Salivary duct carcinoma: a clinical and histologic review with implications for trastuzumab therapy

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.

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.

Systemic therapies for salivary gland carcinoma (excluding adenoid cystic carcinoma): REFCOR recommendations by the formal consensus method

OBJECTIVE

To determine the therapeutic indications for systemic medical treatment in the management of salivary gland carcinoma (excluding adenoid cystic carcinoma) according to the clinical situation.

MATERIALS AND METHODS

The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group who drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group, according to the formal consensus method.

RESULTS

Salivary gland carcinoma is rare and there is currently insufficient evidence to indicate chemotherapy at the localized stage. At the metastatic stage, initial management can be based on a phase of monitoring for indolent disease. Some histological subtypes (salivary duct carcinoma and adenocarcinoma) are more aggressive and require systemic treatment from the outset. To guide systemic treatment, it is recommended to perform immunohistochemistry and molecular biology analyses (overexpression of HER2 and androgen receptors, NTRK fusion, next-generation sequencing).

CONCLUSION

Salivary gland carcinoma is a rare tumor for which there are currently few effective medical treatments. It is therefore recommended to include patients in clinical trials.

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.

ERBB2 amplification status in 67 salivary duct carcinomas assessed by immunohistochemistry, fluorescence in situ hybridization, and targeted exome sequencing

Salivary duct carcinoma (SDC) is an aggressive salivary gland malignancy with poor survival. Approximately 30% SDC harbor HER2 amplification and response to trastuzumab has been reported. However, a systematic approach for HER2 status assessment in this tumor type has not been established. A total of 67 tumor samples were evaluated for HER2 protein overexpression or ERBB2 gene amplification using at least 2 methods: immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and/or targeted exome next-generation sequencing (NGS). NGS assessed ERBB2 copy number fold change (FC) and total copy number (TCN). HER2 status was first determined by IHC/FISH according to the 2018 ASCO/CAP breast cancer guidelines. FISH results, the "gold standard", were compared with the NGS results. All (15/15) IHC positive, 35% (6/17) equivocal, and no (0/19) IHC negative SDC were HER2 amplified by FISH. HER2 FISH signal/cell showed a good correlation with FC (Spearman correlation: 0.708, R²: 0.501, p < 0.0001) and TCN (Spearman correlation: 0.763, R²: 0.582, p < 0.0001). Receiver operating characteristics curve estimation showed an area under curve (AUC) of 0.975 for ERBB2 FC. FC cutoff of ≥1.8 corresponded to an accuracy of 95.2% for ERBB2 amplification (Youden's index: 0.84, sensitivity: 89.47%, specificity: 100%). FC < 1.3 could be reliably classified as ERBB2 not amplified and FC ≥ 1.3 and <1.8 as equivocal. TCN estimation showed AUC of 0.981. TCN cutoff of >6.0 corresponded to an accuracy of 92% for HER2 amplification (Youden's index: 0.81, sensitivity: 81.2%, specificity: 100%). TCN < 4 could be reliably classified as ERBB2 not amplified and TCN ≥ 4.0 and ≤6.0 as equivocal. FC and TCN were binarized with respective cutoffs of ≥1.8 and ≥6.0 and the proportion of agreement with FISH were 95% and 92%, respectively. The assessment of ERBB2 copy number by NGS is accurate and reliable with FC or TCN nearly equivalent to FISH in identifying HER2 amplified SDC.

Paraneoplastic cerebellar degeneration with anti-Yo antibodies and an associated submandibular gland tumor: a case report

Background

As a debilitating syndrome, paraneoplastic cerebellar degeneration (PCD) remains challenging to treat. Further, anti-Yo antibody (directed against human cerebellar degeneration-related protein 2) detection in patients with PCD is associated with unsatisfactory responses to existing therapies. Here, we present the case of a 60-year-old woman who developed PCD with anti-Yo antibodies and a submandibular gland tumor.

Case presentation

A 60-year-old woman presented with a 5-day history of unsteadiness of gait and inadequate coordination of her extremities, along with truncal instability. Although walking without aid was possible, dysmetria of all four limbs, trunk, and gait ataxia was observed. While routine biochemical and hematological examinations were normal, the patient’s blood was positive for anti-Yo antibodies. When the neurological symptoms deteriorated despite administration of intravenous methylprednisolone, fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) images with contrast enhancement were performed, which showed a tumor in the left submaxillary gland. She underwent total left submandibular gland resection, including the tumor; histological and immunohistochemical results revealed a salivary duct carcinoma. She was administered intravenous methylprednisolone, followed by 10 plasma exchange sessions, intravenous immunoglobulins, and cyclophosphamide therapy. Following treatment, her symptoms were not alleviated, even after the reduction of anti-Yo titers.

Conclusions

Although tumor detection was delayed, early tumor detection, diagnosis, and PCD treatment are essential because any delay can result in the progression of the disorder and irreversible neurological damage. Therefore, we recommend that the possibility of a salivary gland tumor should be considered, and whole-body dual-modality CT, including the head and neck, and FDG-PET should be performed at the earliest for patients with well-characterized paraneoplastic antibodies when conventional imaging fails to identify a tumor.

HER2 Positivity in Histological Subtypes of Salivary Gland Carcinoma: A Systematic Review and Meta-Analysis

Background

HER2 aberrations in salivary gland carcinomas (SGC) as well as benefit of HER2 directed therapy have been reported in small studies. However, reliable estimates of the prevalence of HER2 positivity in SGC and its various histological subtypes are lacking.

Objective

To assess the prevalence of HER2 positivity in histological subtypes of salivary gland carcinomas (SGC).

Methods

Studies were identified by a systematic review of the literature. Data on in situ hybridization (ISH) and immunohistochemistry (IHC) were extracted to derive pooled prevalence estimates calculated by a random effects model. Characteristics of the studies were extracted for subgroup analysis.

