A retrospective evaluation of submandibular gland involvement in oral cavity cancers: a case for gland preservation

Submandibular gland involvement in oral cavity squamous cell carcinoma: a retrospective multicenter study

BACKGROUND

The submandibular gland (SMG) is routinely excised during neck dissection. Given the importance of the SMG in saliva production, it is important to understand its involvement rate by cancer tissue and the feasibility of its preservation.

METHODS

Retrospective data were collected from five academic centers in Europe. The study involved adult patients affected by primary oral cavity carcinoma (OCC) undergoing tumor excision and neck dissection. The main outcome analyzed was the SMG involvement rate. A systematic review and a meta-analysis were also conducted to provide an updated synthesis of the topic.

RESULTS

A total of 642 patients were enrolled. The SMG involvement rate was 12/642 (1.9%; 95% CI 1.0-3.2) when considered per patient, and 12/852 (1.4%; 95% CI 0.6-2.1) when considered per gland. All the glands involved were ipsilateral to the tumor. Statistical analysis showed that predictive factors for gland invasion were: advanced pT status, advanced nodal involvement, presence of extracapsular spread and perivascular invasion. The involvement of level I lymph nodes was associated with gland invasion in 9 out of 12 cases. pN0 cases were correlated with a reduced risk of SMG involvement. The review of the literature and the meta-analysis confirmed the rare involvement of the SMG: on the 4458 patients and 5037 glands analyzed, the involvement rate was 1.8% (99% CI 1.1-2.7) and 1.6% (99% CI 1.0-2.4), respectively.

CONCLUSIONS

The incidence of SMG involvement in primary OCC is rare. Therefore, exploring gland preservation as an option in selected cases would be reasonable. Future prospective studies are needed to investigate the oncological safety and the real impact on quality of life of SMG preservation.

Cell-Free Therapies: The Use of Cell Extracts to Mitigate Irradiation-Injured Salivary Glands

Radiotherapy is a standard treatment for head and neck cancer patients worldwide. However, millions of patients who received radiotherapy consequently suffer from xerostomia because of irreversible damage to salivary glands (SGs) caused by irradiation (IR). Current treatments for IR-induced SG hypofunction only provide temporary symptom alleviation but do not repair the damaged SG, thus resulting in limited treatment efficacy. Therefore, there has recently been a growing interest in regenerative treatments, such as cell-free therapies. This review aims to summarize cell-free therapies for IR-induced SG, with a particular emphasis on utilizing diverse cell extract (CE) administrations. Cell extract is a group of heterogeneous mixtures containing multifunctional inter-cellular molecules. This review discusses the current knowledge of CE's components and efficacy. We propose optimal approaches to improve cell extract treatment from multiple perspectives (e.g., delivery routes, preparation methods, and other details regarding CE administration). In addition, the advantages and limitations of CE treatment are systematically discussed by comparing it to other cell-free (such as conditioned media and exosomes) and cell-based therapies. Although a comprehensive identification of the bioactive factors within CEs and their mechanisms of action have yet to be fully understood, we propose cell extract therapy as an effective, practical, user-friendly, and safe option to conventional therapies in IR-induced SG.

Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review

In patients with head and neck cancer, irradiation (IR)-sensitive salivary gland (SG) tissue is highly prone to damage during radiotherapy (RT). This leads to SG hypofunction and xerostomia. Xerostomia is defined as the subjective complaint of dry mouth, which can cause other symptoms and adversely affect the quality of life. In recent years, diagnostic techniques have constantly improved with the emergence of more reliable and valid questionnaires as well as more accurate equipment for saliva flow rate measurement and imaging methods. Preventive measures such as the antioxidant MitoTEMPO, botulinum toxin (BoNT), and growth factors have been successfully applied in animal experiments, resulting in positive outcomes. Interventions, such as the new delivery methods of pilocarpine, edible saliva substitutes, acupuncture and electrical stimulation, gene transfer, and stem cell transplantation, have shown potential to alleviate or restore xerostomia in patients. The review summarizes the existing and new diagnostic methods for xerostomia, along with current and potential strategies for reducing IR-induced damage to SG function. We also aim to provide guidance on the advantages and disadvantages of the diagnostic methods. Additionally, most prevention and treatment methods remain in the stage of animal experiments, suggesting a need for further clinical research, among which we believe that antioxidants, gene transfer, and stem cell transplantation have broad prospects.

