Patterns and treatment of neck metastases in patients with salivary gland cancers

The prognostic value of selective neck dissection in early-stage major salivary gland carcinoma: a population-based analysis

Objective

This population-based study aims to assess the survival benefits of selective neck dissection (SND) compared to neck observation in patients with T1/T2N0M0 major salivary gland malignancy (MSGC).

Methods

We conducted a retrospective review of T1/T2N0M0 MSGC patients who underwent primary tumor surgical extirpation with or without elective neck dissection in the Surveillance, Epidemiology, and End Results database (SEER) from 2004-2015. The impact of SND and clinical variables on overall survival (OS) and disease-specific survival (DSS) was evaluated using Univariate and Multivariate Cox proportional hazards regression models. Kaplan-Meier survival curves were generated, and survival rates were assessed via the log-rank test.

Results

Of 3778 post-operative T1-T2N0M0 MSGC patients, 2305 underwent elective neck dissection, while 1473 did not. Median follow-up was 106 months. Univariate and Multivariate analysis identified SND as a prognostic factor for OS in all the study population. After stratified analysis, we found that in the poorly high-grade (differentiated and undifferentiated) patients, the survival showed a significant OS and DSS benefit after receiving SND compared with the neck observations [HR for OS (95%CI): 0.571(0.446-0.731), P<0.001] and [HR for DSS (95%CI): 0.564(0.385-0.826), P=0.003], other than in the well differentiated or moderately differentiated subgroup. Especially, when the pathological is squamous cell carcinoma, the results show that the people underwent SND had better prognosis, not only in OS [HR (95%CI): 0.532(0.322-0.876), P=0.013], but also in DSS [HR (95%CI): 0.330(0.136-0.797), P=0.014]. The multivariate analysis also yielded encouraging results, compared with neck observation, receiving SND bought about a significant independent OS (adjusted HR, 0.555; 95% CI, 0.328-0.941; P=0.029) and DSS (adjusted HR, 0.349; 95% CI, 0.142-0.858; P=0.022) advantage in high grade squamous cell carcinoma MSGC patients. The Kaplan-Meier survival curves also demonstrated that adjusted SND still had significantly better OS(P=0.029) and DSS(P=0.022) than the observation group in patients with high-grade squamous cell carcinoma of MSGC.

Conclusion

Poorly differentiated and undifferentiated T1/T2N0M0 major salivary gland malignancy treated with selective neck dissection demonstrated superior survival compared to neck observation, especially in the pathological subtype of squamous cell carcinoma. These findings suggest the potential benefits of multimodal therapy for appropriately selected patients, emphasizing significant clinical implications.

Topography and probability diagram of cervical and intra-parotid lymph node metastasis in parotid gland cancer

In parotid gland cancer (PGC), cervical lymph node metastasis (LNM) and intra-parotid LNM are known as significant indicators of poor prognosis. However, the topography of LNM in the affected parotid gland and the lymphatic progression of PGC has never been explored in detail. This was a retrospective analysis of data from 423 patients with previously untreated primary PGC (2005 to 2020), excluding patients with squamous cell carcinoma, lymphoma or metastatic disease in the parotid gland. The pattern of LNM was analyzed by neck sub-level and parotid sub-site. Using the conditional probability of neck level involvement, a probability diagram was plotted on several thresholds to visualize the sequential progression of LNM in PGC. The pattern of LNM progression was found to be similar between low- and high-grade pathology, but the incidence differed significantly (8.0% vs. 45.4%). Intra-parotid LNs and level IIa LNs were the most common sites (57.3% and 61.0%) of LNM in PGC, followed by level III (31.7%), Ib (25.6%), IV (22.0%), IIb (20.7%) and Va (20.7%) LNM. In intra-parotid LNs, the incidence of LNM in the deep parotid LNs was relatively low (9.4%); most intra-parotid LNMs were observed in the superficial parotid (90.6%) and peri-tumoral (in contact with the tumor) (31.3%) LNs. LNM to levels Ia, Vb and contra-lateral LNM occurred only in the very late stage. Our results provide detailed information about LNM progression in PGC at the sub-level and can help clinicians decide the treatment extent, including surgery or radiation.

The evolving landscape of salivary gland tumors

Salivary gland cancers are a rare, histologically diverse group of tumors. They range from indolent to aggressive and can cause significant morbidity and mortality. Surgical resection remains the mainstay of treatment, but radiation and systemic therapy are also critical parts of the care paradigm. Given the rarity and heterogeneity of these cancers, they are best managed in a multidisciplinary program. In this review, the authors highlight standards of care as well as exciting new research for salivary gland cancers that will strive for better patient outcomes.

Current management and future challenges in salivary glands cancer

Salivary gland cancers (SGCs) are rare, accounting for less than 5% of all malignancies of the head and neck region, and are morphologically heterogeneous. The diagnosis is mainly based on histology, with the complementary aid of molecular profiling, which is helpful in recognizing some poorly differentiated, borderline, or atypical lesions. Instrumental imaging defines the diagnosis, representing a remarkable tool in the treatment plan. Ultrasound and magnetic resonance are the most common procedures used to describe the primary tumour. The treatment of SGCs is multimodal and consists of surgery, radiotherapy, and systemic therapy; each treatment plan is, however, featured on the patient and disease's characteristics. On 24 June 2022, in the meeting "Current management and future challenges in salivary gland cancers" many experts in this field discussed the state of the art of SGCs research, the future challenges and developments. After the meeting, the same pool of experts maintained close contact to keep these data further updated in the conference proceedings presented here. This review collects the insights and suggestions that emerged from the discussion during and after the meeting per se.