Results

Fifty studies including 3372 patients were identified, providing data on sixteen histological subtypes. Based on the meta-analysis, the estimated prevalence of HER2 positivity were 43% (95% CI: 36% – 51%) in salivary duct carcinoma (SDC), 39% (95% CI: 32% – 45%) in carcinoma ex pleomorphic adenoma (CEP), 17% (95% CI: 7.5% – 33%) in squamous cell carcinoma (SCC), 13% (95% CI: 7.6% – 21%) in adenocarcinoma NOS (ADC), 6.7% (95% CI: 0.17%-32%) in poorly differentiated carcinoma, 5.5% (95% CI: 2.9% – 9.6%) in mucoepidermoid carcinoma, 4.3% (95% CI: 1.4% – 13%) in myoepithelial carcinoma, 1.8% (95% CI: 0.04%-9.6%) in epithelial-myoepithelial carcinoma, 0.45% (95% CI: 0.0097% – 18%) in acinic cell carcinoma and 0.15% (0.037% – 5.4%) in adenoid cystic carcinoma. Estimates for five additional subtypes were assessed.

Conclusion

Prevalence of HER 2 positivity in SGC varies greatly based on histological subtype, with SDC, CEP, SCC, and ADC displaying the highest rates.

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.

HER2-positive metastatic, parotid salivary duct carcinoma treated with a trastuzumab/pertuzumab-based chemotherapy: A case report

This case highlights the rare entity, salivary duct carcinoma (SDC), which is difficult to diagnose and manage. It is the first published case of a metastatic, HER2-positive parotid SDC successfully treated by a dual anti-HER2 treatment associated to a chemotherapy.

Primary squamous cell carcinoma of major salivary gland: "Sapienza Head and Neck Unit" clinical recommendations

Primary squamous cell carcinoma of salivary gland (SCG) is an extremely rare type of malignant salivary gland tumor, which in turn results in scarcity of data available regarding both its treatment and associated genetic alterations. A retrospective analysis of 12 patients with primary SCG was conducted, along with analysis of the association between treatment, clinical/pathological characteristics, and outcomes. Most patients (8) were staged IVa, with the majority of them (10) having G3 fast growing cancer. Local and systemic recurrence were reported in only three out of nine parotid cases (0 out of 2 submandibular SCGs). In two out of eight patients local relapse occurred after integrated treatment, while recurrence occurred in two out of three patients undergoing exclusive surgery. Five patients eventually died. Treatment of resectable disease must be aggressive and multimodal, with achievement of loco-regional control in order to reduce rate of recurrence and improve outcomes. Metastatic disease would require a therapeutic strategy tailored to the molecular profile in order to improve the currently disappointing results.

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.

Systemic therapy for metastatic salivary gland tumors—challenges and novel concepts

Salivary gland cancers (SGC) are a rare and heterogeneous group of malignancies. Most frequently tumors arise in the parotid gland. The most common histologic subtypes are adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Rare subtypes include salivary ductal carcinoma (SDC), mammary analogue secretory carcinoma (MASC) and adenocarcinoma not other specified (AC NOS). For locally advanced or metastatic disease, chemotherapy has been the mainstay of therapy. The course of disease differs markedly between the subtypes, especially ACC usually presents as slowly progressing disease. Due to the rarity of these tumors only small phase I/II studies exist, which report efficacy of cytotoxic regimens in advanced SGC. However, due to advances in the understanding of tumor biology and molecular testing, drugable genetic changes like androgen receptor (AR) status, HER2/neu overexpression and neurotrophic tyrosine receptor kinase (NTRK) gene fusion have evolved as potential therapy targets in subsets of SGC. Consequently therapy with androgen receptor blockade (ARB) can be offered to patients with AR expressing tumors. Anti-HER2 therapy with trastzumab is an option for the treatment of tumors with overexpression of HER2/neu and finally NTRAK inhibitors can be used for tumors harboring a NTRK gene fusion. Taken together, due to the small number of patients, data from large phase III studies for the treatment of SGC are missing. However, promising targeted therapy approaches have been recently undertaken.

Targeted therapy with trastuzumab for epidermal growth factor receptor 2 (HER2)-positive advanced salivary duct carcinoma: A case report

Herein we report two cases of advanced and/or metastatic salivary duct carcinoma that relapsed after standard first-line chemotherapy. As overexpression of human epidermal growth factor receptor 2 (HER2) (3+) was observed by immunohistochemistry, the patients were treated with trastuzumab plus paclitaxel. One patient showed a complete response lasting over 2.5 years after the commencement of therapy; however, the other patient had no response to trastuzumab combined therapy. Dual fluorescence in situ hybridization was performed after the initiation of chemotherapy; the first case was positive for HER2 gene amplification, while the second case was negative. Our experiences suggest that therapy with HER2 blockers should be considered as options for treatment of HER2-positive salivary duct carcinoma. However, HER2 protein overexpression and gene amplification should be investigated further as therapeutic biomarkers.

The repertoire of genetic alterations in salivary duct carcinoma including a novel HNRNPH3-ALK rearrangement

Salivary duct carcinoma (SDC) is a rare, aggressive malignancy with limited treatment options and poor outcome. Twenty-nine primary resected SDC, including 15 SDC de novo (SDCDN), and 14 SDC ex pleomorphic adenoma (SDCXPA) were subjected to the massive parallel sequencing assay (MSK-IMPACT) targeting 287 to 468 cancer-related genes. TP53 was the most frequently altered gene (69%). TP53 mutations and ERBB2 amplification were more frequent in SDCXPA than in SDCDN (P = .0007 and P = .01, respectively). Potentially targetable mutations were detected in 79% (23/29) of SDC involving ERBB2 (31%), PIK3CA (28%), HRAS (21%), ALK (7%) and BRAF (3%), and 22% (5/23) of those cases harbored possible primary resistance mutations involving CCNE1, NF1 and PTEN. A novel HNRNPH3-ALK rearrangement was found in one SDCDN. In another case, EML4-ALK fusion detected in the primary tumor was associated with ALK G1202R secondary resistance mutation in the post-treatment metastasis. A germline analysis of the DNA repair genes revealed a case with a pathogenic BRCA1 E23fs germline variant. SDCDN and SDCXPA are genetically distinct. Although the majority of SDC may be amenable to molecular targeted therapy, concurrent possible resistance mutations may be found in a significant minority of cases. A broad genomic profiling is necessary to ensure detection of rare but clinically actionable somatic alterations in SDC.

