A 20-Year Review of 75 Cases of Salivary Duct Carcinoma

Immediate lengthening temporalis myoplasty for facial palsy reconstruction following facial nerve inclusive total parotidectomy

Immediate lengthening temporalis myoplasty (Labbé procedure) for immediate dynamic facial reanimation after nerve-inclusive parotidectomy in the elderly population is undocumented in the literature. The aim of this work was to determine whether the Labbé approach could achieve immediate, good functional and static results in elderly patients with acquired facial palsy. A retrospective analysis of five patients with parotid malignancies involving the facial nerve who underwent parotidectomy and an immediate Labbé procedure was performed. The House-Brackmann and Sunnybrook scores for facial palsy were used as objective measurements of the functional outcome. All patients underwent total parotidectomy, neck dissection, Labbé procedure, immediate temporary tarsorrhaphy, brow lift, and postoperative radiotherapy. Mean patient age was 83 (range 73-87) years. The average resected tumour size was 3.54 cm. The mean duration of surgery was 324 min and length of hospital stay 4 days. All patients experienced an improvement in House-Brackmann of one grade postoperative (grade V to IV in four, grade VI to V in one); the Sunnybrook score improved by 31 points on average (mean preoperative 3.8 vs postoperative 34.8). An immediate Labbé procedure following ablative parotid malignancy resection is a reliable and safe reconstructive procedure in a carefully selected elderly population, providing acceptable immediate static and dynamic hemifacial mimetic function and eliminating an additional facial palsy correction procedure.

Apalutamide and Goserelin for Androgen Receptor-Positive Salivary Gland Carcinoma: A Phase II Nonrandomized Clinical Trial, YATAGARASU

PURPOSE

To assess the efficacy and safety of apalutamide plus goserelin for androgen receptor (AR)-positive unresectable or recurrent/metastatic salivary gland carcinoma.

PATIENTS AND METHODS

This trial was an open-label, single-arm, multicenter phase II study. Patients with histologically confirmed unresectable or recurrent/metastatic salivary gland carcinoma with AR expression were included. The primary endpoint was the overall response rate (ORR) according to RECIST v1.1 by an independent central radiology review in the first 24 response-evaluable (RE) patients who had been observed at least 24 weeks from study initiation (primary RE patients). The efficacy was to be declared when at least 8 of the 24 primary RE patients responded.

RESULTS

A total of 31 patients were enrolled. In the first 24 primary RE patients with a median follow-up of 7.4 months, confirmed ORR by independent central radiology review was 25.0% [6/24 patients; 95% confidence interval, 9.8%-46.7%; P = 0.11 (one-sided)], which did not meet the predefined criteria of efficacy. Clinical benefit rate (ORR + rate of stable disease for at least 24 weeks) and median progression-free survival were 50.0% and 7.4 months, respectively. Both median duration of response and overall survival were not reached. Exploratory analyses showed a better ORR of 54.5% (6/11) in patients with AR positivity ≥70% and no history of prior systemic therapy. Grade 3 or higher treatment-emergent adverse events were reported in 35.5% (11/31), which included skin rash, anemia, leukopenia, and cancer pain.

CONCLUSIONS

Although this study did not meet the predefined efficacy criteria, apalutamide plus goserelin showed clinically meaningful efficacy in a subset of patients with AR-positive salivary gland carcinoma and safety consistent with prior experience in prostate cancer.

The extent of androgen receptor and HER2 expression allows for targeted therapy in most cases of salivary duct carcinoma: analysis of clinical and histopathological data in a tertiary care center

PURPOSE

The incidence of salivary duct carcinoma (SDC) seems to be underestimated due to inaccurate classification. Further, the frequency of SDC patients with targeted therapy options according to current guidelines is unclear. Therefore, this study aimed at (a) describing the proportion of SDC among salivary gland carcinoma (SGC) before and after reclassification of cases initially classified as adenocarcinoma, not otherwise specified (ANOS); and (b) quantifying the frequency of SDC patients with targeted therapy options.

METHODS

All patients with SDC or ANOS treated in a tertiary care center between 1996 and 2023 were identified. Histopathological diagnosis was verified for patients primarily diagnosed with SDC and reviewed for patients initially diagnosed with ANOS. Clinical data for SDC patients were retrieved from clinical charts. Immunohistochemical (IHC) androgen receptor (AR) and HER2 staining was performed.

RESULTS

Among 46 SDC, 34 were primarily diagnosed as SDC and 12 had initially been classified as ANOS. The proportion of SDC among SGC was 12.1% and was rising when comparing the time periods 2000-2015 (7.1-11.5%) versus 2016-2023 (15.4-18.1%). Nuclear AR staining in > 70% of tumor cells was found in 56.8% and HER2 positivity (IHC 3 +) in 36.4% of cases. 70.5% of patients showed AR staining in > 70% of tumor cells and/or HER2 positivity and therefore at least one molecular target. 5-year overall and disease-free survival (DFS) were 62.8% and 41.0%. Multivariate Cox regression revealed positive resection margins (HR = 4.0, p = 0.03) as independent negative predictor for DFS.

CONCLUSIONS

The results suggest a rising SDC incidence and show that the extent of the AR and HER2 expression allows for targeted therapy in most SDC cases.

High-grade salivary carcinomas: A current insight on diagnostic pathology and the key to clinical decision making

High-grade carcinomas of the salivary glands are a group of several tumor entities with highly malignant histologic appearances, and have an aggressive biological behavior accompanied by poor a prognosis. In general, they require more intensive treatment than low- or intermediate-grade carcinomas. High-grade salivary carcinomas are rare and the microscopic features often overlap between different tumor types, making an appropriate diagnosis challenging in daily practice settings. However, with recent rapid advances in molecular pathology and molecular-targeted therapy in this field, there is a growing need to properly classify tumors, rather than just diagnosing the cases as "high-grade carcinomas". This leads to specific treatment strategies. In this article, we review representative high-grade salivary gland carcinomas, including salivary duct carcinoma and its histologic subtypes, high-grade mucoepidermoid carcinoma, solid-type adenoid cystic carcinoma, and high-grade transformation of low- or intermediate-grade carcinomas, and discuss their differential diagnoses and clinical implications. Other rare entities, such as neuroendocrine carcinoma, NUT carcinoma, and metastatic carcinoma, should also be considered before diagnosing high-grade carcinoma, NOS. Of these tumors, salivary duct carcinoma has received the most attention because of its strong association with androgen deprivation and anti-HER2 therapies. Other tumor-type-specific treatments include anti-TRK therapy for high-grade transformation of secretory carcinoma, but further therapeutic options are expected to be developed in the future. It should be emphasized that detailed histological evaluation with adequate sampling, in addition to the effective use of molecular ancillary tests, is of the utmost importance for a suitable diagnosis.

The prognostic value of selective neck dissection in early-stage major salivary gland carcinoma: a population-based analysis

Objective

This population-based study aims to assess the survival benefits of selective neck dissection (SND) compared to neck observation in patients with T1/T2N0M0 major salivary gland malignancy (MSGC).

Methods

We conducted a retrospective review of T1/T2N0M0 MSGC patients who underwent primary tumor surgical extirpation with or without elective neck dissection in the Surveillance, Epidemiology, and End Results database (SEER) from 2004-2015. The impact of SND and clinical variables on overall survival (OS) and disease-specific survival (DSS) was evaluated using Univariate and Multivariate Cox proportional hazards regression models. Kaplan-Meier survival curves were generated, and survival rates were assessed via the log-rank test.