Vascular clinical anatomy of the submandibular gland

OBJECTIVE

The aim of this study is to describe in depth the precise anatomy of the vascular supply of the submandibular gland, trying to determine the existence of patterns of glandular vascularization. Knowledge of these patterns could facilitate surgical management of the gland and the submandibular gland flap.

MATERIAL AND METHODS

Neck dissections of formaldehyde preserved human cadavers were performed. Submandibular and transmandibular approaches were used during the dissections. All the vascular branches found were registered and classified into 2groups: main or accessory branches. The anatomical data analyzed was: The diameter and length of the main and accessory branches, as well as the most important measurements of the submandibular gland flap pedicle.

RESULTS

33 glands were dissected to study the arterial supply of the submandibular gland (17 right, 16 left; 17 males, 16 females) and 29 were dissected to study the venous supply (15 left, 14 right; 15 males,14 females). A total of 123 arterial branches were found reaching the 33 submandibular glands (47 main and 76 accessories) and 116 venous branches were found draining the 29 submandibular glands (47 main branches and 69 accessory branches). A constant main venous branch that ran parallel to the Wharton duct and drained in the sublingual vein was found in all of cases (Concomitant Wharton Duct Vein or CWDV).

CONCLUSION

The CWDV is a constant venous branch for the drainage of the gland and should be considered as venous pedicle during the dissection of submandibular gland flaps.

Clinicopathological study of involvement of the submandibular gland in oral squamous cell carcinoma

Our purpose was to provide a pathological basis for preservation of the submandibular glands during neck dissection for oral squamous cell carcinoma (SCC) by investigating whether intraglandular lymph nodes exist in submandibular glands, and the modes of involvement of submandibular glands in oral SCC. We studied the records of 95 patients with oral SCC (other than that in the floor of the mouth) treated at our hospital from January 2017 to June 2018. The specimens of submandibular glands discarded after neck dissection were analysed, and serially sectioned. Sections 5μm thick were obtained at 0.5mm intervals and stained with haematoxylin and eosin for examination under light microscopy. A total of 116 specimens were obtained from the 95 patients, and about 5000 slides were evaluated. No intraglandular lymph nodes were detected in the submandibular glands. In the subgroup of patients whose primary tumours had extended into the floor of the mouth, four submandibular glands were involved by direct spread of the primary tumour. In the subgroup with metastases to level Ib lymph nodes, four submandibular glands were involved by extranodal extension from the metastatic nodes. No intraglandular lymph nodes or micrometastases were detected. We conclude that no intraglandular lymph nodes are present in submandibular glands, which may be involved by direct extension of the primary carcinoma or metastatic cervical lymph nodes with extranodal extension. Preservation of the submandibular glands during neck dissection seems to be feasible and safe in selected patients with oral SCC.

Involvement of the submandibular gland in oral squamous cell carcinoma patients with positive lymph nodes

BACKGROUND

No consensus exists about submandibular glands (SMGs) involvement in oral squamous cell carcinoma (OSCC) patients with cervical lymph node metastasis. We aimed to investigate the prevalence of SMG involvement in OSCC patients with positive lymph nodes.

METHODS

Retrospective analysis of data of 302 study subjects with positive lymph nodes in OSCC operated between January 2002 and December 2012.

RESULTS

Only 1/302 (0.3%) study subject had SMG involvement. The mode of spread was by direct extension of the primary carcinoma. Extracapsular spread of level IB lymph nodes was seen in 12/302 (4%) patients. Only one of these patients had involvement of the fibrous tissue around the SMG.

CONCLUSION

SMG involvement is very rare in OSCC patients with cervical lymph node metastasis. Preservation of the ipsilateral SMG during neck dissection might be oncologically safe when involvement by direct spread is unlikely.

