Elective neck dissection in patients with head and neck adenoid cystic carcinoma: an international collaborative study

Outcomes in Minor Salivary Gland Tumors-A 20+ Year Tertiary-Care Center Experience

Objective

Minor salivary gland carcinomas are challenging to study due to their rarity and heterogeneity. We aim to further characterize clinical characteristics, treatment, and outcomes over 20 years within a single institution.

Study Design

Retrospective chart review was conducted on 210 patients who received primary treatment for minor salivary gland malignancy from 2000 to 2022.

Setting

Single tertiary-care center.

Methods

Multivariable Cox proportional hazards method was used to examine the relationship between pre-determined clinically important variables and outcomes.

Results

Five-year overall survival was 77.8% (72.0-84.1). Advanced clinical T stage portended over a 2 times higher risk of death and recurrence. High pathologic grade was associated with a near 3 times higher risk of death and recurrence. There was a predominance of occult nodal metastases in level II for oral cavity and oropharynx site tumors.

Conclusion

Clinical T stage and grade were important for overall survival, local, regional, and distant recurrence-free survival. Occult nodal metastases occurred most often in level II.

Adenoid Cystic carcinoma of minor salivary glands (AdCCmSG): a multidisciplinary update

INTRODUCTION

Adenoid cystic carcinoma of minor salivary glands (AdCCmSG) represents a 'rarity in the rarity,' posing a clinical challenge in lack of standardized, evidence-based recommendations. At present, AdCCmSG management is mostly translated from major salivary gland cancers (MSGCs). Ideally, AdCCmSG diagnostic-therapeutic workup should be discussed and carried out within a multidisciplinary, high-expertise setting, including pathologists, surgeons, radiation oncologists and medical oncologists.

AREAS COVERED

The present review provides an overview of epidemiology and pathologic classification. Moreover, the most recent, clinically relevant updates in the treatment of AdCCmSG (Pubmed searches, specific guidelines) are critically discussed, aiming to a better understanding of this rare pathologic entity, potentially optimizing the care process, and offering a starting point for reflection on future therapeutic developments.

EXPERT OPINION

The management of rare cancers is often hindered by limited data and clinical trials, lack of evidence-based guidelines, and hardly represented disease heterogeneity, which cannot be successfully tackled with a 'one-size-fits-all' approach. Our goal is to address these potential pitfalls, providing an easy-to-use, updated, multidisciplinary collection of expert opinions concerning AdCCmSG management as of today's clinical practice. We will also cover the most promising future perspectives, based on the potential therapeutic targets highlighted within AdCCmSG's molecular background.

Salivary gland adenoid cystic carcinoma in the U.S population: Importance of grade, site of metastases, and adjuvant radiation for survival

BACKGROUND

Adenoid cystic carcinoma (AdCC) is a rare and relatively heterogenous salivary gland malignancy, for which there is debate regarding grading, and clinical prognostic factors, including the role of adjuvant radiotherapy.

METHODS

Surveillance, Epidemiology, and End Results (SEER) data were reviewed for AdCC cases from 2000 to 2018.

RESULTS

A total of 1978 patients with AdCC were identified. Most patients were between 50 and 59 years of age (21.4 %), female (59.9 %), and Caucasian (76.8 %). Most tumors were localized at presentation (44.3 %), and moderately differentiated (or grade II) (43.7 %). Overall and DSS 5-year survival rates were 70.7 % (95 % CI, 69.9-78.8), and 78.6 % (95 % CI, 77.6-79.6). The best overall 5-year survival rate was observed for those treated with surgery plus radiation, 76.8 % (95 % CI, 75.5-78.1). Multivariate analysis revealed male sex, age > 65 (H.R. 2.659 (95 % CI,2.291-3.098), p < .001), grade III/IV (H.R.5.172 (95 % CI, 3.418-7.824), p < .001), nodal metastasis, distant metastasis (H.R. 2.400 (95 % CI, 2.178-2.645), p < .001), chemotherapy only, and combination therapy as negative prognostic factors, and receiving surgery plus radiation therapy (H.R.0.586 (95 % CI, 0.505-0.679), p < .001) as a positive prognostic factor. When limited just to the lungs, had much better survival than those patients with distant metastases to other sites such as the bones and liver (p < .001).

CONCLUSION

This SEER study identifies grade, particularly III and IV, to be the strongest single predictor of worse survival. Patients did best when treated with surgery and postoperative radiotherapy. These results can inform future management of patients with this challenging cancer type.

Omission of radiotherapy to lymph node level III in patients with cN0 adenoid cystic carcinoma of the major salivary gland: a single center experience

PURPOSE

Due to the rarity of adenoid cystic carcinoma (ACC) of the major salivary gland, there is no consensus on the extent of prophylactic neck irradiation (PNI) for patients with clinically negative lymph nodes (cN0) disease.

MATERIALS AND METHODS

We conducted a retrospective analysis of all patients with ACC of the major salivary gland who received treatment at our center between January 2010 and April 2020. The primary endpoint was regional failure-free survival (RRFS). Secondary endpoints included overall survival (OS), distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), and acute toxicity.

RESULTS

A total of 139 patients were included in the analysis. For cN0 patients, the 5-year RRFS, OS, DMFS, and LRFS were 93.2%, 90.2%, 75.7%, and 91.4%, respectively. Multivariate analysis revealed that PORT was an independent prognostic factor for RRFS and LRFS. No statistically significant differences were observed between the Level III sparing PNI group and the Standard PNI group in terms of RRFS, OS, DMFS, and LRFS. The doses delivered to the larynx and thyroid in the Level III sparing PNI group were significantly lower than those in the Standard PNI group.

CONCLUSION

In patients with cN0 ACC of the major salivary gland, PNI improves regional control, and the level III nodal region sparing radiotherapy does not increase the risk of level III recurrence, while potentially reducing toxicity.