Results

Of 3778 post-operative T1-T2N0M0 MSGC patients, 2305 underwent elective neck dissection, while 1473 did not. Median follow-up was 106 months. Univariate and Multivariate analysis identified SND as a prognostic factor for OS in all the study population. After stratified analysis, we found that in the poorly high-grade (differentiated and undifferentiated) patients, the survival showed a significant OS and DSS benefit after receiving SND compared with the neck observations [HR for OS (95%CI): 0.571(0.446-0.731), P<0.001] and [HR for DSS (95%CI): 0.564(0.385-0.826), P=0.003], other than in the well differentiated or moderately differentiated subgroup. Especially, when the pathological is squamous cell carcinoma, the results show that the people underwent SND had better prognosis, not only in OS [HR (95%CI): 0.532(0.322-0.876), P=0.013], but also in DSS [HR (95%CI): 0.330(0.136-0.797), P=0.014]. The multivariate analysis also yielded encouraging results, compared with neck observation, receiving SND bought about a significant independent OS (adjusted HR, 0.555; 95% CI, 0.328-0.941; P=0.029) and DSS (adjusted HR, 0.349; 95% CI, 0.142-0.858; P=0.022) advantage in high grade squamous cell carcinoma MSGC patients. The Kaplan-Meier survival curves also demonstrated that adjusted SND still had significantly better OS(P=0.029) and DSS(P=0.022) than the observation group in patients with high-grade squamous cell carcinoma of MSGC.

Conclusion

Poorly differentiated and undifferentiated T1/T2N0M0 major salivary gland malignancy treated with selective neck dissection demonstrated superior survival compared to neck observation, especially in the pathological subtype of squamous cell carcinoma. These findings suggest the potential benefits of multimodal therapy for appropriately selected patients, emphasizing significant clinical implications.

John MA. A 22-year single institution review of 119 cases of salivary duct carcinoma

Objective

Salivary duct carcinoma (SDC) is a rare and aggressive salivary gland malignancy. Herein, we present the largest single-institution review of SDC to date.

Methods

This is a retrospective cohort study of all histologically confirmed cases of SDC seen at our institution from January 1, 2002, to August 1, 2022. Patient demographics, treatment, histological characteristics, tumor staging, and outcomes were extracted from the electronic medical record. Kaplan-Meier and Cox regression survival analyses were performed.

Results

This study included 119 patients with a mean age of 66.2 years. Most primary tumors arose from the parotid gland (72.3%), and 23.5% were noted to be carcinoma ex-pleomorphic adenoma. 57.1% of patients presented with regional lymph node metastasis, whereas 23.5% presented with distant disease. Kaplan-Meier analysis demonstrated a 62.4% 5-year overall survival (OS) and a 69.0% 5-year disease-specific survival (DSS). Univariate analyses indicated that presence of regional lymph node disease (p<.001), distant metastasis (p<.001), perineural invasion (p = .027), and lymphovascular invasion (p = .018) were predictive of decreased OS and DSS. Trastuzumab administration was not associated with survival in HER-2-positive patients receiving chemotherapy. Multivariate analyses demonstrated that presence of nodal disease (HR 30.337, 95% CI 2.782-330.851, p = .005) and carcinoma ex pleomorphic adenoma (HR 5.54, 95% CI 1.024-29.933, p = .047) were associated with decreased OS.

Conclusion

Our patients had more favorable survival rates compared to prior studies, which may be due to lower incidence of nodal disease. Factors associated with worse survival included nodal and distant metastases, perineural invasion, lymphovascular invasion, and tumor size.

Level of Evidence

Level 3.

Gastric Metastasis from Salivary Duct Carcinoma Mimicking Scirrhous Gastric Cancer

A 59-year-old man underwent submandibular gland excision for salivary duct carcinoma (SDC). One year later, esophagogastroduodenoscopy indicated gastric diffuse mucosal thickening with luminal contraction, mimicking scirrhous gastric carcinoma. Biopsy specimens showed dense proliferation of neoplastic cells expressing androgen receptor and human epidermal growth factor 2, indicating SDC. Gastric diffuse infiltrative metastasis is generally characteristic of gastric metastasis from invasive ductal carcinoma, which shows histologic features similar to SDC. This is the first known report of gastric diffusely infiltrating metastasis in an SDC patient. Rapidly progressing, diffuse gastric wall thickening should also be considered indicative of salivary tumor-associated gastric metastasis.

HER2-targeted therapies for salivary gland cancers

Salivary gland cancers (SGCs) are a heterogeneous group of rare tumors including various histological subtypes with different molecular profiling. Human epidermal growth factor receptor 2 (HER2) is one of the most intriguing and studied molecular alterations with prognostic and predictive roles. Indeed, HER2 overexpression is commonly correlated with aggressive histological subtypes and poorer prognosis. However, HER2 may represent the target of personalized treatment. We performed a literature review of use of anti-HER2 targeted agents for treatment of recurrent or metastatic SGCs. The efficacy and safety of anti-HER2 were firstly evaluated in patients affected with other solid tumors, mostly breast and gastric cancers. For SGCs the literature is mainly comprised of case reports or case series and small clinical trials. The most common used drug is trastuzumab in combination with chemotherapy (i.e. taxanes, capecitabine, carboplatin, eribulin) or with another anti-HER2 targeted agent (i.e. pertuzumab). The use of anti-HER2 therapies induces improvement in clinical responses, which are mostly durable. Besides, new anti-HER2 drugs such as antibody-drug conjugates (ADC) (i.e. trastuzumab emtansine, trastuzumab deruxtecan) have been introduced in this setting inducing further therapeutic advances. Anti-HER2 treatment strategy is emerging as potentially effective in selected HER2 overexpressing SGCs. However, prospective and multicentric clinical trials are needed to evaluate the efficacy of these therapeutic regimens within larger cohorts and to assess the most appropriate treatment sequence strategy.

A phase 2 multicenter study of docetaxel-PM and trastuzumab-pkrb combination therapy in recurrent or metastatic salivary gland carcinomas

BACKGROUND

Salivary duct carcinoma (SDC) is uncommon but is the most aggressive subtype of salivary gland carcinomas. The high positivity rate for human epidermal growth factor receptor 2 (HER2) led to an investigation of the efficacy of HER2-targeted agents. Docetaxel-PM (polymeric micelle) is a low-molecular-weight, nontoxic, biodegradable, and docetaxel-loaded micellar formulation. Trastuzumab-pkrb is a biosimilar to trastuzumab.

METHODS

This was a multicenter, single-arm, open-label phase 2 study. Patients with HER2-positive (immunohistochemistry [IHC] score of ≥2+ and/or HER2/chromosome enumeration probe 17 [CEP17] ratio of ≥2.0) advanced SDCs were enrolled. Patients received docetaxel-PM (75 mg/m2 ) and trastuzumab-pkrb (8 mg/kg in the first cycle and 6 mg/kg in subsequent cycles) every 3 weeks. Primary end point was objective response rate (ORR).

RESULTS

A total of 43 patients were enrolled. The best objective responses were partial response in 30 (69.8%) patients and stable disease in 10 (23.3%) patients, leading to an ORR of 69.8% (95% confidence interval [CI], 53.9-82.8) and a disease control rate of 93.0% (80.9-98.5). Median progression-free survival, duration of response, and overall survival were 7.9 (6.3-9.5), 6.7 (5.1-8.4), and 23.3 (19.9-26.7) months, respectively. Patients with HER2 IHC score of 3+ or HER2/CEP17 ratio ≥2.0 demonstrated better efficacies compared to those with HER2 IHC score of 2+. Thirty-eight (88.4%) patients experienced treatment-related adverse events (TRAE). Because of TRAE, nine (20.9%), 14 (32.6%), and 19 (44.2%) patients required temporary discontinuation, permanent discontinuation, or dose reduction, respectively.

CONCLUSIONS

The combination of docetaxel-PM and trastuzumab-pkrb demonstrated promising antitumor activity with a manageable toxicity profile in HER2-positive advanced SDC.

PLAIN LANGUAGE SUMMARY

Salivary duct carcinoma (SDC) is uncommon but is the most aggressive subtype of salivary gland carcinomas. SDC shares morphological and histological similarities with invasive ductal carcinoma of breast, which led to an investigation of hormonal receptor and human epidermal growth factor receptor 2 (HER2)/neu expression status in SDC. In this study, patients with HER2-positive SDC were enrolled and treated with combination of docetaxel-polymeric micelle and trastuzumab-pkrb. Promising antitumor activities were shown with objective response rate of 69.8%, disease control rate of 93.0%, median progression-free survival of 7.9 months, median duration of response of 6.7 months, and median overall survival of 23.3 months.