The preservation and application of the submandibular gland in oral squamous cell carcinoma (STROBE)

This prospective study aimed to investigate metastases of oral squamous cell carcinoma (OSCC) to cervical lymph nodes and submandibular glands and to analyze the safety and feasibility of preserving and using submandibular glandular flaps to repair postoperative OSCC defects.Overall, 330 patients with OSCC who met the inclusion criteria were enrolled in the study from January 2014 to July 2018. OSCC metastasis to cervical lymph nodes and submandibular glands was investigated using intraoperative frozen section and postoperative pathological observation. Fifteen patients who underwent repair of postoperative OSCC defects with submandibular glandular flaps were monitored for postoperative wound healing, complications, pathology, and appearance satisfaction and were followed up long term.Among the 330 patients with OSCC, the most common type was tongue cancer (138/330); 204 patients were node negative and 126 were node positive. Of 363 samples of the submandibular gland, 7 were metastatic with stage IV lesion, 5 were directly invaded by the primary tumor, and 2 were metastatic with extranodal extension in level Ib. None of the submandibular gland samples showed intraglandular hematogenous and nodal metastases. The repair of OSCC defects with submandibular glandular flaps was successful in all 15 patients, including 11 males and 4 females, with an age range of 19-74 years and a mean of 51 years. Of 15 patients, some had complications with heart and cerebrovascular diseases, diabetes, or chronic respiratory disease. All the submandibular glandular flaps survived postoperatively without any complications, and the mucosification on the surface was adequate. Follow-ups (median duration: 14 months) revealed the satisfactory recovery of shape and function without any local recurrences or distant metastases.Direct invasion is the main form of OSCC metastasis to the submandibular gland, while hematogenous and nodal metastases are uncommon. Preservation of the submandibular gland is oncologically safe. Thus, repair of postoperative OSCC defects with submandibular gland flaps is a feasible and promising procedure.

Submandibular Gland Invasion by Oral Cavity Cancers: A Systematic Review

OBJECTIVE

The submandibular gland (SMG) is typically included in level I neck dissection specimens despite limited data demonstrating SMG invasion. The main objective of this article is to determine the rate and pathways of SMG invasion by squamous cell carcinoma of the oral cavity and oropharynx.

DATA SOURCES

A systematic review of relevant studies was performed, evaluating articles identified via the PubMed, Cochrane, and Medline databases.

REVIEW METHODS

Descriptive features of primary tumors, primary treatment modalities, the rate and pathway of SMG invasion, and survival outcomes, if present, were reported following the PRISMA guidelines.

RESULTS

The initial literature search yielded 273 articles, of which 17 met inclusion criteria. A total of 2306 patients with 2792 SMG resections were analyzed. Fifty-eight resections (2.0%) were revealed to have tumor involvement. Among patients with SMG tumor involvement, the most common invasion pathway was direct SMG invasion by primary tumor (43 of 58, 74.1%). The second-most common mode of SMG invasion was from involved adjacent lymph nodes (10 of 58, 17.2%). Only 3 SMG resections out of 2792 (0.1%) had isolated metastatic parenchyma without evidence of direct tumor invasion or invasion by involved lymph nodes.

CONCLUSION

Given this rarity of SMG involvement, preservation of SMG might be feasible in selected patient population. However, additional studies need to examine the functionality of preserved SMGs among patients who receive postoperative adjuvant radiation therapy.

Rate of Submandibular Gland Involvement in Oral Squamous Cell Carcinoma

PURPOSE

Whether the submandibular gland (SMG) can be preserved during neck dissection in the surgical treatment of oral squamous cell carcinoma (OSCC) is controversial. This study investigated the SMG involvement rate and provides a basis for preserving the SMG during neck dissection in appropriate cases of OSCC.

MATERIALS AND METHODS

A comprehensive systematic review was conducted on the PubMed and MEDLINE, Embase, and Cochrane Library databases for studies on SMG involvement in OSCC published before December 2017 with a data analysis technique. Predictor variables were numbers of patients and resected SMGs, primary site, and tumor, node, and metastasis stage. Outcome variables were the number of involved SMGs and mode of involvement. Other variables, namely first author, publication year, mean age, and condition of neck lymph nodes at level Ib, also were extracted. A random-effects model was used to analyze the rate of SMG involvement in OSCC.

