Clinical outcomes of bulky parotid gland cancers: need for self-examination and screening program for early diagnosis of parotid tumors

Abstract

Background: Early detection and diagnosis of parotid gland cancer (PGC) are essential to improve clinical outcomes, because Tumor-Node-Metastasis stage at diagnosis is a very strong indicator of prognosis in PGC. Nevertheless, some patients still present with large parotid mass, maybe due to the unawareness or ignorance of their disease. In this study, we aimed to present the clinical outcomes of bulky PGC (defined by a 4 cm cutoff point for T3-4 versus T1-2 tumors), to emphasize the necessity of a self-examination tool for parotid gland tumor.

Methods: We retrospectively reviewed 60 consecutive cases with bulky (equal to and greater than 4 cm in the longest diameter, determined radiologically) malignant tumors arising from the parotid gland from 1995 to 2016. The clinical and pathological factors were analyzed to identify risk factors for poor outcomes using Cox proportional hazard models. In addition, we designed a self-examination tool for parotid gland tumors, similar to breast self-examination for breast cancer detection.

Results: Patients with bulky parotid cancer showed 48.9% 5-year and 24.5% 10-year overall survival rates and a 47.9% risk of high-grade malignancy. The common pathological diagnoses were carcinoma ex pleomorphic adenoma (18.3%), adenocarcinoma (16.7%), mucoepidermoid carcinoma (16.7%), salivary duct carcinoma (16.7%), and adenoid cystic carcinoma (11.7%). Survival analyses revealed that tumor size (hazard ratio, HR = 1.262 upon increase of 1 cm, 95% confidence interval, 95%CI 1.059-1.502), lymph node metastasis (HR = 2.999, 95%CI 1.048-8.583), and high tumor grade (HR = 4.148, 95%CI 1.215-14.154) were independent prognostic factors in multivariable analysis. Functional preservation of the facial nerve was possible only in less than half of patients.

Conclusion: In bulky PGC, lymph node metastasis at diagnosis and high tumor grade indicated poor survival outcomes, and functional outcomes of the facial nerve were suboptimal. Thus, a public effort seems to be necessary to decrease these patients with bulky PGC, and to increase patients' self-awareness of their disease. As a way of early detection, we proposed a parotid self-examination tool to detect parotid gland tumors at an early stage, which is similar to breast self-examination.

Keywords: Advanced stage, prognosis; Parotid gland; Surgery; Tumor.

Fig. 1

A flow chart of subject enrollment

Fig. 2

Survival plots of patients with bulky parotid gland cancer. a Overall survival (OS) (N = 60) and disease-free survivals (DFS) (N = 49 with curative surgery). b Survival plots stratified by cN and (c) tumor grade of enrolled subjects

Fig. 3

Proposed steps for self-examination of the parotid gland. a Understand the location of the parotid gland. b Palpate the parotid gland carefully to detect any lump. c Palpate the area from the parotid gland to mouth angle and nostril (accessory parotid gland). d Palpate the area between the jaw bone and the mastoid bone. Instruction: Normally, you can detect only bony structures [cheek bone (zygoma), jaw bone (mandible), and ear bone (mastoid bone)] around the parotid gland. If you feel any mass in the parotid self-examination, persistent for more than 2 weeks, you should visit a specialist for diagnosis