ERBB2 Amplification and HER2 Expression in Salivary Duct Carcinoma: Evaluation of Scoring Guidelines and Potential for Expanded Anti-HER2 Therapy

Salivary duct carcinoma (SDC) is aggressive with limited therapeutic options. A subset of SDC display human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry, and some show ERBB2 gene amplification. Guidelines for HER2 scoring are not firmly established. Recent advances in breast carcinoma have established a role for anti-HER2 therapies in lesions with low HER2 expression lacking ERBB2 amplification. Delineating HER2 staining patterns in SDC is critical for evaluating anti-HER2 treatments. In total, 53 cases of SDC resected at our institution between 2004 and 2020 were identified. Androgen receptor (AR) and HER2 immunohistochemistry and ERBB2 fluorescence in situ hybridization were performed in all cases. AR expression was scored for percentage positive cells and categorized as positive (>10% of cells), low positive (1%-10%), or negative (<1%). HER2 staining levels and patterns were recorded, scored using 2018 ASCO/CAP guidelines, and categorized into HER2-positive (3+ or 2+ with ERBB2 amplification), HER2-low (1+ or 2+ without ERBB2 amplification), HER2-very low (faint staining in <10% of cells), or HER2-absent types. Clinical parameters and vital status were recorded. Median age was 70 years, with a male predominance. ERBB2-amplified tumors (11/53; 20.8%) presented at lower pT stages (pTis/pT1/pT2; P = .005, Fisher exact test) and more frequently had perineural invasion (P = .007, Fisher exact test) compared with ERBB2 nonamplified tumors; no other pathologic features differed significantly by gene amplification status. In addition, 2+ HER2 staining by 2018 ASCO/CAP criteria was most common (26/53; 49%); only 4 cases (8%) were HER2-absent status; 3+ HER2 staining was found in 9 tumors, and all were ERBB2 amplified. Six patients with HER2-expressing tumors received trastuzumab therapy, including 2 with ERBB2-amplified tumors. Overall survival and recurrence-free survival did not differ significantly based on ERBB2 status. This work suggests that 2018 ASCO/CAP guidelines for HER2 evaluation in breast carcinoma could be applied to SDC. Our findings also show broad overexpression of HER2 in SDC raising the possibility that more patients may benefit from anti-HER2-directed therapies.

Targeting human EGFR 2 (HER2) in salivary gland carcinoma

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2) protein overexpression, gene amplification, and activating mutations have been identified in a subset of salivary gland carcinoma (SGC) histologies (HER2-positive), especially in salivary duct carcinoma, and represent an important therapeutic target.

AREAS COVERED

The evidence for targeting HER2 in the adjuvant setting is limited to small retrospective series. Conversely, there are prospective trials supporting the use of anti-HER2 therapy in patients with unresectable, recurrent, or metastatic HER2-positive SGC, including trastuzumab plus docetaxel, trastuzumab plus pertuzumab, trastuzumab-pkrb plus nanoxel, trastuzumab emtansine (T-DM1), and trastuzumab deruxtecan (T-Dxd).

EXPERT OPINION

HER2-targeting should be considered for patients with advanced HER2-positive SGC. There are no data to guide the selection of one anti-HER2 agent over another in the palliative setting. Trastuzumab plus docetaxel can be considered for patients with a high disease burden, while trastuzumab plus pertuzumab is a good option for patients with low disease burden or borderline performance status. T-DM1 or T-Dxd can be considered upon disease progression on trastuzumab-combination therapies, although these antibody-drug conjugates can also be used upfront. Future research should investigate predictive biomarkers, the combination of HER2 and androgen blockade, and the application of novel therapies from breast cancer.

Prognostic models for estimating survival of salivary duct carcinoma: a population-based study

PURPOSE

In a large salivary duct carcinoma (SDC) cohort, we aimed to investigate the clinical factors influencing their survival outcomes and to further establish prognostic models.

METHODS

Data of patients with SDC were extracted from the Surveillance, Epidemiology, and End Results database (1975-2019). A retrospective analysis was conducted to explore the prognostic factors on overall survival (OS) and disease-specific survival (DSS), and corresponding nomograms were established.

RESULTS

A steady upward trend in the incidence of SDC was observed over the past four decades. Totally, 399 patients (280 in the training set and 199 in the testing set) were enrolled. Advanced T stage, lymph node metastasis, distant metastasis, and surgery were associated with favorable OS and DSS. Besides, age > 80 years exhibited worse OS. The selected variables above were used to construct nomograms and online web calculators that could accurately predict patient survival. In addition, risk stratification systems were generated to identify low- and high-risk patients. As the risk level increased, the risk of both patient mortality and disease-specific mortality increased.

CONCLUSIONS

The SDC incidence was low, but steadily increasing. The proposed prognostic models provided a robust and efficient approach to predict survival and risk stratification in SDC patients.

A molecular guide to systemic therapy in salivary gland carcinoma

Salivary gland carcinomas (SGC) are a rare and variable group of head and neck cancers with historically poor response to cytotoxic chemotherapy and immunotherapy in the recurrent, advanced, and metastatic settings. In the last decade, a number of targetable molecular alterations have been identified in SGCs including HER2 upregulation, androgen receptor overexpression, Notch receptor activation, NTRK gene fusions, and RET alterations which have dramatically improved treatment outcomes in this disease. Here, we review the landscape of precision therapy in SGC including current options for systemic management, ongoing clinical trials, and promising future directions.

Role of HER2 in Prognosis of Salivary Duct Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVES

Salivary duct carcinoma (SDC) is a rare, aggressive malignancy with a poor prognosis. These tumors frequently stain positive for HER2/ErbB2, but data on the prognostic significance of HER2 status in SDC are mixed. We sought to determine whether HER2 status affects survival outcomes in SDC.

METHODS

PubMed, Embase, and Web of Science databases were searched from inception to October 2020. Eligibility was restricted to studies reporting HER2/ErbB2 overexpression in histologically confirmed de novo SDC or SDC ex pleomorphic adenoma, with corresponding overall (OS) and disease-free (DFS) survival measures. Separate multivariable and univariable meta-analyses were performed using random-effects models. Statistical heterogeneity was estimated by Cochran's Q and I² tests. Funnel plots were generated and Egger's test was used to assess for publication bias. The risk of bias was assessed with the Newcastle-Ottawa Scale.

RESULTS

Of 183 unique citations, 14 studies of 663 patients were included. Most included studies determined HER2 status according to ASCO/CAP guidelines. The univariable meta-analysis did not reveal an effect between HER2 status and OS (HR 1.09, 95% CI 0.84-1.42). In the multivariable analysis, HER2 positivity was associated with a HR of 1.49 for OS (95% CI 0.96-2.30). Fewer studies reported data for DFS than OS, with no relationship between HER2 status and DFS found on multivariable or univariable meta-analyses.

CONCLUSION

In patients with salivary duct carcinoma, HER2 positivity was not found to be associated with worse overall survival. This information may be useful when counseling patients and considering treatment options. Laryngoscope, 133:476-484, 2023.

Metastatic Salivary Duct Carcinoma with ERBB2 Amplification and Sequential Response to Ado-Trastuzumab Emtansine and Neratinib: A Case Report

Introduction

Salivary duct carcinoma (SDC) is an aggressive and rare subtype of salivary gland carcinoma. Surgical excision and radiotherapy are standard of care for early cancer. Chemotherapies with taxanes and platinum show overall response rates between 39% and 50%. SDCs are often associated with an overexpression of the androgen receptor (AR) and HER2/neu which have recently become druggable targets.

