Approaches to the Management of Metastatic Adenoid Cystic Carcinoma

Molecular characterization of the salivary adenoid cystic carcinoma immune landscape by anatomic subsites

Adenoid cystic carcinoma (AdCC) is a slow-growing salivary gland malignancy that relapses frequently. AdCCs of the submandibular gland exhibit unique differences in prognosis and treatment response to adjuvant radiotherapy compared to other sites, yet the role of tumor anatomic subsite on gene expression and tumor immune microenvironment (TIME) composition remains unclear. We used 87 samples, including 48 samples (27 AdCC and 21 normal salivary gland tissue samples) from 4 publicly available AdCC RNA sequencing datasets, a validation set of 33 minor gland AdCCs, and 39 samples from an in-house cohort (30 AdCC and 9 normal salivary gland samples). RNA sequencing data were used for single sample gene set enrichment analysis and TIME deconvolution. Quantitative PCR and multiplex immunofluorescence were performed on the in-house cohort. Wilcoxon rank-sum, nonparametric equality-of-medians tests and linear regression models were used to evaluate tumor subsite differences. AdCCs of different anatomic subsites including parotid, submandibular, sublingual, and minor salivary glands differed with respect to expression of several key tumorigenic pathways. Among the three major salivary glands, the reactive oxygen species (ROS)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway signature was significantly underexpressed in AdCC of submandibular compared to parotid and sublingual glands while this association was not observed among normal glands. Additionally, the NRF2 pathway, whose expression was associated with favorable overall survival, was overexpressed in AdCCs of parotid gland compared to minor and submandibular glands. The TIME deconvolution identified differences in CD4+ T cell populations between AdCC of major and minor glands and natural killer (NK) cells among AdCC of minor, submandibular, and parotid glands while plasma cells were enriched in normal submandibular glands compared to other normal gland controls. Our data reveal key molecular differences in AdCC of different anatomic subsites. The ROS and NRF2 pathways are underexpressed in submandibular and minor AdCCs compared to parotid gland AdCCs, and NRF2 pathway expression is associated with favorable overall survival. The CD4+ T, NK, and plasma cell populations also vary by tumor subsites, suggesting that the observed submandibular AdCC tumor-intrinsic pathway differences may be responsible for influencing the TIME composition and survival differences.

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.

Case report: [18F]FAPI-42 PET/CT visualize primary adenoid cystic carcinoma not detected by [18F]FDG

Adenoid cystic carcinoma (ACC) is a rare salivary gland cancer. Still, its growth and invasion progress is slow, and its hematogenous metastasis is ACC's most common distant metastasis. Because of the broad expression and low background uptake of fibroblast activation protein (FAP) in tumor stroma, FAPI is considered another potential tracer of ACC in addition to FDG. In this case, we report a patient who was diagnosed with metastatic ACC liver cancer by fine needle aspiration biopsy (FNAB) and underwent PET/CT examination of [18F]FDG and [18F]FAPI-42 to find the primary cancer lesion. Finally, the primary cancer lesion was found in the left submandibular gland and was pathologically confirmed as ACC after resection.

Primary and Recurrent Intraosseous Adenoid Cystic Carcinoma-Analysis of Two Cases and Literature Review

Adenoid cystic carcinoma (ACC) is a rare malignant tumor that mostly occurs in minor glands, especially in the palate. Intraosseous adenoid cystic carcinoma (IACC) is rarer. There is no clear conclusion on the clinical, radiologic and pathological characteristics of IACC because of few reported IACC cases, leading to insufficient understanding of IACC. We reviewed 52 previous reports of primary IACC (PIACC) and analyzed the clinical features of those patients involved, attempting to provide a better understanding of PIACC. Moreover, we present a case of primary PIACC and a case of recurrent IACC (RIACC). The two patients showed similarities in clinical and pathological results, along with slight differences in radiological and immunohistochemical results. The patient of case 1 seemed to display a worse prognosis, which can only be proved after long term follow-up.

The neutrophil-to-lymphocyte ratio in salivary gland cancers treated with pembrolizumab

BACKGROUND

A minority of patients with recurrent/metastatic (R/M) salivary gland cancers (SGCs) benefit from immune checkpoint inhibitors (ICIs), necessitating reliable biomarkers for ICI response prediction.

METHODS

Retrospective observational study of R/M SGC patients treated with pembrolizumab between 2016 and 2022, with a primary outcome of 6-month progression-free survival (PFS) and secondary outcome of 2-year overall survival (OS). Univariate and multivariable Cox proportional hazards models were employed.