Systematic Review and Meta-Analysis on the Incidence of Level-Specific Cervical Nodal Metastasis in Primary Parotid Malignancies

OBJECTIVE

In primary parotid gland malignancies, the incidence of level-specific cervical lymph node metastasis in clinically node-positive necks remains unclear. This study aimed to determine the incidence of level-specific cervical node metastasis in clinically node-negative (cN0) and node-positive (cN+) patients who presented with primary parotid malignancies.

DATA SOURCES

Electronic databases (MEDLINE, EMBASE, PubMed, Cochrane).

REVIEW METHODS

Random-effects meta-analysis was used to calculate pooled estimate incidence of level-specific nodal metastasis for parotid malignancies with 95% confidence intervals (CIs). Subgroup analyses of cN0 and cN+ were performed.

RESULTS

Thirteen publications consisting of 818 patients were included. The overall incidence of cervical nodal involvement in all neck dissections was 47% (95% CI, 31%-63%). Among those who were cN+, the incidence of nodal positivity was 89% (95% CI, 75%-98%). Those who were cN0 had an incidence of 32% (95% CI, 14%-53%). In cN+ patients, the incidence of nodal metastasis was high at all levels (level I 33%, level II 73%, level III 48%, level IV 39%, and level V 37%). In cN0 patients, the incidence of nodal metastasis was highest at levels II (28%) and III (11%).

CONCLUSION

For primary parotid malignancies, the incidence of occult metastases was 32% compared to 89% in a clinically positive neck. It is recommended that individuals with a primary parotid malignancy requiring elective treatment of the neck have a selective neck dissection which involves levels II to III, with the inclusion of level IV based on clinical judgment. Those undergoing a therapeutic neck dissection should undergo a comprehensive neck dissection (levels I-V).

Patterns of Lymph Node Metastasis in Parotid Cancer and Implications for Extent of Neck Dissection

OBJECTIVE

The role and extent of neck dissection in primary parotid cancer are controversial. Herein, we characterize patterns of lymph node metastasis in parotid cancer.

STUDY DESIGN

Retrospective analysis.

SETTING

National Cancer Database.

METHODS

Patients with the 6 most common histologic subtypes of parotid cancer were selected. Primary outcomes were the distribution of positive lymph nodes by level and overall survival assessed by Cox analysis. Secondary outcomes included predictors of extended lymph node involvement (≥3 lymph nodes or Level IV/V involvement), via logistic regression.

RESULTS

Six thousand nine hundred seventy-seven patients with acinic cell carcinoma, adenocarcinoma, adenoid cystic carcinoma, carcinoma ex pleomorphic adenoma (CExPA), mucoepidermoid carcinoma, and salivary duct carcinoma (SDC) were included. Among cN0 patients, 8.2% of low-grade tumor patients had occult nodal metastasis versus 30.9% in high-grade tumor patients. Elective neck dissection was not associated with an overall survival benefit (adjusted hazard ratio: 1.10; 0.94-1.30, p = .238). Among cN+ tumors, CExPA (odds ratio [OR]: 1.88, 1.05-3.39, p = .034) and high-grade pathology (OR: 3.03, 1.87-4.93, p < .001) were predictive of having ≥3 pathologic nodes. CExPA (OR: 2.13, 1.22-3.72, p = .008), adenocarcinoma (OR: 1.60, 1.11-2.31, p = .013), SDC (OR: 1.92, 1.17-3.14, p < .01), and high-grade pathology (OR: 3.61, 2.19-5.97, p < .001) were predictive of Level IV/V neck involvement.

CONCLUSIONS

In parotid malignancy, nodal metastasis distribution is dependent on histology and grade. High-grade tumors and certain histologies (SDC and adenocarcinoma) had a higher incidence of occult nodes. Comprehensive neck dissection should also be considered for node-positive high-grade tumors, SDC, and adenocarcinoma.

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.

Salivary gland cancer: ESMO-European Reference Network on Rare Adult Solid Cancers (EURACAN) Clinical Practice Guideline for diagnosis, treatment and follow-up

•This ESMO–EURACAN Clinical Practice Guideline provides key recommendations for managing salivary gland cancer. •The guideline covers clinical and pathological diagnosis, staging and risk assessment, treatment and follow-up. •Treatment algorithms for parotid, submandibular, sublingual and minor salivary gland cancer are provided. •The author group encompasses a multidisciplinary group of experts from different institutions and countries in Europe. •Recommendations are based on available scientific data and the authors’ collective expert opinion.