Case Presentation

Here, we report on an 84-year-old male patient with metastatic SDC of the right parotid gland. In 2017, he underwent a right total parotidectomy, a right neck dissection, and an infratemporal fossa clearance followed by 6 weeks of radiotherapy. In 2018, due to metastatic spread in the lungs, bones, and pararenal gland, a pathological workup of the tumor tissue was performed and revealed both AR and HER2 overexpression, respectively. Consequently, he underwent androgen deprivation therapy and, due to asymptomatic progression, sequentially human epidermal growth factor receptor 2 (HER-2)-targeted therapy with ado-trastuzumab emtansine and neratinib, which led to stable disease during the course of about 18 months. The electronically captured patient-reported outcome had demonstrated a good tolerance of all three therapeutic lines.

Conclusion

In conclusion, since effective standard therapeutic treatment options for SDC may often not be tolerable in older patients, the implementation of personalized and adaptive treatments, especially in patients with rare tumor types, might offer valuable treatment options.

Establishment of experimental salivary gland cancer models using organoid culture and patient-derived xenografting

Purpose

Depending on its histological subtype, salivary gland carcinoma (SGC) may have a poor prognosis. Due to the scarcity of preclinical experimental models, its molecular biology has so far remained largely unknown, hampering the development of new treatment modalities for patients with these malignancies. The aim of this study was to generate experimental human SGC models of multiple histological subtypes using patient-derived xenograft (PDX) and organoid culture techniques.

Methods

Tumor specimens from surgically resected SGCs were processed for the preparation of PDXs and patient-derived organoids (PDOs). Specimens from SGC PDXs were also processed for PDX-derived organoid (PDXO) generation. In vivo tumorigenicity was assessed using orthotopic transplantation of SGC organoids. The pathological characteristics of each model were compared to those of the original tumors using immunohistochemistry. RNA-seq was used to analyze the genetic traits of our models.

Results

Three series of PDOs, PDXs and PDXOs of salivary duct carcinomas, one series of PDOs, PDXs and PDXOs of mucoepidermoid carcinomas and PDXs of myoepithelial carcinomas were successfully generated. We found that PDXs and orthotopic transplants from PDOs/PDXOs showed similar histological features as the original tumors. Our models also retained their genetic traits, i.e., transcription profiles, genomic variants and fusion genes of the corresponding histological subtypes.

Conclusion

We report the generation of SGC PDOs, PDXs and PDXOs of multiple histological subtypes, recapitulating the histological and genetical characteristics of the original tumors. These experimental SGC models may serve as a useful resource for the development of novel therapeutic strategies and for investigating the molecular mechanisms underlying the development of these malignancies.

The Therapeutic Landscape of Salivary Gland Malignancies-Where Are We Now?

Salivary gland malignancies (SGMs) account for less than 5% of new diagnoses in head and neck tumors. If feasible, surgery is the preferred treatment modality. Nevertheless, some malignancies have a tendency of recurrence, with possible distant metastasis. Alternative treatment strategies, such as primary radiation or chemotherapeutics, often present low response rates. As a result, there is an unmet need for novel therapeutic approaches. Nowadays, target-based therapies (e.g., small inhibitors and immunotherapy) are used by the medical oncologist for possible treatment of advanced SGMs. Based on recent published trials, some novel treatments may provide additional disease control for some patients. However, sample sizes are small, the general findings are unsatisfactory, and a lot of uncertainties remain to be elucidated. Nevertheless, research shows that patients do not benefit from blind administration of systemic treatments and therefore a more personalized approach is highly needed. The aim of this review paper is to summarize the most recent advances in the biological understanding and molecular pathways of salivary gland cancers, the association of these pathways with the current treatments used and their implications for more personalized targeted-based therapies.

Identification of novel prognostic and predictive biomarkers in salivary duct carcinoma via comprehensive molecular profiling

Molecular targets and predictive biomarkers for prognosis in salivary duct carcinoma (SDC) have not been fully identified. We conducted comprehensive molecular profiling to discover novel biomarkers for SDC. A total of 67 SDC samples were examined with DNA sequencing of 464 genes and transcriptome analysis in combination with the clinicopathological characteristics of the individuals. Prognostic biomarkers associated with response to combined androgen blockade (CAB) treatment were explored using mRNA expression data from 27 cases. Oncogenic mutations in receptor tyrosine kinase (RTK) genes or genes in the MAPK pathway were identified in 55 cases (82.1%). Alterations in the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway were identified in 38 cases (56.7%). Interestingly, patient prognosis could be predicted using mRNA expression profiles, but not genetic mutation profiles. The risk score generated from the expression data of a four-gene set that includes the ADAMTS1, DSC1, RNF39, and IGLL5 genes was a significant prognostic marker for overall survival in the cohort (HR = 5.99, 95% confidence interval (CI) = 2.73–13.1, p = 7.8 × 10−6). Another risk score constructed from the expression of CD3E and LDB3 was a strong prognostic marker for progression-free survival for CAB treatment (p = 0.03). Mutations in RTK genes, MAPK pathway genes, and PI3K/AKT pathway genes likely represent key mutations in SDC tumorigenesis. The gene expression profiles identified in this study may be useful for stratifying patients who are good candidates for CAB treatment and may benefit from additional systemic therapies.

The implicated clinical factors for outcomes in 304 patients with salivary duct carcinoma: Multi-institutional retrospective analysis in Japan

Background

Salivary duct carcinoma (SDC) is a high‐grade salivary malignancy that frequently occurs as the carcinomatous component of carcinoma ex pleomorphic adenoma. We herein examined the clinical factors affecting outcomes in a large cohort of SDC.

Methods

We selected 304 SDC cases and investigated clinical characteristics and the factors affecting outcomes.

Results

The median age of the cases examined was 68 years, the most common primary site was the parotid gland (238 cases), and there was a male predominance (M/F = 5:1). Outcomes were significantly worse when the primary tumor site was the minor salivary glands (SG) than when it was the major SG. Outcomes were also significantly worse in pN(+) cases (161 cases) than in pN0 cases, particularly those with a metastatic lymph node number ≥11. The cumulative incidence of relapse and distant metastases was significantly higher in stage IV cases than in stage 0–III cases.

Conclusions

The absolute number of lymph node metastases, higher stages, and the minor SG as the primary tumor site were identified as factors affecting the outcome of SDC.

Occult nodal metastasis in major salivary gland malignancy: An update from the National Cancer Database

OBJECTIVES

Malignant salivary gland tumors are rare neoplasms that are vastly heterogenous in their histological patterns and clinical behaviors. As a consequence, studies have lacked the robust sample sizes needed to define treatment strategies. In this study, we used the National Cancer Database to identify the incidence of occult nodal metastasis and effect on overall survival for the most common malignant salivary gland subtypes. A retrospective review of patients in the National Cancer Database with primary site malignancies of major salivary glands between 2004 and 2016 was performed. Subjects included in the study underwent surgical treatment with and without adjuvant radiation and had complete information on TNM pathological stage.

MATERIALS AND METHODS

8,689 patients with primary malignant salivary gland cancer were analyzed. The sample was stratified by histologic subtype. Univariate analysis of lymph node metastasis of the whole cohort showed a higher risk of death (p < 0.001), when compared to those without. Also when comparing occult vs evident metastasis, the risk of death was higher for the latter (p < 0.001).

RESULTS AND CONCLUSION

Occult cervical lymph node metastasis ranged from 14.9% to 35.8% in malignant salivary gland cancers, depending on histological subtype. Occult nodal metastasis was a poor prognostic factor with significantly worse overall survival.

Demography, patterns of care, and survival outcomes in patients with salivary duct carcinoma: an individual patient data analysis of 857 patients

Aim:

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy. The optimal treatment protocols are debated.

Methodology:

A systematic search and individual patient data analysis of published cases of SDC was performed. SPSS v21 was used for statistical analysis.

Results:

Data of 857 patients available. Median overall survival (OS) and progression-free survival (PFS) of the entire cohort 42 months and 24 months. Nodal involvement, males, primary size >5 cm, androgen receptor (AR) negativity significantly worse OS. Patients with surgery had a favorable median PFS (p = 0.000) and OS (p = 0.077). Patients with adjuvant radiation had better PFS (30 vs 18 months; p = 0.077).

