Long-term outcomes and clinicogenomic correlates in recurrent, metastatic adenoid cystic carcinoma

Molecular Profiling and the Impact of Treatment on Outcomes in Adenoid Cystic Carcinoma Type I and II

PURPOSE

Adenoid cystic carcinoma (ACC) is an uncommon salivary gland cancer with no approved therapies available to treat advanced, incurable disease. Recent molecular profiling efforts have identified two important subtypes: the more aggressive ACC-I is characterized by Notch pathway alterations and MYC amplification whereas ACC-II demonstrates a more indolent phenotype and TP63 overexpression.

EXPERIMENTAL DESIGN

This retrospective observational cohort study involved de-identified samples from 438 patients with ACC with tumor samples sent for commercially-available molecular profiling (Caris Life Sciences). Next-generation whole-exome and whole-transcriptomic sequencing was performed on primary and metastatic samples. Immunostaining for PD-L1 and RNA deconvolution (quanTIseq) was used to explore the tumor immune microenvironment (TME). Real-world clinical and survival outcome metrics were extracted from insurance claims data.

RESULTS

MYC expression was 1.61-fold higher (39.8 vs. 24.7; P < 0.0001) among NOTCH1-mutant ACC-I tumors, whereas MYB/L1 fusion rates were similar among ACC-I/II. The median B-cell fraction in the TME was higher among ACC-II (7.1% vs. 5.8%; P < 0.01), although infiltrating T cells subsets were low among either ACC subgroup (both <1%). When pooling systemic treatment categories, ACC-I patients had worse outcomes with available therapies (HR, 3.06; 95% confidence interval, 1.65-5.68; P < 0.01), with no significant difference in overall survival between ACC-I/II based on chemotherapy or VEGFR tyrosine kinase inhibitor exposure in smaller subsets.

CONCLUSIONS

We confirmed the previously reported associations with MYC and TP63 in the prognostically relevant subgroups of ACC-I and -II, respectively, and report immunologic differences among these subtypes. Survival outcomes are comparatively worse in ACC-I regardless of treatment type.

A Phase II Trial of Rivoceranib, an Oral Vascular Endothelial Growth Factor Receptor 2 Inhibitor, for Recurrent or Metastatic Adenoid Cystic Carcinoma

PURPOSE

This open-label, single-arm, phase II study evaluated the vascular endothelial growth factor receptor 2 (VEGFR2) tyrosine kinase inhibitor (TKI) rivoceranib in patients with recurrent or metastatic (R/M) adenoid cystic carcinoma (ACC).

PATIENTS AND METHODS

Eligible patients had confirmed disease progression per Response Evaluation Criteria in Solid Tumors (RECIST) with ≥20% increase in radiologically or clinically measurable lesions or appearance of new lesions within the preceding 6 months. Patients received oral rivoceranib 700 mg once daily. Primary outcomes were objective response rate (ORR) by investigator review and by blinded independent review committee (BIRC).

RESULTS

Eighty patients were enrolled and 72 were efficacy evaluable. Seventy-four patients had distant metastases and 49 received prior systemic treatment (14 received VEGFR TKIs). Per investigator and BIRC, respectively, ORR was 15.3% [95% confidence interval (95% CI), 7.9-25.7] and 9.7% (95% CI, 4.0-19.0); median duration of response was 14.9 months (95% CI, 4.9-17.3) and 7.2 months (95% CI, 3.5-8.4); and median progression-free survival was 9.0 months (95% CI, 7.3-11.5) and 9.0 months (95% CI, 7.7-11.5). Grade ≥3 treatment-related adverse events occurred in 56 patients (70.0%); the most common were hypertension (34, 42.5%) and stomatitis (6, 7.5%). Four grade 5 events occurred with one attributed to rivoceranib (epistaxis). Sixty-eight patients (85.0%) had ≥1 dose modifications and 16 patients (20.0%) discontinued rivoceranib for toxicity.

CONCLUSIONS

In patients with progressing R/M ACC, rivoceranib demonstrated antitumor activity and a manageable safety profile consistent with other VEGFR TKIs.