Noteworthy Factors to Decide Therapeutic Strategy for Carcinoma ex Pleomorphic Adenoma of Parotid Gland: A Preliminary Study Statistical Analysis of 22 Cases from Single Institution

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor, and its prognosis is determined by the histological progression beyond the adenoma capsule. However, a preoperative evaluation of the histological progression remains challenging, and there is no consensus regarding treatment strategies for CXPA. Herein, we aimed to predict the histological progression preoperatively and develop an appropriate treatment strategy for CXPA. We retrospectively reviewed 22 patients with parotid gland CXPA recorded at our hospital. The clinicopathological characteristics were assessed, and survival analysis was performed. T3≤ or N+ were common in widely invasive CXPA (WICXPA) (p < 0.05). A tumor diameter > 40 mm and the N+ status were associated with poor prognosis considering overall survival (OS) and locoregional recurrence rate (LRC) (p < 0.05). Patients with facial nerve paralysis exhibited better OS and LRC than those without facial nerve paralysis. More than 90% of patients with WICXPA experienced distant metastases. Meanwhile, there were no cases of recurrence or death due to intracapsular and minimally invasive CXPA. A preoperative advanced T stage or N+ status was suspected as WICXPA. Tumors > 40 mm in size and N+ status necessitate high-intensity local treatment. Facial nerve invasion can be controlled by nerve resection. Postoperative systemic therapy could control distant metastases.

Oncological outcomes of patients with salivary gland cancer treated with surgery and postoperative intensity-modulated radiotherapy: a retrospective cohort study

BACKGROUND

Salivary gland cancer (SGC) is relatively rare and constitutes a variety of histological subtypes. Previously published studies of SGC patients suggest that postoperative radiation using conventional radiotherapy (RT) or 3-dimensional (3D) conformal radiotherapy may have led to suboptimal oncological outcomes.

METHODS

We identified 60 patients with major SGC treated with surgery followed by postoperative intensity-modulated radiotherapy (IMRT). Data for overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRRFS), distant metastasis-free survival (DMFS), prognostic factors, and treatment-related toxicities were analyzed. Survival was analyzed using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

With a median follow-up of 55.5 months, based on Kaplan-Meier analyses, the OS and PFS rates for SGC patients at 3, 5, and 10 years were 90.7%, 85.1%, and 85.1% and 80.1%, 72.7%, and 63.1%, respectively. The LRRFS and DMFS rates at 3, 5, and 10 years were 87.4%, 82.1%, and 82.1% and 85.3%, 78.4%, and 66.1%, respectively. In multivariable analysis (MVA), the node stage (N stage) was an independent predictor of PFS [P=0.047; hazard ratio (HR) =0.089]. A positive margin was a significant prognostic factor for PFS (P=0.036; HR =4.086), LRRFS (P=0.026; HR =5.064), and DMFS (P=0.011; HR =6.367). Major nerve involvement was significantly correlated with PFS (P=0.034; HR =2.394) and DMFS (P=0.008; HR =2.115). The interval from surgery to radiotherapy predicted PFS (P=0.036; HR =3.934) and DMFS (P=0.012; HR =6.231). Adenoid cystic carcinoma (ACC) was the most common histology (n=21; 35%). For ACC, the 5-year OS, PFS, LRRFS, and DMFS were 100%, 67.7%, 76.2%, and 90.2%, respectively. The most common acute toxicities were mucositis and dermatitis, and xerostomia was the most common late adverse event. Lung metastasis was the most common pattern of distant failure.

CONCLUSIONS

N stage, positive margin, major nerve involvement, and interval from surgery to radiotherapy were important factors associated with PFS, LRRFS, and DMFS. Postoperative IMRT leads to improved survival for SGC patients, with acceptable toxicities.

The rate of occult nodal metastasis in submandibular gland malignancies: A case series and meta-analysis

OBJECTIVE

Submandibular gland (SMG) malignancies are exceedingly rare. Lymph node metastasis is one of the most important determinants of outcome in SMG malignancies. The aim of this study was to investigate the overall rate of occult neck nodal metastasis in SMG malignancies.

STUDY DESIGN

The study design is a meta-analysis of all studies on patients with a primary SMG malignancy, without evidence of neck nodal metastasis, who underwent an elective neck dissection (END). The search strategy identified 158 papers that appeared in print from January 1980 to July 2020. All eligible patients from the Tel-Aviv Medical Center were analyzed and consolidated into a case series. A total of 12 retrospective studies that included 306 suitable patients met inclusion criteria.

RESULTS

The risk for occult metastasis in primary SMG malignancies was 0.0% to 50.0%, with a fixed effect model of 19.52% (95% CI, 14.9%-24.5%). The analyzed studies included a wide range of pathologies. The most common malignancies were adenoid cystic carcinoma and mucoepidermoid carcinoma.

CONCLUSIONS

The overall rate of occult neck metastasis in SMG malignancies is relatively high, and an END should be the default intervention in these cases. An END is unwarranted in tumors judged clinically to be low stage and low grade.

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.

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.

Prognostic scoring models in parotid gland carcinoma

BACKGROUND

The aim was to identify prognostic factors and test three prognostic scoring models that predicted the risk of recurrence in patients with parotid gland carcinoma.

METHODS

All Danish patients with parotid gland carcinoma, treated with curative intent, from 1990 to 2015 (n = 726) were included. Potential prognostic factors were evaluated using Cox regression and competing risk analyses. The concordance of each prognostic model was estimated using Harrel's C index.

RESULTS

The study population consisted of 344 men and 382 women, with a median age of 63 years. Age above 60 years, high grade histology, T3/T4 tumor, regional lymph node metastases, and involved surgical margins were all associated with a significant reduction in recurrence-free survival. The prognostic model that agreed best with actual outcomes had a C-index of 0.76.

CONCLUSION

Prognostic scoring models may improve individualized follow-up strategies after curatively intended treatment for patients with parotid gland carcinoma.

