Phase II randomized trial comparing vinorelbine versus vinorelbine plus cisplatin in patients with recurrent salivary gland malignancies

Vascular Endothelial Growth Factor Receptor Inhibitors for Recurrent or Metastatic Adenoid Cystic Carcinoma: A Systematic Review and Meta-Analysis

Importance

There is no systemic therapy for recurrent or metastatic adenoid cystic carcinoma (ACC) approved by the US Food and Drug Administration.

Objective

To examine the efficacy, safety, and tolerability of vascular endothelial growth factor receptor (VEGFR) inhibitors in recurrent or metastatic ACC.

Data Sources

PubMed, Embase, and Cochrane Library were systematically searched for studies of VEGFR inhibitors in recurrent or metastatic ACC from database inception to August 31, 2023.

Study Selection

Inclusion criteria were prospective clinical trials of recurrent or metastatic ACC treated with VEGFR inhibitors, reporting at least 1 outcome of interest specifically for ACC. Of 1963 identified studies, 17 (0.9%) met inclusion criteria.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) reporting guideline was followed to extract data. Data were pooled using a random-effects generalized linear mixed model with 95% CIs.

Main Outcomes and Measures

The primary efficacy outcome was best overall response to VEGFR inhibitors, including objective response, stable disease, or progressive disease (PD). Safety and tolerability outcomes included incidence of grade 3 or higher adverse events, rates of exit from trial due to PD or drug-related toxic effects, and dose reduction rate (DRR).

Results

A total of 17 studies comprising 560 patients with recurrent or metastatic ACC treated with 10 VEGFR inhibitors were included. The objective response rate was 6% (95% CI, 3%-12%; I2 = 71%) and stable disease was the most frequent best overall response (82%; 95% CI, 74%-87%; I2 = 67%). The 6-month disease control (defined as objective response and stable disease) rate was 54% (95% CI, 45%-62%; I2 = 52%). The rate of grade 3 or higher adverse events was 53% (95% CI, 42%-64%; I2 = 81%) and of DRR was 59% (95% CI, 40%-76%). Most patients (57%; 95% CI, 44%-70%; I2 = 83%) continued therapy until PD; 21% (95% CI, 15%-28%; I2 = 62%) of patients suspended therapy for toxic effects. In subgroup analysis by specific VEGFR inhibitor, the objective response rate was 14% (95% CI, 7%-25%; I2 = 0%), stable disease rate was 76% (95% CI, 63%-85%; I2 = 0%), proportion treated until PD was 61% (95% CI, 14%-94%; I2 = 94%), and DRR was 78% (95% CI, 66%-87%; I2 = 39%) with lenvatinib. Corresponding axitinib results were objective response rate of 8% (95% CI, 4%-15%; I2 = 0%) and stable disease rate of 85% (95% CI, 72%-92%; I2 = 69%), with 73% (95% CI, 63%-82%; I2 = 0%) of patients treated until PD, and the DRR was 22% (95% CI, 12%-38%; I2 = 77%). Rivoceranib had the highest objective response rate (24%; 95% CI, 7%-57%) but high heterogeneity among studies (I2 = 95%) and the lowest rate of patients who continued therapy until PD (35%; 95% CI, 20%-55%; I2 = 90%).

Conclusions and Relevance

This systematic review and meta-analysis found that VEGFR inhibitors were associated with high rates of disease stabilization in recurrent or metastatic ACC. Of 10 included VEGFR inhibitors, lenvatinib and axitinib were associated with the best combined and consistent efficacy, safety, and tolerability profiles, substantiating their inclusion in treatment guidelines.

Trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2-expressing salivary gland carcinoma: a pooled analysis of two phase I studies

BACKGROUND

HER2-expressing salivary gland carcinoma (SGC) is associated with poor prognosis. Trastuzumab deruxtecan (T-DXd, DS-8201) has shown evidence of antitumor activity for several HER2-expressing solid tumors in multiple studies. This study aimed to present the efficacy and safety of T-DXd in patients with HER2-expressing SGC from a pooled analysis.

METHODS

Patients with HER2-expressing SGC were pooled from two phase I, open-label studies of T-DXd: a two-phase, multiple-dose, first-in-human study (NCT02564900) and a single-sequence crossover drug-drug interaction study (NCT03383692). Endpoints included efficacy (objective response rate [ORR], duration of response [DoR] and progression-free survival [PFS]) and safety.

RESULTS

This pooled analysis included 17 patients with SGC (median age: 57 years; male: 88.2%); median (range) follow-up duration was 12.0 (2.3-‍34.8) months. Among these patients, 14 had received prior HER2-targeted agents and 13 had undergone prior radiotherapy. The investigator-assessed confirmed ORR was 58.8% (95% confidence interval [CI], 32.9-‍81.6). The median (95% CI) DoR and PFS were 17.6 months (4.0 to not evaluable [NE]) and 20.5 months (11.1-NE), respectively. All 17 patients reported treatment-emergent adverse events (TEAEs); 76.5% reported TEAEs of grade ≥3. The most common TEAEs were decreased appetite (94.1%), nausea (88.2%) and neutrophil count decreased (76.5%). Of the 17 patients, five (29.4%) reported adjudicated drug-related interstitial lung disease (grade 1, n = 3; grade 2, n =1; grade 3, n = 1).

CONCLUSION

The results of this pooled analysis provide evidence that clinical benefit is achievable with T-DXd in patients with HER2-expressing SGC.

CLINICAL TRIAL INFORMATION

FIH study, NCT02564900; DDI study, NCT03383692.

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.

A comparison of two chemotherapy regimens in advanced, recurrent, or metastatic salivary gland carcinoma

Background

The efficacy of chemotherapy in locally advanced, recurrent, and metastatic salivary gland carcinomas (LA-R/M SGCs) is still undefined. We aimed to compare the efficacy of two chemotherapy regimens in LA-R/M SGC.

Materials and Methods

This prospective study compared paclitaxel (Taxol) plus carboplatin (TC) versus cyclophosphamide, doxorubicin, plus cisplatin (CAP) regimen in terms of overall response rate (ORR), clinical benefit rate (CBR), progression-free survival (PFS), and overall survival (OS).