RESULTS

Twenty R/M SGC patients were included. After adjustment, NLR as a continuous variable was independently associated with 6-month PFS (HR 1.30, 95% CI 1.10-1.54, p = 0.002) and 2-year OS (HR 1.33, 95% CI 1.07-1.66, p = 0.010). Similarly, NLR ≥ 5 was associated with higher hazards of progression at 6 months (HR 12.85, 95% CI 2.17-76.16, p = 0.005) and death at 2 years (HR 11.25, 95% CI 1.67-75.77, p = 0.013).

CONCLUSIONS

Higher pretreatment NLR was independently associated with inferior 6-month PFS and 2-year OS in pembrolizumab-treated R/M SGC patients.

Comparison of different estimated glomerular filtration rates for monitoring of kidney function in oncology patients

Background

Tyrosine kinase inhibitors (TKIs) are associated with kidney function deterioration. A shift is ongoing towards glomerular filtration rate (GFR) equations based on other protein markers, such as cystatin C (CSTC) and β-trace protein (BTP). We evaluated various GFR equations for monitoring of kidney function in actively treated oncology patients.

Methods

We monitored 110 patients receiving a TKI. Blood and urine were collected during therapy. Serum analysis included creatinine (Cr), CSTC and BTP; for consequent GFR determination. Urine was analysed for protein, albumin, immunoglobulin G, and α-1-microglobulin. A similar analysis was done in a patient subgroup receiving immune checkpoint inhibitors (ICI) as prior or subsequent line of therapy.

Results

Cr remained constant during TKI treatment (P = 0.7753), whereas a significant decrease in CSTC (from week 2 onward, P < 0.0001) and BTP (at weeks 2 and 4, P = 0.0100) were noticed. Consequently, GFR estimations, using CSTC and/or BTP as a biochemical parameter, showed an apparent increase in GFR, whereas this was not observed for Cr-related GFR estimations. As a result, the GFR gap (ΔGFR) was significantly different from week 2 onward between Cr-based and CSTC-based GFR and between BTP-based and CSTC-based GFR. Glomerular damage was noticed with significant increase in urine protein-to-creatinine ratio, albumin-to-creatinine ratio and immunoglobulin G (all P < 0.0001). No change in α-1-microglobulin was seen. ICI treatment had no effect on Cr (P = 0.2262), CSTC (P = 0.7341), and BTP concentrations (P = 0.3592).

Conclusion

GFR equations, in which CSTC is incorporated, fail to correctly estimate the GFR in oncology patients treated with TKIs. As TKI-treated patients show clear signs of glomerular injury, further assessment is needed on how to correctly monitor the kidney function in actively treated oncology patients.

Locally Advanced Adenoid Cystic Carcinoma of the Breast-A Case Report with a Review of the Literature

Breast cancer (BC) is a heterogeneous disease distinguished by four main subtypes based on the expression of estrogen, progesterone receptors, and human epidermal growth factor-2 on the cancer cells. Triple-negative breast cancer (TNBC) consists of approximately 10-20% of all BCs and is characterized by a poor prognosis. Adenoid cystic carcinoma (ACC) of the breast is a rare, special type of TNBC with low metastatic potential and usually favorable prognosis. There are no established recommendations concerning systemic therapy in advanced ACC. We present a case of a 70-year-old woman with locally advanced ACC with progression after radical mastectomy, and review the literature concerning the treatment of metastatic disease focused on systemic therapy.

Prognostic Significance of Primary Tumor Surgery in Adenoid Cystic Carcinoma Patients With Distant Metastases at Diagnosis: A Population-Based Database Analysis in Head and Neck Region

Purpose: Adenoid cystic carcinoma (ACC) is an aggressive cancer that often leads to poor prognosis, especially when it has metastasized. The prognostic significance of primary tumor surgery (PTS) for ACC with distant metastasis (DM) at the time of diagnosis has not been extensively studied. Methods: Using data from the surveillance, epidemiology, and end results (SEER) database from 2010 to 2019, we identified patients with ACC in head and neck region and synchronous DM. We evaluated the effect of PTS on different patterns of metastasis using Kaplan-Meier analysis, log-rank tests, and multivariate Cox regression analysis to assess the therapeutic benefit of PTS in the overall cohort and various subgroups. Results: Of the 192 identified patients with synchronous metastatic ACC of head and neck, 91 (47.4%) underwent PTS. Patients who received PTS had significantly better survival than nonsurgical patients (median overall survival: 19 vs 43 months, P = .006). Cox regression analysis also showed that PTS was associated with improved survival (HR = .46, 95% CI: 0.42-0.88; P = .028). In sub-analyses, except for patients with liver metastases [overall survival (OS), P = .107, cancer-specific survival (CSS), P = .153], PTS consistently conferred significant survival benefits in patients with bone metastases (OS, P = .041, CSS, P = .065) and lung metastases (OS, P = .016, CSS, P = .027). PTS also led to better survival in patients who did not receive radiotherapy (median OS: 13 vs 52 months, P = .007). Conclusion: Our study suggests that PTS in metastatic ACC patients of head and neck improved overall and CSS, particularly in those with bone or lung metastases and those who did not receive radiotherapy. However, further prospective studies are needed to confirm these findings, and the indications for PTS in metastatic ACC should be carefully evaluated by a multidisciplinary board.