Salivary glands adenoid cystic carcinoma: a molecular profile update and potential implications

Adenoid cystic carcinoma (ACC) is an aggressive tumor with a high propensity for distant metastasis and perineural invasion. This tumor is more commonly found in regions of the head and neck, mainly the salivary glands. In general, the primary treatment modality for ACC is surgical resection and, in some cases, postoperative radiotherapy. However, no effective systemic treatment is available for patients with advanced disease. Furthermore, this tumor type is characterized by recurrent molecular alterations, especially rearrangements involving the MYB, MYBL1, and NFIB genes. In addition, they also reported copy number alterations (CNAs) that impact genes. One of them is C-KIT, mutations that affect signaling pathways such as NOTCH, PI3KCA, and PTEN, as well as alterations in chromatin remodeling genes. The identification of new molecular targets enables the development of specific therapies. Despite ongoing investigations into immunotherapy, tyrosine kinase inhibitors, and anti-angiogenics, no systemic therapy is approved by the FDA for ACC. In this review, we report the genetic and cytogenetic findings on head and neck ACC, highlighting possible targets for therapeutic interventions.

Polar Vessel: A New Ultrasound Sign for Complementary Diagnosis of Major Salivary Gland Adenoid Cystic Carcinoma

OBJECTIVES

To investigate the characteristic ultrasonographic findings of adenoid cystic carcinoma (ACC) in major salivary glands and identify the value of polar vessel in color Doppler flow imaging (CDFI) for the diagnosis of ACC.

METHODS

From January 2017 to December 2021, 76 patients with parotid and submandibular gland tumors, including 14 patients with ACC, as confirmed by surgery and histopathology, were enrolled. Their clinicopathologic information and ultrasound (US) features were recorded and analyzed. The performance of polar vessel in CDFI for differentiating ACC from non-ACC (benign tumors and mucoepidermoid carcinoma [MEC]) was analyzed.

RESULTS

ACC in the major salivary gland was more likely to be associated with pain symptoms (P = .027) and unclear borders and rough edges in grayscale US (P = .002, .015, respectively) than benign tumors. Compared to MEC, ACC tended to feature a homogeneous internal echo (P = .008). ACC of the major salivary gland had a significantly higher incidence of polar vessel sign than that of non-ACC (benign tumors and MEC) (P < .0001, .0001, respectively). The polar vessel sign showed good performance in distinguishing between ACC and non-ACC, with an area under the receiver operating characteristic curve of 0.857, a sensitivity of 71.4%, a specificity of 100%, and an accuracy of 94.7%. Positive predictive value and negative predictive value were calculated at 100% and 93.9%, respectively.

CONCLUSIONS

The US sign of polar vessel has high diagnostic efficiency, and it may have important potential for use as a new complementary sign for the diagnosis of ACC in major salivary glands.

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.

Transcriptomic insights into adenoid cystic carcinoma via RNA sequencing

Background: The aim of this study was to investigate the underlying mechanisms of adenoid cystic carcinoma (ACC) at the transcriptome level. Materials and methods: We obtained paired tumor and normal salivary gland tissues from 15 ACC patients, which were prepared for RNA sequencing. Results: Gene enrichment analysis revealed that the upregulated pathways were mainly involved in axonogenesis, and the downregulated pathways were mainly related to leukocyte migration, the adaptive immune response, lymphocyte-mediated immunity, and the humoral immune response. T-cells, B-cells and NK cells showed low infiltration in ACC tissues. In addition to the gene fusions MYB-NFIB and MYBL1-NFIB, a new gene fusion, TVP23C-CDRT4, was also detected in 3 ACC tissues. PRAME was significantly upregulated in ACC tissues, while antigen-presenting human leukocyte antigen (HLA) genes were downregulated. Conclusion: We found a new gene fusion, TVP23C-CDRT4, that was highly expressed in ACC. PRAME may be an attractive target for ACC immunotherapy.

Single-cell RNA sequencing identifies a paracrine interaction that may drive oncogenic notch signaling in human adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (ACC) is a rare, biologically unique biphasic tumor that consists of malignant myoepithelial and luminal cells. MYB and Notch signaling have been implicated in ACC pathophysiology, but in vivo descriptions of these two programs in human tumors and investigation into their active coordination remain incomplete. We utilize single-cell RNA sequencing to profile human head and neck ACC, including a comparison of primary ACC with a matched local recurrence. We define expression heterogeneity in these rare tumors, uncovering diversity in myoepithelial and luminal cell expression. We find differential expression of Notch ligands DLL1, JAG1, and JAG2 in myoepithelial cells, suggesting a paracrine interaction that may support oncogenic Notch signaling. We validate this selective expression in three published cohorts of patients with ACC. Our data provide a potential explanation for the biphasic nature of low- and intermediate-grade ACC and may help direct new therapeutic strategies against these tumors.