Assessing the Impact of Charged Particle Radiation Therapy for Head and Neck Adenoid Cystic Carcinoma: A Systematic Review and Meta-Analysis

Purpose: Head and neck adenoid cystic carcinoma (HNACC) is a radioresistant tumor. Particle therapy, primarily proton beam therapy and carbon-ion radiation, is a potential radiotherapy treatment for radioresistant malignancies. This study aims to conduct a meta-analysis to evaluate the impact of charged particle radiation therapy on HNACC. Methods: A comprehensive search was conducted in Pubmed, Cochrane Library, Web of Science, Embase, and Medline until December 31, 2022. The primary endpoints were overall survival (OS), local control (LC), and progression-free survival (PFS), while secondary outcomes included treatment-related toxicity. Version 17.0 of STATA was used for all analyses. Results: A total of 14 studies, involving 1297 patients, were included in the analysis. The pooled 5-year OS and PFS rates for primary HNACC were 78% (95% confidence interval [CI] = 66-91%) and 62% (95% CI = 47-77%), respectively. For all patients included, the pooled 2-year and 5-year OS, LC, and PFS rates were as follows: 86.1% (95% CI = 95-100%) and 77% (95% CI = 73-82%), 92% (95% CI = 84-100%) and 73% (95% CI = 61-85%), and 76% (95% CI = 68-84%) and 55% (95% CI = 48-62%), respectively. The rates of grade 3 and above acute toxicity were 22% (95% CI = 13-32%), while late toxicity rates were 8% (95% CI = 3-13%). Conclusions: Particle therapy has the potential to improve treatment outcomes and raise the quality of life for HNACC patients. However, further research and optimization are needed due to the limited availability and cost considerations associated with this treatment modality.

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.

Elective Neck Dissection Improves Regional Control in cN0 Minor Salivary Gland Carcinoma in the Oral Cavity

PURPOSE

Consensus regarding whether elective neck dissection (END) provides better outcomes than observation in clinically node negative minor salivary gland (MSG) carcinoma is lacking. Therefore, this study aimed to compare the impact of END with that of observation on regional control (RC) and overall survival (OS) and to detect the predictors for lymph-node metastasis in oral MSG carcinoma.

PATIENTS AND METHODS

A single-institution, retrospective cohort study was designed; it included patients with clinically node negative oral MSG carcinoma treated at a tertiary teaching hospital between January 2002 and January 2022. The primary predictor variable was END and primary outcome variables were RC and OS. The secondary outcome variable was lymph-node metastasis. Other covariates included demographic and pathologic features, TNM stage, and adjuvant treatment. The Kaplan-Meier method and Cox proportional hazards model were used to determine the effect of END on RC and OS. The chi-squared test and logistic regression models were used to identify independent predictors for lymph-node metastasis.

RESULTS

A total of 268 patients (107 men and 161 women) with a mean age of 46.4 ± 15.5 years were included. The 5-year RC rate was statistically different between the observation and END groups (75%; 95% confidence interval [CI], 67%-83; 95% CI, 81%-93%, respectively; P = .014). Cox regression analysis confirmed that END (hazard ratio [HR] 2.395; 95% CI: 1.433-8.275; P = .034) was independently associated with a decreased risk of regional recurrence. The 5-year OS rates for the observation and END groups were 66% (95% CI, 56-76%) and 76% (95% CI, 66-86%), respectively, and the difference was not statistical (P = .057). Occult metastasis occurred in 24.6% of patients. Primary tumor location on the tongue/floor of the mouth (odds ratio [OR], 4.287; 95% CI, 1.773-9.125; P = .011), T3/4 stage (OR, 3.286; 95% CI, 1.228-8.253; P = .021), and high-grade disease (OR, 6.674; 95% CI, 2.199-14.326; P < .001) were independently associated with an increased risk of occult metastasis.

CONCLUSIONS

RC was better with END than with observation, but OS was comparable with the two approaches. Primary tumor location on tongue/floor of the mouth, T3/4 stage, and high-grade disease were associated with an increased risk of lymph-node metastasis.

Approaches to the Management of Metastatic Adenoid Cystic Carcinoma

High rates of recurrence and distant metastasis are a foremost challenge in the management of adenoid cystic carcinoma (ACC), occurring in approximately 40% of all ACC patients. Despite the morbidity and mortality resulting from recurrent/metastatic (R/M) disease, there are no FDA-approved systemic agents for these patients. In this review, we summarize pertinent ACC pathophysiology and its implications for different systemic treatment regimens in R/M ACC. We review the evidence for the most widely used systemic agents - cytotoxic chemotherapy and tyrosine kinase inhibitors (TKIs) targeting VEGFR - in addition to immune checkpoint inhibitors and non-TKI biologic agents. Exciting emerging targets for R/M ACC, including inhibitors of Notch signaling, stemness, PRMT5, and Axl, are also discussed. Lastly, we review local therapies for small-volume lung disease in patients with oligometastatic ACC, specifically pulmonary metastasectomy and stereotactic body radiation therapy (SBRT). Future development of targeted molecular agents which exploit the underlying biology of this disease may yield novel therapeutic options to improve clinical outcomes in patients with R/M ACC.

Occult neck metastases risk factors and the role of elective neck dissection in cT3-4N0 adenoid cystic carcinoma of the parotid gland

Objectives

To determine the predictor for occult neck metastases and the role of elective neck dissection (END) in cT3-4N0 parotid adenoid cystic carcinoma (ACC).

Methods

Patients with surgically treated parotid ACC were retrospectively enrolled. Predictors of occult neck metastases and the effect of END on disease specific survival (DSS), overall survival (OS), locoregional control survival (LRC), and distant metastasis free survival (DMS) were analyzed.

Results

Occult neck metastases occurred in 35 (19.7%) of the 178 patients undergoing an END. The tumor stage [p=0.011, 4.215 (1.387–10.435)] and intra-parotid lymph node metastasis [p=0.032, 3.671 (1.693–8.775)] were related to the possibility of occult neck metastases independently. The END group had better 10-year LRC than the observation group (56% vs. 43%, p=0.002) and also better 10-year DMS than the observation group (43% vs. 32%, p<0.001). The two groups had similar 10-year DSS (40% vs. 33%, p=0.230) and OS (31% vs. 23%, p=0.094) rates. Furthermore, the Cox model confirmed that END was independently associated with better LRC rate [p=0.022, 2.576 (1.338–6.476)] and better DMS [p=0.011, 2.343 (1.274–7.462)].

