Importance:
Acinic cell carcinoma is a rare salivary gland malignancy, and recurrent disease has been shown to have an adverse effect on survival. Intraoperative tumor spillage is a known risk factor for recurrence for some parotid neoplasms, notably pleomorphic adenoma, but the impact of tumor spillage on risk of recurrence for acinic cell carcinoma is unknown.
Objective:
To determine the incidence of intraoperative tumor spillage and impact of spillage on the risk of recurrence for acinic cell carcinoma of the parotid gland.
Design:
Retrospective medical record review at a single tertiary academic hospital of pediatric and adult patients diagnosed between 1983-2018 with acinic cell carcinoma of the parotid gland.
Main Outcomes and Measures:
Primary outcome was recurrence, either locoregional or distant. Patient demographics and surgical resection characteristics were obtained and compared between the intraoperative tumor spillage vs. no tumor spillage groups.
Results:
79 patients with acinic cell carcinoma of the parotid gland were identified, with a slight female preponderance (58.3%) and mean age at diagnosis of 50.4 ± 18.1 years. 16 patients (20.2%) had intraoperative tumor spillage. 25 patients (31.6%) experienced tumor recurrence with a mean overall time to recurrence of 51.1 ± 54.9 months (range: 6-203 months). Of those who had recurrence, 13 (52%) experienced a second recurrence after second surgical resection with a mean time to second recurrence of 48.1 ± 65.4 months (range: 3 – 194 months).
Between the intraoperative tumor spillage vs. no tumor spillage cohorts, there was no difference in the incidence of tumor recurrence (4 patients (25%) vs. 21 patients (33.3%), p=0.522) or overall mean time to recurrence (57.5 months vs. 49.9 months, p=0.804). However, when stratifying based on early (<1 year) vs. late recurrence (>1 year) in both cohorts, there was a statistically significant difference in pattern of recurrence (19.0% non-spillage within one year vs. 75% spillage within one year, p<0.05). Out of those who had one recurrence, there was no difference in the incidence of patients with a second recurrence (12 patients (57.1%) vs. 1 patient (25%), p=0.238).
Conclusions and Relevance:
We found no difference in overall recurrence rates in the intraoperative tumor spillage vs. no tumor spillage groups. However, there was a statistically significant difference in the time to recurrence, with the intraoperative tumor spillage group experiencing earlier recurrences. Further study is needed to determine if other risk factors are associated with both intraoperative tumor spillage and tumor recurrence.