Adenoid Cystic Carcinoma of the Breast May Be Exempt from Adjuvant Chemotherapy

Consistent standards regarding whether postoperative adjuvant chemotherapy is required in the treatment of adenoid cystic carcinoma of the breast (ACCB) are currently lacking. Using clinical data from the Surveillance, Epidemiology, and End Results (SEER) database (1988−2015), and the National Cancer Center of China (2004−2020), we retrospectively analyzed patients with ACCB who received radical treatment. A total of 661 patients were eligible. The median age at diagnosis was 61 years; 99.5% of patients were initially diagnosed with stage I and II breast cancer, and 76.7% had triple-negative breast cancer. Only 12.4% of patients received adjuvant chemotherapy. Multivariate analysis showed that patients with lymph node metastasis and non-radiotherapy had worse overall survival (OS) (p < 0.05). Patients with lymph node metastasis, stage IIB and III, histological grade ≥ 2, and non-radiotherapy had worse breast cancer-specific survival (BCSS) (p < 0.05). Adjuvant chemotherapy did not improve the OS or BCSS. Patients treated with adjuvant chemotherapy also had no better survival outcomes after propensity score matching. External data verification confirmed that chemotherapy did not improve disease-free survival or OS. Adjuvant chemotherapy cannot improve the clinical outcomes of ACCB, even in subgroups with a high risk of recurrence and metastasis.

Survival and prognosis of metastatic head and neck adenoid cystic carcinoma

BACKGROUND

To investigate the clinical characteristics, treatment, and prognosis of patients with metastatic head and neck adenoid cystic carcinoma (HNACC).

METHOD

The clinical data of metastatic HNACC from 1999 to 2020 at the National Cancer Center of China were retrospectively collected.

RESULTS

One hundred seventy-four patients with metastatic HNACC were enrolled and median overall survival (OS) was 45.6 months. Univariate analysis indicated that smoking history, disease-free interval (DFI), number and sites of metastases, and systemic therapy were associated with OS. In the multivariate analysis, non-smokers, DFI ≥3 years, and lung metastasis were prognostic factors. Local therapy for localized disease could prolong survival in patients with both recurrent and metastatic disease.

CONCLUSION

No smoking history, DFI ≥3 years, and lung metastasis were favorable prognostic factors. Local therapy for metastases could not provide survival benefits, but local therapy for localized disease may prolong survival. Whether initial systemic therapy could improve prognosis needs further exploration.

MYB-NFIB fusion transcript in Adenoid Cystic Carcinoma: current state of knowledge and future directions

Adenoid cystic carcinoma (ACC) is the most common type of salivary gland cancer that can also arise in other primary sites. Regardless of the site, most ACC cases carry a recurrent chromosomal translocation - t(6;9)(q22-23;p23-24) - involving the MYB oncogene and the NFIB transcription factor. Generally, a long sequence of MYB is fused to the terminal exons of NFIB, yet the break can occur in different exons for both genes, resulting in multiple chimeric variants. The fusion status can be determined by a number of methods, each of them with particular advantages. In vitro and in vivo studies have been conducted to understand the biological consequences of MYB-NFIB translocation, and such findings could contribute to improving the current inefficient therapeutic options for disseminated ACC. This review provides a discussion on relevant evidence in the context of ACC MYB-NFIB translocations to determine the current state of knowledge and discuss future directions.

A Contemporary Review of Molecular Therapeutic Targets for Adenoid Cystic Carcinoma

Simple Summary

Adenoid cystic carcinoma (ACC) is a salivary malignancy known for slow growth, a propensity for perineural spread, local recurrence following resection, and indolent distant metastases. Current treatments in recurrent/metastatic (R/M) ACC are generally of limited impact and often palliative in nature. Herein, we review the preclinical and clinical literature on molecular alterations in ACC with the potential for targeted therapeutics. We further review other molecular targets of ongoing investigation and active clinical trials for patients with ACC, offering a contemporary summary and insight into future therapeutic strategies.