Conclusions

Occult neck metastases in cT3-4N0 parotid ACC was not common. A T4 tumor with intra-parotid lymph node metastasis had the highest possibility of occult neck metastases. END had no effect on DSS or OS but significantly decreased the risk of locoregional recurrence and distant metastasis.

Occult Neck Metastases in Head and Neck Adenoid Cystic Carcinoma: A Systematic Review and Meta-Analysis

Introduction: Adenoid cystic carcinoma (AdCC) is a rare tumor whose clinical course is burdened by local recurrence and distant dissemination. Lymph node metastasis is not believed to be common and its clinical impact is controversial. The aim of this study was to determine: (1) the prevalence of occult metastasis at diagnosis in cN0 head and neck AdCC, (2) its prognostic role, and (3) the consequent need to perform elective neck dissection (END). Material and Methods: A systematic review and meta-analyses following PRISMA guidelines was performed. PubMed, Embase, and Central databases were questioned up to July 2021 to identify studies reporting on the prevalence of occult neck metastases in head and neck AdCC. A single-arm meta-analysis was then performed to determine the pooled prevalence of occult lymph node metastases among the retained studies. Results: Of the initial 6317 studies identified, 16 fulfilled the inclusion criteria, and they were included in the meta-analysis. Of a population of 7534 patients, 2530 cN0 patients were treated with END, which revealed 290/2530 cases of occult metastases (pN+/cN0). Meta-analysis of the results of END in the 16 studies estimated an overall prevalence of occult metastases at diagnosis of 17%. No further subgroup analysis was possible to identify factors influencing lymph node involvement and the prognostic role of END. Conclusions: Taking 20% as an historically proposed cut off, a 17% prevalence of occult metastases represents a borderline percentage to get a definitive conclusion about the indication to END for head and neck AdCC. A more advanced UICC stage, an oropharyngeal minor salivary glands origin, and a high-grade transformation are factors to be considered in a comprehensive patient’s tailored therapeutic strategy. Multicenter prospective studies are the key to finding stronger recommendations on this topic.

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

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

Prognostic indicators in clinically node-negative malignant primary salivary tumours of the parotid: A multicentre experience

OBJECTIVES

Nodal metastasis is an important prognosticator in primary parotid cancers. The management of the clinically node-negative neck is an area lacking consensus. This study investigates the occult nodal metastasis rate, and prognostic indicators in primary parotid cancers.

MATERIALS AND METHODS

We performed a multicentre retrospective case note review of patients diagnosed and treated surgically with curative intent between 1997 and 2020. Demographic, clinic-pathological and follow-up data was recorded.

RESULTS

After exclusions, 334 patients were included for analysis, with a median follow-up of 48 months. The overall rate of occult lymph node metastasis amongst patients undergoing elective neck dissection was 22.4%, with older age, high-grade and more advanced primary tumours being associated with higher rates. On multivariable analysis, age ≥ 60 years (HR = 2.69, p = 0.004), high-grade tumours (HR = 2.70, p = 0.005) and advanced primary tumours (pT3-4, HR = 2.06, p = 0.038) were associated with worse overall survival. Occult nodal metastasis on final pathology was associated with a close-to-significant reduction in regional recurrence free survival (HR = 3.18, p = 0.076).

CONCLUSION

This large series confirms the significant occult lymph node metastasis rate in primary parotid cancer, and demonstrates the importance of primary histology, tumour grade and stage in predicting survival outcome. This data supports the use of elective neck dissection in patients with high-risk tumours.

[Endolaryngeal resection of the larynx for adenocystic cancer]

Adenocystic carcinoma accounts for 3-5% of all malignant neoplasms of the head and neck organs. Due to the rarity of detecting this cancer in the larynx, treatment options are still controversial: surgery with postoperative radiation therapy or surgery alone. Patient A., 64 years old, turned to the City Clinical Oncological Hospital No. 1 in October 2019 with complaints of moderate pain when swallowing, sensation of a foreign body. Fibrolaryngoscopy revealed an exophytic form of growth bright red color formation with a small tuberous surface up to 12 mm in size in the area of the free left edge of the epiglottis. There was a thickening of the pharyngeal-epiglottis fold. Histological examination revealed adenocystic cancer. Diagnosed with Laryngeal cancer with cT1N0M0. On December 23, 2019, endolaryngeal resection of the larynx was performed using an operating microscope in the volume R0. This observation is of interest both in morphological terms (extremely rarely detected cancer of the larynx) and in terms of treatment (an organ-preserving operation was performed - endolaryngeal resection of the larynx).

Laryngeal adenoid cystic carcinoma: Radical or conservative surgery?

PURPOSE

The present paper describes our experience in surgical treatment of laryngeal ACC, and discuss the effectiveness of conservative surgery.

METHODS

We retrospectively reviewed the clinical charts of 17 patients with laryngeal ACC treated surgically at the Otolaryngology Unit of Vittorio Veneto Hospital (Italy) from November 1989 to April 2020.

RESULTS

Fourteen patients underwent partial laryngectomy, and three had a total laryngectomy. Five patients (29%) experienced a laryngeal ACC relapse after a disease-free survival of 66.6 ± 50.1 months. The distant metastasis rate was 17%. At latest follow-up, two patients had died of distant metastatic disease after 156 and 243 months.

CONCLUSIONS

Radical surgery for laryngeal ACC does not warrant free margins and even cases with positive deep margins rarely experience any relapsing disease. We recommend that surgical treatment for laryngeal ACC be as conservative as possible.

