Is there a role for hormonal therapy in neuroendocrine carcinoma of the breast? A Paradigmatic case report

Neuroendocrine neoplasms of the breast: a review of literature

Primary neuroendocrine neoplasms (NENs) of the breast are characterized by neuroendocrine architectural and cytological features, which must be supported by immunohistochemical positivity for neuroendocrine markers (such as Chromogranin and Synaptophysin). According to the literature, making a diagnosis of primary neuroendocrine breast cancer always needs to rule out a possible primary neuroendocrine neoplasm from another site. Currently, the latest 2022 version of the WHO of endocrine and neuroendocrine neoplasms has classified breast NENs as well-differentiated neuroendocrine tumours (NETs) and aggressive neuroendocrine carcinomas (NECs), differentiating them from invasive breast cancers of no special type (IBCs-NST). with neuroendocrine features. The current review article describes six cases from our series and a comprehensive review of the literature in the field of NENs of the breast.

Management of Neuroendocrine Breast Carcinoma (NEBC): Review of Literature

Extra pulmonary high-grade poorly differentiated neuroendocrine carcinomas (EP-NECs) are rare tumors that usually arise in the gastrointestinal and genitourinary tracts. Primary neuroendocrine carcinoma of the breast (NEBC) is extremely rare, representing less than 0.1% of all breast cancers and less than 1% of neuroendocrine neoplasms. Consequently, they can be misdiagnosed as other types of breast cancer, however, proper immunohistochemical (IHC) studies can assist with making the correct diagnosis. Management of NEBC can be challenging given the paucity of evidence-based literature and should not routinely follow the therapeutic guidelines of other breast cancers. In this article, we review the current literature regarding the management of NEBC.

Retrospective literature review of primary neuroendocrine neoplasms of the breast (BNEN) in 209 Chinese patients: Treatment and prognostic factor analysis

Background

The prognostic factors and optimal choice of treatment for primary neuroendocrine neoplasms of the breast (BNEN) remain to be defined.

Methods

Patients diagnosed with BNEN in China were retrospectively reviewed from the literature following the systematic search of China National Knowledge Infrastructure (CNKI), Chinese biomedical literature service system (sinomed), wanfang medical network, and Pubmed database. The clinical characteristics and different treatment modalities of patients with BNEN were evaluated.

Results

A total of 209 cases with BNEN were enrolled. There were 204 female and 5 male patients. The median age was 51 years old (range, 17–82). Out of 209 patients with BNEN, 208 (99.5%) patients were treated with surgery (SG), 44 patients (21.1%) had received radiotherapy (RT), 173 patients (82.8%) experienced chemotherapy (CT). A total of 158 patients with hormone receptor (HR) positive (87.8%, 158/180) were treated with endocrine treatment (ET). The median follow-up time was 52.4 months (range, 6–144). The 3-year overall survival (OS) rate and 3-year disease-free survival (DFS) rate for the whole group were 93.7% and 85.3%, respectively. In univariate analyses, Ki67 expression ≥20%, HR negative, neuroendocrine carcinomas (NECs) were associated with decreased OS and DFS (P < 0.05). Patients treated with anthracycline/taxane-containing CT regimens, or taxane-containing CT regimens had superior OS and DFS than patients without those (P < 0.05). Among 69 patients with stage I who received CT had no significant differences in OS or DFS compared to those without CT. Multivariate Cox regression analysis showed that gender, HR expression, pathologic subtype, and CT were independent prognostic factors for DFS but not OS (P > 0.05).

Conclusions

The best selection of patients to get the most benefit from different treatment modalities warrant further exploration. The clinicopathological parameters including gender, HR expression, ki67 expression, pathologic type, stage, tumor size, and lymph node status may serve as both indicators of diagnosis and prognosis, and guide treatment decisions for BNEN.

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Surgery is a cornerstone of BNEN.

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ET may have a long-term superior effect on patients with HR-positive.

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Low-risk BNEN patients may be spared CT and managed with ET.

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Many clinicopathological parameters were very important for BNEN.

Neuroendocrine Neoplasms of the Breast: The Latest WHO Classification and Review of the Literature

Simple Summary

Breast tumors exhibiting neuroendocrine differentiation are a heterogeneous group of tumors that have been variously defined in previous World Health Organization (WHO) classifications. In the WHO Classification of Tumours, 5th edition, neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) of the breast, both of which are invasive cancers, are classified as neuroendocrine neoplasms (NENs) of the breast. However, the clinical significance of NE differentiation in breast cancers, especially in NETs of the breast, is not yet fully understood, and a large overlap appears to exist between breast cancers showing NE differentiation and invasive breast cancer of no special type (IBC-NST). While breast NECs show distinct clinical and morphological features, diagnosis of NETs based on the morphological characteristics alone can be challenging; one reason is that breast NETs do not necessarily have the same morphological characteristics as those of NENs arising in other organs. Thus, the heterogeneity of breast tumors with neuroendocrine differentiation and the changes in their classifications over the years have left many open issues that still need to be resolved. In this review, we shall summarize the history of breast “NENs,” including of mixed types of tumors and the characteristics of these tumors, and discuss their differences from NENs arising in other organs.