Surgical treatment of the neck in patients with salivary gland carcinoma

BACKGROUND

Elective neck dissection (END) in patients with salivary gland carcinoma is controversial and there are no universally accepted guidelines.

METHODS

Patients were identified from the Danish Head and Neck Cancer Group. Between 2006 and 2015, 259 patients with primary salivary gland carcinoma were treated with END. Variables potentially associated with regional metastases were analyzed using logistic regression. Neck recurrence-free survival was calculated using the Kaplan-Meier method.

RESULTS

Occult metastases were found in 36 of the patients treated with END (14%) and were particularly frequent among patients with T3/T4 tumors and high-grade histology tumors. In multivariate analyses, high-grade histology and vascular invasion were associated with occult metastases.

CONCLUSION

We recommend END of levels II and III for patients with high-grade or unknown histological grade tumors, and for T3/T4 tumors. Levels I, II, and III should be included in END in patients with submandibular, sublingual, or minor salivary gland carcinomas.

The impact of nodal status in major salivary gland carcinoma: A multicenter experience and proposal of a novel N-classification

OBJECTIVES

Despite differences in oncological behavior, the 8th edition of AJCC TNM staging currently proposes the same N-classification for major salivary glands (MSG) carcinoma and squamous cell carcinoma of the upper aerodigestive tract. The present study aims to investigate a more reliable definition of N-categories for MSG carcinoma.

MATERIALS AND METHODS

A retrospective multicenter study was performed, including 307 patients treated for primary MSG carcinoma from 1995 to 2019. Outcome measures included overall survival (OS), disease specific survival, and local, regional, and distant recurrence. Survival analysis was performed using log-rank test and Cox proportional-hazards model. Overall number (ON) and largest diameter (LD) of nodal metastases, including intra-parotid metastases, were considered to develop three novel proposals of N-classification; their performance were compared with the current TNM staging using Akaike information criterion (AIC), Bayesian information criterion (BIC), and Nagelkerke pseudo-R2.

RESULTS

Intra-parotid nodes, ON and LD of nodal metastases emerged as major prognosticators for OS, while extra-nodal extension did not impact on any survival. The current N-classification did not show a satisfactory OS stratification. Three novel N-classifications were developed according to number of metastatic nodes (0 vs 1-3 vs ≥ 4) and/or their maximum diameter (<20 mm vs ≥ 20 mm). They all showed better accuracy in OS stratification, and achieved better AIC, BIC and Nagelkerke pseudo-R2 indices when compared to current N-classification.

CONCLUSION

All the proposed N-classifications improved OS stratification and could help in defining a specific N-classification for MSG carcinoma. Their validation and assessment in an external cohort is needed.

Rate of Occult Neck Nodal Metastasis in Parotid Cancer: A Meta-Analysis

BACKGROUND

The risk for occult neck nodal metastasis in carcinoma of the parotid gland is inconclusive. Therefore, addressing a negative neck prophylactically and the extent to do so remain controversial. This systematic review aimed to determine the rate of occult nodal metastasis for each neck level, and consequently, to elucidate the proper extent of elective neck dissection (END).

METHODS

A meta-analysis of all studies that included patients with a diagnosis of parotid malignancies who underwent an END was performed. The risk for occult nodal metastasis was calculated for each neck level separately.

RESULTS

The search strategy identified 124 papers from January 1980 to December 2019 in the various databases. Nine retrospective studies (n =548) met the inclusion criteria. The risk for occult neck nodal metastasis ranged from 0.0 to 9.43% with a random-effect model of 2.2% for level 1 (n =459), from 3.4 to 28.38% with a random-effect model of 16.51% for level 2 (n =548), from 0.0 to 21.63% with a random-effect model of 4.23% for level 3 (n =518), from 0.0 to 17.02% with a fixed-effect model of 0.39% for level 4 (n =310), and from 0.0 to 11.63% with a fixed-effect model of 1.7% for level 5 (n =417).

CONCLUSION

The rate of occult neck nodal metastasis in parotid malignancies is low, with neck level 2 the most commonly involved. The results of this meta-analysis prevented the authors from substantiating the appropriate extent of an END in parotid cancer.

Does neck dissection affect post-operative outcomes in parotidectomy? A national study

OBJECTIVE

To characterize post-operative complications in parotidectomy with neck dissection.

METHODS

Patients age ≥ 18 receiving a parotidectomy or parotidectomy with neck dissection between 2005 and 2017 were eligible for inclusion. Patients with unknown demographic variables were excluded. Univariate and multivariable logistic regression analyses were performed.

RESULTS

A total of 13,609 parotidectomy patients were analyzed, 11,243 (82.6%) without neck dissection and 2366 (17.4%) with neck dissection. Both length of surgery (mean minutes ± standard deviation [SD] = 335.9 ± 189.2 vs. 152.9 ± 99.0, p < 0.001) and length of hospital stay (mean days ± SD = 3.90 ± 4.76 vs. 1.04 ± 2.14, p < 0.001) were greater with dissection. 13.9% of parotidectomies with neck dissection and 3.5% without dissection (p < 0.001) had at least one complication, which remained significant after multivariable adjustment (Odds Ratio[OR] = 1.565 (95%CI = 1.279-1.914), p < 0.001). The increase in post-operative complications was predominately driven by an increased transfusion rate (7.4% vs. 0.5%, p < 0.001). Multivariable analysis also demonstrated no significant difference in rates of returning to the operating room (OR = 1.122 (95%CI 0.843-1.493), p > 0.05) or rates of readmission (OR = 1.007 (95%CI 0.740-1.369), p > 0.05). Parotidectomy with neck dissection was more likely to be inpatient (OR = 4.411 (95%CI 3.887-5.004), p < 0.001) and to be ASA class 3 (OR = 1.367 (95%CI 1.194-1.564), p < 0.001).