Impact of tumor site on the prognosis of salivary gland neoplasms: A systematic review and meta-analysis

In numerous types of cancer, the primary tumor site can show a correlation with disease behavior and survival outcomes. In salivary gland tumors (SGTs) this association remains controversial. This study assessed the association between primary sites of SGTs and prognosis. Studies from five databases were assessed and a meta-analysis was performed using studies that presented 95 % confidence interval (95 % CI), hazard ratio (HR) and survival analysis. Gathered information from 46,361 patients showed that site had a prognostic impact on SGTs. Tumors involving minor salivary glands showed worse overall survival (HR = 1.60; 95 % CI = 1.17-2.19; p = 0.003), disease-specific survival (HR=1.63; 95 % CI = 1.12-2.37; p = 0.01), and cause-specific survival (HR=2.10; 95 % CI = 1.72-2.55; p = 0.00001). Tumors from major salivary glands showed better recurrence-free survival (HR=2.31; 95 % CI = 1.77-3.02; p = 0.00001), and locoregional control of disease (HR=2.66; 95 % CI = 1.20-5.91; p = 0.02). Our results showed that the primary site of SGTs has an impact on patient prognosis.

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.

Prognostic value of elective neck dissection in adenoid cystic carcinoma of head and neck: a meta-analysis. A call for randomized trials and international consensus

Adenoid cystic carcinoma of head and neck (AdCCHN) is an uncommon salivary gland cancer characterized for infrequent neck metastases, and high rate of local and distant recurrence. The aim of this meta-analysis was to analyse the significance of elective neck dissection (END) in terms of overall survival (OS) in patients with AdCCHN. A systematic literature search and meta-analysis was performed. Endpoint assessed by this meta-analysis included 5-year OS (death from any cause). Statistical heterogeneity was assessed using the Cochrane Q test and I² statistic. A pooled odds ratio (OR) was reported with 95% confidence interval (CI). There were 1934 patients in the END arm and 3083 in the observation group. The pooled OR, calculated for END vs. observation, was 0.94. Patients receiving END had similar risk for death compared to observation cohort (P=0.76). No significant difference in final outcome after patient stratification based on T stage was identified (OR for T1/T2 1.27, P=0.39; OR for T3/T4 0.95, P=0.90). Observation for cN0 neck is a reasonable option in AdCCHN. These findings suggest the need for prospective trials on indications and extent of END in AdCCHN.

Elective neck dissection in primary parotid carcinomas: A systematic review and meta-analysis

BACKGROUND

To estimate the rate of occult cervical lymph node metastases in cN0 patients affected by primary parotid carcinomas and to scrutinize the evidence on the indication and extent of elective neck dissection in these neoplasms.

METHODS

Medline, Embase, Web of Science, Cochrane Library and Scopus were searched until August 31, 2020, to identify studies reporting the use of elective neck dissection in the management of malignant parotid tumours. The PRISMA checklist was used. A single arm meta-analysis was then made to determine the pooled rate of occult lymph node metastases. Risk of bias of the included studies was assessed through the ROBINS-E tool.

RESULTS

The initial search returned 20 541 articles, of which twelve met the inclusion criteria and were included in the meta-analysis. They comprised 1310 patients with parotid carcinoma, of whom 542 cN0 underwent elective neck dissection, which led to the diagnosis of lymph node metastasis (pN+/cN0) in 113 cases. Meta-analysis of the results of elective neck dissection showed an overall rate of occult metastases of 0.22 (99% CI: 0.14-0.30). Locally advanced or high-grade tumours were the commonest indications for elective neck dissection in the included studies. The most dissected lymph node levels were I-II-III, and level II was the commonest site of occult nodal metastases.

CONCLUSIONS

An occult metastasis rate of 0.22 (99% CI: 0.14-0.30) represents a not negligible percentage value, which should encourage further research to outline the most appropriate elective neck management in cN0 patients with parotid carcinomas.

Perineural Invasion in Adenoid Cystic Carcinoma of the Salivary Glands: Where We Are and Where We Need to Go

Adenoid cystic carcinoma of the salivary gland (SACC) is a rare malignant tumors of the head and neck region, but it is one of the most common malignant tumors that are prone to perineural invasion (PNI) of the head and neck. The prognosis of patients with SACC is strongly associated with the presence of perineural spread (PNS). Although many contributing factors have been reported, the mechanisms underlying the preferential destruction of the blood-nerve barrier (BNB) by tumors and the infiltration of the tumor microenvironment by nerve fibers in SACC, have received little research attention. This review summarizes the current knowledge concerning the characteristics of SACC in relation to the PNI, and then highlights the interplay between components of the tumor microenvironment and perineural niche, as well as their contributions to the PNI. Finally, we provide new insights into the possible mechanisms underlying the pathogenesis of PNI, with particular emphasis on the role of extracellular vesicles that may serve as an attractive entry point in future studies.

The impact of clinicopathological factors on clinical outcomes in patients with salivary gland adenoid cystic carcinoma: a multi-institutional analysis in Japan

BACKGROUND

Owing to the low incidence of adenoid cystic carcinoma (AdCC), reliable survival estimates and prognostic factors remained unclarified.

METHODS

In this multi-institutional retrospective analysis, we collected 192 AdCC cases, and investigated the impact of clinicopathological factors on clinical outcomes of the patients. All AdCC cases were of salivary gland origin and were surgically treated with curative intent. Diagnoses of AdCC were validated by a central pathology review by expert pathologists.

RESULTS

The 5-year overall survival (OS) and disease-free survival (DFS) rates were 92.5 and 50.0%, respectively. Treatment failure occurred in 89 patients (46%) with the distant failures in 65 (34%). Multivariate analysis indicated that pN2 and a pathologically positive surgical margin were independent prognostic factors for both OS and DFS. Histological grade III was an independent prognostic factor for OS. A primary site in the submandibular gland, pT3/4, pN1, and histological grade II were independent prognostic factors for DFS. Postoperative radiation therapy (PORT) improved the locoregional control (LRC) rate. Prophylactic neck dissection was not associated with a better OS or better LRC among patients with cN0. Facial nerve dissection did not improve clinical outcomes in parotid AdCC cases without facial nerve palsy.

CONCLUSIONS

A higher TN classification, a pathologically positive surgical margin, and a higher histological grade were associated with a lower OS. PORT improved LRC rates but neck dissection failed to improve clinical outcomes in patients with cN0. As the distant metastasis was frequent, effective systemic therapy is imperative to improve the survival of AdCC patients.