Role of the pretreatment neutrophil-to-lymphocyte ratio in the survival of primary parotid cancer patients

BACKGROUND

To analyze the value of the pretreatment neutrophil-to-lymphocyte ratio (NLR) in the survival of patients with parotid cancer.

METHODS

In total, 249 patients were enrolled. Information including age, sex, pretreatment NLR, and pathologic variables such as, tumor stage, intraparotid node (IPN) metastasis, and follow-up findings was extracted and analyzed.

RESULTS

IPN metastasis was noted in 45 (18.1%) patients, and the mean NLR was 2.48, with a range from 1.5 to 6.1. The NLR was significantly associated with tumor stage, disease stage, and disease grade. A total of 73 patients died of the disease, and the 10 -year disease-specific survival (DSS) rate was 62%. In patients with an NLR<2.48, the 10 -year DSS rate was 68%; in patients with an NLR≥2.48, the 10 -year DSS rate was 58%, and the difference was significant (P=0.006). Cox model analysis showed that the NLR was an independent prognostic factor for DSS.

CONCLUSION

The long-term survival of primary parotid cancer patients is relatively favorable, and the pretreatment NLR is significantly associated with prognosis.

Salivary gland tumors: Molecular characterization and therapeutic advances for metastatic disease

Salivary gland cancers represent a rare group of tumors composed by over 20 histological subtypes. Initially treated as one single disease, its diagnosis, prognosis, and treatment are currently being stratified based on morphology. More recently, insight has been provided on the molecular characterization of each subtype, further improving diagnostic accuracy and paving the way for personalized therapy. In this article, we provide a comprehensive review of recent breakthroughs, preliminary results of novel therapy, and future directions on the treatment of these complex malignancies.

Radiotherapy as salvage treatment of salivary duct carcinoma in major salivary glands without radical operations

Background

Salivary duct carcinoma (SDC) is an extremely rare and highly malignant carcinoma, and surgical radical resection is the most effective therapy. However, there were quite a proportion of patients receiving non-radical resections, and how to treat them remained controversial. Thus, the aim of this study is to evaluate whether postoperative radiotherapy could be a salvage treatment of SDC in major salivary glands without radical operations.

Patients and methods

We identified 40 pathologically diagnosed SDC patients who came to our hospital and did not receive radical operations. Thirty-three patients received at least one treatment (remedial operation, postoperative radiotherapy and chemotherapy), and seven patients only chose observation and received no further treatment. The prognostic indicators of the local-regional control (LRC) and distant disease-free survival were analyzed using the Kaplan-Meier methods and the Cox proportional hazards regression models.

Results

Thirteen patients experienced local-regional recurrence or local progression, and distant metastases were observed in 15 patients. Through multivariate analysis, we found that postoperative radiotherapy was associated with better LRC, but this kind of treatment did not show significant efficacy in the prevention of distant metastasis.

Conclusion

SDC is a rare, aggressive malignancy, and a substantial proportion of these patients experienced inadequate initial treatments. Although postoperative radiotherapy could not decrease distant metastases, it might help to improve LRC in patients with SDC.

Bone marrow metastases in salivary duct carcinoma of the parotid gland

Salivary duct carcinoma (SDC) is a rare and extremely aggressive salivary gland cancer. An 81-year-old woman with SDC underwent a total parotidectomy with facial nerve sacrifice and a neck dissection. Following surgery, she was diagnosed with disseminated bone marrow metastases. She underwent chemotherapy and trastuzumab for palliation. We present a case of SDC of the parotid which was diagnosed with disseminated bone marrow metastasis following surgery for the primary. This case also highlights the importance of having a high index of suspicion while evaluating highly aggressive tumours like SDC for any atypical findings during workup.

Salivary duct carcinoma: Prospective multicenter study of 61 cases of the Réseau d'Expertise Français des Cancers ORL Rares

BACKGROUND

The purposes of this study were to describe the characteristics of a prospective multicenter series of patients with salivary duct carcinoma and to investigate prognostic factors.

METHODS

Patients included for salivary duct carcinoma between 2009 and 2016 in the Réseau d'Expertise Français des Cancers ORL Rares (REFCOR) database were selected. Immunohistochemical analyses were performed.

RESULTS

Sixty-one patients were included in this study. The primary site was the parotid gland in 90% of the cases. Fifty-seven percent of the tumors were stage IV, 65% of patients had lymph node involvement, and 10% had metastases. Tumors showed androgen receptor (89%) and human epidermal growth factor receptor 2 (HER2)/neu (36%). Ninety-four percent of patients underwent surgery and 86% had postoperative radiotherapy. Six patients were treated with targeted therapies. The 3-year overall survival (OS) was 74% and the 3-year disease-free survival (DFS) was 44%. Tumor stages III to IV reduced DFS (hazard ratio [HR] 4.3; P = .04). The N2/3 class reduced distant metastasis-free survival (HR 7.3; P = .007).

CONCLUSION

Salivary duct carcinoma prognosis is poor and is correlated with tumor stage and lymph node classification. Androgen receptor and HER2/neu should be tested as they offer the possibility of targeted therapies.

Salivary duct carcinoma

PURPOSE OF REVIEW

The review puts new information on geno- and phenotype of salivary duct carcinoma (SDC) in the perspective of the updated 2017 WHO classification.

RECENT FINDINGS

The proportion of SDC is increasing. This may be because of a true rise in incidence, but certainly to better diagnostic tests and changed WHO definitions. In this light, a substantial proportion of carcinoma expleomorphic adenoma is now attributed to the category of SDC. 'Low-grade SDC' and 'SDC in-situ' of the former WHO classification, are now named low-grade and high-grade intraductal carcinoma (IDC), respectively. Recent series quantify biologic aggressiveness: perineural growth, vascular invasion, and extracapsular extension in lymph node metastasis are each observed in two out of three patients with SDC. Most patients die within 3 years, but once 5-year disease-free survival is reached, further disease activity is exceptional. The typical molecular biological profile with high human epidermal growth factor receptor 2 and androgen receptor expression is increasingly successfully exploited in clinical trials for advanced SDC.

