Transoral endoscopic head and neck surgery (eHNS) for minor salivary gland tumors of the oropharynx

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.

Contemporary Review of Submandibular Gland Sialolithiasis and Surgical Management Options

One of the most common disorders of the salivary glands is obstructive sialolithiasis. Salivary gland obstruction is important to address, as it can significantly impact patient quality of life and can progress to extensive cellulitis and abscess formation if left untreated. For small and accessible stones, conservative therapies often produce satisfactory outcomes. Operative management should be considered when stones are inaccessible or larger in size, and options include sialendoscopy, laser lithotripsy, extracorporeal shockwave lithotripsy, transoral surgery, and submandibular gland adenectomy. Robotic approaches are also becoming increasingly used for submandibular stone management. The purpose of this review is to summarize the modern-day management of submandibular gland obstructive sialolithiasis with an emphasis on operative treatment modalities. A total of 77 articles were reviewed from PubMed and Embase databases, specifically looking at the pathophysiology, clinical presentation, diagnosis, and management of submandibular sialolithiasis.

National analysis of positive surgical margins in oropharyngeal salivary gland malignancies

OBJECTIVE

Positive surgical margins (PSM) are associated with worse survival in oropharyngeal salivary gland malignancies (OPSGM), but existing literature is limited to small series. Our objective was to identify risk factors for PSM using the national cancer database (NCDB), including a transoral robotic surgical (TORS) approach.

METHODS

NCDB was queried for patients with T1-T4a OPSGM undergoing resection between 2010 and 2017. Risk factors for PSM were determined using logistic regression. Overall survival (OS) was analyzed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

Of 785 patients, 165 (21.0 %) had PSM. Age, stage T4a tumors (OR 2.00, 95 % Confidence Interval [CI]: 1.03-3.88), adenoid cystic carcinoma (OR 2.02, 95 % CI: 1.29-3.18), and treatment at lower volume institutions (OR 1.68, 95 % CI: 1.09-2.59) were all independently associated with PSM. TORS versus a non-robotic approach was not associated with PSM (23.9 % vs 20.4 %, p 0.358), respectively. Positive margins were independently associated with a worse OS than negative margins (HR 1.63, 95 % CI: 1.03-2.59). Adjuvant radiation therapy was associated with improved survival in high grade tumors with positive margins.

CONCLUSION

This study represents the largest review assessing risk factors for positive margins in OPSGM. Histologic type (adenoid cystic carcinoma), age, T4a tumor stage and treatment at a lower volume institution were all predictive of positive margins. With increasing use of TORS over the last decade, there does not appear to be a greater risk of positive margins using this modality in select patients.

LEVEL OF EVIDENCE

N/A.

National Analysis of Oropharyngeal Salivary Gland Malignancies Treated With Transoral Robotic Surgery

OBJECTIVES

(1) To compare perioperative outcomes and overall survival of patients with oropharyngeal salivary gland malignancies (OPSGMs) treated with transoral robotic surgery (TORS) versus other approaches. (2) To identify clinical factors associated with a robotic surgical approach.

STUDY DESIGN

Retrospective analysis of the National Cancer Database (NCDB).

SETTING

NCDB.

METHODS

Data obtained from the NCDB were analyzed between 2010 and 2017 for patients with T1-T4a OPSGMs without distant metastases treated surgically. Patients were stratified by surgical approach (TORS vs nonrobotic), and clinicopathologic factors were compared with the t test or chi-square test for continuous or categorical variables, respectively. Overall survival was analyzed by patient demographics and clinical factors according to Kaplan-Meier and Cox proportional hazards models. Factors associated with TORS were assessed with logistic regression.

RESULTS

A total of 785 patients were analyzed. A non-soft palate primary site (odds ratio, 12.9; 95% CI, 6.6-25.2) and treatment at an academic facility (odds ratio, 2.0; 95% CI, 1.2-3.5) were independently associated with TORS. There were no significant differences in the positive margin rate, 30-day mortality, or overall survival between the groups. The 30-day unplanned readmission rate was higher in patients treated with TORS versus nonrobotic resections (5.8% vs 1.7%, P = .0004). When stratified by tumor subsite, there was a significant decrease in hospital length of stay in patients with tongue base tumors undergoing TORS versus nonrobotic resections (P = .029).

CONCLUSION

This study suggests that TORS may be a viable treatment modality for appropriately selected patients with OPSGM.

Multicenter Study of Carbon-ion Radiotherapy for Oropharyngeal Non-squamous Cell Carcinoma

BACKGROUND/AIM

To evaluate treatment outcomes of carbon-ion radiotherapy for oropharyngeal non-squamous cell carcinoma at four carbon-ion facilities in Japan.

PATIENTS AND METHODS

We retrospectively analyzed the cases of 33 patients with oropharyngeal non-squamous cell carcinoma who were treated with carbon-ion radiotherapy between November 2003 and December 2014.

RESULTS

The histology included adenoid cystic carcinoma (n=25) and mucosal malignant melanoma (n=4). No patients had T1 tumors; 23 had T4 tumors. The most-commonly prescribed dose was 57.6 Gy (RBE) in 16 fractions. The median follow-up period was 34.8 months (range=4.2-122.8 months). The 3-year local control and overall survival rates were 94.7% and 90.7%, respectively. There were no grade ≥4 acute adverse events. Only one patient experienced a grade ≥4 late adverse event. No patients experienced late adverse events related to swallowing or salivary function.

CONCLUSION

Carbon-ion radiotherapy appears to be a promising treatment option for oropharyngeal non-squamous cell carcinoma.

A new landmark for lingual artery identification during transoral surgery: Anatomic-radiologic study

BACKGROUND

A landmark for the identification of the lingual artery (LA) through a transoral perspective can provide surgeons with an easy method to prevent and manage intraoperative bleeding during transoral approach to the base of tongue (BOT).

METHODS

Thirteen tongue and five head and neck specimens were dissected to identify and assess the reliability of the lingual point (LP) as a new landmark for the LA at BOT. The pathway of 42 LAs was radiologically evaluated; axial depth and vertical offset were measured for each LA.

RESULTS

Dissection study: a description of LP is provided; the LA was easily identified in all specimens (36/36 sides) using LP as a landmark. Radiologic study: the mean depth of the LA was 4.2 mm, the mean vertical offset was 1.3 mm.

CONCLUSIONS

LP is a simple and reliable landmark for identification of the LA, potentially helping surgeons to prevent and manage intraoperative bleeding.

Robotic Management of Salivary Glands

There are numerous salivary gland pathologies for which robotic surgery can provide benefit. This article reviews the primary indications for use of transoral robotic surgery for salivary gland neoplasms. It also discusses transoral and retroauricular robotic approaches for pathology of the submandibular gland and prestyloid parapharyngeal space. These approaches have the advantage of avoiding a visible scar and are additionally minimally invasive in other ways as well. Robotic surgery offers advantages in several different modules of salivary gland surgery, similar to those it offers for oropharyngeal cancer, including improved optics, manual dexterity, and teamwork.

Current Indications for Transoral Robotic Surgery in Oropharyngeal Cancer

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) is increasing dramatically and is conclusively linked to increasing rates of human papillomavirus (HPV) infection. HPV-related oropharyngeal cancers have been shown to occur in a unique demographic group and show favorable oncologic outcomes compared with HPV-negative OPSCC. There has been a paradigm shift in the treatment of early-stage OPSCC, with most patients now undergoing primary surgery in the United States. Transoral robotic surgery is associated with excellent oncologic and functional outcomes in the treatment of OPSCC and is increasingly being used for a broader range of oropharyngeal indications.