Ultrasonographic findings as a prognostic factor in parotid cancer

Abstract

ObjectiveRecent advancements in high-resolution ultrasonography (US) have established it as a critical tool for evaluating parotid lesions. However, the lack of standardized diagnostic criteria limits the utility of US in determining malignancy. This study investigates the potential role of US as a prognostic factor in parotid cancer.MethodsPatients diagnosed with and surgically treated for parotid cancer at our tertiary referral center from January 2016 to December 2022 were included in this retrospective cohort study. We retrospectively obtained patient data including US images and clinical factors and analyzed their correlation with various adverse features and oncological outcomes, including five-year disease-free survival (5Y DFS) and overall survival (5Y OS).ResultsA total of 126 patients were included. The 5Y DFS and 5Y OS were 81.7% ± 3.7% and 81.2% ± 4.1% respectively. Multivariate analysis revealed that age (DFS; HR 2.75 [1.76-4.29], p = .023, OS; HR 3.38 [2.06-5.54], p = .014), clinical nodal stage (DFS; HR 5.87 [3.74-9.21], p < .001, OS; HR 9.34 [5.48-15.91], p < .001) and the presence of posterior enhancement artifact on US (DFS; HR 0.33 [0.21-0.53], p = .019, OS; HR 0.34 [0.20-0.57], p = .037) were significant variables. In patients with early-stage parotid cancer who showed posterior enhancement, the extent of surgery did not affect treatment outcomes.ConclusionPosterior acoustic enhancement on ultrasonography is a favorable prognostic factor in parotid cancer. For patients with early-stage cancer who demonstrate posterior enhancement, minimizing the extent of surgery does not compromise oncologic outcomes.

Keywords: Parotid cancer; adverse features; oncological outcomes; posterior acoustic enhancement; ultrasonographic findings.

Figure 1.

Examples of ultrasound (US) terminology used in evaluation of parotid lesions. (a) An example of a round, well-defined, homogeneous, hypoechoic tumor with posterior acoustic enhancement. (b) Tumor with an irregular shape. (c) Tumor with an ill-defined margin. (d) Tumor with a heterogeneous echotexture. (e) An example of a hyperechoic tumor. (f) Tumor with posterior acoustic enhancement artifact. (g) Small highly echogenic spots indicating the presence of microcalcification. (h) Blood-flow signals on a Doppler US image, indicating its vascular nature.

Figure 2.

Kaplan–Meier survival curves depicting 5Y DFS and 5Y OS of patients with parotid cancer. (a) 5Y DFS 81.7% ± 3.7%, (b) 5Y OS 81.2% ± 4.1%.

Figure 3.

Survival analysis of patients with parotid cancer with posterior acoustic enhancement. (a, b) Kaplan–Meier curves showing five-year disease-free survival (5Y DFS) and 5-year overall survival (5Y OS), stratified by the presence of posterior enhancement; (c, d) 5Y DFS and 5Y OS of patients with parotid cancer with posterior enhancement, stratified by the extent of parotidectomy; (e, f) 5Y DFS and 5Y OS of patients with parotid cancer with posterior enhancement, stratified by the addition of concurrent elective neck dissection.