Submandibular gland cancer: Specific features and treatment considerations

Lymph node surgery for salivary gland cancer: REFCOR recommendations by the formal consensus method

OBJECTIVE

To determine the indications for neck dissection in the management of parotid, submandibular or minor salivary gland cancers depending on the clinical situation: i.e., clinical lymph node involvement (cN+) or not (cN0); low or high risk of occult nodal metastasis; diagnosis of malignancy before, during or after surgery.

MATERIAL AND METHODS

The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group which drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group according to the formal consensus method.

RESULTS

In cN+ salivary gland cancer, ipsilateral neck dissection is recommended. In cN0 salivary gland cancer, ipsilateral neck dissection is recommended, except for tumors at low risk of occult nodal metastasis. If definitive pathology reveals a high risk of occult nodal involvement, additional neck treatment is recommended: ipsilateral neck dissection or elective nodal irradiation.

CONCLUSION

The rate of occult lymph node involvement, and therefore the indication for elective neck dissection, depends primarily on the pathologic grade of the salivary gland cancer.

Recurrence after primary salivary gland carcinoma: Frequency, survival, and risk factors

BACKGROUND

Primary salivary gland carcinomas (SGC) are rare neoplasms that present therapeutic challenges especially in recurrent tumors. The aim of this study was to investigate the incidence and distribution of tumor recurrence, associated risk factors, and survival.

METHODS

This analysis includes data from 318 patients treated for SGC between 1992 and 2020. Survival analysis was performed using the Kaplan-Meier method. Univariate and multivariate analyses were used to identify risk factors associated with recurrence.

RESULTS

21.7% of the patients developed recurrent disease after a mean of 38.2 months. In multivariate analysis, positive-resection margins, vascular invasion, and tumor localization in the submandibular gland and small salivary glands were independent factors for recurrence. The 5-year overall survival was 67%, the 5-year disease-free survival was 54%.

CONCLUSION

Tumor recurrence in SGC occurred in one out of five patients. In highly aggressive entities and patients with risk factors, treatment intensification should be considered.

Surgery of major salivary gland cancers: REFCOR recommendations by the formal consensus method

OBJECTIVE

To determine the role of surgery of the primary tumor site in the management of primary major salivary gland cancer.

MATERIAL AND METHODS

The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group, which drafted a non-systematic narrative review of the literature published on Medline, and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group, according to the formal consensus method.

RESULTS

Treatment of salivary gland tumor is mainly surgical. The gold standard for parotid cancer is a total parotidectomy, to obtain clear margins and remove all intraparotid lymph nodes. For low-grade tumors, partial parotidectomy with wide excision of the tumor is acceptable in the case of postoperative diagnosis on definitive histology. In the event of positive margins on definitive analysis, revision surgery should be assessed for feasibility, and performed if possible.

CONCLUSION

Treatment of primary major salivary gland cancer is based on surgery with clear resection margins, as far away as possible from the tumor. The type of surgery depends on tumor location, pathologic type and extension.

Occult Nodal Metastases in Individuals with Clinically Node-Negative Salivary Gland Malignancies

OBJECTIVES

Salivary gland malignancies comprise a heterogeneous group of pathologies, for which treatment of the clinically negative neck may vary depending on numerous factors. Herein we present data on occult nodal metastases (ONM) as well as survival and recurrence from a large series of cN0 salivary gland malignancies.

METHODS

Retrospective chart review was conducted on 532 patients, with 389 patients with major salivary gland cancers and 143 patients with minor salivary gland cancers. Demographic and treatment data were included and rates of ONM, overall survival, local recurrence, regional recurrence, and distant recurrence were analyzed.

RESULTS

We found that the overall rate of ONM for parotid was 27% (63/235), for submandibular/sublingual was 35% (18/52), and for minor was 15% (4/26). Analysis of ONM rate at each nodal level was also performed, finding higher rates of level IV and V ONM than prior studies. Submandibular/sublingual and minor salivary gland malignancies showed a predominance of ONMs at levels I-III. Our survival and recurrence rates were similar to those found in previous studies.

CONCLUSION

Our data also demonstrate a predominance of ONM in levels I-III for submandibular/sublingual and minor salivary gland cancers, suggesting elective dissection in these levels.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1705-1715, 2024.

Radical Resection of Malignant Tumors of Major Salivary Glands: Is This Possible?