SUMMARY

The aggressive SDC is increasingly diagnosed. Despite intensive combined surgery and radiation therapy, many patients recur, for whom new bullets, targeting the molecular biological mechanisms, are the subject of ongoing clinical trials.

Clinicopathological Behavior and Treatment-related Outcome of Rare Salivary Duct Carcinoma: The Shaukat Khanum Memorial Cancer Hospital Experience

Background

Salivary gland tumors are rare salivary gland malignancies with resemblance to ductal breast carcinoma. We have described clinicopathological behavior and treatment outcomes of this rare malignancy.

Methods

Salivary duct carcinoma patients treated from 2010 to 2015 were retrospectively analyzed for clinicopathological characteristics and treatment-related outcomes of the disease.

Results

A total of 12 patients with salivary duct carcinoma were included in the study. All were males with mean age of 52.58 ± 13.43. Parotid gland was the most commonly involved major salivary gland while buccal mucosa and anterior tongue were most common oral cavity sub-sites involving minor salivary glands. The disease-free survival was 75% at 10 months and 25% at 20 months. The mean follow-up time was 12 months. There were three local recurrences and one distant metastasis.

Conclusion

Salivary duct carcinoma is a locally aggressive tumor with tendency for local recurrence and distant metastasis. Adverse features such as perineural invasion, extra-capsular spread and advanced nodal disease may worsen prognosis.

Epigenetic inactivation of galanin receptors in salivary duct carcinoma of the parotid gland: Potential utility as biomarkers for prognosis

Salivary duct carcinoma (SDC) constitutes one of the most aggressive cancers in the salivary gland and is associated with a poor prognosis; however, no established systemic therapy options are available. SDC exhibits biological similarity to prostate and breast cancers, therefore anti-hormone therapy and molecular target therapies are available, however with limited beneficial effects. Galanin and galanin receptors (GALRs) are well established as molecular biomarkers to predict the survival rate and risk of recurrence of head and neck squamous cell carcinoma. The present study investigated the clinicopathological features of patients with SDC and the methylation status of their galanin and GALR genes to demonstrate the prognostic value for this disease. The median overall survival (OS) was 37.2 months. T-stage, N-stage, disease stage, tumor size, and preoperative facial paralysis were significantly associated with OS, whereas human epidermal growth factor receptor 2 (HER2) overexpression was not. GALR1 and GALR2 methylation rates in tumor tissues were significantly increased compared with normal tissues with 9.85- and 4.49-fold increase, respectively. p27^kip1 and p57^kip2 expression significantly inversely correlated with the methylation rate of GALR1 and GALR2. In addition, the observed GALR1 and/or GALR2 methylation rates were significantly correlated with a decrease in OS. These results suggest that GALR1 and GALR2 may serve as potential prognostic factors and therapeutic targets in SDC.

Androgen deprivation therapy for androgen receptor-positive advanced salivary duct carcinoma: A nationwide case series of 35 patients in The Netherlands

Background

Salivary duct carcinoma, an aggressive subtype of salivary gland cancer, is mostly androgen receptor‐positive. Only limited data are available on androgen deprivation therapy (ADT).

Methods

Patients with advanced androgen receptor‐positive salivary duct carcinoma treated with first‐line ADT were retrospectively evaluated for clinical benefit (ie, partial response [PR] and stable disease, progression‐free survival [PFS] and overall survival [OS]). The OS was compared with patients with advanced salivary duct carcinoma who received best supportive care.

Results

Thirty‐four of 35 patients who were ADT‐treated were evaluable: 6 patients had a PR (18%) and 11 had stable disease (32%) leading to a clinical benefit ratio of 50%. The median PFS for the ADT‐treated patients was 4 months and the median duration of clinical benefit was 11 months. The median OS was 17 months versus 5 months in 43 patients receiving best supportive care (P = .02).

Conclusion

We recommend ADT in advanced androgen receptor‐positive salivary duct carcinoma given its response and clinical benefit. © 2017 Wiley Periodicals, Inc. Head Neck, 2017

The localization of pre mRNA splicing factor PRPF38B is a novel prognostic biomarker that may predict survival benefit of trastuzumab in patients with breast cancer overexpressing HER2

Cancer biomarkers that can define disease status and provide a prognostic insight are essential for the effective management of patients with breast cancer (BC).

The prevalence, clinicopathological and prognostic significance of PRPF38B expression in a consecutive series of 1650 patients with primary invasive breast carcinoma were examined using immunohistochemistry. Furthermore, the relationship(s) between clinical outcome and PRPF38B expression was explored in 627 patients with ER-negative (oestrogen receptor) disease, and 322 patients with HER2-overexpressing disease.

Membranous expression of PRPF38B was observed in 148/1388 (10.7%) cases and was significantly associated with aggressive clinicopathological features, including high grade, high mitotic index, pleomorphism, invasive ductal carcinoma of no specific type (IDC-NST), ER-negative, HER2-overexpression and p53 mutational status (all p < 0.01). In patients with ER-negative disease receiving chemotherapy, nuclear expression of PRPF38B was significantly associated with a reduced risk of relapse (p = 0.0004), whereas membranous PRPF38B expression was significantly associated with increased risk of relapse (p = 0.004; respectively) at a 5 year follow-up. When patients were stratified according to ER-negative/HER2-positive status, membranous PRPF38B expression was associated with a higher risk of relapse in those patients that did not receive trastuzumab therapy (p = 0.02), whereas in those patients with ER-negative/HER2-positive disease that received trastuzumab adjuvant therapy, membranous PRPF38B expression associated with a lower risk of relapse (p = 0.00018).

Nuclear expression of PRPF38B is a good prognostic indicator in both ER-negative patients and ER-negative/HER2-positive BC (breast cancer) patients, whereas membranous localisation of PRPF38B is a poor prognostic biomarker that predicts survival benefit from trastuzumab therapy in patients with ER-negative/HER2-overexpressing BC.