Results

Between October 2011 and April 2019, 48 patients with LA-R/M SGCs were recruited. The ORRs of first-line TC and CAP regimens were 54.2% and 36.3%, respectively (P = 0.57). The ORRs in recurrent and de novo metastatic patients were 50.0% and 37.5% for TC and CAP, respectively (P = 0.26). The median PFS of TC and CAP arms were 10.2 and 11.9 months, respectively (P = 0.91). In the subanalysis, patients with adenoid cystic carcinoma (ACC) had longer PFS in the TC arm (14.5 vs. 8.2 months, P = 0.03), irrespective of the tumor grade (low grade: 16.3 vs. 8.9 months, high grade: 11.7 vs. 4.5 months; P = 0.03). The median OS rates were 45.5 and 19.5 months for TC and CAP groups, respectively (P = 0.71).

Conclusion

For patients with LA-R/M SGC, there was no significant difference between first-line TC and CAP in terms of ORR, PFS, and OS.

RadioLigand Therapy with [177Lu]Lu-PSMA-617 for Salivary Gland Cancers: Literature Review and First Compassionate Use in France

Salivary gland cancers are rare tumors comprising a large group of heterogeneous tumors with variable prognosis. Their therapeutic management at a metastatic stage is challenging due to the lack of therapeutic lines and the toxicity of treatments. [¹⁷⁷Lu]Lu-PSMA-617 (prostate-specific membrane antigen) is a vectored radioligand therapy (RLT) initially developed to treat castration-resistant metastatic prostate cancer with encouraging results in terms of efficacy and toxicity. Many malignant cells could be treated with [¹⁷⁷Lu]Lu-PSMA-617 as long as they express PSMA as a consequence of androgenic pathway activation. RLT may be used when anti-androgen hormonal treatment has failed, particularly in prostate cancer. [¹⁷⁷Lu]Lu-PSMA-617 has been proposed in certain salivary gland cancers, though the expression of PSMA is demonstrated by a significant uptake using [⁶⁸Ga]Ga-PSMA-11 PET scan. This theranostic approach could be a new therapeutic option, warranting prospective investigation in a larger cohort. We review the literature on this subject and offer a clinical illustration of compassionate use in France as a perspective for administering [¹⁷⁷Lu]Lu-PSMA-617 in salivary gland cancer.

Recent Advances, Systemic Therapy, and Molecular Targets in Adenoid Cystic Carcinoma of the Head and Neck

With an incidence of 3-4.5 cases per million, adenoid cystic carcinoma (ACC) of the head and neck is one of the most common tumors of the parotid and sublingual salivary glands. In the clinical course, ACC is shown to have an aggressive long-term behavior, which leads to the fact that radical surgical resection of the tumor with tumor-free margins remains the "gold standard" in treating ACC. Particle radiation therapy and systemic molecular biological approaches offer new treatment options. However, risk factors for the formation and prognosis of ACC have not yet been clearly identified. The aim of the present review was to investigate long-term experience of diagnosis and treatment as well as risk and prognostic factors for occurrence and outcome of ACC.

Molecular Targets in Salivary Gland Cancers: A Comprehensive Genomic Analysis of 118 Mucoepidermoid Carcinoma Tumors

INTRODUCTION

Salivary gland carcinomas (SGC) are histologically diverse cancers and next-generation sequencing (NGS) to identify key molecular targets is an important aspect in the management of advanced cases.

METHODS

DNA was extracted from paraffin embedded tissues of advanced SGC and comprehensive genomic profiling (CGP) was carried out to evaluate for base substitutions, short insertions, deletions, copy number changes, gene fusions and rearrangements. Tumor mutation burden (TMB) was calculated on approximately 1.25 Mb. Some 324 genes in the FoundationOne CDX panel were analyzed.

RESULTS

Mucoepidermoid carcinoma (MECa) mutations were assessed. CDKN2A and CDKN2B GA were common in mucoepidermoid carcinoma (MECa) (52.5 and 30.5%). PIK3CA was also common in MECa (16.9%). ERBB2 amplification/short variants (amp/SV) were found in MECa (5.9/0%). HRAS GA was common in MECa (14.4%) as well. Other targets, including BAP1, PTEN, and KRAS, were noted but had a low incidence. In terms of immunotherapy (IO)-predictive markers, TMB > 10 was more common in MECa (16.9%). PDL1 high was also seen in MECa (4.20%).

CONCLUSION

SGC are rare tumors with no FDA-approved treatment options. This large dataset reveals many opportunities for IO and targeted therapy contributing to the continuously increased precision in the selection of treatment for these patients.

Systemic and Targeted Therapies in Adenoid Cystic Carcinoma

OPINION STATEMENT

Adenoid cystic carcinoma (ACC) is an often-indolent type of salivary gland cancer (SGC). A subset of patients develops progression or aggressive disease warranting systemic therapy in the recurrent/metastatic (R/M) setting. We recommend genomic testing for all patients with R/M disease to aid with prognostication and eligibility for potential experimental therapies. Here, we review the currently available treatment options (cytotoxic chemotherapies and vascular endothelial growth factor receptor (VEGFR)-targeting tyrosine kinase inhibitors (TKIs)). Based on limited data, we nominate regimens which may have more favorable efficacy profiles. Among the cytotoxic chemotherapies, several regimens are acceptable when incorporating a platinum agent. Among the VEGFR-targeting TKIs, lenvatinib and axitinib are the preferred options. Larger, randomized studies prioritizing combinations with mechanistic synergism are needed. Predictive biomarkers are critical, as there is currently little evidence to guide sequencing of available options for individual patients. Immunotherapy is an available option, but has been associated with only modest benefit in ACC. We go on to review other therapies that have been studied and nominate those with promise based on early clinical data.

Adenoid cystic carcinoma of the head and neck: Patterns of recurrence and implications for intensity-modulated radiotherapy

BACKGROUND

We seek to inform radiotherapy (RT) delivery for adenoid cystic carcinoma of the head and neck (ACC) by evaluating RT techniques and recurrence patterns.

