Disparities in Postoperative Therapy for Salivary Gland Adenoid Cystic Carcinomas

Pediatric Salivary Gland Pathology

Benign and malignant salivary gland disorders are uncommon in the pediatric population; however, these can be frequently seen in pediatric otolaryngology or oral and maxillofacial surgery practices. The astute clinician should be aware of the clinical presentation, diagnosis, and management options for common inflammatory, infectious, benign, and malignant disorders of salivary glands.

Patterns and Trends in Adjuvant Therapy for Major Salivary Gland Cancer

OBJECTIVE

To investigate adjuvant therapy indications, utilization, and associated survival disparities in major salivary gland cancer (MSGC).

STUDY DESIGN

Retrospective cohort study.

SETTING

The 2006 to 2017 National Cancer Database.

METHODS

Patients with surgically resected MSGC were included (N = 11,398). pT3-4 classification, pN2-3 classification, lymphovascular invasion, pathologic extranodal extension (pENE), and positive surgical margin (PSM) were considered indications for adjuvant radiotherapy (aRT). pENE and PSM were considered possible indications for adjuvant chemotherapy. Multivariable logistic and Cox regression models were implemented.

RESULTS

Among 6694 patients with≥ $\ge $ 1 indication for aRT, 1906 (28.5%) received no further treatment and missed aRT. Age, race, comorbidity status, facility type, and distance to reporting facility were associated with missed aRT (P < .025). Among 4003 patients with ≥1 possible indication for adjuvant chemoradiotherapy (aCRT), 914 (22.8%) received aCRT. Patients with pENE only (38.5%) and both pENE and PSM (44.0%) received aCRT more frequently than those with PSM only (17.0%) (P < .001). Academic facility was associated with aCRT utilization (P < .05). aCRT utilization increased between 2006 and 2017 in both academic (14.8% vs 23.9%) and nonacademic (8.8% vs 13.5%) facilities (P < .05). Among 2691 patients with ≥1 indication for aRT alone, missed aRT portended poorer OS (hazard ratio [HR]: 1.61, 95% confidence interval [CI]: 1.28-2.03, P < .001). Among 4003 patients with ≥1 possible indication for aCRT, aRT alone (HR: 1.02, 95% CI: 0.89-1.18, P = .780) and aCRT were associated with similar OS.

CONCLUSION

Missed aRT in MSGC occurs frequently and portends poorer OS. Further studies clarifying indications for aCRT are required.

Surgical Resection Improves Overall Survival in cT4b Major Salivary Gland Cancer

OBJECTIVE

To compare surgical and nonsurgical definitive treatment in cT4b major salivary gland cancer (MSGC).

STUDY DESIGN

Retrospective cohort study.

SETTING

The 2004 to 2019 National Cancer Database.

METHODS

The NCDB was queried for patients with cT4b MSGC (N = 976). Patients undergoing definitive treatment with (1) surgical resection + adjuvant therapy, (2) radiotherapy (RT) alone, or (3) chemoradiotherapy (CRT) were included in Kaplan-Meier and Cox survival analyses.

RESULTS

Of 219 patients undergoing definitive treatment, 148 (67.6%) underwent surgical resection + adjuvant therapy and 71 (32.4%) underwent RT or CRT. There were no documented mortalities within 90 days of surgical resection. Tumor diameter and nodal metastasis were associated with decreased odds of undergoing definitive treatment (P < 0.025). Patients with positive surgical margins (PSM) had higher 5-year overall survival (OS) than those undergoing definitive RT or CRT (48.5% vs 30.1%, P = 0.018) and similar 5-year OS as those with negative margins (48.5% vs 54.0%, P = 0.205). Surgical resection + adjuvant therapy (adjusted hazard ratio: 0.55, 95% confidence interval [CI]: 0.37-0.84) was associated with higher OS than definitive RT or CRT (P < 0.025). A separate cohort of 961 patients with cT4a tumors undergoing surgical resection + adjuvant therapy was created; cT4a and cT4b (hazard ratio: 1.02, 95% CI: 0.80-1.29, P = 0.896) tumors had similar OS.