Conclusion:

SDC has modest survival. Surgery and adjuvant radiation should be advocated for all patients. AR expression appears prognostic for survival.

Salivary duct cancer (SDC) is a rare cancer. The exact care choices are debated. All published cases of SDC were pooled and analysis was carried out. Data from 857 patients were available. Median survival of the entire cohort was 42 months. Nodal involvement, males, large tumour, androgen receptor (AR) negativity worsened survival. Patients who underwent operation and radiation were better able to take care of illness. SDC has modest survival. Operation and radiation should be made available for all patients. AR expression changes survival results.

Salivary duct carcinoma: A report of 70 FNA cases and review of the literature

BACKGROUND

Although usually recognized as malignant, fine-needle aspiration (FNA) biopsy of salivary duct carcinoma (SDC) has been confused with other primary salivary gland (SG) neoplasms. This article undertook an analysis of a large collection of SDC FNA cases to assess diagnostic accuracy, specificity, and cytopathology.

METHODS

Cytopathology files were searched for SDC with histopathologic validation. FNA biopsy smears were performed using standard techniques.

RESULTS

Seventy cases from 56 patients (M:F, 1.9:1; age range, 26-92 years; mean age, 65 years) met inclusion criteria. All had tissue confirmation of SDC. FNA sites included: parotid gland (42, 60% cases), neck (10), submandibular gland (7), pre-/post-auricular area (5), face/cheek (3), mediastinal lymph nodes (2), and clavicle (1). Aspirates were from primary (52, 74%), metastatic (12, 17%), and locally recurrent (6, 9%) neoplasms. FNA diagnoses included: SDC (19, 27%), favor/suspicious for SDC (7, 10%), high-grade carcinoma (11), adenocarcinoma (9), carcinoma (6), malignant (6), SG neoplasm (5), atypia (3), SDC versus another malignancy (2), and pleomorphic adenoma (2). Large polygonal cells in groups and single forms showed cribriforming, variable necrosis, pseudopapillae, and oncocytic change. Androgen receptor staining was positive in all cases.

CONCLUSIONS

FNA biopsy is accurate and reliable in classifying SDC as a malignant neoplasm, but much less so for identification as a specific tumor type. Using the Milan system, 86% of aspirates were classified as either malignant or suspicious for malignancy. A recurring pitfall includes sampling error in cases of SDC ex pleomorphic adenoma.

Targeted Therapy, Chemotherapy, Immunotherapy and Novel Treatment Options for Different Subtypes of Salivary Gland Cancer

Surgical resection remains the first line treatment for salivary gland cancer (SGC). In the case of locally advanced disease, surgery is followed by adjuvant radiotherapy. Surgical resection should be favored in resectable locoregional recurrent disease as well, and even the complete resection of all distant oligometastases has clinical benefit for the patients. For inoperable and disseminated metastatic disease, a multitude of systemic therapies including chemotherapy, targeted therapy, and immunotherapy are available. In this review, the current therapeutic options for inoperable recurrent or metastatic SGCs are summarized. Systemic treatment can achieve prolonged progression-free and overall survival, while the overall prognosis remains poor. Current clinical trials include only a limited number of patients and mostly combine different histologic subtypes. Additionally, no randomized controlled trial comparing different therapeutic options has been performed. In the future, further studies with a larger patient cohort and ideally only one histologic subtype are needed in order to improve the outcome for SGC patients. However, this may be difficult to accomplish due to the rarity and diversity of the disease. Additionally, molecular analyses need to be performed routinely in order to individualize treatment and to go one step further towards precision medicine.

Nonconvulsive Status Epilepticus Caused by Cerebrospinal Fluid Dissemination of a Salivary Duct Carcinoma: A Case Report

Salivary duct carcinoma (SDC) is a rare and highly aggressive salivary gland tumor with rapid growth, distant metastasis, and a high recurrence rate. Moreover, the parotid gland is the most common site with a poor prognosis. A lower frequency of distance metastasis to the liver, skin, and brain has also been reported, although the lungs, bones, and lymph nodes are the most common sites of SDC metastasis. We report a case of nonconvulsive status epilepticus (NCSE) in a 73-year-old male comatose patient having SDC of the parotid gland with an unusual metastasis to the skin and brain diagnosed by frequent cerebrospinal fluid examinations. Meningeal carcinomatosis usually has a poor prognosis, and NCSE is a reversible cause of altered mentation. Clinicians should know the unique set of epilepsy etiologies in patients with malignant tumors.

Elective neck dissection in salivary gland malignancies: Systematic review and meta-analysis

We defined the occult nodal metastasis (ONM) rate of clinical node-negative salivary gland malignancies and examined the role of elective neck dissection (END). Meta-analysis querying four databases, from inception of databases to March 25th, 2020. Fifty-one studies with 11 698 patients were included. ONM rates were 64% for salivary ductal carcinoma (SDC), 51% for undifferentiated carcinoma, 34% for carcinoma ex-pleomorphic adenoma (CXPA), 32% for adenocarcinoma not otherwise specified (ANOS), 31% for lymphoepithelial carcinoma (LE), 20% for mucoepidermoid carcinoma, 17% for acinic cell carcinoma, and 17% for adenoid cystic carcinoma. T3/T4 tumors had a 2.3 times increased risk of ONM than T1/T2 tumors. High-grade tumors had a 3.8 times increased risk of ONM than low/intermediate-grade tumors. ONM rates were exceedingly high for T3/T4, high-grade, and undifferentiated, SDC, ANOS, CXPA, and LE tumors, indicating the potential role of END.

Enhancer RNA Profiling in Smoking and HPV Associated HNSCC Reveals Associations to Key Oncogenes

Smoking and HPV infection are known causes for the vast majority of head and neck squamous cell carcinomas (HNSCC) due to their likelihood of causing gene dysregulation and genomic alterations. Enhancer RNAs (eRNAs) are non-coding RNAs that are known to increase nearby and target gene expression, and activity that has been suggested to be affected by genetic and epigenetic alterations. Here we sought to identify the effects of smoking and HPV status on eRNA expression in HNSCC tumors. We focused on four patient cohorts including smoking/HPV+, smoking/HPV-, non-smoking/HPV+, and non-smoking/HPV- patients. We used TCGA RNA-seq data from cancer tumors and adjacent normal tissue, extracted eRNA read counts, and correlated these to survival, clinical variables, immune infiltration, cancer pathways, and genomic alterations. We found a large number of differentially expressed eRNA in each patient cohort. We also found several dysregulated eRNA correlated to patient survival, clinical variables, immune pathways, and genomic alterations. Additionally, we were able to find dysregulated eRNA nearby seven key HNSCC-related oncogenes. For example, we found eRNA chr14:103272042-103272430 (eRNA-24036), which is located close to the TRAF3 gene to be differentially expressed and correlated with the pathologic N stage and immune cell populations. Using a separate validation dataset, we performed differential expression and immune infiltration analysis to validate our results from the TCGA data. Our findings may explain the association between eRNA expression, enhancer activity, and nearby gene dysregulation.

Treatment patterns and outcomes of palliative systemic therapy in patients with salivary duct carcinoma and adenocarcinoma, not otherwise specified

BACKGROUND

Salivary duct carcinoma (SDC) and adenocarcinoma, not otherwise specified (adeno-NOS), are rare salivary gland cancers. Data on the efficacy of systemic therapy for these diseases are limited.

METHODS

Data were retrospectively collected from patients seen at The University of Texas MD Anderson Cancer Center during 1990 to 2020. Objective response rate (ORR) was assessed per RECIST v1.1. Recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS) were assessed by Kaplan-Meier method. Cox regression model was performed to identify predictors of survival.