Salivary duct carcinoma: An aggressive salivary gland malignancy with opportunities for targeted therapy

Salivary duct carcinoma (SDC) is a rare, aggressive salivary malignancy that is often diagnosed at an advanced stage. Previously, little was known about outcomes of this disease due to its rarity. In the past several years, much has been learned about salivary duct carcinoma after publication of outcomes from several large single-institution series and national database searches. Recent studies of genomic alterations have helped elucidate the biology and pathogenesis of this aggressive disease. Here we review outcomes of the disease, effects of treatment, prognostic factors, and genomic alterations in SDC. Studies of targeted therapy and promising future directions are also discussed.

Biomarker immunoprofile in salivary duct carcinomas: clinicopathological and prognostic implications with evaluation of the revised classification

Salivary duct carcinoma (SDC) is an uncommon, aggressive malignant neoplasm histologically resembling high-grade mammary ductal carcinoma. SDC can arise de novo or ex pleomorphic adenoma. To clarify the correlation of biomarker immunoprofile with clinicopathological findings and clinical outcome of SDC, we conducted immunohistochemistry for EGFR, HER2, HER3, AR, CK5/6, p53, and Ki-67, along with HER2 fluorescence in situ hybridization in 151 SDCs. SDCs ex pleomorphic adenoma more commonly overexpressed EGFR, HER2, HER3, and Ki-67 than de novo SDCs (P = 0.015, < 0.001, 0.045, and 0.02, respectively). In multivariate analysis, AR− and CK5/6+ were associated with shorter progression-free survival (P = 0.027 and 0.004, respectively). Moreover, patients with p53-extreme negative/positive demonstrated poorer overall survival (P = 0.007). On assessing the revised classification by the combination of biomarker expression, the percentages of each subtype were as follows: ‘apocrine A’ (AR+/HER2−/Ki-67-low) (24%), ‘apocrine B’ (AR+/HER2−/Ki-67-high) (18%), ‘apocrine HER2’ (AR+/HER2+) (35%), ‘HER2-enriched’ (AR−/HER2+) (12%), and ‘double negative’ (AR−/HER2−) (11%). ‘Double negative’ was further subclassified into ‘basal-like’ (EGFR and/or CK5/6+) (7%) and ‘unclassified’ (3%). Consequently, patients with ‘apocrine A’ showed a better progression-free survival than those with any other subtypes. Our revised immunoprofiling classification was valuable for predicting the survival and might be useful in personalized therapy for patients with SDC.

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

IMPORTANCE

Salivary duct carcinoma is a rare, aggressive malignancy of the salivary glands. Owing to its rare nature, clinical data are limited, and only a few clinical studies comprise more than 50 patients.

OBJECTIVE

To review the University of Pittsburgh Medical Center's experience with salivary duct carcinoma over a 20-year period, focusing on demographics, presentation, treatment, and outcome.

DESIGN, SETTING, AND PARTICIPANTS

This investigation was a retrospective cohort study in a multihospital institution with tertiary referral. A pathology database was reviewed for all cases of histopathologically diagnosed salivary duct carcinoma from January 1, 1995, to October 20, 2014. Patients who were referrals for pathology review only and were never seen at the institution were excluded. In total, 75 study patients were identified. The electronic medical record was reviewed for details regarding demographics, presentation, treatment, and outcome, including overall survival (OS) and disease-free survival (DFS). This study was supplemented with a review of the institution's Head and Neck Oncology Database for further clinical details.

MAIN OUTCOMES AND MEASURES

Primary outcome measures consisted of OS and DFS.

RESULTS

The study sample comprised 75 participants with a mean age at diagnosis of 66.0 years (age range, 33-93 years), and 29% (n = 22) were female. Most primary tumors were from the parotid gland (83%), with the next most frequent site being the submandibular gland (12%). Overall, 41% of the cases were carcinoma ex pleomorphic adenoma. Rates of other histologic features included the following: perineural invasion (69%), extracapsular spread (58%), ERBB2 (formerly HER2) positivity (31%) (62% of those who were tested), and vascular invasion (61%). The median OS was 3.1 years, and the median DFS was 2.7 years. Univariate Kaplan-Meier survival analyses demonstrated that facial nerve sacrifice and extracapsular spread were associated with lower OS (2.38 vs 5.11 years and 2.29 vs 6.56 years, respectively) and DFS (2.4 vs 3.88 years and 1.44 vs 4.5 years, respectively). Although underpowered, multivariable analysis demonstrated significantly worse OS in patients with N2 and N3 disease (hazard ratio [HR] 8.42, 95% CI, 1.84-38.5) but did not show significantly worse DFS or OS for facial nerve sacrifice or extracapsular spread. There was no association between ERBB2 positivity and survival and no difference in survival between patients receiving radiation therapy vs radiation therapy plus chemotherapy. No patients had recurrence or distant metastasis after 5 disease-free years.

CONCLUSIONS AND RELEVANCE

Salivary duct carcinoma is an aggressive disease. A large number of cases in this review were carcinoma ex pleomorphic adenoma and had classic negative prognostic indicators, such as perineural invasion, vascular invasion, and extracapsular spread. ERBB2 positivity was not associated with any difference in survival. Facial nerve involvement appears to indicate worse prognosis, as does nodal stage higher than N1. Recurrence and metastasis after 5 years are rare.

