carcinoma in situ (DCIS), a noninvasive form of breast cancer, has increased markedly in recent decades, and DCIS now accounts for approximately 20% of breast cancers diagnosed by mammography. Laboratory and patient data suggest that DCIS is a precursor lesion for invasive cancer. The appropriate classification of DCIS has provoked much debate; a number of classification systems have been developed, but there is a lack of uniformity in the diagnosis and prognostication of this disease. Further investigation of molecular markers should improve the classification of DCIS and our understanding of its relationship to invasive disease. Controversy also exists with regard to the optimal management of DCIS patients. In the past, mastectomy was the primary treatment for patients with DCIS, but as with invasive cancer, breast-conserving surgery has become the standard approach. Three randomized trials have reported a statistically significant decrease in the risk of recurrence with radiation therapy in combination with lumpectomy compared with lumpectomy alone, but there was no survival advantage with the addition of radiotherapy. Two randomized trials have suggested an additional benefit, in terms of recurrence, with the addition of adjuvant tamoxifen therapy, although in one trial the benefit was not statistically significant. Current data suggest that tamoxifen use should be restricted to patients with estrogen receptor-positive DCIS. Neither trial demonstrated a survival benefit with adjuvant tamoxifen. Ongoing and recently completed studies should provide information on outcomes in patients treated with lumpectomy alone and on the effectiveness of aromatase inhibitors as an alternative to tamoxifen.

Evolving entities and changing concepts in breast pathology

Among the evolving entities and changing concepts in breast pathology are those relating to columnar cell hyperplasia, pseudoangiomatous stromal hyperplasia, mucocele-like lesions, pleomorphic lobular carcinoma in situ, pseudo-Paget's disease of nipple, microinvasive carcinoma of breast, spindle cell metaplastic carcinoma, and minimal metastatic disease in axillary lymph nodes. Pathologists, as well as physicians involved in the management of breast diseases, need to be aware of these recent developments in breast pathology since the recognition and understanding thereof may have considerable clinical relevance.

Ductal carcinoma in situ with microinvasion

BACKGROUND

Ductal carcinoma in situ (DCIS) accounts for nearly 20% of new breast cancer diagnoses and ductal carcinoma in situ with microinvasion (DCIS-MI) is found in 5% to 10% of DCIS. Controversy exists regarding the appropriate local treatment as well as whether or not examination of the axilla should be performed either by sentinel lymph node biopsy (SLNB), axillary lymph node dissection (ALND) or not at all.

METHODS

A MEDLINE search was performed using the keywords ductal carcinoma in situ and microinvasion. Recent articles pertaining to the definition and characterization of DCIS-MI as well as treatment and prognosis were analyzed.

CONCLUSIONS

The data at this time demonstrate no survival benefit for patients undergoing mastectomy versus lumpectomy and radiation. Numerous studies demonstrate axillary lymph node involvement to be as high as 20% with DCIS-MI; therefore, we believe that axillary sampling is essential. We recommend SLNB, which is accurate, provides information necessary for staging and treatment, and is associated with less morbidity than traditional ALND.

The finding of invasive cancer after a preoperative diagnosis of ductal carcinoma-in-situ: causes of ductal carcinoma-in-situ underestimates with stereotactic 14-gauge needle biopsy

BACKGROUND

For the evaluation of nonpalpable lesions of the breast, image-guided 14-gauge automated needle biopsy is increasingly replacing wire-localized excision. When ductal carcinoma-in-situ (DCIS) is diagnosed at core biopsy, invasive cancer is found in approximately 17% of excision specimens. These so-called DCIS underestimates pose a problem for patients and surgeons, because they generally cause extension of treatment. We evaluated DCIS underestimates in detail to assess reasons for missing the invasive component at core biopsy. This evaluation also included a histological comparison with true DCIS (DCIS at core biopsy and excision).

METHODS

Between 1997 and 2000, DCIS was diagnosed at 14-gauge needle biopsy in 255 patients. In 41 cases (16%), invasive cancer was found at excision. We performed a thorough histopathological and radiological review of all these DCIS underestimates, including a histological comparison with core biopsy specimens of 32 true DCIS cases. We assessed the main reason for missing the invasive component at core biopsy.

RESULTS

Causes for DCIS underestimates were categorized into "mainly radiological" (n = 20), "mainly histopathological" (n = 15), and "histological disagreements" (n = 6). High-grade DCIS and periductal inflammation in core biopsies made a DCIS underestimate 2.9 and 3.3 times more likely, respectively.

CONCLUSIONS

A variety of radiological and histopathological reasons contribute to the DCIS underestimate rate. Approximately half of these are potentially avoidable.