Should a neck dissection be performed on patients with cN0 adenoid cystic carcinoma? A REFCOR propensity score matching study

BACKGROUND

Patterns of nodal involvement in adenoid cystic carcinoma (ACC) of the head and neck have not been sufficiently assessed to guide a decision of prophylactic neck dissection (ND). The objective of this study is to analyse the influence of ND on event-free survival (EFS) for patients with cN0 ACC.

PATIENTS AND METHODS

A multicentre prospective study was conducted between 2009 and 2018. Patients presenting cN0 non-metastatic ACC on any site, and who received surgery on the tumour, were included. EFS was the main judgement criterion. A comparative survival analysis between the groups that received a ND versus those that did not was performed, using a propensity score. Analyses were carried out using the R software.

RESULTS

Between 2009 and 2018, 322 patients with cN0 ACC were included, out of which 58% were female. The average age was 53 years. Tumours were in minor salivary glands in 58% of cases, and 52% had T3/T4 stages. ND was performed on 46% of patients. Out of them, seven had histological lymph node invasion, out of which six had tumour infiltration in the mucosa of oral cavity. After propensity score, the median EFS for N0 patients with ND was 72 months (95% Confidence Interval (CI) [48-81]), compared to 73 months (95% CI [52-85]) for patients without ND (HR = 1.33; 95% CI [0.82-2.16]; p = 0.2).

CONCLUSION

ND of cN0 patients does not provide any benefit on EFS, which suggests that its application on such patients is not necessary.

Laryngeal adenoid cystic carcinoma: Three cases reports

INTRODUCTION

Laryngeal adenoid cystic carcinoma (LACC) is an extremely rare malignant neoplasm. The etiology of LACC remains unknown, and it is characterized by multiple recurrences, slow progression, and late distant metastasis. This study aimed to provide more information regarding the characteristics, diagnosis, and treatment of LACC by analyzing 3 clinical cases and reviewing the literature on this topic.

PATIENT CONCERNS

Here, we present all 3 cases of LACC within the period between 2010 and 2019. Dyspnea was the most commonly observed symptom in these patients, followed by hoarseness, pharyngeal paresthesia, and difficulty swallowing.

DIAGNOSIS

All patients were pathologically confirmed as LACC.

INTERVENTIONS

All the patients underwent a combined therapy of surgical resection plus external irradiation.

OUTCOMES

The follow-up time was between 2 and 6 years; no local recurrence occurred in any of the 3 patients. Lung metastasis was found in 1 patient 6 years after surgery.

CONCLUSION

LACC is usually a slowly progressing cancer; the main treatment methods are surgery and radiotherapy, and the adequate radiotherapy dose should usually be greater than 60 Gy. The 5-year disease-specific survival rate is high; however, distant metastasis may still occur in patients with LACC even beyond 5 years after treatment. Therefore, patients with LACC require long-term surveillance.

An evidence-based analysis of the management of N0 neck in patients with cancer of the parotid gland

Introduction: Management of clinically negative neck (cN0) in patients with parotid gland cancer is controversial. Treatment options can include observation, elective neck dissection or elective radiotherapy. Areas covered: We addressed the treatment options for cN0 patients with parotid gland cancer. A literature review was undertaken to determine the optimal management of this group of patients. Expert opinion: Patients with parotid carcinoma and clinically negative neck have various options for their management. The analysis of tumor stage, histology and grade is essential to better define patients at risk for occult lymph node metastasis. These patients can be managed by surgery, radiotherapy or their combination, depending on the presence of risk factors, the moment at which such risk factors are detected, patient-related clinical conditions, medical provider expertise and institutional facilities.

Elective neck dissection in adenoid cystic carcinoma of head and neck: yes or no? A systematic review

PURPOSE

Adenoid cystic carcinoma of head and neck (AdCCHN) is salivary gland malignancy known for its slow progression accompanied with perineural invasion, rare lymphatic spread to the neck, high rate of local recurrence and delayed onset of distant metastases. While local recurrence and distant metastases are most common patterns of relapse and cause of death in AdCCHN, it has been debated whether lymph node involvement affects the course of the disease. The aim of this systematic review was to address this important issue and to recommend guidelines on clinically node-negative neck management in patients with AdCCHN.

METHODS

A systematic review of the published literature on cases of elective neck dissection (END) among patients with AdCCHN was performed.

RESULTS

This analysis included a total of 5767 AdCCHN patients with 2450 ENDs, ranging from 10 to 1190. Elective lymphadenectomy was employed in 42.5% of patients with AdCCHN (range 9.2-100%). The overall rate of occult neck metastases in patients with AdCCHN was reported to range between 0 and 43.7%, the average being 13.9%.

CONCLUSIONS

If performed, END should be limited to levels I-III of the ipsilateral neck since occult metastases are exclusively located within these neck regions. Although END is associated with a prolonged regional recurrence-free period, it influence on final outcome or survival is still controversial. This review strongly supports conduction of prospective trials on indications, prognostic significance and extent of END in AdCCHN.

Current thinking in the management of adenoid cystic carcinoma of the head and neck

Adenoid cystic carcinoma (ACC) is an aggressive, rare, malignant tumour that accounts for about 1% of all head and neck neoplasms and 10% of all salivary gland tumours. It is characterised by frequent local recurrences and distant metastases. Growth is slow but relentless, and progression poses a challenge to head and neck clinicians. Many small retrospective studies have described its clinical management, but the lack of multicentre, randomised, controlled trials has resulted in inconsistencies in management globally. We have focused on three key management-related controversies: the role of elective neck dissection (END) for the N0 neck; the role of adjuvant treatment or radiotherapy; and finally, the follow-up protocol, particularly cross-sectional surveillance imaging of the full body or chest computed tomography (CT) alone, and options for treatment if metastases are found. The paucity of published studies may reflect the inconsistencies that exist in the management of ACC of the head and neck in the UK. The collaboration of head and neck centres would, we think, help to correct the imbalance in these three domains of care.