Expression of Hormone Receptors and HER-2 in Benign and Malignant Salivary Gland Tumors

With the advent of targeted therapies, expression of sex hormone receptors and HER-2 in salivary gland tumors (SGTs) is of clinical interest. Previous reports of estrogen (ER) and progesterone (PR) receptor expression have varied. Androgen receptor (AR) and HER-2 overexpression are frequently reported in salivary duct carcinoma (SDC), but have not been studied systematically in other SGTs. This study examines ER, PR, AR, and HER-2 expression in SGTs. Immunohistochemistry for ER, PR, AR, and HER-2 was performed on 254 SGTs (134 malignant). ER, PR, and AR expression was scored using Allred system. HER-2 expression was scored using Dako HercepTest guidelines. FISH for HER-2 amplification was performed on select cases with HER-2 overexpression (2-3+). No SGT demonstrated strong expression of ER or PR. Combined strong AR and HER-2 expression was seen in 22 carcinomas: 14/25 SDC, 3/16 poorly differentiated, two oncocytic, and one each carcinoma ex pleomorphic adenoma, squamous cell, and intraductal carcinoma. Eighteen additional high grade carcinomas had HER-2 overexpression with absent, weak, or moderate AR expression; eight high grade carcinomas had isolated strong AR expression with 0-1+ HER-2 staining. Of 15 tested cases, six demonstrated HER-2 amplification by FISH, all of which had 3+ immunoreactivity. Neither benign nor malignant SGTs had strong expression of ER or PR. None of the benign SGTs overexpressed AR or HER-2. Coexpression of AR and HER-2 should not define SDC, but immunostaining should be considered in high grade salivary carcinomas, as some show overexpression and may benefit from targeted therapy.

Characterization, treatment and outcomes of salivary ductal carcinoma using the National Cancer Database

OBJECTIVES

To analyze clinical, treatment and outcome data for patients with salivary ductal carcinoma in a large population-based sample.

MATERIALS AND METHODS

The National Cancer Database was queried to identify patients diagnosed with salivary ductal carcinoma between 2004 and 2013. Kaplan Meier and Cox regression analysis were used to assess overall survival (OS) and identify impact of specific variables on OS.

RESULTS

A total of 495 patients were identified. The most common site of tumor origin was the parotid (80%). 130 patients (26.3%) presented with early stage (I-II) disease, 257 patients (51.9%) with locoregionally advanced pathologic stage (III-IVB) disease and 41 patients (8.3%) with metastatic disease. The 5year OS for these patients was 79.5%, 40.4% and 0% respectively. At presentation, 46.6% had node positive disease. Surgery was performed in 100% of patients with early stage disease, 98.4% with advanced disease and 90.2% with metastatic disease. Radiation therapy, generally postoperative radiation, was given to 58.5% of patients with stage I-II disease, 71.6% with stage III-IVB disease and 53.7% with metastatic disease. Chemotherapy was utilized in 5.4% of patients with stage I-II disease, 35% with stage III-IVB and 70.7% with metastatic disease. On multivariable analysis, there were no significant differences in OS based on receipt of adjuvant radiotherapy, chemotherapy, or chemoradiotherapy.

CONCLUSION

Salivary ductal carcinoma represents an uncommon and aggressive subset of salivary tumors for which current adjuvant treatments do not have a detectable impact on overall survival.

Salivary duct carcinoma treated with cetuximab-based targeted therapy: A case report

Salivary duct carcinoma is a highly aggressive disease with a poor prognosis. Surgical resection is currently the only curative treatment, as there is no effective systemic therapy for this malignancy. Recently, trastuzumab has been shown to exhibit therapeutic efficacy in the treatment of salivary duct carcinoma; similarly, molecularly targeted agents, such as cetuximab, are expected to be useful for salivary duct carcinoma treatment. We herein describe the case of a 56-year-old man diagnosed with salivary duct carcinoma in the left submandibular region, with ipsilateral multiple metastases to the neck lymph nodes. Radical resection of the tumor and submandibular gland with neck dissection were performed. One month after radical surgery, computed tomography (CT) scans indicated metastasis in the lower lobe of the left lung. CT-guided transthoracic fine-needle aspiration biopsy revealed a single metastasis and lung metastasectomy was immediately performed. The tumor cells of the primary lesion and those of the lung metastasis were immunohistochemically positive for epidermal growth factor receptor. One month later, multiple right lung metastases appeared, and the patient was treated with cisplatin/5-fluorouracil (5-FU) chemotherapy plus cetuximab, achieving a complete radiographic response. However, multiple lung metastases developed during adjuvant weekly cetuximab monotherapy. Subsequently, treatment with S-1 and weekly cetuximab was initiated, and the multiple lung metastases have been maintained as stable disease for 5 months. To the best of our knowledge, this is the first report of cetuximab use for the treatment of salivary duct carcinoma. Although cisplatin/5-FU chemotherapy plus cetuximab was efficacious in treating the lung metastasis, cetuximab monotherapy was insufficient for controlling tumor growth.

New concepts of personalized therapy in salivary gland carcinomas

Salivary gland carcinomas are rare tumours and therapy strategies are less standardized than in lung, gastric or breast cancer. Therapy is based on surgery, but not all carcinomas are completely resectable, e.g. because carcinomas often show infiltration of nerves. For further therapy decision pathology is recommended, but evaluation of potential targets for personalized therapy is not part of the routine panel. Many salivary gland carcinomas can be resistant to radio- and/or chemotherapy, which limits therapeutic options. This review summarizes new concepts for personalized therapy in salivary gland carcinoma patients. Targeting growth receptors HER2, EGFR, AR and ER is possible but, in some studies, potential target molecules were not adequately tested before therapy. In addition, approximately 20-25% of carcinomas have RAS mutation (mainly H-RAS), which could explain resistance to therapy. Possible therapy options in the future could be immunomodulation (inhibition of PDL1/PD1 signalling), nanoparticles (gold nanoparticles conjugated to cetuximab can increase radiosensitivity) and drug delivery systems (trastuzumab emtansine/T-DM1).

New Developments in Salivary Gland Pathology: Clinically Useful Ancillary Testing and New Potentially Targetable Molecular Alterations

Accurate diagnosis of salivary gland tumors can be challenging because of the many diagnostic entities, the sometimes extensive morphologic overlap, and the rarity of most tumor types. Ancillary testing is beginning to ameliorate some of these challenges through access to newer immunohistochemical stains and fluorescence in situ hybridization probes, which can limit differential diagnostic considerations in some cases. These ancillary testing strategies are especially useful in small biopsy samples, including aspiration cytology. Molecular techniques are also expanding our understanding of salivary gland tumor pathology and are helping to identify potential targets that may improve treatment for some of these tumors. Here, we summarize the clinical use of new immunohistochemical markers in our practice and review the current understanding of chromosomal rearrangements in salivary gland tumor pathology, emphasizing the prospects for exploiting molecular alterations in salivary gland tumors for diagnosis and targeted therapy. We find that immunohistochemistry and fluorescence in situ hybridization are powerful tools toward the diagnosis of salivary gland tumors, especially when used in a systematic manner based on morphologic differential-diagnostic considerations. As new targeted therapies emerge, it will become increasingly vital to incorporate appropriate molecular testing into the pathologic evaluation of salivary gland cancers.