The clinical significance for primary tumor surgery in metastatic head and neck adenoid cystic carcinoma

PURPOSE

This study aimed to determine the prognostic significance and optimal candidates for primary tumor surgery (PTS) among patients with metastatic head and neck adenoid cystic carcinoma (HNACC).

METHODS

The data were retrieved from Surveillance, Epidemiology, and End Results (SEER) database. Patients with metastatic HNACC at the initial diagnosis were included in this study. Univariate survival analysis was performed using the Kaplan-Meier method, and the difference in survival curves between PTS and non-PTS groups was estimated using the log-rank test. Multivariate analysis was performed to evaluate the independent prognostic factors associated with overall survival (OS) and cancer-specific survival (CSS).

RESULTS

Overall, 155 patients were eligible, of whom 93 underwent palliative PTS. Patients with lung metastasis alone were more likely to undergo PTS. PTS was associated with significantly improved OS and CSS compared with non-PTS. In the multivariate model, patients who underwent PTS had better OS than those who did not undergo PTS; however, no improvement was observed in the CSS. Subgroup analyses further revealed that patients aged < 60 years with T3-4 or N0 classification might benefit from PTS.

CONCLUSION

PTS significantly improved the OS of patients with metastatic HNACC. PTS had a favorable prognostic impact on highly selected patients, namely, those aged < 60 years with T3-4 and N0 classification, which could be adopted in future clinical practice.

Claudin expression in pulmonary adenoid cystic carcinoma and mucoepidermoid carcinoma

Background: Although the expression of tight junction protein claudins (CLDNs) is well known in common histological subtypes of lung cancer, it has not been investigated in rare lung cancers. The aim of our study was to examine the expression of different CLDNs in pulmonary salivary gland tumors. Methods: 35 rare lung cancers including pathologically confirmed 12 adenoid cystic carcinomas (ACCs) and 23 mucoepidermoid carcinomas (MECs) were collected retrospectively. Immunohistochemical (IHC) staining was performed on formalin fixed paraffin embedded (FFPE) tumor tissues, and CLDN1, -2, -3, -4, -5, -7, and -18 protein expressions were analyzed. The levels of immunopositivity were determined with H-score. Certain pathological characteristics of ACC and MEC samples (tumor grade, presence of necrosis, presence of blood vessel infiltration, and degree of lymphoid infiltration) were also analyzed. Results: CLDN overexpression was observed in both tumor types, especially in CLDN2, -7, and -18 IHC. Markedly different patterns of CLDN expression were found for ACC and MEC tumors, especially for CLDN1, -2, -4, and -7, although none of these trends remained significant after correction for multiple testing. Positive correlations between expressions of CLDN2 and -5, CLDN3 and -4, and CLDN5 and -18 were also demonstrated. Tumors of never-smokers presented lower levels of CLDN18 than tumors of current smokers (p-value: 0.003). Conclusion: This is the first study to comprehensively describe the expression of different CLDNs in lung ACC and MEC. Overexpression of certain CLDNs may pave the way for targeted anti-claudin therapy in these rare histological subtypes of lung cancer.

Comparison of Paclitaxel plus Carboplatin versus Observation in Patients with Recurrent or Metastatic Adenoid Cystic Carcinoma of the Head and Neck

INTRODUCTION

Although systemic therapy, including multi-kinase inhibitors and cytotoxic chemotherapy, is an option for recurrent or metastatic adenoid cystic carcinoma of the head and neck (HNACC), it is not proven whether these therapies can prolong overall survival (OS). The present study investigated the impact of cytotoxic chemotherapy on survival outcomes compared with observation without chemotherapy.

METHODS

We retrospectively reviewed the medical records of the patients diagnosed with recurrent or metastatic HNACC. We compared the survival outcomes, including survival time from recurrence/metastasis (OS) patients who received systemic chemotherapy with paclitaxel (200 mg/m2) and carboplatin (area under the curve 6) (TC) on day 1 of a 3-week cycle and observation alone. Subgroup analysis was conducted to identify patients who can get benefit from TC.