METHODS

We identified patients with ACC treated with curative-intent RT from 2005 to 2021. Imaging was reviewed to determine local recurrence (LR).

RESULTS

Ninety-one patients were included. The 5-year LR risk was 12.2% (6.6-22.7). One patient each experienced a marginal and out-of-field recurrence. Patients receiving >60 Gy postoperatively had a 5-year LR risk of 0% compared to 10.7% (4.2-27.2) with ≤60 Gy. Those receiving 70 and <70 Gy definitively had a 5-year LR risk of 15.2% (2.5-91.6) and 33.3% (6.7-100.0), respectively. No patients had regional nodal failure.

CONCLUSIONS

Modern, conformal RT for ACC results in low rates of LR. Doses >60 and 70 Gy may improve control in the postoperative and definitive settings, respectively. Elective nodal treatment can be omitted in well-selected patients.

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.

Salivary gland cancers in elderly patients: challenges and therapeutic strategies

Salivary gland carcinomas (SGCs) are the most heterogeneous subgroup of head and neck malignant tumors, accounting for more than 20 subtypes. The median age of SGC diagnosis is expected to rise in the following decades, leading to crucial clinical challenges in geriatric oncology. Elderly patients, in comparison with patients aged below 65 years, are generally considered less amenable to receiving state-of-the-art curative treatments for localized disease, such as surgery and radiation/particle therapy. In the advanced setting, chemotherapy regimens are often dampened by the consideration of cardiovascular and renal comorbidities. Nevertheless, the elderly population encompasses a broad spectrum of functionalities. In the last decades, some screening tools (e.g. the G8 questionnaire) have been developed to identify those subjects who should receive a multidimensional geriatric assessment, to answer the question about the feasibility of complex treatments. In the present article, we discuss the most frequent SGC histologies diagnosed in the elderly population and the relative 5-years survival outcomes based on the most recent data from the Surveillance, Epidemiology, and End Results (SEER) Program. Moreover, we review the therapeutic strategies currently available for locoregionally advanced and metastatic disease, taking into account the recent advances in precision oncology. The synergy between the Multidisciplinary Tumor Board and the Geriatrician aims to shape the most appropriate treatment pathway for each elderly patient, focusing on global functionality instead of the sole chronological age.

Economic Evaluation of a Tumour-Agnostic Therapy: Dutch Economic Value of Larotrectinib in TRK Fusion-Positive Cancers

BACKGROUND

Larotrectinib is the first tumour-agnostic therapy that has been approved by the European Medicines Agency. Tumour-agnostic therapies are indicated for a multitude of tumour types. The economic models supporting reimbursement submissions of tumour-agnostic therapies are complex because of the multitude of indications per model.

OBJECTIVE

The objective of this paper was to evaluate the cost effectiveness of larotrectinib compared with standard of care in patients with cancer with tropomyosin receptor kinase fusion-positive tumour types in the Netherlands.

METHODS

A previously constructed cost-effectiveness model with a partitioned survival approach was adapted to the Dutch setting, simulating costs and effects of treatment in patients with tropomyosin receptor kinase fusion-positive cancer. The cost-effectiveness model conducts a naïve comparison of larotrectinib to a weighted comparator standard-of-care arm. Dutch specific resource use and costs were implemented and inflated to reflect 2019 euros. The analysis includes a lifetime horizon and a societal perspective.

RESULTS

Larotrectinib versus Dutch standard of care resulted in 5.61 incremental (QALYs) and €232,260 incremental costs, leading to an incremental cost-effectivenes ratio of €41,424/QALY. The probabilistic sensitivity analysis reveals a 88% chance of larotrectinib being cost effective compared with the pooled comparator standard-of-care arm at the applicable €80,000/QALY willingness-to-pay threshold in the Netherlands.

CONCLUSIONS

The incremental cost-effectivenes ratio was well below the applicable threshold for diseases with a high burden of disease in the Netherlands (€80,000). At this threshold, larotrectinib was estimated to be a cost-effective treatment for patients with tropomyosin receptor kinase fusion-positive cancer compared with current standard of care in the Netherlands.

Metastatic Adenoid Cystic Carcinoma: Genomic Landscape and Emerging Treatments

OPINION STATEMENT

Adenoid cystic carcinoma (ACC) is a heterogeneous cancer that commonly develops in the salivary glands. Approximately 40 to 50% of patients with ACC develop recurrence and/or metastasis. Although most patients with ACC have slow-growing disease, a subset experiences aggressive disease with early visceral and/or bone metastasis. Thus far, there is no consensus on the best time to start palliative treatment in patients with indolent disease. The only systemic therapies available for recurrent or metastatic ACC are cytotoxic agents and multikinase inhibitors targeting vascular endothelial growth factor receptor, and both types of therapy have modest activity. Studies integrating proteomics, genomics, and clinical data have revealed distinct molecular ACC subtypes, ACC-I and ACC-II, with ACC-I generally associated with more aggressive disease biology. ACC-I tumors were enriched for NOTCH1-activating mutation and upregulation of MYC and MYC targets, while ACC-II tumors exhibited upregulation of TP63 and receptor tyrosine kinases. These findings highlight the importance of patient selection for surveillance and targeted therapy development in ACC. In recent clinical trials of targeted therapy in ACC, patients are being selected according to tumor molecular profile (e.g., presence of NOTCH-activating mutations), which represents a major advance in the field. Ongoing collaborative research focusing on the development of novel therapeutic strategies for ACC patients based on disease biology will increase the drug armamentarium and improve survival outcomes for these patients in dire need.

Evaluation of pembrolizumab monotherapy in patients with previously treated advanced salivary gland carcinoma in the phase 2 KEYNOTE-158 study

AIM

We evaluated pembrolizumab monotherapy in patients with advanced salivary gland carcinoma on the phase 2 KEYNOTE-158 study (NCT02628067).