CONCLUSIONS

Nationwide data demonstrates that parotidectomy with neck dissection is associated with increased rates of post-operative complications; however, neck dissection did not significantly impact readmission or reoperation rates. These findings indicate that neck dissection is a relatively safe addition to parotidectomy and provide novel evidence in the management of parotid malignancies.

Elective neck dissection in patients with salivary gland carcinoma: A systematic review and meta-analysis

OBJECTIVE

Elective neck dissection in patients with salivary gland carcinoma and clinically negative lymph nodes is controversial. Reported proportion of occult nodal metastases vary with histological subtype, tumour classification and preoperative diagnostic methods. This is a systematic review and meta-analysis on the role of END in salivary gland carcinoma.

METHODS

A search in PubMed, Embase and Cochrane was performed. Original articles in English with data on tumour characteristics, clinical and pathological N-classification, and neck dissection were included. Reporting Items for Systematic Reviews and Meta-analyses were followed. Random effect modelling was performed to pool the data. Meta-analysis of proportions was performed for occult metastases overall, for T3/T4 versus T1/T2 tumours and for tumours with high-grade versus low-grade histology. Heterogeneity across studies was assessed with I-squared statistics.

RESULTS

We included 22 articles in the qualitative synthesis and meta-analysis. The pooled proportion of occult metastases was 21%. In patients with T3/T4 tumour, the pooled proportion of occult metastases was 36%, and in patients with high-grade histology, it was 34%. Most studies concluded that END should be performed in patients with advanced T-classification and high-grade histology tumours. Nine studies assessed occult metastases per level.

CONCLUSION

The overall occult metastases proportion does not require END in all patients with salivary gland carcinoma. We recommend END in patients with high-grade or unknown histology or T3/T4 tumours. END should involve level II and III, and level I should be included in tumours in the submandibular gland, sublingual gland and minor oral salivary glands.

Submandibular gland cancers: prognostic factors and survival analysis

PURPOSE

The aim of this study is to evaluate prognosis and prognostic factors affecting oncological outcome.

METHODS

Records of the subjects managed for a submandibular gland cancer (SGC) between January 1997 and June 2014 were retrospectively reviewed. Survival outcomes were analyzed. All subjects had a minimum follow up of 5 years or until death.

RESULTS

Of 24 subjects (13 male, 11 female), 16 (64.6%) were adenoid cystic carcinoma (ACC). Eight patients had clinically positive neck nodes and 2 of the 16 clinically negative necks were also positive histologically. None of the subjects had distant metastases at presentation. The Kaplan-Meier 5-year estimated locoregional control (LRC), distant metastasis free survival (DMFS), disease free survival (DFS) and overall survival (OS) were 62.5%, 83.3%, 58.3% and 66.7%, respectively. American Joint Committee on Cancer (AJCC) overall stage and extra glandular extension (EGE) proved to be significant predictors of LRC. Only smoking was found to be a significant factor related with lower DMFS and only EGE significantly lowered DFS. Positive nodal stage and positive surgical margin were proved to be significant predictors of OS.

CONCLUSION

Surgery alone is effective in subjects with early stage, noninvasive and low-grade cancers. Despite aggressive treatment, locoregional recurrence was common in subjects who were at advanced stage.

Risk factors for survival and distant metastasis in 125 patients with head and neck adenoid cystic carcinoma undergoing primary surgery

PURPOSE

Adenoid cystic carcinoma (AdCC) is generally slow growing but has highly metastatic potential to distant organs. Several factors and biomarkers are associated with metastasis and treatment outcomes, although further definition is needed. Therefore, this study aimed to evaluate the risk factors for survival and distant metastasis in patients with head and neck AdCC.

METHODS

This study included 125 patients with previously untreated AdCC who underwent primary surgery with or without radiotherapy in our tertiary referral centre. Univariate and multivariate Cox proportional hazard regression analyses were used to identify risk factors associated with overall survival (OS), cause-specific survival (CSS), disease-free survival (DFS), and distant metastasis-free survival (DMFS). Factors associated with OS in patients with distant metastasis were separately analysed.

RESULTS

During a median follow-up of 9.8 years (range 3.0-22.6 years), 58 patients (46.4%) had distant metastasis and 29 (23.2%) died of disease. Multivariate analyses showed that lymphovascular invasion, lymph node metastasis, and distant metastasis were independent factors of OS and CSS outcomes (all P < 0.05). The T classification and extranodal extension were independent factors of DFS and DMFS outcomes (P < 0.05). After patients presented with distant metastasis, the median survival was 5.8 years. Multivariate analyses showed that extranodal extension and regional recurrence were independent factors of survival after occurrence of distant metastasis (P < 0.05).

CONCLUSION

Several clinicopathological factors can predict distant metastasis and survival of patients with AdCC treated with primary surgery. This may promote post-treatment surveillance in patients with AdCC.