RESULTS

Seventy-five patients (32 in TC and 43 in observation) were analyzed. There was no difference in median OS between TC and observation (52.2 months vs. 44.0 months, hazard ratio 0.76, 95% confidence interval 0.32-1.30, p = 0.21). Landmark analysis to reduce immortal bias also showed no difference between TC and observation in terms of OS. Subgroup analysis showed nonsignificant trends toward longer OS in asymptomatic patients with pulmonary metastasis and without bone metastasis.

CONCLUSIONS

In our non-randomized comparison, patients who underwent TC did not show prolonged survival time from recurrence and/or metastasis diagnosis compared with observation alone in patients with recurrent or metastatic HNACC. Although systemic chemotherapy is a possible option for metastatic/recurrent HNACC, initial observation might be a valid strategy for asymptomatic patients without extrapulmonary diseases. Further research is warranted to identify the optimal patients and therapeutic regimens to prolong OS in HNACC.

PD-1 and PD-L1 expression in rare lung tumors

Background: Our knowledge is still limited about the characteristics and treatment of rare lung tumors. The aim of our study was to determine programmed cell death ligand-1 (PD-L1) and programmed cell death-1 (PD-1) expression in rare pulmonary tumors to assess the potential role of immunotherapy. Methods: 66 pathologically confirmed rare lung tumors including 26 mucoepidermoid carcinomas (MECs), 27 adenoid cystic carcinomas (ACCs), and 13 tracheobronchial papillomas (TBPs) were collected retrospectively. Immunohistochemical (IHC) staining was performed on formalin fixed paraffin embedded (FFPE) tumor tissues, and PD-L1 expression on tumor cells (TCs) and immune cells (ICs), and PD-1 expression on ICs were determined. The cut off value for positive immunostaining was set at 1% for all markers. Results: PD-L1 expression on TCs was observed in two cases of MEC (7.7%), one case of ACC (3.7%), and was absent in TBP samples. PD-L1 expression on ICs could be demonstrated in nine cases of MEC (34.6%), four cases of ACC (14.8%), and was absent in TBPs. All PD-L1 TC positive tumors were also PD-L1 IC positive. Higher expression level than 5% of PD-L1 TC and/or IC was observed only in one ACC and in two MEC patients. Among them, strong PD-L1 immunopositivity of >50% on TCs and of >10% on ICs could be demonstrated in one MEC sample. PD-L1 expression of ≥1% on ICs was significantly more common in MEC, than in TBP (p < 0.001). In MEC ≥1% PD-L1 TC or IC expressions were significantly more common in patients aged 55 or older, than in younger patients (p = 0.046, and p = 0.01, respectively). PD-1 expression on ICs was found in five cases of MEC (19.2%), four cases of ACC (14.8%), and in two cases of TBP (15.4%). Only one MEC case showed a higher than 5% expression level of PD-1 on ICs. Conclusion: This retrospective study comprehensively demonstrated the rare expression of PD-L1 and PD-1 in pulmonary MEC, ACC, and TBP. However, we found very strong PD-L1 immunopositivity on both TCs and ICs in one MEC sample, which warrants further investigations in a larger cohort.

Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial-myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

Robotic resection of a single adenoid cystic tumor liver metastasis using ICG fluorescence. A case report and literature review

Adenoid cystic carcinoma (AdCC) is a rare tumor that typically develops in the salivary glands and less frequently in other sites of the head and neck region. Only a few cases of resected metachronous liver metastases have been reported. Minimally invasive surgery is currently the gold standard of care for liver resections; furthermore, the use of Indocyanine Green (ICG) is continuously increasing in surgical practice, especially in cases of primary liver tumors and colorectal liver metastases, due to its capacity to enhance liver nodules. We report the case of a 54-year-old male with a single liver metastasis of AdCC, located in SIII, who presented in our center 9 months after resection of a primary tumor of the laryngotracheal junction and adjuvant proton therapy. A 25-mg injection of ICG (0.3 mg/kg) was administered 48 h before surgery in order to highlight the tumor and perform an ICG-guided resection. The lesion was clearly visible during surgery, and, given its position and the proximity to the main lobar vessels of the left lobe, we opted for a left lateral sectionectomy. The outcome was unremarkable, with no major postoperative complications. The administration of ICG 48 h before surgery seems to be a valid tool even in cases of AdCC liver metastases, providing surgeons with better visualization of the lesion and improving the precision of the resection.