CONCLUSION

A minority of patients with cT4b MSGC undergo definitive treatment. Surgical resection + adjuvant therapy was safe and associated with higher OS than definitive RT or CRT, despite high rate of PSM. In the absence of clinical trial data, appropriately selected patients with cT4b MSGC may benefit from surgical resection.

Adenoid Cystic Carcinoma of the Minor Salivary Glands: A Systematic Review and Meta-Analysis of Clinical Characteristics and Management Strategies

BACKGROUND

Intraoral adenoid cystic carcinoma (ACC) arising from minor salivary glands (MSG) is a rare malignancy associated with delayed diagnosis and unfavorable outcomes. This study aimed to comprehensively review ACC of MSGs, focusing on clinical characteristics, imaging modalities, treatment approaches, and long-term outcomes.

METHODS

A systematic search was conducted in PubMed, Web of Science, and MEDLINE databases to identify relevant articles reporting cases of ACC of MSGs between January 1997 and March 2023. The study was registered in PROSPERO (ID: CRD42023449478). A total of 10 studies that met the inclusion criteria were selected for critical review. In total, 902 patients were diagnosed with ACC of MSGs with an age range of 44.3 to 63 years, and an average age of 56.6 years. The female to male ratio ranges from 1:1 to 2.4:1. Regarding the primary site of ACC, the palate was the most common location, accounting for 30.5% to 83.3%, followed by the buccal mucosa, floor of the mouth, and lip and the retromolar area. For histology, the solid mass pattern was the most prevalent, seen in 95.2% of patients, followed by the cribriform pattern. Regarding treatment modalities, surgery was the most common approach, applied in 76.3% of cases, with a combination of surgery and radiotherapy used in 29.0% of cases. A smaller fraction, 3.2%, received a combination of surgery, chemotherapy, and radiotherapy, and 8.3% underwent radiotherapy alone. Local recurrence rates varied between 1% and 28.5%, and distant metastasis occurred in 18.2% to 33.3% of cases, predominantly to lymph nodes (14.5%). An analysis of overall survival across various stages and patient numbers indicated a 5-year survival rate of 68.0%. The findings of this study provide valuable insights for physicians in making treatment decisions and emphasize the need for ongoing research and collaborative clinical efforts to improve the management and outcomes of this challenging disease.

CONCLUSION

ACC of MSGs is a multifaceted condition typically manifesting as asymptomatic enlargement and ulceration. This disease is marked by distinct histopathological patterns and perineural invasion (PNI). Recognizing these distinctive aspects is key in shaping the treatment plan, which can range from surgical procedures to radiation therapy, chemotherapy, and evolving targeted treatments. Continuous research and collaborative clinical efforts remain critical for ongoing progress in the treatment and management of this challenging condition.

Adenoid Cystic Carcinoma of Salivary Glands: A Ten-Year Review and an Assessment of the Current Management, Surgery, Radiotherapy, and Chemotherapy

Adenoid cystic carcinoma (ACC) is a rare cancer that arises from the salivary glands and other sites in the body, such as the lung and breast. Although the tumor accounts for 10% of all salivary gland malignancies, it only accounts for 1% of head and neck malignancies. It can affect both major and minor salivary glands; here, it is called salivary gland adenoid cystic carcinoma or SACC, with a slight predilection to the latter, and commonly manifests between the 6_th and 7_th decades of life. The disease also shows a slight female predilection, with a reported female to male ratio of 3 : 2. Lesions of SACC are often insidious and slow-growing, and symptoms such as pain and altered sensation are frequently associated with advanced stages of the disease. Salivary adenoid cystic carcinoma is characterized by perineural invasion (PNI), a distinctive feature that potentially plays a significant role in the tumor's relapse and recurrence, which is approximately 50%. The disease is not prevalent, and its etiopathogenesis is poorly understood, although several genetic patterns and biomarkers have been linked to its initiation and/or progression. The discovery of these mutations and biomarkers has encouraged several clinical studies to use therapeutic agents to target the specific receptors on the cancer cells to potentially prevent further proliferation of the tumor cells and metastasis of the disease. Diagnosis of SACC is often challenging and frequently requires a combination of clinical examination, imaging, and histopathology. Management of SACC is primarily surgical excision, while radiotherapy has shown to be effective in improving local control in cases with microscopic residual disease. However, treatment of recurrent or metastatic tumors by radiotherapy with or without chemotherapy has so far shown limited success. The aim of this thesis is to provide an update of literature on SACC with a particular focus on the latest management approaches and future trends.