Cancers of the Major Salivary Gland

Salivary gland malignancies are rare tumors that comprise multiple histologic entities with diverse clinical behavior. Mucoepidermoid carcinoma is the most frequent primary salivary malignancy, followed by adenoid cystic and acinic cell carcinoma. Although most salivary malignancies are asymptomatic, presentation with a rapidly enlarging mass may be accompanied by pain, functional neurologic deficits, soft-tissue invasion, or nodal enlargement. Assessment of clinical behavior and physical exam greatly contributes to diagnostic workup. Preoperative imaging, to include ultrasound, computed tomography, or magnetic resonance imaging, may assist with surgical planning. Limitations of preoperative fine-needle aspiration cytology mean that, in some cases, definitive histologic diagnosis may not be established until therapeutic surgery is undertaken. Treatment strategies rely on oncologic resection of the primary site with negative margins as well as adjuvant radiotherapy in patients with high-risk features, such as high-grade histology, advanced T class, or perineural invasion. Regional lymphadenectomy is recommended for involved nodal basins. Patients with clinically node-negative disease at high risk for occult nodal metastases may be considered for elective lymphadenectomy or radiotherapy. Use of chemotherapy in the adjuvant setting, in combination with radiotherapy, remains controversial. The rate of objective response to palliative chemotherapy in recurrent or metastatic salivary gland malignancy remains low. In studies that include a significant proportion of adenoid cystic carcinomas, whether disease stability represents an indolent disease process or the true effect of a therapeutic drug may be difficult to discern. Recognition of genetic alterations and protein expression unique to salivary malignancies presents exciting new opportunities for molecularly targeted therapy, although the response to molecularly targeted therapy in studies has been modest thus far.

Impact of lymph node sampling on survival in cN0 major salivary gland adenoid cystic carcinoma

BACKGROUND

The role of elective neck dissection in the management of major salivary gland adenoid cystic carcinoma is unclear.

METHODS

Data were retrospectively extracted from the National Cancer Center Database. The study cohort included 1504 patients with adenoid cystic carcinoma of major salivary glands with clinical N0 necks who were treated with surgery between 2004 and 2014. The cohort was divided into four groups based on number of lymph nodes (LNs) examined on pathology: 0, 1-8, 9-17, and ≥18 LNs.

RESULTS

The rate of occult nodal metastasis was 9.0%. Number of LNs removed was not associated with survival (Reference, 0 LNs; HR = 0.98, 95% CI 0.73-1.32 for 1-8 LNs; HR = 1.22, 95% CI 0.80-1.88 for 9-17 LNs; HR = 0.94, 95% CI 0.61-1.46 for ≥18 LNs) after adjusting for important covariates.

CONCLUSIONS

LN sampling is not associated with survival in cN0 major salivary gland ACC.

The role of elective neck dissection in patients with adenoid cystic carcinoma of the head and neck

OBJECTIVE

To investigate the frequency and outcomes of elective neck dissection (END) for adenoid cystic carcinoma (ACC) of the head and neck.

METHODS

The National Cancer Database was queried for a cohort study of patients with ACC of the major salivary glands, nasal cavity/nasopharynx, hard/soft palate, tongue, floor of mouth, larynx, and oral cavity who underwent primary surgical resection from 2004 to 2014. Multivariable logistic regression was used to identify predictors of END and occult nodal metastasis. Overall survival (OS) was estimated using the Kaplan-Meier method and modeled with Cox proportional hazards regression.

RESULTS

Among 2,807 patients with ACC treated surgically, 636 (22.7%) underwent END. Patients with ACC of the salivary glands and tongue most frequently underwent END; patients with hard/soft palate (odds ratio [OR] 0.06, P < 0.001) and nasal cavity/nasopharynx (OR 0.05, P < 0.001) ACC rarely underwent END compared to patients with major salivary gland cancer. Increasing tumor (T) stage (T4 vs. T1, OR 3.02, P < 0.001) was associated with END. Patients with advanced T3 to T4 ACC of the major salivary glands demonstrated extended OS associated with END (5-year OS 78.1% vs. 70.4%, P = 0.041) on Kaplan-Meier analysis and with END with adjuvant radiation therapy (hazard ratio 0.55, P = 0.027) using Cox proportional hazards regression. Elective neck dissection for T4 ACC of the salivary glands (21.3%) and tongue (25.5%) most consistently revealed occult nodal metastasis.

CONCLUSION

Elective neck dissection for ACC of the major salivary glands or tongue is most likely to reveal occult nodal metastasis. Elective neck dissection is associated with extended OS for advanced-stage ACC of the major salivary glands.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2094-2104, 2019.

Solitary pulmonary metastasis from a gingival cancer of 36 years ago: A case report

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An adenoid cystic carcinoma is characterized by a long-term behavior and late recurrences.

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The recurrences of ACC after more than 30 years have not been reported.

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The precise preoperative diagnosis was very difficult due to a history of tongue cancer one year previously in the present case.

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We should never overlook a history of any malignancy even if it is over 30 years prior.

Introduction

Unlike a squamous cell carcinoma (SqCC), an adenoid cystic carcinoma (ACC) is an uncommon histology of all head and neck cancers. The clinical significance of a pulmonary metastasectomy differs greatly between these two types of cancers. A solitary pulmonary nodule in a patient with a history of both these different malignancies is a diagnostic and therapeutic challenge.

Presentation of case

An 81-year-old woman presented with a right lung nodule detected by chest computed tomography (CT) one year after a tongue SqCC surgery. She had a remote history of gingival cancer 36 years prior, which was not assessed in detail during the initial work up. We suspected that the nodule was a primary lung cancer and she underwent a right basal segmentectomy. Histology revealed an ACC, which was proven to be a metastasis from the gingival cancer.

Discussion

An ACC is an uncommon type of cancer arises mainly in the salivary glands. It is characterized by a long-term behavior and the histology of ACC is a favorable prognostic factor. With its favorable histology and disease free interval of over 30 years, a better outcome would be expected than that of a primary lung tumor or a metastasis from the tongue SqCC. Furthermore, we could have made a differential diagnosis of a metastatic ACC before the surgery with more careful research for a previous history of a gingival cancer.

Conclusion

Our case emphasized that a precise history taking of any malignancy, even if that of more than 30 years prior, is crucial.