Systemic therapy in metastatic salivary gland carcinomas: A pathology-driven paradigm?

Salivary gland carcinomas (SGCs) represent one of the most complex tumors from a pathological point of view. According to the World Health Organization (WHO) classification (2005), twenty-four malignant histotypes are recognized, almost all characterized by specific morphological and genetic features as well as by particular clinical behavior. Loco-regional relapse and distant metastases are quite common. Distant metastases are diagnosed in 25-55% of the patients and only 20% of them are alive after 5years. Adenoid cystic carcinoma (ACC) is the most common (60%) malignant histotype observed in patients with metastatic disease, whilst the other histotypes such as mucoepidermoid carcinoma, salivary duct carcinoma, adenocarcinoma, not otherwise specified (NOS), and myoepithelial carcinoma are rarer. The most common therapeutic approach in cases of metastatic disease is systemic chemotherapy, although the results with this type of approach are poor both in terms of response rate and overall outcome. No consensus has yet been reached on what the standard regimen of chemotherapy should be in this setting. New therapies are under investigation e.g. antiangiogenic agents, histone deacetylase inhibitors, and hormonal deprivation treatment. We have focused our review on systemic treatments in ACC and in non-ACC tumors, including in this latter group all SGC histotypes other than ACC.

Significant and durable clinical benefit from trastuzumab in 2 patients with HER2-amplified salivary gland cancer and a review of the literature

BACKGROUND

Salivary ductal carcinoma and carcinoma ex pleomorphic adenoma (CEPA) are aggressive salivary gland cancers with poor prognosis. The standard of care is resection with or without radiotherapy, and there are no established systemic therapy options.

METHODS

We describe 1 patient with metastatic CEPA and 1 patient with metastatic recurrent salivary duct carcinoma whose tumors were evaluated by comprehensive genomic profiling. Testing identified human epidermal growth factor receptor 2 (HER2) amplification in both patients, and an additional activating HER2 mutation in the CEPA case.

RESULTS

Both patients were treated with the HER2-targeting monoclonal antibody trastuzumab (herceptin) plus chemotherapy and experienced rapid responses. Subsequently, both patients were given single-agent maintenance trastuzumab and continue to experience durable disease control.

CONCLUSION

Given the poor prognosis for salivary gland cancers and the limited treatment options upon recurrence or metastasis, patients should be tested for all classes of HER2 alterations. In cases with HER2 overexpression or activation, targeted therapies, such as trastuzumab are promising. © 2016 Wiley Periodicals, Inc. Head Neck 39: E40-E44, 2017.

Outcomes and prognostic factors for surgery followed by modern radiation therapy in parotid gland carcinomas

OBJECTIVE

To evaluate the outcomes and prognostic factors in patients with parotid gland cancers treated with adjuvant radiotherapy with or without chemotherapy.

METHODS

Eighty-five patients with parotid gland cancers were identified between October 2001 and September 2011. The median radiation dose was 66 Gy (range, 9-76 Gy). The outcomes assessment included overall survival, locoregional control, distant metastasis-free survival and disease-free survival.

RESULTS

The stage distribution was 20 patients  (23.5%) in stage I, 28 (32.9%) stage II, 14 (16.5%) stage III and 23 (27.1%) stage IV. Fifty-five patients (64.7%) had positive margins and 23 patients (27.1%) had close margins (<0.5 cm). Lymph node extracapsular spreading occurred in nine patients. The adjuvant therapy included radiotherapy alone in 47 patients (55.3%) and concurrent chemoradiotherapy in 38 patients (44.7%). With a median follow-up of 4.5 years (range, 0.4-11 years), the 5-year overall survival, locoregional control, distant metastasis-free survival and disease-free survival were 82.0, 88.4, 82.4 and 77.5%, respectively. Based on multivariate analysis, N1/N2 was a significant negative prognostic factor for distant metastasis-free survival, disease-free survival and overall survival. Perineural invasion was a significant negative prognostic factor for locoregional control, distant metastasis-free survival and disease-free survival. Patients 50 years or older had significantly worse distant metastasis-free survival, disease-free survival and overall survival.

CONCLUSIONS

Surgery and radiotherapy treatment could achieve excellent outcomes in a modern cohort. However, N1/N2, perineural invasion and age ≥50 years, but not positive margins, are significant factors associated with a worse prognosis.

Clinicopathological features and treatment outcomes of the rare, salivary duct carcinoma of parotid gland

BACKGROUND

Salivary ductal carcinoma (SDC) of parotid gland is a rare and aggressive entity; accounting for 1-3 % of all malignant salivary gland tumors, 0.2 % of epithelial salivary gland neoplasms, 0.5 % of salivary gland carcinomas, and 1.1 % of parotid gland carcinomas. Here in we aimed to evaluate the clinico-pathological features and treatment outcomes of parotid gland SDC in Saudi population.

METHODS

Among 38 patients with parotid malignancies, who were treated in two major tertiary care referral cancer centers between December 2007 and December 2014, seven cases (18.4 %) were found to have SDC, which were investigated for clinicopathological features, locoregional recurrences (LRRs), distant metastasis (DM) and survival rates.

RESULTS

Mean age of cohort was 62.3 years (range: 41-83) and female predominant (71.4 %). All patients underwent total parotidectomy and ipsilateral neck dissection. Mean tumor size was 3.4 cm (range: 2.1-5.3); perineural invasion (85.8 %); lymph node involvement (42.9 %); and HER-2 neu overexpression (28.6 %). Postoperative radiation therapy (PORT) was given to six patients (dose: 50-66 Gy). Median follow-up was 20.2 months (range: 11-48). LRRs were seen in five (71.4 %) patients (base of skull, 3 patients; cervical nodes, one patient; parotid bed, one patient). LRRs were salvaged with resection (two patients) and re-irradiation (one patient with base of skull). DM in lungs was seen in three patients (42.8 %); one treated with carboplatin/paclitaxel based chemotherapy. The 4-year disease free and overall survival rates were 16.7 % and 40 % respectively.