RESULTS

The analysis included 200 patients (110 with SDC and 90 with adeno-NOS); 77% had androgen-receptor-positive tumors and 47% had HER2-positive (2+-3+) tumors. Most patients without metastasis at diagnosis underwent surgery (98%) and postoperative radiotherapy (87%). Recurrence rate was 55%, and the median RFS was 2 years. Nodal involvement and positive surgical margins were associated with recurrence (P < .005). Among patients with stage IVA-B disease, addition of systemic therapy to local therapy increased OS (P = .049). The most-used palliative-systemic-therapy regimen was platinum doublet ± trastuzumab. For first-line therapy, the ORR and median PFS were 33% and 5.76 months, respectively, and for second-line therapy the ORR and median PFS were 25% and 5.3 months, respectively. ORR and PFS were higher with HER2-targeting agents. Median OS was 5 years overall and 2 years for metastatic disease. Older age and higher stage were associated with worse OS.

CONCLUSION

Adding systemic therapy to local therapy may improve outcomes of patients with locoregionally advanced SDC or adeno-NOS. Except for HER2-targeted therapy, response to palliative systemic therapy is limited. These findings may be used as a benchmark for future drug development.

Carcinosarcoma ex pleomorphic adenoma of the parotid gland: a case report

Carcinosarcoma ex pleomorphic adenoma is an extremely rare malignant neoplasm of the salivary gland that originates from a pre-existing benign tumor. Malignant transformation of the pleomorphic adenoma is extremely rare. The management of carcinosarcoma ex pleomorphic adenoma remains challenging because of its rarity, behavioral aggressiveness and resemblance to benign pleomorphic adenoma. Herein, we present the case of a 75-year-old male resident of Saudi Arabia with a history of a swelling in the right parotid gland for more than 25 years, which grew slowly with time. He underwent surgical removal with superficial parotidectomy. Afterward, histological examination of the resected tumor revealed features of carcinosarcoma, and he was diagnosed with carcinosarcoma ex pleomorphic adenoma. He presented again with recurrence of the tumor, which was managed with total parotidectomy and a combination of radiotherapy and chemotherapy. At 12-month follow-up, the patient showed no evidence of disease recurrence or distant metastasis.

Salivary Duct Carcinoma in the External Auditory Canal Causing Ipsilateral Hearing Loss

Background: Salivary duct carcinoma (SDC) is a rare aggressive tumor. Most tumors are not confined to the salivary ducts; rather, they invade the major and minor salivary glands. Only a few case reports on such tumors in other primary sites have appeared. Case presentation: A 40-year-old male complained of right hearing loss (a common condition), but we made an extremely rare diagnosis of an SDC in the external auditory canal (EAC). EAC cancers are frequently misdiagnosed. In our patient, the otoscope revealed a smooth, bulging subcutaneous lesion with a non-epithelial defect suggestive of a benign lesion. However, an SDC of the EAC was confirmed through pathological and immunohistochemical analysis. Conclusions: We suggest detailed evaluation of even smooth EAC subcutaneous lesions to avoid erroneous diagnoses. To the best of our knowledge, this is the first report of SDC in the EAC.

Rare Diseases of the Salivary Glands and of Facial Nerve

Salivary gland diseases are rare. In the European Union (EU) a disease is considered to be rare if not more than 5 of 10,000 people are affected by it. According to estimates in Germany are about 4 million people with a rare disease. In the EU are about 30 million people with rare diseases [1]. In the present work most of the described diseases of salivary glands and of the facial nerve fall in this category. They form a very heterogeneous group whose treatment takes place mainly in specialized centers. Still, it is essential for the otolaryngologist to identify and to diagnose these diseases in order to initiate the right therapeutic steps. The work is a compilation of innate andacquired rare salivary gland disorders and of rare facial nerve disorders. The etiologies of inflammatory diseases, autoimmune disorders and tumors are taken into account. For the individual topics, the current literature, if available, was evaluated and turned into summarized facts. In this context the development of new processes, diagnostics, imaging and therapy are considered. Genetic backgrounds of salivary gland tumors and the trends in the treatment of tumorous lesions of the facial nerve are picked up. Furthermore, also rare diseases of the salivary glands in childhood are described. Some of them can occur in adults as well, but differ in frequency and symptoms. Due to the rarity of these diseases, it is recommended to tread these in centers with special expertise for it. Finally, the difficulties of initiation of studies and the problems of establishing disease registries concerning salivary gland disorders are discussed. This is very relevant because these pathologies are comparatively seldom.

Clinicopathological and immunohistochemical behavior of ductal carcinoma of the salivary and lacrimal gland in a Mexican Mestizo population

PURPOSE

Salivary gland tumors are rare and include benign and malignant entities with different behavior and prognosis. Salivary gland carcinoma accounts for 0.2% of all cancers and 5-9% of head and neck carcinomas. We aim to describe the clinicopathological characteristics and discuss the immunohistochemical findings of salivary ductal carcinoma.

METHODS

We obtained 17 cases (2.3%) of salivary ductal carcinoma (SDC) from 727 patients with parotid tumors at our cancer center from a database covering a 22-year period (1996-2018). Two pathologists confirmed the diagnosis and excluded 6 cases. Eleven cases were assessed by immunohistochemistry (IHC) for HER2, estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), mammaglobin, P53, GATA3, S100, cytokeratins (7,8,14,18, and 20), P63, PAX8, calponin, and SOX10.

RESULTS

Eleven SDC cases were in advanced stage, and 80% had metastasis. All cases were surgically treated, and 40% received different adjuvant chemotherapy regimens. we found that most patients were dead of disease. The histological and immunohistochemical analysis showed that 70% of cases were high-grade, 40% were positive for HER2, and 50% for AR. Moreover, a high Ki-67 proliferative index was detected in all cases. We observed luminal differentiation in 50% of cases.

CONCLUSION

SDC is a rare entity and survival is very poor. It is histologically similar to ductal carcinoma of the breast. However, important differences exist that help to distinguish them in case of synchronous cancers. The clinical behavior of SDC seems to be more aggressive and IHC analysis is useful for designing therapies.

Parotid Salivary Duct Carcinoma With a Prominent Squamous Component: Immunohistochemical Profile, Diagnostic Pitfalls, and Therapeutic Implications

Salivary duct carcinoma of the parotid gland is a highly aggressive epithelial malignancy morphologically resembling high-grade, invasive, and in situ breast carcinoma. It can occasionally present with variable morphology making it diagnostically challenging in cases with unusual morphological components. Ancillary testing, particularly androgen receptor (AR) positivity on immunohistochemistry, can be very helpful in cases that demonstrate extensive squamous morphology, since AR positivity is uncommon in both the primary salivary gland and metastatic squamous cell carcinomas to the parotid. In this report, we describe a case of salivary duct carcinoma that showed only a squamous cell carcinoma component on the initial primary tumor site biopsy, as well as in subsequent contralateral neck lymph node and skin metastases. Apart from the variable morphology, the typical salivary duct and squamous cell carcinoma tumor components also showed significant immunohistochemical differences, including differential staining of human epidermal growth factor receptor 2/neu. The associated diagnostic pitfalls, distinct immunoprofiles of the tumor components, helpful adjuncts for making the correct diagnosis, and associated therapeutic implications are discussed.

Successful Treatment with Nivolumab in a Patient with Metastatic Salivary Duct Carcinoma

Salivary duct carcinoma (SDC) is a rare and highly aggressive malignancy. A 58-year-old man presented with a right-sided submandibular mass and metastatic lesions in the right supraclavicular and inferior internal jugular nodes. He underwent right submandibulectomy and right neck dissection followed by adjuvant chemoradiotherapy. However, relapse occurred in the hilar lymph node and lumbar spine. Although radiotherapy was performed, a second relapse appeared in the hilar lymph nodes and sacral bone. Immunohistochemical analysis revealed negativity for programmed death ligand-1 (PD-L1) in the primary tumor specimen. The patient then received the anti-programmed death-1 (PD-1) antibody nivolumab. His metastatic lesions were completely eliminated after 48 weeks of therapy. This case reveals that anti-PD-1 antibodies are effective even against PD-L1-negative SDC.