In primary therapy, a universally recognized surgical indication applies to all tumors of the salivary glands. According to the classic rule, radical resection of a head and neck tumor requires clean margins of at least 5 mm, although recent studies have shown that for certain locations, 1 mm may be sufficient. In the surgical resection of a tumor of the salivary glands, especially of the parotid gland, can these rules be respected? Owing to the complex branching and connections of the facial nerve within the parotid gland, even a medium-sized malignant tumor may be in contact with a branch of the nerve, thus raising the question of its preservation. The facial nerve is so important from a functional and aesthetic point of view that it is commonly believed that it should be preserved unless it is incorporated into the tumor. This is a compromise between an oncological resection, that is, the complete excision of the tumor with no residual cancer cells left behind, and quality of life. Almost all authors try to overcome this lack of radicality by indicating postoperative (chemo)radiotherapy. In this article, the pros and cons of nerve preservation will be analyzed by examining the published studies on this topic.

Number and ratio of metastatic lymph nodes impacts the prognosis of submandibular gland cancer

This study aimed to assess the impact of the number and ratio of metastatic lymph nodes (LNs) on prognosis in submandibular gland cancer. To this end, patients were selected from the Surveillance, Epidemiology, and End Results database retrospectively. The effect of the number and ratio of metastatic LNs and the American Joint Committee on Cancer (AJCC) N stage on disease-specific survival (DSS) and overall survival (OS) was analyzed. In addition, prognostic models based on LN evaluation methods were developed to predict the OS and DSS. A total of 914 patients were included. Binary recursive partitioning analysis determined the optimal cut-off number of metastatic LNs (0 vs. 1-2. vs. 3+). The presence of 3+ metastatic LNs carried the greatest impact on prognosis, followed by 1-2 positive LNs occurrences. The ratio of metastatic LNs was an independent factor for DSS and OS. The model had a higher likelihood ratio and C-index than those in the Cox model based on the AJCC N stage. Quantitative LN burden and ratio of metastatic LNs provides better survival stratification than the AJCC N stage.

Endoscope-Assisted Hairline Approach for Head and Neck Masses: A Review

Conventional surgery through a transcervical incision is indicated for the treatment of certain tumors in the head and neck. However, this method can cause multiple problems, including scarring and cosmetic concerns. The endoscope-assisted hairline approach, which serves as an alternative to conventional surgical procedures, is gaining popularity due to its excellent cosmetic and functional outcomes. However, given the anatomical complexity involved, the endoscope-assisted hairline technique is not frequently employed in head and neck surgery. The evolution of the hairline surgical approach has been influenced by changes in disease conditions and recent advances in surgical tools. This review article discusses the use of endoscope-assisted hairline approaches in the resection of head and neck masses, focusing on the surgical procedure and postoperative clinical outcomes.

Prognostic factors and treatment considerations of submandibular gland carcinomas: A population-based study

OBJECTIVES

The therapeutic regimen of submandibular gland carcinoma (SGC) has not reached consensus, especially for the neck treatment of patients with cN0.

MATERIALS AND METHODS

Patients with SGC were identified from the medical database of Shanghai Ninth People's Hospital. Kaplan-Meier analysis, univariate and multivariate Cox regression were employed to evaluate the survival and independent prognostic factors.

RESULTS

Two hundred and fifteen patients with SGC were retrospectively reviewed. The 5-year disease-free survival (DFS) and overall survival (OS) rates were 71.5% and 77.8%, respectively. Multivariate analysis revealed that histological grade, cT classification, cN classification, and perineural invasion (PNI) were independent prognostic factors for DFS, while histological grade, cT classification, cN classification, and age were those for OS. The neck dissection showed no significant survival benefit for patients with cN0. Lung was the most common site of distant metastasis (16.7%).

CONCLUSIONS

Histological grade, cT classification, cN classification, age, and PNI were independent prognostic factors of patient with SGC, which should be the main considerations for making therapeutic regimens. Our study also verifies the neck dissection of patient with cN0 is unnecessary, and postoperative radiotherapy (PORT) is vital for patients with pN+.

Incidence and spread pattern of lymph node metastasis from submandibular gland cancer

OBJECTIVES

To clarify the indication of neck dissection (ND) for patient with submandibular gland (SMG) cancer.

METHODS

A total of 43 patients with SMG cancer were retrospectively analyzed. Forty-one patients underwent ND: Levels I-V in 19 patients, Levels I-III in 18 patients, and Level Ib in 4 patients. The other two patients did not undergo ND, since preoperative diagnoses were benign. Postoperative radiotherapy was performed in 19 patients with positive surgical margin, high grade cancer or stage IV disease.

RESULTS

LN metastases were pathologically confirmed in all patients with cN + and 6 out of 31 patients with cN-. No patients developed regional recurrence during follow-up periods. Ultimately, LN metastases were pathologically confirmed in 17 of 27 high grade, one out of 9 intermediate grade, but not in 7 low grade.

CONCLUSIONS

Prophylactic neck dissection should be considered in T3/4 and high grade SMG cancers.