Positive lymph node number and extranodal extension for predicting recurrence and survival in patients with salivary gland cancer

BACKGROUND

This study compared our proposed N classification including the addition of the number of positive lymph node (LN+) and extranodal extension (ENE) with the current and previous American Joint Committee on Cancer (AJCC) N classifications in salivary gland cancer (SGC).

METHODS

This study involved 172 SGC patients who underwent surgery. Cox proportional hazard regression analyses were used to identify factors associated with overall survival (OS) and disease-free survival (DFS).

RESULTS

In multivariate analyses, LN+ number, LN ratio, and ENE were associated with OS and DFS outcomes (all P < .05). Our new N classification proposed three categories: N0 (0 LN+), N1 (1 LN+), and N2 (≥2 LN+ or ENE). The C-index of our N classification showed improvement in OS prediction (0.768) compared with the AJCC seventh (0.743) and eighth (0.756) edition N classifications.

CONCLUSIONS

Our proposed N classification incorporating LN+ number and ENE may improve prediction of post-treatment survival and recurrence in patients with SGC.

Predictors of survival and recurrence after primary surgery for cervical metastasis of unknown primary

PURPOSE

Cervical metastasis from unknown primary (CUP) is commonly classified as an advanced overall stage. P16 or human papillomavirus (HPV) positivity in metastatic lymph nodes (LN) might be associated with a favorable survival outcome of CUP. Therefore, we evaluated the prognostic values of p16 immuno-positivity in LN and other clinicopathological factors in patients with squamous cell carcinoma CUP (SCCUP).

METHODS

This study involved 83 patients who underwent therapeutic neck dissection and panendoscopic examination and biopsy for suspected CUP. P16 immunostaining and HPV typing in LN were performed in 56 patients. Cox proportional hazard regression analyses were used to identify factors associated with overall survival (OS) and disease-free survival (DFS).

RESULTS

Postoperatively, primary tumors (PT) were found in 32 (38.6%) patients, mainly (90.6%) in the oropharynx, and not found in 51 (61.4%) patients. The clinicopathological data (except for histological grade) and 5-year OS and DFS rates did not significantly differ between patients with and without PT identification (all P > 0.05). P16 positivity was associated with favorable OS and DFS outcomes in the patients with PT (P < 0.05) but not in those without PT (P > 0.1). Multivariate analyses showed that age (> 60 years) and LN ratio (≥ 0.1) were the independent predictors of OS and DFS outcomes (all P < 0.05). P16 positivity or other factors were not independent factors.

CONCLUSION

Age and LN ratio are significant risk factors of survival and recurrence after primary surgery for SCCUP. Prognostic significance of LN p16 positivity should be further studied.

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.

Anatomic extent of lymph node metastases as an independent prognosticator in node-positive major salivary gland carcinoma: A study of the US SEER database and a Chinese multicenter cohort

BACKGROUND

We aimed to explore whether the anatomic extent of lymph node metastases (AE-LNM) could independently predict prognosis of node-positive major salivary gland carcinoma (MaSGC).

METHODS

A total of 376 pathologically node-positive MaSGC patients were identified from the Surveillance, Epidemiology and End Results database and constituted the training cohort. Using the X-Tile program, these patients were divided into three groups based on AE-LNM degrees. Discrimination of overall survival (OS) and disease-specific survival (DSS) was evaluated and compared with the 8th American Joint Committee on Cancer (AJCC) pN classification. The results were externally validated by 220 patients in a Chinese multicenter cohort (Validation cohort).

RESULTS

Using the training cohort, AE-LNM was divided into Extent 1 (spread to parotid LNs or level I), Extent 2 (spread to level II-IV) and Extent 3 (spread to level V or bilateral LNs or rare LNs). Regarding both OS and DSS, the AE-LNM model revealed clear separation of survival curves, while the pN classification failed to discriminate the prognosis of pN1 and pN2 patients. When we incorporated both the AE-LNM model and AJCC pN classification into the same multivariate Cox analyses, AE-LNM was still an independent prognostic factor, while the AJCC pN classification lost its significance. These results were externally validated by the validation cohort.

CONCLUSION

AE-LNM is an independent nodal prognosticator for node-positive MaSGC and may have improved discriminative ability over the current AJCC pN classification. Integration of anatomic extent of LNM into the current AJCC N classification could be considered.

Oncological outcomes of parotid gland malignancies: a retrospective analysis of 74 patients

INTRODUCTION

Salivary gland malignancies are rare neoplasms whose management has been evolving over the last two decades. Nevertheless, patient outcomes have not improved accordingly.

OBJECTIVE

In the present paper, factors and variables that could influence Overall, Disease-Specific and Disease-Free Survival, and Loco-Regional Control were analyzed.

METHODS

Chart data from 74 patients who underwent parotid gland surgery were retrospectively analyzed and stratified for tumor histology, grading, size, pT stage, pN stage, extracapsular spread, involved salivary gland lobe, and age at diagnosis. Major outcomes were estimated at 5 years by Kaplan-Meier curves.

RESULTS

Advanced stage, high grade, and lymph nodes involvement greatly impaired patient outcomes. Furthermore, in our cohort, the age at diagnosis ≥ 55 was a cause of poorer disease survival likely due to a different distribution in tumor histotypes between older and younger patients. Despite the two groups were homogeneous for the numerosity of squamous cell carcinomas, older patients were more rarely affected by mucoepidermoid and acinic cell carcinomas, which have generally better prognosis. Finally, patients aged ≥ 55 had a more frequent pathological involvement of the deep lobe of the parotid gland if compared to the younger counterpart.