Abstract

Breast tumors with neuroendocrine (NE) differentiation comprise an uncommon and heterogeneous group of tumors, including invasive breast cancer of no special type (IBC-NST) with NE features, neuroendocrine tumors (NETs), and neuroendocrine carcinoma (NEC). The most recent World Health Organization (WHO) classification in 2019 defined neuroendocrine neoplasms (NENs) of the breast (Br-NENs) as tumors in which >90% of cells show histological evidence of NE differentiation, including NETs (low-grade tumors) and NEC (high-grade). Due to the low prevalence of these tumors and successive changes in their diagnostic criteria over the years, only limited evidence of these tumors exists, derived mainly from case reports and retrospective case series. Breast tumors with NE differentiation are usually treated like the more commonly occurring IBC-NSTs. Immunohistochemistry (IHC) of breast tumors with NE differentiation usually shows a hormone receptor (HR)-positive and human epidermal growth factor type 2 (HER2)-negative profile, so that hormonal therapy with cyclin-dependent kinase (CDK)4/6 inhibitors or other targeted agents would be reasonable treatment options. Herein, we present a review of the literature on breast tumors with NE differentiation as defined in the latest WHO 2019 classification, and discuss the clinical management of these tumors.

Primary neuroendocrine carcinoma of the breast: a rare presentation and review of the literature

Primary neuroendocrine carcinoma of the breast (NEBC) is a very rare occurrence accounting for less than 0.1% of all breast cancers. Typically, the tumor presents with ER- and PgR-positive and HER-2-negative status. Despite its luminal type, NEBC is associated with a more aggressive clinical course and poorer prognosis compared to the other types of invasive breast cancer. Clinical and radiological findings are nonspecific. The most common clinical manifestation is a palpable mass whereas in mammography the tumor most commonly appears as a round or oval mass without spiculated margins. Herein, a very rare case of NEBC is described in an asymptomatic patient who presented with an area of architectural distortion and the presence of microcalcifications that was incidentally detected on a screening mammography. A review of the literature has also been conducted. The diagnosis of NEBC requires a thorough investigation to exclude the possibility of a metastatic neuroendocrine tumor from another site because the two entities require different treatment approaches. Due to the rarity of the disease, the optimal therapeutic approach has not been clearly defined. Surgical resection is the mainstay of treatment. Further research is needed to better understand the molecular characteristics of NEBC and identify novel targeted therapies.

Neuroendocrine breast carcinoma: a rare but challenging entity

Breast carcinoma with neuroendocrine differentiation, also known as neuroendocrine breast carcinoma (NEBC), includes a heterogeneous group of rare tumors, which account for 2–5% of all invasive breast carcinomas. Because of their low incidence, most of the current limited knowledge of these tumors derives from anecdotal case reports or small retrospective series. The diagnosis of NEBC is based on the presence of morphological features similar to gastrointestinal and lung NETs and neuroendocrine markers. NEBCs are usually hormone receptors positive and HER2 negative, but despite this luminal phenotype, most recent studies suggested that NEBC could be associated with worse prognosis compared to invasive breast cancer without neuroendocrine differentiation. Due to its rarity and lack of randomized data, there is little evidence to guide the choice of treatment, so NEBC is currently treated as any invasive breast carcinoma not-otherwise specified. Recently, attempts to molecularly characterize NEBC have been made, in order to provide new targets for a more personalized treatment of this uncommon entity.

[Neuroendocrine tumors of the breast: Myth or reality? A systematic review]

Primary neuroendocrine breast carcinomas are rare and little-known tumors. Only a limited number of studies on neuroendocrine breast carcinomas have been reported in the literature, and the vast majority of them are small retrospective series or case reports. According to the World Health Organization (WHO), they account for only 2 % to 5 % of breast cancers. Their diagnosis relies on the presence of a neuroendocrine architecture and the expression of neuroendocrine markers (chromogranin A and/or synaptophysin). The revised 2012 WHO classification subdivides them into three categories: (i) well-differentiated neuroendocrine carcinomas, (ii) poorly differentiated neuroendocrine carcinomas or small-cell carcinomas, and (iii) invasive breast carcinomas with neuroendocrine differentiation. Their clinical features and radiological characteristics are not different from those of other types of breast cancer. Because of discordant results, their clinical outcome is still poorly defined. So far, no standard treatment has been established, and most clinicians draw on their experience of invasive ductal cancer. The role of specific treatments like platinum-based chemotherapy, somatostatin analogues, peptide receptor radionucleide therapy or temozolomide remains unclear. A better knowledge of the molecular pathways involved in their carcinogenesis could help to identify new potential therapeutic targets. The efficacy of targeted therapies has to be studied.

Neuroendocrine Carcinoma of the Breast: Current Evidence and Future Perspectives

: Neuroendocrine carcinoma of the breast is considered a rare entity, and for this reason there are no data from prospective clinical trials on its optimal management. Early stage tumors are usually treated with the same strategy used for the other types of invasive breast cancer. Anthracycline- and taxane-based regimens represent the most frequently administered chemotherapy in neoadjuvant and adjuvant setting, as well as for metastatic disease, although combinations of platinum compounds and etoposide have been widely used, in particular for small-cell histology and tumors with a high proliferation index. For metastatic disease, a multimodality therapeutic strategy can be considered on an individual basis, with chemotherapy, endocrine therapy, peptide receptor radionuclide therapy, radiation therapy, surgery, or a combination of the above. In the near future, a better knowledge of the biology of these tumors will hopefully provide new therapeutic targets for personalized treatment. In this review, we discuss the current evidence and the future perspectives on diagnosis and treatment of neuroendocrine carcinoma of the breast.

IMPLICATIONS FOR PRACTICE

Neuroendocrine carcinoma of the breast (NECB) is a distinct entity of breast cancer. Clinical features and morphology are not helpful to distinguish NECB from other subtypes of breast cancer; therefore, immunohistochemistry markers for neuroendocrine differentiation, mainly chromogranin and synaptophysin, should be routinely used to confirm the diagnosis, especially in cases of mucinous or solid papillary carcinoma in which the suspicion of NECB may be relevant. Adjuvant treatment should be offered according to the same recommendations given for the other types of invasive breast cancer. An accurate diagnosis of NECB is also important in the metastatic setting, in which a multimodality approach including specific therapies such as peptide receptor radionuclide therapy can be considered.