METHODS

Eligible patients had histologically/cytologically confirmed advanced salivary gland carcinoma with prior failure or intolerance to standard therapy, measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1., and ECOG performance status 0-1. Patients were enrolled irrespective of tumour PD-L1 expression. Patients received pembrolizumab 200 mg Q3W for up to 35 cycles (∼2 years). Radiographic imaging occurred every 9 weeks through month 12, then every 12 weeks. PD-L1 positivity was defined as combined positive score ≥1 (evaluated using PD-L1 IHC 22C3 pharmDx). The primary endpoint was objective response rate per RECIST v1.1.

RESULTS

In total, 109 patients were enrolled (PD-L1-positive, 25.7%). At the data cutoff (October 5, 2020), median follow-up was 53.3 (range, 50.8-56.3) months. Objective response rate was 4.6% (95% CI, 1.5-10.4%) among all patients (complete response, n = 1; partial response, n = 4) and was 10.7% (95% CI, 2.3-28.2%) in patients with PD-L1-positive disease and 2.6% (95% CI, 0.3-9.1%) in patients with PD-L1-negative disease. Duration of response was ≥24 months for all 5 responders; median duration of response was not reached (range, 25.1-49.8+ months). Median progression-free survival and overall survival were 4.0 (95% CI, 2.6-4.2) and 21.1 (95% CI, 15.9-25.5) months, respectively. Treatment-related adverse events occurred in 75.2% (grade 3-4, 15.6%; grade 5, 0%) of patients. Immune-mediated adverse events occurred in 22.0% of patients (grade 3, 5.5%; grade 4-5, 0).

CONCLUSIONS

A small subset of patients with advanced salivary gland carcinoma treated with pembrolizumab had a response; all had response duration ≥2 years. The safety profile of pembrolizumab was manageable.

Cytotoxic effects of targeted agent alone or with chemotherapy in the treatment of adenoid cystic carcinoma: a preclinical study

Adenoid cystic carcinoma (ACC) is a rare malignancy characterized by high incidence of relapse. When relapsing, ACC has an indolent but relentless behaviour, thus leading to a poor long-term prognosis. The treatment of choice of relapsing ACC remains surgery followed by radiotherapy, whenever feasible. Therapeutic weapons are limited to systemic drugs. The most widely used chemotherapy regimen is the combination of cisplatin and doxorubicin, however with low response rate and not long lasting; there is also a lack of alternatives for second line therapies in case of disease progression. Therefore, a more comprehensive strategy aimed at identifying at preclinical level the most promising drugs or combination is clearly needed. In this study, the cytotoxic effects of two standard chemotherapy drugs, cisplatin and doxorubicin, and of five targeted therapy-drugs was tested in vitro, on an h-TERT immortalized ACC cell line, and in vivo, on zebrafish embryos with ACC tumoral cell xenograft. Then, combinations of one standard chemotherapy drug plus one targeted therapy drug were also evaluated, in order to find the best treatment strategy for ACC. Data obtained demonstrated that both vorinostat and olaparib significantly increased the standard chemotherapy cytotoxic effects, suggesting new interesting therapeutic options for ACC.

Beyond Surgical Treatment in Adenoid Cystic Carcinoma of the Head and Neck: A Literature Review

Introduction

Adenoid cystic carcinoma (AdCC) is a rare tumour as it accounts for about 10% of all salivary gland neoplasms. It occurs in all age groups with a predominance of women, but no risk factors have been identified to date. Although AdCC behaves as a slow-growing tumour, it is characterized by multiple and late recurrences. Therefore, we aim to update the knowledge of the treatment options in advanced and recurrent cases.

Materials and Methods

We performed a systematic literature review to provide a synthesis of the practical knowledge required for AdCC non-surgical management. Altogether, 99 out of the 1208 available publications were selected for analysis.

Results

AdCC is described as a basaloid tumour consisting of epithelial and myoepithelial cells. Immunohistochemistry is useful for diagnosis (PS100, Vimentin, CD117, CKit, muscle actin, p63) and for prognosis (Ki67). Identified mutations could lead to therapeutic opportunities (MYB-NFIB, Notch 1). The work-up is mainly based on neck and chest CT scan and MRI, and PET-CT with 18-FDG or PSMA can be considered. Surgical treatment remains the gold standard in resectable cases. Post-operative intensity modulated radiotherapy is the standard of care, but hadron therapy may be used in specific situations. Based on the available literature, no standard chemotherapy regimen can be recommended.

Conclusion

There is currently no consensus on the use of chemotherapy in AdCC, either concomitantly to RT in a postoperative setting or at a metastatic stage. Further, the available targeted therapies do not yet provide significant tumour response.

Treatment of Recurrent or Metastatic Adenoid Cystic Carcinoma

PURPOSE OF REVIEW

Adenoid cystic carcinoma (ACC) is a rare and heterogeneous malignancy of secretory glands. Recurrence after curative-intent treatment is common, and approximately 40% of patients develop metastatic disease, for which consensus is lacking regarding therapeutic approaches. Here, we review the available therapies for recurrent/metastatic (R/M) ACC and offer our perspectives on future treatment options.

RECENT FINDINGS

Proteogenomic studies of ACC revealed two molecular subtypes with therapeutic implications: ACC-I (37% of cases) and ACC-II (63%); each has distinct disease biology and prognosis. Molecular drivers, such as NOTCH1, have emerged as potential therapeutic targets for ACC-I and are being explored in clinical trials. Despite its biological heterogeneity, treatment for R/M ACC is not personalized and limited to cytotoxic agents and VEGFR inhibitors, which produce modest responses and significant toxicity. The increasing understanding of ACC's molecular biology might guide the development of biomarkers for patient selection and new therapies development.