CONCLUSION

The rarity of some salivary gland tumor histotypes requires further high-number series to fully understand the prognostic factors for both patient survival and recurrence development. In our cohort, the age at diagnosis ≥ 55 raises concerns that play crucial roles in disease survival shortening.

AHNS series: Do you know your guidelines? Diagnosis and management of salivary gland tumors

This article is the next installment of the series "Do you know your guidelines" presented by the Education Committee of the American Head and Neck Society. Guidelines for the workup and management of tumors of the major and minor salivary glands are reviewed.

The limited role of elective neck dissection in patients with cN0 salivary gland carcinoma

PURPOSE

To evaluate whether elective neck dissection (END) was beneficial for cN0 patients with salivary gland carcinoma.

MATERIALS AND METHODS

The rates of regional failure-free survival and disease-free survival were calculated using Kaplan-Meier methods and Cox models. The risk factors for occult lymph node metastasis (OLNM) in cN0 patients undergoing END was analyzed using logistic regression. A nomogram was formulated to calculate the estimated probability of OLNM.

RESULTS

Neck dissection was performed in 84 patients (43.3%). OLNM was detected in eight of the patients who underwent END. During the follow-up period, regional recurrences involving cervical lymph nodes were found in 10 patients. Cox model analysis revealed that neck dissection was not related to regional failure-free survival and disease-free survival. Logistic regression analysis revealed that older age, neural symptoms, and positive adjacent lymph nodes were associated with OLNM. A nomogram comprising age, neural symptoms, and adjacent lymph nodes was developed to predict the risk of OLNM.

CONCLUSION

The incidence of OLNM was low in cN0 patients after detailed preoperative evaluations. There was no strong evidence supporting END as a conventional therapy in cN0 patients with salivary cancers. Our nomogram is a simple and practical instrument for strengthening the prediction of OLNM.

Development of a novel salivary gland cancer lymph node staging system

BACKGROUND

Current lymph node (LN) staging for salivary gland cancer (SGC) is extrapolated from mucosal head and neck squamous cell carcinoma. However, given its unique biology and clinical behavior, it is possible that a SGC-specific LN staging system would be more accurate.

METHODS

Patients from the National Cancer Data Base with nonmetastatic SGC of the head and neck who were diagnosed from 2004 through 2013 and underwent surgical resection and neck dissection removing at least 10 LNs were included. Multivariable models were constructed to assess the association between survival and LN factors, including number of metastatic LNs, extranodal extension, LN size, and lower LN involvement.

RESULTS

Overall, 4520 patients met the inclusion criteria. An increasing number of metastatic LNs was found to be strongly associated with worse survival without plateau. The risk of death increased more rapidly up to 4 LNs (hazard ratio, 1.34; 95% confidence interval, 1.27-1.41 [P < .001]), and was more gradual for additional LNs >4 (hazard ratio, 1.02; 95% confidence interval, 1.01-1.03 [P < .001]). LN size, extranodal extension, and lower LN involvement appeared to have no impact on survival when accounting for the number of metastatic LNs. Recursive partitioning analysis was used to create a novel SGC LN staging system in which N0 indicates 0 positive LNs, N1 indicates 1 to 2 positive LNs, N2 indicates 3 to 21 positive LNs, and N3 indicates ≥ 22 positive LNs. This system exhibited greater concordance than the current American Joint Committee on Cancer (eighth edition) system.

CONCLUSIONS

Quantitative LN burden is an important determinant of survival in patients with SGC. Use of this variable may improve SGC staging. Cancer 2018. © 2018 American Cancer Society.

Neck dissection for salivary gland malignancies

Salivary gland carcinomas are diverse, and their biological behavior and surgical management are also variable and somewhat controversial. Cervical lymph node status is an important prognostic variable for salivary gland malignancies. Neck dissection should be undertaken if there is clinical or radiographic evidence of associated nodal metastasis in the neck. However, indications for elective neck dissections in a clinically N0 neck remains a controversial topic. This article describes indications for elective neck dissection in salivary gland malignancies, provides a detailed review of the neck dissection technique, and discusses postoperative management of these patients.

Contemporary Management of Benign and Malignant Parotid Tumors

To report the standard of care, interesting new findings and controversies about the treatment of parotid tumors. Relevant and actual studies were searched in PubMed and reviewed for diagnostics, treatment and outcome of both benign and malignant tumors. Prospective trials are lacking due to rarity of the disease and high variety of tumor subtypes. The establishment of reliable non-invasive diagnostics tools for the differentiation between benign and malignant tumors is desirable. Prospective studies clarifying the association between different surgical techniques for benign parotid tumors and morbidity are needed. The role of adjuvant or definitive radiotherapy in securing loco-regional control and improving survival in malignant disease is established. Prospective clinical trials addressing the role of chemotherapy/molecular targeted therapy for parotid cancer are needed. An international consensus on the classification of parotid surgery techniques would facilitate the comparison of different trials. Such efforts should lead into a clinical guideline.