Epidemiology, outcomes, and prognostic factors in submandibular gland carcinomas: a national DAHANCA study

PURPOSE

The aim of this study is to present incidence, histological subtypes, survival rates, and prognostic factors based on a national cohort of patients with salivary gland carcinoma.

METHODS

All Danish patients with submandibular gland carcinoma diagnosed from 1990 to 2015 (n = 206) were included and analyzed following histological re-evaluation. Data were collected by the Danish Head and Neck Cancer Group (DAHANCA). Overall, disease-specific and recurrence-free survival were evaluated. Prognostic factors were analyzed with multivariate Cox Hazard Regression.

RESULTS

The study population consisted of 109 (53%) men and 97 (47%) women, median age 62 years (range 11-102). Adenoid cystic carcinoma was the most frequent subtype (50%). Tumour classification T1/T2 (75%) and N0 (78%) was most frequent. The mean crude incidence was 0.17/100,000/year. Most patients (n = 194, 94%) were treated with primary surgery, and 130 (67%) received postoperative radiotherapy. The 5- and 10-year survival rates were for overall survival 64% and 41%, disease-specific survival 74% and 61%, and recurrence-free survival 70% and 56%, respectively. Survival rates were higher for adenoid cystic carcinoma compared to other subtypes, but the difference was not significant in multivariate analysis. Recurrence occurred in 69 patients, and 37 (53.6%) of them had recurrence in a distant site. Advanced T-classification and regional lymph-node metastases had significant negative impact on survival rates.

CONCLUSION

The incidence of submandibular gland carcinoma in Denmark was 0.17/100,000/year and stable during the time period. The most frequent subtype was adenoid cystic carcinoma. Half of the recurrences presented in a distant site, and multivariate analysis confirmed that advanced stage was independent negative prognostic factor for recurrence and survival.

Lactobacillus for ribosome peptide editing cancer

This study reviews newly discovered insect peptide point mutations as new possible cancer research targets. To interpret newly discovered peptide point mutations in insects as new possible cancer research targets, we focused on the numerous peptide changes found in the 'CSP' family on the sex pheromone gland of the female silkworm moth Bombyx mori. We predict that the Bombyx peptide modifications will have a significant effect on cancer CUP (cancers of unknown primary) therapy and that bacterial peptide editing techniques, specifically Lactobacillus combined to CRISPR, will be used to regulate ribosomes and treat cancer in humans.

Sintilimab combined with chemotherapy successfully treated a patient with advanced submandibular gland tumor

Primary submandibular gland tumors are relatively rare. Due to its low incidence and broad spectrum phenotypic, biological and clinical heterogeneity types, a wide range of options have been developed to treat this tumor. To date, however, efficacious standard treatment regimens are lacking. Here, the authors present a case of a patient with an advanced submandibular gland tumor. Histological and imaging results diagnosed the case as stage IV submandibular gland adenocarcinoma with multiple metastases. The patient was subjected to systemic platinum-based chemotherapy combined with sintilimab. A primary lesion complete response was observed after six cycles of treatment. This case affirms the efficacy of the PD-1 inhibitor sintilimab combined with platinum-based chemotherapy as a first-line treatment for advanced submandibular gland tumors.

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.

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.

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.

Preoperative evaluation and treatment consideration of parotid gland tumors

BACKGROUND

The nature of parotid tumors often remains unknown preoperatively and final histopathology may reveal unexpected malignancy. Still, the use of fine-needle aspiration cytology (FNAC) and imaging varies in the management of these tumors.

METHODS

We evaluated the preoperative examinations and management of all 195 parotid gland tumors diagnosed within our catchment area of 1.6 million people during 2015.

RESULTS

Altogether 171 (88%) tumors were classified as true salivary gland neoplasms. FNAC showed no false malignant findings, but it was false benign in 5 (2.6%) cases. Preoperative MRI was utilized in 48 patients (25%). Twenty (10%) malignancies included 16 salivary gland carcinomas. Pleomorphic adenomas accounted for 52% of all adenomas. For 24 (40%) Warthin tumors, surgery was omitted.

CONCLUSION

The proportion of malignancies was lower than generally presented. Our proposed guidelines include ultrasound-guided FNAC with certain limitations. MRI is warranted in selected cases, but seems unnecessary routinely.

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.

Major and minor salivary gland tumours

Salivary glands carcinomas are very rare epithelial malignant tumors. In 2013 in Europe, 7800 new diagnoses were estimated, 8.5 % of all head and neck cancer. The last WHO classification (2017) counts more than 20 malignant histotypes, this variety as well as the rarity of some of them needs a skilled pathologist for diagnosis. Surgery remains the mainstay of management followed by radiation in high-grade and high-risk pathological features cases. The intensity modulated radiotherapy (IMRT) should be preferred over conformational radiotherapy techniques as adjuvant and exclusive treatment in advanced cases. Particle radiotherapy (i.e. protons, carbon ions) can have a role in advanced/unresectable disease since it was proved to have better results over photons in loco-regional control both in adenoid cystic carcinoma and in other histotypes. Although chemotherapy is still the most frequent treatment for metastatic patients, several new compounds (i.e. anti-angiogenic agents, tailored agents, checkpoint inhibitors) are under investigation.