Systemic therapy for salivary gland malignancy: current status and future perspectives

Salivary gland malignancies are rare neoplasms that have a broad histological spectrum and a variety of biologic behaviors. Salivary gland malignancies are known as chemo-resistant tumors, which render optimal treatment challenging. This review summarizes the role of systemic therapy for salivary gland malignancies. To date, the advantage of adding concurrent chemotherapy has remained undefined for both postoperative and inoperable locally advanced salivary gland malignancy patients undergoing radiotherapy. For recurrent/metastatic disease, local and/or systemic treatment options should be discussed in a multidisciplinary setting with consideration to both patient needs and tumor factors. For symptomatic patients or those who may compromise organ function, palliative systemic therapy can be a reasonable option based on the results of phase II studies. Platinum combination regimens as first-line therapy have been widely accepted. Personalized therapies have become established options, particularly for androgen receptor-positive, HER2-positive and NTRK fusion-positive salivary gland malignancies (i.e. androgen receptor and HER2 in salivary duct carcinoma and NTRK3 in secretory carcinoma). For patients with adenoid cystic carcinoma, multi-targeted tyrosine kinase inhibitors have also been developed. Anti-PD1 checkpoint inhibitors have shown limited activity to date. Investigation of active systemic treatments for salivary gland malignancy remains a significant unmet need. Future directions might include a more comprehensive genomic screening approach (usually next-generation sequencing-based) and combination strategies using immune checkpoint inhibitors. These are rare malignancies that require ongoing effort in the conduct of high-quality clinical trials.

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.

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.

Docetaxel plus cisplatin in recurrent and/or metastatic non-squamous-cell head and neck cancer: a multicenter phase II trial

The clinical utility of systemic therapy and genomic profiling in non-squamous-cell head and neck cancer (NSCHNC) has not been fully elucidated. This phase II trial evaluated the efficacy and safety of docetaxel and cisplatin combination in the first-line setting. Eligibility criteria were recurrent and/or metastatic NSCHNC; progressive disease within the last 6 months; no prior systemic therapy; and ECOG performance status of 0-1. Patients received docetaxel (75 mg/m² on day 1) and cisplatin (75 mg/m² on day 1), repeated every 21 days for 6 cycles. The primary endpoint was confirmed objective response rate (ORR). The secondary endpoints included progression-free survival (PFS), overall survival (OS), and adverse events. Next-generation sequencing (NGS) was performed using the Ion AmpliSeq Cancer Hotspot Panel v2. Twenty-three patients were enrolled from November 2012 to October 2016, of whom 8 were male. Median age was 57 years. Ninety-six percent of cases were metastatic. Among 22 evaluable patients, confirmed ORR was 45% (95% confidential interval 24-68%). With a median follow-up period of 18.8 months, median PFS and OS were 6.7 and 20.1 months, respectively. Grade 3/4 adverse events included febrile neutropenia (39%) and anemia (22%). No treatment-related deaths were observed. NGS analysis revealed potential treatment targets, including ERBB2, KIT, and ALK. The docetaxel and cisplatin combination regimen can be considered a new treatment option in recurrent and/or metastatic NSCHNC, although primary prophylaxis for febrile neutropenia should be considered. Diverse genomic alterations may lead novel treatment options.This trial was registered with the UMIN Clinical Trials Registry as UMIN000008333 on [September 1st, 2012].

Salivary Gland Cancers

Salivary gland carcinomas are a rare and heterogenous group of cancers with varying underlying biology and clinical behavior. A quickly evolving body of data has advanced the understanding of these tumors, leading to effective therapeutics for several histologic subtypes. Biologically rational clinical trials have developed from an understanding of MYB and NOTCH signaling in adenoid cystic carcinoma. The recognition of androgen receptor signaling and HER2-targeted therapy has offered therapeutic options in non-ACC salivary cancers. The use of TRK inhibitors in salivary secretory carcinoma has led to exceptional responses. Immunotherapy is an exciting new therapeutic avenue that requires further exploration.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

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.

Prognosis and management of recurrent and/or metastatic head and neck adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a rare tumor, usually arising in the salivary gland, accounting for 1% of all head and neck cancers. ACC may have a long-term poor prognosis, as about 40% of radically treated patients will recur locoregionally and up to 60% will develop distant metastasis. Factors influencing risk of recurrence have been well studied, but few data exist about prognostic factors in Recurrent/Metastatic (RM) setting. Moreover, treatment of RM ACC is often a challenge for clinicians, in the context of a rare disease, which may have an indolent clinical behavior or less frequently a quicker growth and with a paucity of available clinical trials. This review critically analyzes pathological and molecular prognostic factors in RM ACC and make an overview on actual therapeutic choices and future direction of therapy. Recognized prognostic factors in RM ACC are the presence and site of distant metastasis (lung vs other), the presence of nodal metastasis and of extranodal extension, skull base recurrence, disease free interval, lymphovascular invasion, solid histotypes and grading of disease, and the presence of mutation of NOTCH1 family, PI3K, and TP53. Due to disappointing results with chemotherapy, new approaches are under study, also on the basis of biomolecular research. Ongoing clinical trials are evaluating treatment targeting MYB and NOTCH1 alterations, immunotherapy or combination of targeted treatments and immune checkpoint inhibitors.

Radiation-induced toxicities and outcomes after radiotherapy are independent of patient age in elderly salivary gland cancer patients: results from a matched-pair analysis of a rare disease

Purpose

This study analyzed survival and toxicity after (chemo)radiotherapy for primary salivary gland cancer patients aged ≥ 65 years and compared these results with younger patients using a matched-pair analysis.

Methods

Twenty-nine elderly patients with primary salivary gland carcinomas treated with (chemo)radiotherapy from 2008 to 2020 at University of Freiburg Medical Center were analyzed for oncological outcomes and therapy-associated toxicities. Local/locoregional control (LRC), progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan–Meier method, and the influence of clinical parameters on patient outcomes was assessed. A matched-pair analysis was performed after matching with patients < 65 years.

Results

Nine patients (31.0%) received definitive (chemo)radiotherapy, and 20 patients (69.0%) were treated in the adjuvant setting. 2-year LRC, PFS and OS ranged at 82.4%, 53.7% and 71.8%, respectively. Smoking (HR 3.980, p = 0.020), reduced performance status (HR 3.735, p = 0.016) and higher comorbidity burden (HR 4.601, p = 0.005) correlated with inferior OS. Using a matched-pair analysis with younger patients, elderly patients exhibited a trend towards reduced OS (HR 3.015, p = 0.065), but not PFS (HR 1.474, p = 0.371) or LRC (HR 1.324, p = 0.633). Acute and chronic grade 3 toxicities occurred in 31.0% and 12.5% of elderly patients, respectively, and the matched-pair analysis revealed no significant differences between age groups regarding treatment-related toxicities.