The effect of adjuvant radiotherapy on clinical outcomes in early major salivary gland cancer

BACKGROUND

This study investigated the effects of adjuvant radiotherapy on outcomes in early-stage major salivary gland cancers.

METHODS

A total of 655 patients were identified, including 355 (54.2%) received adjuvant radiotherapy and 300 (45.8%) had surgery alone. The effect of adjuvant radiotherapy on 5-year locoregional recurrence and disease-specific survival (DSS) was calculated using the Kaplan-Meier method, Wilcoxon rank sum test, and Cox proportional hazards model.

RESULTS

There were no significant differences in locoregional recurrence and DSS between patients receiving adjuvant radiotherapy and those not in both univariate and multivariable analysis. Although patients with positive margin status had a higher locoregional recurrence and those with moderate/poor differentiation had a worse DSS, stratified analysis still indicated there were no protective effects from the use of adjuvant radiotherapy.

CONCLUSIONS

The use of adjuvant radiation therapy was not associated with improved locoregional recurrence and DSS, even for those with high-risk histopathological factors.

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.

Analysis of postoperative radiotherapy for non-metastatic head and neck adenoid cystic carcinoma based on SEER data

OBJECTIVE

The postoperative role of adjuvant radiotherapy in non-metastatic head and neck adenoid cystic carcinoma (ACC) remains controversial. We analyzed adjuvant radiotherapy's effect on surgical patient survival.

METHODS

Patients diagnosed with ACC from 2004 to 2015 in the Surveillance, Epidemiology, and End Results database were analyzed. The overall survival (OS) and disease-specific survival (DSS) of patients after adjuvant radiotherapy were assessed using the Kaplan-Meier and multivariate Cox methods. Propensity score matching (PSM) was performed to adjust confounders between patients with or without adjuvant radiotherapy; a forest plot was generated by subgroup analysis.

RESULTS

The study included 742 patients. In the PSM cohort, adjuvant radiotherapy did not improve OS or DSS. Radiotherapy was not a protective factor for OS or DSS in the univariate and multivariate Cox proportional hazard models. In the subgroup analysis, postoperative radiotherapy improved the OS of female and N1-stage patients and those with oropharyngeal tumors or over 79 years and the DSS of N1-stage patients.

CONCLUSIONS

Postoperative radiotherapy showed different benefits in ACC patients, and postoperative radiotherapy recommendations should be individualized. Female and N1-stage ACC patients and those with oropharyngeal tumors or patients over 79 years without distant metastases postoperatively could benefit from adjuvant radiotherapy.

A Systematic Review of Head and Neck Cancer Health Disparities: A Call for Innovative Research

OBJECTIVE

(1) Describe the existing head and neck cancer health disparities literature. (2) Contextualize these studies by using the NIMHD research framework (National Institute on Minority Health and Health Disparities). (3) Explore innovative ideas for further study and intervention.

DATA SOURCES

Ovid MEDLINE, Embase, Web of Science, and Google Scholar.

REVIEW METHODS

Databases were systematically searched from inception to April 20, 2020. The PRISMA checklist was followed (Preferred Reporting Items for Systematic Reviews and Meta-analyses). Two authors reviewed all articles for inclusion. Extracted data included health disparity population and outcomes, study details, and main findings and recommendations. Articles were also classified per the NIMHD research framework.

RESULTS

There were 148 articles included for final review. The majority (n = 104) focused on health disparities related to at least race/ethnicity. Greater than two-thirds of studies (n = 105) identified health disparities specific to health behaviors or clinical outcomes. Interaction between the individual domain of influence and the health system level of influence was most discussed (n = 99, 66.9%). Less than half of studies (n = 61) offered specific recommendations or interventions.