Genomic Analysis of Salivary Gland Cancer and Treatment of Salivary Gland Cancers

Salivary gland cancer is a heterogenous group of tumors that presents challenges with both diagnosis and therapy. Recent advances in the classification of salivary gland cancers have led to distinct histologic and genomic criteria that successfully differentiate between cancers with similar clinical behavior and appearance. Genomic abnormalities have led to the emergence of targeted therapies being used in their therapy with drastic improvements in outcomes as well as reductions in treatment-related toxicity. Dramatic results seen with molecular targets, such as HER2, TRK, and others, indicate that this approach has the potential to yield even better treatments for the future.

Enhanced Angiogenesis in Salivary Duct Carcinoma Ex-Pleomorphic Adenoma

Salivary duct carcinoma (SDC) is morphologically similar to breast cancer, with HER2-overexpression reported. With regard to the pattern of disease onset, SDC can arise from de novo or carcinoma ex-pleomorphic adenoma (Ca-ex-PA). Recently, multiple molecular profiles of SDC as well as breast cancer have been reported, with significant differences in HER2 expression between Ca-ex-PA and de novo. We assessed the differences in gene expression between onset classifications. We conducted immunohistochemical analysis and HER2-DISH for 23 patients and classified SDCs into three subtypes as follows: “HER2-positive” (HER2+/any AR), “Luminal-AR” (HER2-/AR+), and “Basal-like” (HER2-/AR-). We assessed the expression levels of 84 functional genes for 19 patients by using a qRT-PCR array. Ten cases were classified as HER2-positive, seven cases as Luminal-AR, and six cases as Basal-like. The gene expression pattern was generally consistent with the corresponding immunostaining classification. The expression levels of VEGFA, ERBB2(HER2), IGF1R, RB1, and XBP1 were higher, while those of SLIT2 and PTEN were lower in Ca-ex-PA than in de novo. The functions of those genes were concentrated in angiogenesis and AKT/PI3K signaling pathway (Fisher’s test: p-value = 0.025 and 0.004, respectively). Multiple machine learning methods, OPLS-DA, LASSO, and RandomForest, also show that VEGFA can be a candidate for the characteristic differences between Ca-ex-PA and de novo. In conclusion, the AKT/PI3K signaling pathway leading to angiogenesis was hyper-activated in all SDCs, particularly in those classified into the Ca-ex-PAs. VEGFA was over-expressed significantly in the Ca-ex-PA, which can be a crucial factor in the malignant conversion to SDC.

Clinical outcomes of bulky parotid gland cancers: need for self-examination and screening program for early diagnosis of parotid tumors

Background

Early detection and diagnosis of parotid gland cancer (PGC) are essential to improve clinical outcomes, because Tumor-Node-Metastasis stage at diagnosis is a very strong indicator of prognosis in PGC. Nevertheless, some patients still present with large parotid mass, maybe due to the unawareness or ignorance of their disease. In this study, we aimed to present the clinical outcomes of bulky PGC (defined by a 4 cm cutoff point for T3–4 versus T1–2 tumors), to emphasize the necessity of a self-examination tool for parotid gland tumor.

Methods

We retrospectively reviewed 60 consecutive cases with bulky (equal to and greater than 4 cm in the longest diameter, determined radiologically) malignant tumors arising from the parotid gland from 1995 to 2016. The clinical and pathological factors were analyzed to identify risk factors for poor outcomes using Cox proportional hazard models. In addition, we designed a self-examination tool for parotid gland tumors, similar to breast self-examination for breast cancer detection.

Results

Patients with bulky parotid cancer showed 48.9% 5-year and 24.5% 10-year overall survival rates and a 47.9% risk of high-grade malignancy. The common pathological diagnoses were carcinoma ex pleomorphic adenoma (18.3%), adenocarcinoma (16.7%), mucoepidermoid carcinoma (16.7%), salivary duct carcinoma (16.7%), and adenoid cystic carcinoma (11.7%). Survival analyses revealed that tumor size (hazard ratio, HR = 1.262 upon increase of 1 cm, 95% confidence interval, 95%CI 1.059–1.502), lymph node metastasis (HR = 2.999, 95%CI 1.048–8.583), and high tumor grade (HR = 4.148, 95%CI 1.215–14.154) were independent prognostic factors in multivariable analysis. Functional preservation of the facial nerve was possible only in less than half of patients.

Conclusion

In bulky PGC, lymph node metastasis at diagnosis and high tumor grade indicated poor survival outcomes, and functional outcomes of the facial nerve were suboptimal. Thus, a public effort seems to be necessary to decrease these patients with bulky PGC, and to increase patients’ self-awareness of their disease. As a way of early detection, we proposed a parotid self-examination tool to detect parotid gland tumors at an early stage, which is similar to breast self-examination.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07902-9.

The tumor immune contexture of salivary duct carcinoma

BACKGROUND

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy. Recently, biomarker studies found promising targetable alterations. In this study, we provide a descriptive analysis of tumor and immune biomarkers and survival associations.

METHODS

We extracted clinical data and performed immunohistochemistry for AR, AR-V7, HER-2, PD-L1, LAG-3, and tumor-infiltrating immune cells.

RESULTS

We included 17 patients. Age ranged from 42 to 85 years old; HER-2 was overexpressed or amplified in 65%. AR was positive in 88% of patients, while AR-V7 was positive in 13% by IHC. We found low scores of immune infiltration and a PD-L1 expression in 53%. We found no clinically significant association between biomarkers and survival outcomes.

CONCLUSION

In this small series of SDC, biomarkers do not seem to correlate with disease biology, although they provide additional treatment options. SDC may harbor a different immune profile compared to other subtypes, with an indication of T-cell dysfunction.

Adjuvant therapy in the management of operable salivary duct carcinoma: correlating evidence with a retrospective review

Background:

Salivary duct carcinoma (SDC) is an extremely rare and aggressive subtype of salivary gland cancer with high morbidity and mortality and poor response to treatment. The current options of treatment include radical surgery followed by radiotherapy (RT) with or without chemotherapy. The aim of this study was to analyse the patterns of recurrences, possible predictors of outcome and role of RT in a cohort of patients with non-metastatic SDC.

Methods:

A retrospective review of patients treated between 2010 and 2019 with histologically proven non-metastatic SDC was conducted.

Results:

Sixteen patients were included in the series. Median follow-up was 25 months. Progression-free survival (PFS) and overall survival (OS) at 12 months were 61% and 80%, respectively. Seven out of the 16 patients had disease progression, distant metastases being most frequent. Four patients died due to disease progression. PFS was significantly worse for patients with pathological neck node positivity (p = 0·036) and peri-parotid nodes (p = 0·007). Local control was significantly associated with RT (p = 0·011). Addition of any chemotherapy, regardless of either concurrent or adjuvant, had no impact on the PFS or OS. Pathological neck node positivity with nodal stage of N2 or higher correlated significantly with worse OS (p = 0·031).

Conclusion:

Salivary ductal carcinoma is an aggressive malignancy with high metastatic potential. Inferior prognosis was observed among patients who had metastatic deposits in either cervical nodes or peri-parotid nodes on histopathology. As systemic failures are more predominant among these patients, larger prospective trials are needed to formulate an optimum strategy for choice and sequencing of first-line systemic therapy.

Postoperative Management of Salivary Gland Tumors

OPINION STATEMENT

Salivary gland tumors represent a heterogeneous group of neoplasms characterized by varied histologies and disease outcomes. Initial treatment for the primary and gross nodal disease is usually surgery. Management of the clinically node-negative neck depends upon the risk of lymph nodal involvement. This is usually determined by the AJCC "T" stage and histology. Both surgery and radiation may be utilized to address the lymph nodes at risk. This is especially important for minor salivary gland tumors. Radiation plays an important role in the adjuvant management of salivary gland tumors by reducing the risk of locoregional recurrence. Certain histologies like adenoid cystic carcinoma have a predilection for neurotropic spread to the skull base. Radiation is particularly important in controlling disease at the skull base. The role of concurrent chemotherapy in the adjuvant treatment of salivary gland tumors is not established and remains an area of active research. Certain histologies like salivary duct carcinoma exhibit readily identifiable molecular targets amenable to targeted therapy. Finally, advanced testing of these tumors using next-generation sequencing can also potentially identify molecular targets amenable to therapy. While useful in the management of metastatic disease, the role of these therapies in the adjuvant setting remains unknown.