CONCLUSION

SDC of parotid gland is a rare and aggressive entity, and most of LRRs were seen in the base of skull, which warrants inclusion of base of skull in clinical target volume in PORT planning. Role of anti HER-2 targeted therapy in SDC with HER-2 neu overexpression needs further investigations.

Sustained response of HER2-positive metastatic salivary adenocarcinoma, not otherwise specified, treated with trastuzumab

OBJECTIVE

Adenocarcinoma-not otherwise specified (AD-NOS) is an aggressive salivary gland carcinoma subtype with poor prognosis. Her2/neu-targeted therapy may be beneficial in cases of overexpression (20% of AD-NOS). Here, a case of metastatic AD-NOS of the submandibular gland showing sustained complete response to trastuzumab is reported, and the existing literature is reviewed.

STUDY DESIGN AND RESULTS

A 68-year-old male with poorly differentiated AD-NOS of the submandibular gland with multiple metastases (T3 N2 bM1) underwent radical surgery and adjuvant radiation. The primary lesion demonstrated Her2/neu overexpression, and treatment with trastuzumab was initiated. The patient remains alive without evidence of disease at 36-months after treatment (three cycles of trastuzumab). Literature review of all published trastuzumab-based therapy studies (1990-2015) for salivary gland carcinoma is included.

CONCLUSIONS

Definitive clinical trials of trastuzumab-based interventions are challenging to undertake in rare tumors. This report adds to increasing evidence for trastuzumab-based therapy in salivary carcinomas, where sustained partial response at 36-months is achievable.

The landscape of gene fusions and somatic mutations in salivary gland neoplasms - Implications for diagnosis and therapy

Recent studies of the genomic landscape of salivary gland tumors have provided important insights into the molecular pathogenesis of these tumors. The most consistent alterations identified include a translocation-generated gene fusion network involving transcription factors, transcriptional coactivators, tyrosine kinase receptors, and other kinases. In addition, next-generation sequencing studies of a few subtypes of salivary neoplasms have revealed hotspot mutations in individual genes and mutations clustering to specific pathways frequently altered in cancer. Although limited, these studies have opened up new avenues for improved classification and targeted therapies of salivary gland cancers. In this review, we summarize the latest developments in this field, focusing on tumor types for which clinically important molecular data are available.

Cytogenetic and immunohistochemical biomarker profiling of therapy-relevant factors in salivary gland carcinomas

OBJECTIVES

There is currently no established algorithm for the molecular profiling of therapy-relevant defects in salivary gland carcinomas (SGC). HER2 overexpression in a subfraction of SGC and low frequencies of EGFR mutations are known. Here, we established receptor and cell signalling profiles of 17 therapy-relevant factors and propose a molecular diagnostic algorithm for SGC.

MATERIALS AND METHODS

Formalin-fixed and paraffin-embedded tissue samples from SGC (n = 38) were analysed with immunohistochemistry and fluorescence in situ hybridisation (FISH).

RESULTS

Two or more expressed receptors and/or receptor gene amplification were detectable in eight of 38 (21%) tumours: HER2 3+/AR 1+, HER3 gene amplification/AR 1+/EGFR 1+, ER 3+/AR 1+, EGFR 2+/PR 1+ and EGFR 2+/PR 1+/AR 1+. No FGFR1-3, MET, ALK1, ROS1, RET, BRAF nor VEGFA defects were detectable, and ERCC1 was not overexpressed. No PD1+ tumour-infiltrating T cells were detectable.

CONCLUSION

Personalised therapy of patients with salivary gland carcinomas should include HER2 and EGFR signalling testing and, in negative cases, evaluation of rare potential target molecules. ERCC1 and PD1 do not appear to be reliable markers for the decision for or against chemotherapy or immunotherapy, respectively.

Perineural Spread in Noncutaneous Head and Neck Cancer: New Insights into an Old Problem

Head and neck malignancies have the propensity to invade nerves. Perineural tumor invasion is common, with some series reporting rates of 30 to 100%. Squamous cell carcinoma and adenoid cystic carcinoma are the most commonly involved tumors. The most commonly involved nerves are the trigeminal (cranial nerve [CN] V) and facial (CN VII) and their branches. Neural spread away from a tumor is encountered less often and usually causes specific symptoms such as pain, muscle weakness, and atrophy, depending on the involved nerves. While clinical symptoms and physical examination may suggest the presence of neural invasion, specific imaging modalities such as fat-suppressed T1-weighted magnetic resonance images, should be utilized to identify perineural tumor spread in its early phases. Perineural tumor spread should be considered and addressed in the treatment planning of patients with head and neck or skull base cancers as it can influence the extent of surgery, and the dosage and fields of radiation therapy. In the current review, we discuss the clinical course of perineural tumor spread and its therapeutic implications.

Pathological response of salivary duct carcinoma to trastuzumab and docetaxel therapy

Salivary duct carcinoma (SDC) has a poor prognosis owing to the high incidence of distant metastasis. Approximately 40 % of SDCs are positive for human epidermal growth factor receptor 2 (HER2), suggesting that anti-HER2 therapy for cases with distant metastasis may be effective. However, the pathological response of SDC metastases to anti-HER2 therapy has not been reported. A 44-year-old man was diagnosed with HER2-positive SDC of the submandibular gland with multiple distant metastases. After six cycles of trastuzumab/docetaxel therapy, the patient achieved clinical partial response for the primary tumor and complete response for the neck and distant metastases. Subsequently, the patient underwent submandibular gland resection and neck dissection. On histopathological examination, very few viable cancer cells were identified in the resected primary tumor. Unfortunately, the patient died of multiple distant metastases 12 months after initial treatment. Trastuzumab/docetaxel therapy can elicit a clinical and pathological response in HER2-positive SDC.