RESULTS

Twelve studies involving 2,126 patients with OSCC who underwent neck dissection were included in the study. Fifty-two SMGs were involved, and the pooled involvement rate was 2% (I² = 73%; 95% confidence interval [CI], 1-3). Forty-eight SMGs were involved through direct spread from the primary site or extracapsular spread of positive lymph nodes, and the pooled involvement rate was 1.9% (I² = 72%; 95% CI, 0.9-3.1). Except for direct spread, 4 SMGs were involved through the intraglandular lymph node or carcinoma growing along Wharton ducts, and the pooled involvement rate was only 0.1% (I² = 0%; 95% CI, 0-0.2).

CONCLUSIONS

The rate of SMG involvement in OSCC is very low, and the most common mode of involvement is by direct spread. The SMG might be preserved during neck dissection in OSCC when it is unlikely to be involved through direct spread.

Oropharyngeal reconstruction with a pedicled submandibular gland flap

Locoregional flaps are widely used for reconstruction of small and medium defects in the oral cavity. The submandibular gland flap is a pedicled flap, which derives its blood supply from the facial artery, based on the submandibular gland. We describe the use of the flap in 20 patients who required oropharyngeal reconstruction with a pedicled submandibular gland flap after resection of a tumour between July 2012 and October 2014. Patients with squamous cell carcinoma were excluded. All flaps were pedicled on the facial vessels (inferiorly in 17 patients and superiorly in 3). The indications were: reconstruction of intraoral mucosal defects (n=13), filling the parapharyngeal dead space (n=6), and obliteration of the mastoid (n=1). All the flaps atrophied, but with no clinical effect. One patient developed partial loss of the flap, and one early leakage. There were no cases of xerostomia, and no signs of recurrence during the postoperative follow-up period of 3-26 months. The flap is useful, as it is simple and reliable for reconstruction of small to medium oropharyngeal defects in carefully selected cases, and gives good cosmetic and functional results.

Current philosophy in the surgical management of neck metastases for head and neck squamous cell carcinoma

Neck dissection is an important treatment for metastases from upper aerodigestive carcinoma; an event that markedly reduces survival. Since its inception, the philosophy of the procedure has undergone significant change from one of radicalism to the current conservative approach. Furthermore, nonsurgical modalities have been introduced, and, in many situations, have supplanted neck surgery. The refinements of imaging the neck based on the concept of neck level involvement has encouraged new philosophies to evolve that seem to benefit patient outcomes particularly as this relates to diminished morbidity. The purpose of this review was to highlight the new paradigms for surgical removal of neck metastases using an evidence-based approach.

Metastasis to submandibular glands in oral cavity cancers: Can we preserve the gland safely?

OBJECTIVE

To analyze submandibular gland (SMG) involvement in cases of oral cavity cancers and decide whether to remove submandibular glands while performing neck dissections for oral cavity cancers to decrease the incidence of xerostomia, a common issue post-operatively.

METHODS

Retrospective analysis of 157 neck dissections out of 204 neck dissections performed for oral cavity carcinomas in the Department of Otolaryngology and Head and Neck Surgery from 2008 to 2013 was done. SMG was bilaterally removed in 6 dissections, hence a total of 163 glands were analyzed. Those involved by tumor in histopathology were further studied for the pattern of involvement.

RESULTS

3.68% (6/163) glands showed involvement by the tumor. 9.20% (15/163) showed chronic sialo-adenitic changes. Four of the six involved glands showed direct contiguous spread from primary lesion, one showed extra-capsular spread from level IB lymph nodes and evidence of both modes of spread was seen in one. Evidence of metastasis was not seen in any of the glands (0%). Literature review showed a metastasis rate of 0.096% (2/2074).

CONCLUSION

Metastatic involvement of submandibular gland is extremely rare. Submandibular gland preservation, in the absence of evidence of gross contiguous involvement, does not affect survival. Hence, SMG can be safely spared during neck dissections for oral cavity squamous cell cancers except in certain situations such as close proximity of the primary lesion to gland, presence of intra-capsular lymph nodes in radiology, gross intraoperative evidence of invasion of the SMG and in salvage surgeries performed in post-irradiated and recurrent cases.