Abstract

ACC is a rare malignant tumor of the salivary glands. In this contemporary review, we explore advances in identification of targetable alterations and clinical trials testing these druggable targets. A search of relevant articles and abstracts from national meetings and three databases, including PubMed, Medline, and Web of Science, was performed. Following keyword search analysis and double peer review of abstracts to ensure appropriate fit, a total of 55 manuscripts were included in this review detailing advances in molecular targets for ACC. The most researched pathway associated with ACC is the MYB–NFIB translocation, found to lead to dysregulation of critical cellular pathways and thought to be a fundamental driver in a subset of ACC disease pathogenesis. Other notable molecular targets that have been studied include the cKIT receptor, the EGFR pathway, and NOTCH1, all with limited efficacy in clinical trials. The ongoing investigation of molecular abnormalities underpinning ACC that may be responsible for carcinogenesis is critical to identifying and developing novel targeted therapies.

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.

Colonic Metastasis of Adenoid Cystic Carcinoma 19 Years after the Primary Tumor Resection

Adenoid cystic carcinoma (ACC) is a tumor characterized by slow growth and late distant metastasis. The lung and breast are the most common sites for metastasis. Colonic metastasis of such a tumor is rare, with few case reports available. Here, we report a case of ACC arising from minor salivary gland that metastasized to the colon 19 years after the primary tumor resection, with literature review of the clinical, histological, and molecular features of ACC. This case raises our awareness of such tumors as a differential diagnosis of colorectal cancer.

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.

Adenoid cystic carcinoma: a review of clinical features, treatment targets and advances in improving the immune response to monoclonal antibody therapy

The natural history of adenoid cystic carcinoma (ACC) is relentless, defined by treatment failure heralded by locoregional recurrence and distant metastatic disease. In this review, we present an update of clinical features, molecular classification, current targeted therapies, immune landscapes and novel treatment targets with their respective clinical trials. The presented results are defined by a lack of overall response rate and limited progression free survival, with restriction to stable disease. In addition, ACC is resistant to immune checkpoint inhibition due to low tumour immunogenicity and lack of PD-L1 expression. Here we present a new prospective research paradigm for ACC, including the potential to target prostate specific membrane antigen (PSMA) and the potential for manipulation of target receptors in the clinic. The presentation of this review aims to promote future research to improve response rates and outcomes for therapeutics undergoing clinical trial in ACC.

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.

The utility of TP53 and PIK3CA mutations as prognostic biomarkers in salivary adenoid cystic carcinoma

OBJECTIVES

Despite wide excision and post-operative irradiation, loco-regional and/or metastatic recurrence is a significant clinical problem in salivary adenoid cystic carcinoma (SACC). Reliable biomarkers are required to tailor post-treatment surveillance to patients at highest risk of recurrence. We sought to determine the utility of TP53 and PIK3CA mutations as prognostic biomarkers in SACC.

MATERIALS AND METHODS

DNA was extracted from archival tumour blocks of 145 SACC patients from 66 UK referral centres and sequenced for TP53 and PIK3CA mutations. Clinical, pathological and outcome data were analysed to determine the impact of the genomic alterations on disease recurrence and overall survival (OS).

RESULTS

TP53 and PIK3CA mutations were identified in 8% (10/121 successful analyses) and 2% (3/121) of cases, respectively. There were too few PIK3CA mutations in this cohort for informative further analysis. TP53-mutated SACC had significantly shorter median OS (5.3 vs. 16.3 years, p = 0.019) and lower 10-year survival (48% vs. 81%) compared with TP53 wild-type ACC. Solid-pattern histopathology was more frequent in TP53-mutated SACC (50% vs. 15%, p = 0.27).

CONCLUSION

TP53-mutated recurrent and metastatic SACC was associated with shorter OS, which was significant when combined with published genomic data sets. Stratifying by TP53 status, in addition to established clinical, pathological and genomic biomarkers, may usefully inform follow-up strategy.