Adenoid cystic carcinoma in ventricle of larynx: An interesting case

RATIONALE

Adenoid cystic carcinomas (ACCs) are malignant tumors and occur in the major and the minor salivary glands. ACCs are rare in the larynx.

PATIENT CONCERNS

A 55-year-old female patient who presented with a 12 months history of paraesthesia pharynges and hoarseness for 4 months. Laryngoscopy showed an endophytic lesion in the right supglottic area with no laryngeal stenosis. And magnetic resonance imaging (MRI) confirmed the presence of a submucosal mass in the supglottic area. Supporting laryngoscope was performed under general anesthesia and a lesion biopsy obtained.

DIAGNOSES

The lesion was sent for frozen-section biopsy, which shows the lesion was the epithelial-derived tumors of salivary gland, but it was impossible to identify the relationship between the tumor and the surrounding normal tissue, and to judge the nature of the tumor further. So, the lesion was sent for the second frozen-section biopsy, an ACC of the larynx was confirmed and margins were negative.

INTERVENTIONS

The patient underwent partial laryngectomy.

OUTCOMES

The patient was doing well except hoarseness during the follow-up period with no evidence of disease recurrence or metastasis for 17 months post-operatively.

LESSONS

Laryngeal ACC is a rare entity. When the nature of lesion cannot be confirmed, multiple biopsies may be required for confirm the diagnosis of pathology. It not only reduces patient's waiting time for surgery, but also define the diagnosis and surgical removal of lesion through a single anesthesia.

Prognostic factors and survival in adenoid cystic carcinoma of the sinonasal cavity

BACKGROUND

Optimal treatment and prognostic factors affecting long-term survival in patients with sinonasal adenoid cystic carcinoma (ACC) have yet to be clearly defined.

METHODS

We conducted a retrospective review of patients treated with curative intent from 1980-2015 at MD Anderson Cancer Center.

RESULTS

One hundred sixty patients met inclusion criteria, including 8 who were treated with radiotherapy alone. Median follow-up time was 55 months. The 5-year overall survival (OS) and disease-free survival (DFS) rates were 67.0% and 49.0%, respectively. The 10-year OS and DFS rates were 44.8% and 25.4%, respectively. Factors that portended for poor survival on multivariate analysis were recurrent disease, any solid type histology, epicenter in the sinus cavity, the presence of facial symptoms, or the original disease not treated with surgery. There was no association between surgical margin status or nodal status and survival.

CONCLUSION

In this large cohort of patients with sinonasal ACC with extended follow-up, long-term survival is better than reported in prior literature. Future research should target patients with adverse risk factors.

Cervical lymph node metastases in salivary gland adenoid cystic carcinoma: a systematic review and meta-analysis

Background

The purpose of this research was to determine whether neck dissection is necessary for the adenoid cystic carcinoma (ACC) of head and neck.

Materials and methods

This article screened the abstract and full-text papers that investigated salivary gland primary ACC of head and neck. Two independent reviewers searched for articles published before October 2017 in three databases (Web of Science, PubMed, and Ovid), having no limits in date and language. Statistical data were analyzed statistically by Review Manager 5.3.

Results

In total, 18 studies involving 2993 patients were included in the analysis. Of the 2993 patients, 473 patients had cervical lymph node metastasis, with a merge frequency of 16% (95% CI: 13-19). Among included articles, only 4 involved cervical lymph node occult metastases, with a merge frequency of 14% (95% CI: 9-20). There were 5 articles containing minor salivary glands (MiSGs) involving 370 patients of which 92 patients had cervical lymph node metastases and the merge frequency was 25% (95% CI: 11-38). Moreover, there were 4 studies on major salivary glands involving 904 patients of which 158 patients had cervical lymph node metastases and the merge frequency was 17% (95% CI: 15-20).

Conclusion

Elective neck dissection is unnecessary for all patients with salivary gland ACC of head and neck. Moreover, compared with major salivary glands, MiSGs have a higher cervical lymph node metastases rate in ACC. The overall cervical lymph node metastases rate of MiSGs is 25%, which is enough to attract our attention. Therefore, we suggest that neck dissection might be applied to ACC of MiSGs.

Effect of simvastatin and microRNA-21 inhibitor on metastasis and progression of human salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (SACC) is a common malignancy of the salivary glands. Epithelial-mesenchymal transition (EMT) and P53 signaling pathway are associated with SACC metastasis and progression. Although simvastatin (SIM) is effective against the growth of many cancer types, its side effects limit its use. microRNA-21 (miR-21) is highly expressed in a variety of tumors and has a role in promoting tumor development. Therefore, the aim of the present study was to evaluate the effect of SIM in combination with miR-21 inhibitor (miR-21i) against lung metastatic SACC cells (SACC-LM). Our results showed that miR-21i was effective in reducing the resistance of SACC-LM to SIM, resulting in SACC-LM acquisition of epithelial traits, cell migration and invasion reduction, growth inhibition and induction of apoptosis. The expression of proteins associated to metastasis and tumor progression were regulated by the combined use of SIM and miR-21i. Thus, our findings demonstrated that such combination was effective in inhibiting SACC-LM progression, suggesting that multi-target therapy against SACC might represent a potentially successful approach in clinical treatment.

Adenoid cystic carcinoma of the larynx in a 70-year-old patient: A case report

Adenoid cystic carcinoma (ACC) is a relatively rare tumor that accounts for <1% of all head and neck malignancies. Laryngeal localization of ACC, which is most commonly hypoglottic, is relatively rare, occurring in 0.07-0.25% of all laryngeal tumors. ACC is characterized as a slow-growing tumor with a high recurrence rate, which often causes dyspnea and hoarseness. ACC exhibits a propensity for perineural invasion and thus, patients may experience pain as a late symptom of the disease. Distant metastasis occurs in 35-50% of cases and the lungs are the most common site of metastasis. Tumors are usually diagnosed by physical examination with fiberoscopy and computed tomography of the neck and chest, due to the high rate of lung metastases. The standard therapy for ACC is surgery followed by radiotherapy. In this study, a 70-year-old patient presented with laryngeal ACC, who underwent total laryngectomy with bilateral neck dissection and adjuvant radiotherapy, is presented. Follow-up examination performed 2 years after surgery revealed no evidence of locoregional recurrence or distant metastases. Previously published literature regarding ACC of the larynx was also reviewed.