CONCLUSIONS

There has been extensive study of health disparities for head and neck cancer, largely focusing on individual patient factors or health care access and quality. This review identifies gaps in this research, with large numbers of retrospective database studies and little discussion of potential contributors and explanations for these disparities. We recommend shifting research on disparities upstream toward a focus on community and societal factors, rather than individual, and an evaluation of interventions to promote health equity.

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.

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.

Positive Surgical Margins in Submandibular Malignancies: Facility and Practice Variation

OBJECTIVES

Identify positive margin rate in a national cohort of patients with submandibular carcinoma, identify predictors of positive margins, and associate margins with overall survival.

STUDY DESIGN

Retrospective cohort.

SETTING

Commission on Cancer-accredited hospitals.

SUBJECTS AND METHODS

We included patients in the National Cancer Database from 2004 to 2014 who were diagnosed with submandibular carcinoma and underwent primary surgical resection. We determined the rate of positive surgical margins and associated patient, tumor, and treatment factors with positive margins via univariable and multivariable logistic regression analysis. We associated margin status with overall survival by Kaplan-Meier curve and Cox proportional hazards regression.

RESULTS

We identified 1150 patients with submandibular malignancy undergoing surgical resection. Positive margin rate was 41.0%. Increased odds of positive margins were seen in patients with advanced T stage (vs T1, T3: odds ratio [OR] = 3.04, P < .001; T4a: OR = 2.89, P < .001), adenoid cystic carcinoma histology (OR = 1.54, P = .020), and those treated at nonacademic facilities (OR = 1.41, P = .008). Patients who underwent a preoperative diagnostic biopsy had decreased odds of positive margins (OR = 0.72, P = .014). Positive margins were associated with reduced overall survival (58% vs 69% 5-year overall survival, P < .001; hazard ratio = 1.49, P = .001) when controlling for patient, tumor, and management factors.

CONCLUSIONS

The national positive margin rate of submandibular carcinoma is 41.0%. Preoperative biopsy and treatment at academic institutions independently decreased the risk of positive margins, and positive margins were independently associated with diminished overall survival. Positive margin rate for submandibular carcinoma may be considered a benchmark for quality of care.

Advanced adenoid cystic carcinoma (ACC) is featured by SWI/SNF chromatin remodeling complex aberrations

Purpose

Adenoid cystic carcinoma (ACC) is a rare neurotropic cancer with slow progression occurring in salivary glands and less frequently in other body parts. ACC is featured by hyperchromatic nuclei and various mutations in genes encoding chromatin-related machineries. The ACC treatment is mainly limited to the radical surgery and radiotherapy while the chemotherapy remains ineffective. As the knowledge about molecular basis of ACC development is limited, we investigated here the molecular features of this disease.

Patients and methods

This study included 50 patients with ACC. Transcript profiling of available ACC samples vs normal salivary gland tissue, quantitative real-time PCR (qRT-PCR) transcript level measurements and the immunohistochemistry (IHC) for SWI/SNF chromatin remodeling complex (CRC) subunits and androgen receptor on surgery-derived paraffin-embedded samples were performed.

Results

Transcriptomic study followed by Gene Ontology classification indicated alteration of chromatin-related processes, including downregulated transcript levels of main SWI/SNF CRC subunits and elevated expression of BRM ATPase-coding SMARCA2 gene in ACC. Subsequent IHC indicated broad accumulation of BRM ATPase and several SWI/SNF subunits, suggesting affected control of their protein level in ACC. The IHC revealed ectopic, heterogeneous expression of androgen receptor (AR) in some ACC cells.

Conclusions

Our study indicated that ACC features aberrant expression of genes controlling chromatin status and structure. We found that the balance between SWI/SNF classes is moved towards the BRM ATPase-containing complex in ACC. As BRM is known to be involved in chemoresistance in cancer cells, this observation may be the likely explanation for ACC chemoresistance.

Electronic supplementary material

The online version of this article (10.1007/s00432-018-2783-5) contains supplementary material, which is available to authorized users.