Conclusion

Treatment-related toxicities as well as LRC and PFS were comparable for salivary gland cancer patients undergoing radiotherapy. Therefore, concerns for more pronounced toxicities or reduced local/locoregional response rates should not guide treatment decisions in affected elderly patients.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06393-x) contains supplementary material, which is available to authorized users.

Ex vivo assessment of targeted therapies in a rare metastatic epithelial-myoepithelial carcinoma

Epithelial-myoepithelial carcinoma (EMC) is a rare subtype of salivary gland neoplasms. Since the initial description of the cancer, just over 300 cases have been reported. EMCs occupy a biphasic cellular differentiation-state defined by the constitution of two cell types representing epithelial and myoepithelial lineages, yet the functional consequence of the differentiation-state heterogeneity with respect to therapy resistance of the tumors remains unclear. The reported local recurrence rate of the cases is approximately 30%, and while distant metastases are rare, a significant fraction of these cases are reported to receive no survival benefit from radio- or chemotherapy given in addition to surgery. Moreover, no targeted therapies have been reported for these neoplasms. We report here the first use and application of ex vivo drug screening together with next generation sequencing to assess targeted treatment strategies for a rare metastatic epithelial-myoepithelial carcinoma. Results of the ex vivo drug screen demonstrate significant differential therapeutic sensitivity between the epithelial and myoepithelial intra-tumor cell lineages suggesting that differentiation-state heterogeneity within epithelial-myoepithelial carcinomas may present an outlet to partial therapeutic responses to targeted therapies including MEK and mTOR inhibitors. These results suggest that the intra-tumor lineage composition of EMC could be an important factor to be assessed when novel treatments are being evaluated for management of metastatic EMC.

A Randomized Phase 2 Study of Pembrolizumab With or Without Radiation in Patients With Recurrent or Metastatic Adenoid Cystic Carcinoma

PURPOSE

We evaluated the safety and efficacy of pembrolizumab (pembro) ± radiation therapy (RT) in a phase 2 study among patients with progressive, metastatic adenoid cystic carcinoma (ACC).

METHODS AND MATERIALS

Eligible patients had metastatic ACC with progression within the last year and ≥1 measurable lesion. Patients were randomized to pembro alone or with RT to 30 Gy in 5 fractions (pembroRT). The primary endpoint was objective response rate outside the RT field. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and local RT responses.

RESULTS

We randomized 20 patients (10 per arm) from 2017 to 2018. We did not observe objective response outside of the radiation treatment field; stable disease (SD) was the best response in 12 (60%) patients and was not different per arm (7 pembro, 5 pembroRT, P = .65). A tumor growth rate decrease (TGR) of >25% was noted among 7 of 12 patients and >75% in 4 patients. There were local responses in the irradiated field among all evaluable pembroRT patients. Median PFS and OS were 4.5/not reached for pembroRT and 6.6 / 27.2 months for pembro patients. One patient developed grade 3 liver enzyme elevation after 27 cycles of therapy. Correlative analyses confirm low levels of programmed death-ligand 1 expression (PD-L1), and CD8 infiltrating T-cells. We identified associations between local response and both MYB/NFIB translocation and PD-L1 expression and between changes in systemic immune populations and RT.

CONCLUSIONS

Pembrolizumab and pembroRT were well tolerated. We observed no objective responses, but 60% of patients with PD before the study achieved SD, the majority with decreased TGR and half (n = 10) with clinical benefit (SD >6 months). We observed favorable local responses within the RT field. Additional strategies are needed to further delay progression and effect response.

Head and Neck Cancers, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Treatment is complex for patients with head and neck (H&N) cancers with specific site of disease, stage, and pathologic findings guiding treatment decision-making. Treatment planning for H&N cancers involves a multidisciplinary team of experts. This article describes supportive care recommendations in the NCCN Guidelines for Head and Neck Cancers, as well as the rationale supporting a new section on imaging recommendations for patients with H&N cancers. This article also describes updates to treatment recommendations for patients with very advanced H&N cancers and salivary gland tumors, specifically systemic therapy recommendations.

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.

First Line Androgen Deprivation Therapy vs. Chemotherapy for Patients With Androgen Receptor Positive Recurrent or Metastatic Salivary Gland Carcinoma-A Retrospective Study

Objectives: There is a lack of effective therapy for recurrent or metastatic salivary gland carcinoma. Androgen deprivation therapy has demonstrated efficacy in cases of salivary duct carcinoma (SDC) and high-grade adenocarcinoma not otherwise specified (NOS) that express androgen receptor.

Materials and Methods: We conducted a single institution retrospective cohort study examining patients treated for recurrent/metastatic SDC or high-grade adenocarcinoma NOS of the salivary gland. Survival analyses were performed to assess for efficacy of first-line androgen deprivation therapy (ADT) vs. first-line conventional cytotoxic chemotherapy. Efficacy of salvage ADT was also assessed.

Results: Fifty-eight patients were reviewed. Thirty-five patients had recurrent/metastatic disease of which 28 had SDC (80%) and 7 had high-grade adenocarcinoma NOS (20%). Median overall survival for first-line ADT was 25 months compared to 25 months for first-line chemotherapy [RR 0.54 (0.23–1.28, p = 0.16)]. Patients treated with first-line ADT had a response rate of 45% (9/20) and patients treated with first-line chemotherapy had a response rate of 14% (2/14). Six patients received salvage ADT with 1 patient demonstrating complete response and 3 with stable disease as best response (clinical benefit rate 67%).

Conclusion: Overall survival for first line ADT and first line cytotoxic chemotherapy was comparable but response rates to first-line ADT were higher than those with first-line chemotherapy. Salvage ADT is active in recurrent/metastatic salivary gland carcinoma.