Microinvasive ductal carcinoma (T1mic) of the breast. The clinicopathological profile and immunohistochemical features of 28 cases

Microinvasive ductal carcinoma of the breast, namely ductal carcinoma in situ with microinvasion (T1mic) as defined by the American Joint Committee on Cancer (AJCC) Staging Manual, is a rare disease, although it is increasing because of widespread use of mammography. The aim of the present study was to describe the clinicopathological and immunohistochemical features of this entity. Twenty-eight patients who were diagnosed as T1mic from January 1997 to August 2002 were studied by using 3-5 mm-thick serial sections with hematoxylin-eosin staining. Immunohistochemical staining for the estrogen receptor (ER), progesterone receptor (PR), p53, Ki-67, and HER-2 were performed. All 28 patients were female, with a mean age of 48.8 years. Twenty-six patients (93%) revealed mammographic abnormalities on routine examination. All foci of the invasions were measured using an ocular micrometer. Invasive foci consisted of isolated cells or cell clusters, or appeared as a tongue-like projection of tumor through the basement membrane of the duct of ductal carcinoma in situ (DCIS). The mean number of invasive foci was 3, and the mean size was 0.6 mm. We found that high nuclear grade and predominant comedo subtype of DCIS components were 57.1% and 46.4%, respectively. Twenty-four cases (86%) demonstrated necrosis of DCIS components. Microinvasion was often associated with periductal stromal reaction (71.5%) and/or a lymphocytic infiltration (78.6%). All patients, excluding two, received axillary resection (the mean number of lymph nodes examined per case was 12), and none had lymph node metastasis. The positive expression of ER and PR strongly related to low grade nuclei and non-comedo subtype; however, the positive expression of HER-2 and P53 related to high grade nuclei and comedo subtype (P<0.01). Ki-67 expression was significantly higher in the high grade nuclei group than in the low grade group (P<0.01). Our study suggested that high nuclear grade and comedo DCIS were more aggressive and more common with microinvasion, and that microinvasion is more likely to be multifocal.

Oestrogen receptor negativity as a marker for high-grade ductal carcinoma in situ of the breast

AIMS

To compare the morphological and immunohistochemical characteristics of oestrogen receptor (ER)-negative and ER-positive ductal carcinoma in situ (DCIS) of the breast, in an attempt to establish more objective criteria for the classification of DCIS.

METHODS AND RESULTS

Sections of 64 cases of in-situ carcinoma of the breast were stained for ER, progesterone receptors (PgR), androgen receptors (AR), c-erbB-2 and p53, using the immunoperoxidase technique. The cases included 60 DCIS and four lobular carcinoma in situ (LCIS). Four DCIS lesions were associated with foci of microinvasion. The 60 DCIS cases included 31 high grade, 23 intermediate grade and six low grade. Twenty-four DCIS cases (40%) were ER-negative and 36 were positive. ER negativity was significantly associated with high nuclear grade (88% versus 27% for ER-positive cases, P < 0.001), PgR negativity (100% versus 25%, P < 0.001), c-erbB-2 positivity (79% versus 14%, P < 0.001) and p53 positivity (58% versus 6%, P < 0.001). There was no difference between ER-negative and -positive DCIS as regards AR expression, with 91% of cases in each group being AR-positive. Of the four cases of DCIS with microinvasion, three were ER- and PgR-negative, all four were c-erbB-2-positive and AR-positive and one was p53-positive. None of the four LCIS was ER, PgR or AR-negative and none was c-erbB-2- or p53-positive.

CONCLUSIONS

There is a highly significant direct relationship between ER negativity in DCIS and high nuclear grade, PgR negativity and c-erbB-2 and p53 positivity. We suggest that immunohistological assessment of ER status may help in providing a more objective way of classifying DCIS.

Pathology of preinvasive and excellent-prognosis breast cancer

Our review of recent developments in breast cancer emphasizes clinical utility of tissue samples from patients. We highlight indicators of increased cancer risk and lesions without metastatic capacity at time of detection (but of sufficient risk of attaining metastatic capacity that treatment is mandated, ie, ductal carcinoma in situ). This review also includes invasive lesions with little capacity for metastatic behavior and indicators of low malignant potential. Histologic criteria for their recognition, as well as biologic and clinical characterization, are discussed. Several papers reviewing the usefulness of histologic grading, emphasizing mitotic counts and definitions of microinvasion, are included.

Are microinvasion and micrometastasis in breast cancer mountains or molehills?

BACKGROUND

The increased rate of early detection of breast cancer due to widespread mammographic screening has led to an increased incidence of in situ as well as microinvasive carcinoma. The enhanced pathological examination to which sentinel lymph nodes are subjected has led to an increased rate of detection of micrometastatic carcinoma. Despite the augmented rate of diagnoses of both diseases, the pathological diagnoses as well as clinical management of these entities continue to be controversial.

DATA SOURCES

A computerized literature search was performed on the Medline and PubMed database from 1990 to date. Relevant earlier publications were also perused. The database of the Department of Pathology at New York Presbyterian Hospital-Well Medical College of Cornell University were also accessed.

CONCLUSIONS

Based on cumulative data, patients diagnosed with either microinvasive or micrometastatic carcinoma of breast have a relatively favorable, albeit guarded, prognosis. Treatment recommendations for both of these disease entities continue to be controversial, and may remain so until additional refined clinicopathological data becomes available.