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.

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.

Effects of patient-specific mobility therapy for TMJ, neck, and shoulder dysfunction after submandibular gland tumor surgery: a case report

Aims: This case report describes a patient-specific mobility therapy (PSMT) program to restore range of motion (ROM) and overcome functional limitations of the temporomandibular joint (TMJ), neck, and shoulder in a 48-year-old man who underwent submandibular gland tumor surgery.Methods: The patient also received transcutaneous electrical stimulation and ultrasound to relieve pain. Treatment was provided four sessions per week for four weeks. The measured outcomes included the Neck Disability Index (NDI), Patient-Specific Functional Scale (PSFS), and mobility of the TMJ, neck, and shoulder.Outcomes: The ROM of the TMJ, neck, and shoulder improved from 4.00 mm to 21.00 mm, 1.67 cm to 6.40 cm, and 9.75° to 56.00°, respectively, during the 1^st intervention phase when compared with the baseline phase, and these gains were also maintained in the later phases. Furthermore, the NDI and PSFS scores improved by 12.75 points (24.50 to 11.75) and 5.25 points (2.00 to 7.25), respectively.Conclusion: These findings demonstrate the success of PSMT in conjunction with transcutaneous electrical stimulation and ultrasound in alleviating pain and improving targeted impairments for this patient following submandibular gland tumor surgery.

Salivary Gland FNA Diagnostics in a Real-Life Setting: One-Year-Experiences of the Implementation of the Milan System in a Tertiary Care Center

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was introduced in 2018 following other organ specific cytopathological reporting systems and it aimed at bringing a practical, evidence-based, user-friendly classification system with characterization and management algorithms. At the Department of Pathology, Fimlab Laboratories, Tampere, Finland all salivary fine needle aspirations (FNAs) have been given cytopathological diagnoses according to the MSRSGC since January 2018. Analyses of a one-year-period (January 2018–December 2018) consisted of 183 salivary FNA samples from 138 patients with correlation to histopathology in 90 cases with surgical follow-up. The MSRSGC performance in patient based analysis was as follows: accuracy was 90.9%, sensitivity was 61.5%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 89.4%, respectively. Risks of malignancy (ROMs) in MSRSGC categories were: 0.0% (0/15) in non-diagnostic category, 100.0% (1/1) in non-neoplastic category biased by only one falsely-negative lymphoma case, 14.3% (1/7) in atypia of undetermined significance category, 0.0% (0/28) in benign neoplasm category, 27.3% (3/11) in neoplasm of uncertain malignant potential category, and 100% for both suspicious for malignancy (4/4) and malignancy (4/4) categories, respectively. The MSRSGC has been proven as a reliable classification system in salivary gland FNA routine diagnostics in a tertiary care center.

Lymph node ratio predictive of recurrence, distant metastasis, and survival in submandibular gland carcinoma patients

PURPOSE

Submandibular gland (SMG) carcinoma has an unfavorable clinical course and a low survival rate. Specific tumor and nodal findings might help predict posttreatment recurrence and survival in SMG carcinoma patients. This study evaluated factors predictive of posttreatment recurrence and survival in SMG carcinoma patients.

METHODS

This study enrolled 99 consecutive patients with previously untreated SMG carcinoma. All patients underwent tumor and metastatic lymph node resection along with or without radiation/chemo-radiation. The predictive clinical and pathological factors for disease-free survival (DFS), distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were determined using univariate and multivariate Cox proportional hazards regression analyses.

RESULTS

The median tumor size was 2.7 cm and 53 patients (53.5%) had high-grade tumors. The rates of initial nodal and distant metastasis at initial presentation or follow-up were 45.5% and 42.4%, respectively. The actuarial 5-year DFS, DMFS, DSS, and OS rates were 46.4%, 55.9%, 61.5%, and 59.7%, respectively. The independent factors associated with poor DFS, DMFS, DSS, and OS outcomes (all p < 0.05) were T3-T4 classification and lymph node ratio. A histological high-grade tumor was an independent prognostic factor predictive of poor DMFS, DSS, and OS outcomes (all p < 0.05).

CONCLUSIONS

A high rate of distant site failure is associated with SMG carcinoma, resulting in a poor survival rate. Lymph node ratio might help predict recurrence, distant metastasis, and death due to SMG carcinoma.

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.