Anlotinib is effective in the treatment of advanced carcinoma ex pleomorphic adenoma of the submandibular gland

Background: Carcinoma ex pleomorphic adenoma (CXPA), a very rare malignancy found mostly in the major salivary glands, has no established standardized treatment.

Case presentation: This report describes a 67-year-old male with advanced CXPA who was effectively treated by anlotinib. Pleomorphic adenoma of the submandibular gland was first diagnosed in 1976 after a surgical resection of a mass underneath the jaw. The patient underwent re-excision 3 years later due to a recurrent pleomorphic adenoma. CXPA was first diagnosed in 2016 after a surgical removal of the left submandibular mass. A lung nodule was found on a chest CT scan in January 2018. Following a CT-guided lung biopsy that demonstrated findings consistent with pulmonary metastasis, the patient underwent local therapy (microwave ablation and radioactive seed implantation) but suffered a recurrence of disease approximately 6 months later. Anlotinib was administered orally at a dose of 12 mg daily on a 2 weeks on/1 week off schedule. A partial response was observed after two cycles of treatment. The disease remains in continued partial response after completion of his sixth cycle.

Conclusion: This is the first report for anlotinib in treating CXPA. Further pre-clinical and clinical studies are needed to validate the efficacy and safety of anlotinib in the treatment of CXPA.

Inhibition of Protein Phosphatase 2A Sensitizes Mucoepidermoid Carcinoma to Chemotherapy via the PI3K-AKT Pathway in Response to Insulin Stimulus

BACKGROUND/AIMS

Protein phosphatase 2A (PP2A) is a ubiquitous serine/threonine phosphatase that mediates cell cycle regulation and metabolism. Mounting evidence has indicated that PP2A inhibition exhibits considerable anticancer potency in multiple types of human cancers. However, the efficacy of PP2A inhibition remains unexplored in mucoepidermoid carcinoma (MEC), especially in locally advanced and metastatic cases with limited systemic treatment. In this study, we demonstrated the therapeutic potency of LB100 in mucoepidermoid carcinoma.

METHODS

In this study, the expression of PP2A was evaluated using immunohistochemical (IHC) staining. The effects associated with LB100 alone and in combination with cisplatin for the treatment of mucoepidermoid carcinoma were investigated both in vitro, regarding metabolism, proliferation, and migration, and in vivo in a mucoepidermoid carcinoma xenograft model. In addition, with LB100 treatment and in response to an insulin stimulus, the expression levels and phosphorylation levels of targets in the PI3K-AKT pathway were determined using western blot analysis and immunoblotting.

RESULTS

The expression of protein phosphatase 2A was significantly upregulated in the clinical specimens of high-grade MECs compared with those of low-/medium-grade MECs and normal controls. In this article, we report that a small molecule PP2A inhibitor, LB100, decreased cellular viability and glycolytic activity and induced G2/M cell cycle arrest. Importantly, LB100 enhanced the efficacy of cisplatin in mucoepidermoid carcinoma cells both in vitro and in vivo. PP2A inhibition by LB100 increased the phosphorylation of insulin receptor substrate 1(IRS-1) on serine residues, downregulated the expression of phosphatidylinositol 3-kinase (PI3K) p110 alpha subunit and dephosphorylated AKT at Ser473 and Thr308 in mucoepidermoid carcinoma cells in response to insulin stimulus.

CONCLUSION

These results highlight the translational potential of PP2A inhibition to synergize with cisplatin in mucoepidermoid carcinoma treatment.

Recurrent parotid gland carcinoma: how effective is salvage surgery?

OBJECTIVE

Recurrent parotid gland carcinomas (PGCs) are poorly characterized and studies focusing on this topic are rare due to their low incidence. The goal of this study is to analyze the therapeutic strategies, prognostic factors, and oncological outcomes of a series of patients with recurrent PGCs.

PATIENTS AND METHODS

Retrospective chart review (1997-2012) of patients with recurrent PGCs was initially treated with curative intent.

RESULTS

We identified 20 patients with recurrent PGCs. Eleven patients presented isolated local, regional, or distant metastases, while the rest had recurrences in multiple sites. Recurrent tumors tended to present more advanced T-stage (p = 0.01) and overall stage (p < 0.001), but not N-stage (p = 0.74) when compared to the initial tumors. Half the patients (50%) had distant metastases at the moment of recurrence diagnosis, and another three developed them after attempted salvage surgery. Only 8/20 patients with isolated local or regional recurrences were surgically salvaged with extended revision parotidectomy and neck dissection, respectively. The remaining 12 patients were managed on palliative basis. Overall survival (31.70 months vs. 20.73 months) and progression-free survival (28.70 months vs. 13.61 months) were not significantly different in patients managed surgically vs. palliatively.

CONCLUSION

Recurrent PGCs are aggressive neoplasms with a high rate of distant metastases. Surgical salvage can be considered in patients with limited local and/or regional recurrences. The alternative to surgical salvage is palliative management with different chemotherapeutic regimens. Survival does not differ between the two strategies in the present series.

Nedaplatin as a Single-Agent Chemotherapy May Support Palliative Therapy for Patients with Adenoid Cystic Carcinoma: A Case Report

Adenoid cystic carcinoma (ACC) is a rare form of adenocarcinoma, which is a broad term describing any cancer that begins in the glandular tissues. It can be found in the head and neck. We report a patient with recurrent ACC arising from the submandibular gland, treated with 100 mg/m² nedaplatin every 4 weeks. Although our patient's lactate dehydrogenase levels, which is produced by ACC, showed a rising trend throughout the treatment, the level decreased for approximately 2 weeks immediately after administration of nedaplatin every 4 weeks. Thus, there is a possibility that the agent may be effective. Complications such as anorexia and nausea were observed, but they were tolerated and manageable. Nedaplatin may be considered as a supportive agent during palliative therapy for patients with ACC. More clinical trials regarding nedaplatin are necessary, as this study may indicate that a medical approach works well for ACC.