Risk of Nodal Metastasis in Major Salivary Gland Adenoid Cystic Carcinoma

Objective

To determine the risk of nodal metastasis, examine risk factors for nodal metastasis, and evaluate the impact of nodal metastasis on survival in patients with major salivary gland adenoid cystic carcinoma.

Study Design

Retrospective cohort study from a large population- based cancer database.

Methods

Data were extracted from the SEER 18 database (Surveillance, Epidemiology, and End Results) of the National Cancer Institute. The study cohort included 720 patients diagnosed with major salivary gland adenoid cystic carcinoma between 1988 and 2013.

Results

The overall rate of lymph node metastasis was 17%. T3 disease (odds ratio, 4.74) and T4 disease (odds ratio, 9.24) were associated with increased risk of nodal metastasis. Age, sex, and site were not associated with nodal metastasis. Nodal metastasis was associated with worse overall survival (hazard ratio, 2.56) and disease-specific survival (hazard ratio, 3.27), after adjusting for T stage, presence of distant metastasis, site, surgical resection, radiotherapy, neck dissection, age, sex, race, marital status, and year of diagnosis.

Conclusion

Major salivary gland adenoid cystic carcinoma carries significant risk of nodal metastasis. Advanced T stage is associated with increased risk of nodal metastasis. Nodal metastasis is associated with worse survival.

Cervical lymph node metastasis in adenoid cystic carcinoma of the major salivary glands

Objective:

To verify the prevalence of cervical lymph node metastasis in adenoid cystic carcinoma of major salivary glands, and to establish recommendations for elective neck treatment.

Methods:

A search was conducted of the US National Library of Medicine database. Appropriate articles were selected from the abstracts, and the original publications were obtained to extract data.

Results:

Among 483 cases of major salivary gland adenoid cystic carcinoma, a total of 90 (18.6 per cent) had cervical metastasis. The prevalence of positive nodes from adenoid cystic carcinoma was 14.5 per cent for parotid gland, 22.5 per cent for submandibular gland and 24.7 per cent for sublingual gland. Cervical lymph node metastasis occurred more frequently in patients with primary tumour stage T3–4 adenoid cystic carcinoma, and was usually located in levels II and III in the neck.

Conclusion:

Adenoid cystic carcinoma of the major salivary glands is associated with a significant prevalence of cervical node metastasis, and elective neck treatment is indicated for T3 and T4 primary tumours, as well as tumours with other histological risk factors.

Population-based trends in outcomes in adenoid cystic carcinoma of the oral cavity

PURPOSE

Adenoid cystic carcinoma (ACC) is a rare malignant epithelial neoplasm of secretory glands of the upper aerodigestive tract. It accounts for 3-5% of head and neck malignancies and most commonly arises from the minor salivary glands of the oral cavity. The clinical behavior of ACC from specific anatomic subsites, including the oral cavity, is not well described in the literature. We aim to elucidate patient demographics, clinicopathologic features, incidence, and survival trends for oral cavity ACC (OCACC).

METHODS

Retrospective population-based analysis of OCACC in the SEER database between 1973 and 2012.

RESULTS

1066 OCACC patients were identified, of which 57.7% were female (P<0.0001). Incidence was 0.049 per 100,000. Whites were most commonly affected (81.1%). The hard palate was the most commonly involved subsite (44.1%). Nodal involvement was seen in 8.4% of cases and distant metastasis was present in 6.2% of cases at the time of presentation. Disease-specific survival (DSS) rates at 1, 5, 10, 15, and 20years were 97.4%, 83.9%, 69.9%, 57.6%, and 46.2%, respectively. Females had a higher 5-year DSS (87.8%) than males (78.4%, P=0.0004). Cases treated with surgery had a favorable prognosis regardless of whether they received radiotherapy (P<0.0001). Nodal involvement reduced 5-year DSS by 51.6% (P<0.0001), while distant metastasis reduced 5-year DSS by 46.4% (P<0.0001).

CONCLUSIONS

OCACC is a rare malignancy with females and whites being more commonly affected. At presentation, regional and distant metastases are uncommon. Poor prognostic indicators include male gender, nonsurgical therapy, nodal involvement, and distant metastasis.

Mechanisms of Perineural Invasion

Perineural invasion (PNI) is the neoplastic invasion of nerves. PNI is widely recognized as an important adverse pathological feature of many malignancies, including pancreatic, prostate, and head and neck cancers and is associated with a poor prognosis. Despite widespread acknowledgment of the clinical significance of PNI, the mechanisms underlying its pathogenesis remain largely unknown. Recent theories of PNI pathogenesis have placed a significant emphasis on the active role of the nerve microenvironment, with PNI resulting from well-orchestrated reciprocal interactions between cancer and host. Elucidating the mechanisms involved in PNI may translate into targeted therapies for this ominous process.

Cervical Lymph Node Metastasis in Adenoid Cystic Carcinoma of the Larynx: A Collective International Review

Adenoid cystic carcinoma (AdCC) of the head and neck is a well-recognized pathologic entity that rarely occurs in the larynx. Although the 5-year locoregional control rates are high, distant metastasis has a tendency to appear more than 5 years post treatment. Because AdCC of the larynx is uncommon, it is difficult to standardize a treatment protocol. One of the controversial points is the decision whether or not to perform an elective neck dissection on these patients. Because there is contradictory information about this issue, we have critically reviewed the literature from 1912 to 2015 on all reported cases of AdCC of the larynx in order to clarify this issue. During the most recent period of our review (1991-2015) with a more exact diagnosis of the tumor histology, 142 cases were observed of AdCC of the larynx, of which 91 patients had data pertaining to lymph node status. Eleven of the 91 patients (12.1%) had nodal metastasis and, based on this low proportion of patients, routine elective neck dissection is therefore not recommended.