Current State of Knowledge on Salivary Gland Cancers

Salivary gland cancers (SGCs), categorized as head and neck cancers (HNCs), constitute about 6% of head and neck cancer diagnoses based on estimate by American Head and Neck Society. Salivary gland tumors originate from different glandular cell types and are thus morphologically diverse. These tumors arise from any of the three major and various minor salivary glands. The incidence of SGCs has slowly increased during the last four decades. The etiology of SGCs is mostly unknown; however, specific gene mutations are associated with certain types of salivary tumors. Treatment options include surgical resection, radiation therapy (RT), chemotherapy, and multimodality therapy. HNC patients treated with RT often develop xerostomia and salivary hypofunction due to damaged salivary glands. In this review, we discuss etiology of SGCs, present findings on the role of autophagy in salivary tumorigenesis, review adverse effects of radiation treatment, and examine remedies for restoration of salivary function.

Submandibular gland cancer: Specific features and treatment considerations

BACKGROUND

In the absence of unified treatment protocol, we evaluated the management and outcomes of submandibular gland cancers in an unselected patient series.

METHODS

We included all patients with resected submandibular gland cancer treated at the Helsinki University Hospital from 2000 to 2010 with a 5-year minimum follow-up.

RESULTS

Twenty-five patients with cancer represented 30% of submandibular gland neoplasms, and most were adenoid cystic carcinomas (ACCs; 56%). At presentation, 3 patients showed clinical signs of probable malignancy. Of 22 neck dissection specimens, 5 patients (20%) had metastases with an occult metastasis rate of 4%. Cancer recurred in 11 patients (44%), of which 7 (28%) were only at a distant site. The 5-year disease-specific survival (DSS) and overall survival (OS) rates were 76%, and disease-free survival (DFS) was 68%.

CONCLUSION

Most tumors were ACCs differing from the histological pattern of parotid gland cancers. Occult metastases were rare. The rarity of submandibular gland cancer, its variable histological pattern, and varying biological behavior warrant centralized management.

Multidisciplinary Management of Salivary Gland Cancers

BACKGROUND

Salivary carcinomas are a rare group of biologically diverse neoplasms affecting the head and neck. The wide array of different histological entities and clinical presentations has historically limited attempts to establish well-defined treatment algorithms. In general, low-risk lesions can be managed with a single treatment modality, whereas advanced lesions require a more complex, multidisciplinary approach.

METHODS

The relevant literature was reviewed, focusing on diagnostic and treatment algorithms for salivary malignancies.

RESULTS

Salivary carcinomas with high-risk features require an aggressive treatment approach with complete surgical resection, neck dissection to appropriate cervical lymph-node basins, and postoperative radiotherapy.

CONCLUSIONS

The heterogeneity of salivary neoplasms represents a unique clinical challenge. Despite the multidisciplinary management paradigm detailed in this review, outcomes for advanced disease are unsatisfactory. Future progress will likely require the addition of novel systemic therapeutic strategies.

Surgical treatment of salivary malignant tumors

Salivary gland malignant tumors (SGMT) are of key interest for head and neck surgeons since surgery with adjuvant radiotherapy is considered the treatment of choice in most of the cases. Some factors, namely rarity, high histologic heterogeneity, and possible occurrence in all the head and neck subsites, contribute to make this topic very controversial; some unclear aspects pertain surgical treatment. When dealing with major salivary gland malignant tumors (MaSGMT), the most debated issues remain the extent of surgery and management of facial nerve. In minor salivary gland malignant tumors (MiSGMT), conversely, surgical planning is influenced by the specific pattern of growth of the different neoplasms as well as the site of origin of the lesion. Finally, two additional issues, the treatment of the neck (therapeutic or elective) and reconstructive strategy after ablative surgery, are of pivotal importance in management of both MaSGMT and MiSGMT. In this review, we discuss the most relevant and controversial issues concerning surgery of SGMT.

Cervical lymph node metastasis in adenoid cystic carcinoma of oral cavity and oropharynx: A collective international review

The purpose of this study was to suggest general guidelines in the management of the N0 neck of oral cavity and oropharyngeal adenoid cystic carcinoma (AdCC) in order to improve the survival of these patients and/or reduce the risk of neck recurrences. The incidence of cervical node metastasis at diagnosis of head and neck AdCC is variable, and ranges between 3% and 16%. Metastasis to the cervical lymph nodes of intraoral and oropharyngeal AdCC varies from 2% to 43%, with the lower rates pertaining to palatal AdCC and the higher rates to base of the tongue. Neck node recurrence may happen after treatment in 0-14% of AdCC, is highly dependent on the extent of the treatment and is very rare in patients who have been treated with therapeutic or elective neck dissections, or elective neck irradiation. Lymph node involvement with or without extracapsular extension in AdCC has been shown in most reports to be independently associated with decreased overall and cause-specific survival, probably because lymph node involvement is a risk factor for subsequent distant metastasis. The overall rate of occult neck metastasis in patients with head and neck AdCC ranges from 15% to 44%, but occult neck metastasis from oral cavity and/or oropharynx seems to occur more frequently than from other locations, such as the sinonasal tract and major salivary glands. Nevertheless, the benefit of elective neck dissection (END) in AdCC is not comparable to that of squamous cell carcinoma, because the main cause of failure is not related to neck or local recurrence, but rather, to distant failure. Therefore, END should be considered in patients with a cN0 neck with AdCC in some high risk oral and oropharyngeal locations when postoperative RT is not planned, or the rare AdCC-high grade transformation.