Radiosensitization of Adenoid Cystic Carcinoma with MDM2 Inhibition

Purpose: Adenoid cystic carcinoma (ACC) is a rare cancer arising from the major or minor salivary gland tissues of the head and neck. There are currently no approved systemic agents or known radiosensitizers for ACC. Unlike the more common head and neck squamous cell carcinomas that frequently harbor TP53 mutations, ACCs contain TP53 mutations at a rate of <5%, rendering them an attractive target for MDM2 inhibition.Experimental Design: We report the successful establishment and detailed characterization of a TP53-WT ACC patient-derived xenograft (PDX), which retained the histologic features of the original patient tumor. We evaluated this model for response to the MDM2 inhibitor AMG 232 as monotherapy and in combination with radiotherapy.Results: AMG 232 monotherapy induced modest tumor growth inhibition, and radiation monotherapy induced a transient tumor growth delay in a dose-dependent fashion. Strikingly, combination treatment of AMG 232 with radiotherapy (including low-dose radiotherapy of 2 Gy/fraction) induced dramatic tumor response and high local tumor control rates 3 months following treatment. Posttreatment analysis revealed that although both AMG 232 and radiotherapy alone induced TP53 tumor-suppressive activities, combination therapy amplified this response with potent induction of apoptosis after combination treatment.Conclusions: These data identify that MDM2 inhibition can provide potent radiosensitization in TP53-WT ACC. In light of the absence of effective systemic agents for ACC, the powerful response profile observed here suggests that clinical trial evaluation of this drug/radiotherapy combination may be warranted to improve local control in this challenging malignancy. Clin Cancer Res; 23(20); 6044-53. ©2017 AACR.

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.

MYB-fusions and other potential actionable targets in adenoid cystic carcinoma

PURPOSE OF REVIEW

Adenoid cystic carcinoma (ACC) is a rare cancer of the secretory glands, typically originating in the salivary glands of the head and neck. The impact of chemotherapy on survival is unclear and there are no standard-of-care treatments for patients with recurrent or metastatic disease. This article reviews recently completed and ongoing clinical trials for patients with ACC and describes recently identified potentially targetable genomic alterations in this orphan disease.

RECENT FINDINGS

In spite of an overall low mutational burden, genotyping of ACC samples has shed some light about the disease biology. In addition to the frequent translocations involving MYB or MYBL, recurrent alterations in genes involved in chromatin deregulation, FGF, PI3K, NOTCH1, and DNA damage repair pathways have been identified. Many of these genomic alterations are targetable and drug screening is ongoing in genotyped ACC patient-derived murine xenografts.

SUMMARY

Clinical studies with targeted agents in unselected ACC patients have not been promising thus far. The identification of potential driver oncogenes suggests that targeted therapy might be effective in molecularly-defined patient subgroups and merits investigation in future clinical studies.

Systemic therapy for recurrent or metastatic salivary gland malignancies

Salivary gland carcinomas are notoriously resistant to therapy and no standard of care exists. Due to the rarity of these malignancies, various histologies, and wide ranging clinical behavior it has been difficult to standardize systemic therapy. We have reviewed clinical prospective studies in the last 15 years with salivary gland malignancies involving cytotoxic chemotherapy and biologic agents including targeted therapies such as anti-HER-2, anti-EGFR therapies, and therapies directed at c-kit. Although the results of most trials are modest at best, there has been an increase in studies for salivary cancer in recent years and there are several promising treatment approaches in evolution. Every effort should be made to treat salivary gland malignancies under a clinical protocol and/or at a large multidisciplinary practice with clinicians experienced in treating these malignancies.

Combination chemotherapy of carboplatin and paclitaxel for advanced/metastatic salivary gland carcinoma patients: differences in responses by different pathological diagnoses

BACKGROUND

A standard chemotherapy for recurrent/metastatic salivary gland cancers has not been established. Combination chemotherapy of carboplatin and paclitaxel should be evaluated as a treatment option.

METHODS

This study retrospectively reviewed salivary gland cancer patients who received combination chemotherapy of carboplatin and paclitaxel. The differences in objective responses and in the prognoses according to the different pathological diagnoses were evaluated.

RESULTS

A total of 38 patients were enrolled in the study; of them, 18 had salivary duct carcinomas (SDCs), nine had adenoid cystic carcinomas (ACCs), and 11 had other pathological diagnoses. Objective responses were observed in 15 (39%) patients. The median progression-free survival (PFS) was 6.5 months, and the median overall survival (OS) was 26.5 months. ACC patients had relatively low response rates (9%), but there were no significant differences in PFS or OS compared to other sub-types. The treatment was well tolerated, with few adverse events.

CONCLUSION

Salivary gland cancer patients showed a moderate clinical response to the combination chemotherapy of carboplatin and paclitaxel. The objective response rates differed according to the pathological diagnoses, but there were no significant differences in prognoses.

Clinical and molecular insights into adenoid cystic carcinoma: Neural crest-like stemness as a target

OBJECTIVES

This review surveys trialed therapies and molecular defects in adenoid cystic carcinoma (ACC), with an emphasis on neural crest-like stemness characteristics of newly discovered cancer stem cells (CSCs) and therapies that may target these CSCs.

DATA SOURCES

Articles available on Pubmed or OVID MEDLINE databases and unpublished data.

REVIEW METHODS

Systematic review of articles pertaining to ACC and neural crest-like stem cells.

RESULTS

Adenoid cystic carcinoma of the salivary gland is a slowly growing but relentless cancer that is prone to nerve invasion and metastases. A lack of understanding of molecular etiology and absence of targetable drivers has limited therapy for patients with ACC to surgery and radiation. Currently, no curative treatments are available for patients with metastatic disease, which highlights the need for effective new therapies. Research in this area has been inhibited by the lack of validated cell lines and a paucity of clinically useful markers. The ACC research environment has recently improved, thanks to the introduction of novel tools, technologies, approaches, and models. Improved understanding of ACC suggests that neural crest-like stemness is a major target in this rare tumor. New cell culture techniques and patient-derived xenografts provide tools for preclinical testing.

CONCLUSION

Preclinical research has not identified effective targets in ACC, as confirmed by the large number of failed clinical trials. New molecular data suggest that drivers of neural crest-like stemness may be required for maintenance of ACC; as such, CSCs are a target for therapy of ACC.