The circular RNAs differential expression profiles in the metastasis of salivary adenoid cystic carcinoma cells

In order to reveal circular RNAs (circRNAs) differential expression profiles and investigate the function and mechanism of circRNAs in the metastasis of salivary adenoid cystic carcinoma (SACC), microarray was used to detect differentially expressed circRNAs in SACC-83 and SACC-lung metastasis (LM) cell lines. Up-regulated circRNAs were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses to further predict their function. Expression of candidate circRNA and microRNA (miRNA) was determined using quantitative real-time polymerase chain reaction (qRT-PCR). Constructed circRNA-miRNA-mRNA co-expression network was based on TargetScan, miRanda databases. Wound healing and transwell assays were completed to examine the effects of hsa_circRNA_001982 and miR-181a-5p on cell migration and invasion. qRT-PCR confirmed hsa_circRNA_092556, hsa_circRNA_101379, and hsa_circRNA_001982 up-regulation in SACC-LM. miR-181a-5p was down-regulated in SACC-LM and correlated with up-regulated hsa_circRNA_001982. Wound healing and transwell assays indicated that silencing hsa_circRNA_001982 inhibited the migration and invasion of the SACC-LM cells. Furthermore, over-expression of hsa_circRNA_001982 promoted the migration and invasion of SACC-83 cells. Interestingly, up-regulation or down-regulation of miR-181a-5p led to the opposite result in wound healing and transwell assays. Overall, differential expression circRNA profiles in SACC-83 and SACC-LM cells may reveal potential targets and a novel mechanism of circRNAs in the metastasis of SACC. Moreover, the interaction of hsa_circRNA_001982/miR-181a-5p is closely related to the metastasis of SACC cells.

Multicentre, retrospective study of the efficacy and safety of nivolumab for recurrent and metastatic salivary gland carcinoma

Although immune-checkpoint inhibitors (ICIs) are effective against various cancers, little is known regarding their role in salivary gland carcinoma (SGC) treatment. Therefore, we evaluated the efficacy and safety of nivolumab monotherapy in patients with recurrent and/or metastatic SGC. In this multicentre retrospective study, nivolumab (240 mg) was administered every 2 weeks. The overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety were examined; the correlation between treatment outcomes and clinicopathological factors was analysed. Twenty-four patients were enrolled; the most common histopathology was salivary duct carcinoma. Eleven tumours were PD-L1-positive; no tumour was microsatellite instability-high. The ORR was 4.2%, and the median PFS and OS were 1.6 and 10.7 months, respectively. One patient continued nivolumab for 28 months without disease progression. One patient showed grade 4 increase in creatine phosphokinase levels and grade 3 myositis. Biomarker analysis revealed significantly increased OS in patients with performance status of 0; modified Glasgow prognostic score of 0; low neutrophil-to-lymphocyte ratio, lactate dehydrogenase, and C-reactive protein; and high lymphocyte-to-monocyte ratio and in patients who received systemic therapy following nivolumab. Although nivolumab's efficacy against SGC was limited, some patients achieved long-term disease control. Further studies are warranted on ICI use for SGC.

Local therapies for liver metastases of rare head and neck cancers: a monoinstitutional case series

INTRODUCTION

Transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) are established procedures for treating hepatocellular cancer and selected malignancies with liver metastasis. The aim of this study is to describe a monoinstitutional case series of local approaches in patients with liver metastases from rare head and neck cancers (HNCs).

METHODS

This is a retrospective series of adult patients with HNC treated with liver locoregional approaches (TACE or RFA) at our institution from 2007 to 2018. In case of chemoembolization, the preferred chemotherapeutic drug was doxorubicin. Response according to RECIST (Response Evaluation Criteria in Solid Tumors) was assessed with contrast-enhanced computed tomography scans.

RESULTS

Thirty-four patients were treated (20 men, median age 58 years) with TACE (27), transarterial embolization (2), or RFA (7). Primary tumours were salivary gland (21), thyroid (6), nasopharyngeal (5), and sinonasal cancers (2). Seventeen patients (50%) had a single metastatic liver nodule; 70% of the remaining 17 patients had at least three liver metastases. The median diameter of the metastatic liver mass undergoing treatment was 39 mm (range 11-100 mm). Median follow-up was 27.6 months. Response rate was 35% (3% complete, 32% partial response). Median progression-free survival and overall survival were 6.9 and 19.6 months, respectively. Treatment-related adverse events occurred in 59% of patients (21% grade ⩾ 3; no grade 5).

DISCUSSION

This retrospective case series demonstrates that locoregional radiologic approaches for rare HNCs with liver metastases are feasible. These procedures deserve further prospective studies before being considered safe and active in these malignancies where the availability of effective systemic treatments is lacking.