Salivary Duct Carcinoma: An Aggressive Salivary Gland Carcinoma with Morphologic Variants, Newly Identified Molecular Characteristics, and Emerging Treatment Modalities

Salivary duct carcinoma (SDC) is a rare, aggressive salivary gland malignancy with significant mortality. Morphologically, most tumors are characterized by apocrine differentiation with a typical immunophenotype of androgen receptor positive/gross cystic disease fluid protein positive/estrogen receptor negative/progesterone receptor negative. Several morphologic variants of SDC exist, representing diagnostic pitfalls. Several differential diagnoses should be considered because prognosis, treatment, and management may be different from SDC. For SDC, current treatment strategies are aggressive and commonly include surgical excision with lymph node dissection and adjuvant radiotherapy. Continued research is examining the utility of androgen deprivation therapy and targeted molecular therapy.

Increased ERBB2 Gene Copy Numbers Reveal a Subset of Salivary Duct Carcinomas with High Densities of Tumor Infiltrating Lymphocytes and PD-L1 Expression

Salivary duct carcinoma (SDC) commonly expresses androgen receptor (AR) and HER2, giving rise to treatment implications. SDC may also express programmed-death-ligand-1 (PD-L1), a predictive marker of response to checkpoint inhibitors. PD-L1 can be associated with genomic instability and high density of tumor infiltrating lymphocytes (TILs). Evaluation of HER2 immunohistochemistry (IHC) in SDC is not standardized, and relationships between ERBB2 copy numbers, PD-L1 expression and TILs in SDC are unknown. We evaluated 32 SDCs for HER2, AR and PD-L1 expression (IHC), ERBB2 status (FISH) and TILs (slide review). HER2 was scored with three different systems (breast, gastric, proposed salivary gland). PD-L1 was evaluated with the combined positive score. Most patients were older men, presenting at advanced clinical stage with nodal or distant metastases. During follow-up (mean 5 years, range 6 months to 21 years), 25 of the 32 patients (78%) died of SDC. We propose a HER2 IHC scoring system which accurately predicts underlying ERBB2 amplification or increased copy numbers in SDC. Most tumors had increased ERBB2 copy numbers (19/32 amplification, 6/32 aneusomy), a finding associated with higher TIL densities (p = 0.045) and PD-L1 expression (p = 0.025). Patients with TILs ≥ 40% had better prognoses (Log-Rank p = 0.013), with TILs being favorable prognosticators in univariate analysis (Hazard ratio: 0.18, p = 0.024). A subset of SDCs with increased ERBB2 copy numbers have higher TILs and PD-L1 expression. TILs ≥ 40% are associated with better prognosis.

Giant Cell Carcinosarcoma of the Parotid Gland With a PLAG 1 Translocation in Association With a Pleomorphic Adenoma With HMGA2 Translocation

OBJECTIVES

Carcinosarcomas of the salivary gland are rare neoplasms and have been described arising de novo or in association with pleomorphic adenoma (PA). PLAG1 and HMGA2 translocations are known to occur in PAs and carcinomas ex PA but are mutually exclusive.

METHODS

We report a case of a carcinosarcoma in the parotid gland of a 77-year-old man with unusual anaplastic sarcomatoid giant cell morphology.

RESULTS

Microscopically, a small separate PA was found adjacent to the carcinosarcoma. By conventional notion, the PA and carcinosarcoma would be considered related, as carcinosarcomas are well known to arise from PAs (carcinosarcoma ex PA). However, fluorescence in situ hybridization (FISH) assay demonstrated PLAG1 translocation in the carcinosarcoma and HMGA2 translocation in the separate PA.

CONCLUSIONS

These findings support that the carcinosarcoma likely originated from another PA with a PLAG1 translocation or de novo but not from the coexisting PA harboring a different translocation. To our knowledge, the case is the first to demonstrate PLAG1 translocation by FISH in a sarcomatous component of any parotid gland tumor, which may help better classify these tumors. In addition, multiple PAs are commonly found in the salivary gland, and to our knowledge, our case is the first to demonstrate that the same parotid gland can host PAs and PA-related tumors with different translocations.

A population-based competing risk survival analysis of patients with salivary duct carcinoma

Background

Salivary duct carcinoma (SDC) is a rare malignancy with high risk of local recurrence and distant metastases of the salivary gland. This study was designed to summarize the clinical and pathological features and to further evaluate them as potential prognostic factors for SDC in the salivary gland.

Methods

Clinical data of 266 patients diagnosed with SDC between 2004 and 2015 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. The prognostic factors affecting overall survival (OS) and cancer-specific survival (CSS) were determined by Kaplan-Meier analyses and Cox proportional hazards model. The nomogram was established to predict OS and CSS for SDC. The predictive accuracy of the nomograms was measured by concordance index (C-index).

Results

The 3- and 5-year OS of SDC patients were 67.41% and 47.86%, while the 3- and 5-year CSS were 84.6% and 60.7%, respectively. The primary site, T stage and M stage were identified as independent prognostic factors for OS by the multivariate analysis, whereas N stage, M stage, the presence of multiple primary carcinomas and the treatment modalities were identified as independent prognostic factors for CSS. The C-index values of the prognostic nomogram based the risk factors affecting SDC OS and CSS were 0.703 (0.646–0.760) and 0.771 (0.691–0.851), respectively.

Conclusions

SDC is an aggressive malignancy with a high proportion of advanced stage and lymph node metastases. Patients with increasing age, submandibular gland malignancy, advanced T stage, advanced N stage, advanced M stage, high lymph node ratio (LNR) and the presence of multiple primary carcinomas tend to have unfavorable outcomes. Radiotherapy or chemotherapy improve CSS remarkably. These factors will aid in effective therapeutic treatment modalities for SDC.

Molecular and Cellular Modelling of Salivary Gland Tumors Open New Landscapes in Diagnosis and Treatment

Salivary gland tumors are neoplasms affecting the major and minor salivary glands of the oral cavity. Their complex pathological appearance and overlapping morphological features between subtypes, pose major challenges in the identification, classification, and staging of the tumor. Recently developed techniques of three-dimensional culture and organotypic modelling provide useful platforms for the clinical and biological characterization of these malignancies. Additionally, new advances in genetic and molecular screenings allow precise diagnosis and monitoring of tumor progression. Finally, novel therapeutic tools with increased efficiency and accuracy are emerging. In this review, we summarize the most common salivary gland neoplasms and provide an overview of the state-of-the-art tools to model, diagnose, and treat salivary gland tumors.

Efficacy of Pyrotinib in HER2-Overexpressing Salivary Duct Carcinoma With Lung Metastasis: A Case Report

Background: Salivary duct carcinoma (SDC), an aggressive and rare malignancy with poor prognosis, is mostly associated with the overexpression of the androgen receptor (AR) and human epidermal growth factor receptor 2 (HER2). However, limited data are available for the targeting of both HER2 and AR in advanced/metastatic SDC.

Case Presentation: A 62-year-old man with advanced SDC accompanied by lung and lymph node metastasis showed disease progression after two lines of chemotherapy and endocrine therapy. Metastatic lesions from the lung biopsy were obtained, and immunohistochemistry (IHC) indicated the overexpression of AR and HER2 (3+). The patient was administered pyrotinib (a pan-ErbB receptor tyrosine kinase inhibitor) and bicalutamide (an androgen receptor antagonist) as a third-line treatment. During the ten months of follow-up, a durable partial response was achieved with this combination.

Conclusions: This is the first clinical study to report the successful application of pyrotinib in a patient with advanced SDC. We recommend that pyrotinib and bicalutamide be used as salvage therapy for AR and HER2-positive advanced metastases in SDC, given the favorable response and clinical benefit.