Active Surveillance for Pleomorphic Adenomas of the Parotid-Tumor Growth Rate, Potential Malignancy, and Surgical Sequalae.

Objective: The outcomes of active surveillance (AS) for pleomorphic adenomas (PA) as an alternative to upfront parotidectomy have not been previously documented in the literature. This cohort study aims to assess the safety and feasibility of AS for parotid gland PA.

Methods: All patients with of previously untreated PA managed between 1990 and 2015 were reviewed. Patients who underwent AS for a minimum of 1 year from the initial consultation were identified. Patient demographics, the reason for AS, tumor growth rate, indication for surgery in those patients eventually operated, final pathology, and surgical sequelae were analyzed.

Results: During the study period, 610 patients with primary PA were treated in our institution. Of whom, 14 (2.3%) underwent AS for a period between 1 and 10 years with a median of 3.73 years (interquartile range [IQR] 1.3-4.9). Patient comorbidities were the most common reason for opting for AS (n = 6, 43%), followed by patients' preference to delay surgery (n = 4, 29%) and older age (n = 2, 14%). The median growth rate was 0.58 mm/year (IQR 0.04, 3.8, range -5.01 to 4.98 mm/year). In patients who eventually underwent parotidectomy (n = 10, 71.4%), the most common reason for intervention was tumor growth (8/10, 80%). Two patients had postsurgical mild transient facial nerve paresis with full recovery, and no carcinomas were discovered on final pathology.

Conclusion: In this selected cohort of patients with PA, the tumor growth rate was lower than traditionally believed. Patients who eventually underwent surgery did not suffer from serious complications and there was no evidence of clinical or pathological malignancy.