Clinical-pathological prognostic factors and treatment failure patterns in T1-2 high-grade parotid gland cancer

Comparison of Partial Versus Superficial or Total Parotidectomy for Superficial T1-2 Primary Parotid Cancers

OBJECTIVES

This study aimed to compare the oncological outcomes of partial versus superficial or total parotidectomy for superficial T1 or T2 primary parotid cancers and investigate their prognostic factors and recurrence patterns.

METHODS

The medical records of 77 patients with T1-2 primary parotid malignancies between May 2003 and March 2022 were retrospectively reviewed. Univariate and multivariate analyses were performed to evaluate the prognostic factors associated with overall survival, disease-free survival, and local and distant recurrence.

RESULTS

The average follow-up duration was 70.2 months (range, 12-202 months). The 5-year overall and disease-free survival rates were 88.7% and 77.1%, respectively. Twenty-two patients underwent partial parotidectomy, and 55 underwent superficial or total parotidectomy. There were no significant differences in the disease recurrence (P=0.320) and mortality rates (P=0.884) of the partial and superficial or total parotidectomy groups. The mean duration of surgery was shorter and the overall complication rates were significantly lower in the partial group than in the superficial or total parotidectomy group (P=0.049). Sixteen cases of recurrence occurred during the study period (20.8%). Univariate analyses showed that high-grade tumors (P=0.006), lymphovascular invasion (P=0.046), and regional lymph node metastasis (P=0.010) were significant risk factors for disease recurrence. Multivariate analysis identified regional lymph node metastasis as an independent prognostic factor for disease recurrence (P=0.027), and lymphovascular invasion as an independent prognostic factor for overall survival (P=0.033).

CONCLUSION

The conservative surgical approach of partial parotidectomy can yield oncological outcomes comparable to those of superficial or total parotidectomy with careful patient selection in T1-2 parotid cancers.

Influence of parotid lymph node metastasis on distant metastasis in parotid gland cancer

Background

The aim of this study was to analyze the impact of the number and extranodal extension (ENE) of positive parotid lymph nodes (LNs) on distant metastasis in parotid cancer.

Methods

Patients with surgically treated parotid cancer were retrospectively enrolled. The hazard ratios (HRs) of the number and ENE of positive parotid LNs on distant metastasis-free survival (DMFS) were evaluated.

Results

In the Cox model, the groups with zero and one positive LN had comparable 10-year DMFS, but those with two positive LNs had an HR of 2.11 (95% CI: 1.36-5.29), and those with three or more positive LNs had an HR of 3.31 (95% CI: 2.05-8.43). The presence of ENE in parotid LNs did not impact the DMFS (p = 0.462; HR: 2.17; 95% CI: 0.84-6.17).

Conclusion

Parotid LN metastasis was associated with decreased DMFS; this effect was mainly driven by the number of positive LNs rather than ENE.

Salivary gland organoid culture maintains distinct glandular properties of murine and human major salivary glands

Salivary glands that produce and secrete saliva, which is essential for lubrication, digestion, immunity, and oral homeostasis, consist of diverse cells. The long-term maintenance of diverse salivary gland cells in organoids remains problematic. Here, we establish long-term murine and human salivary gland organoid cultures. Murine and human salivary gland organoids express gland-specific genes and proteins of acinar, myoepithelial, and duct cells, and exhibit gland functions when stimulated with neurotransmitters. Furthermore, human salivary gland organoids are established from isolated basal or luminal cells, retaining their characteristics. Single-cell RNA sequencing also indicates that human salivary gland organoids contain heterogeneous cell types and replicate glandular diversity. Our protocol also enables the generation of tumoroid cultures from benign and malignant salivary gland tumor types, in which tumor-specific gene signatures are well-conserved. In this study, we provide an experimental platform for the exploration of precision medicine in the era of tissue regeneration and anticancer treatment.

Salivary Gland Function, Development and Regeneration

Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular and genetic levels; the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis and regeneration and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.