Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Program Number: B317
Session Name: Poster Session
Recurrence of Pleomorphic Adenomas Over Four Decades: A Population Based Study
Katelyn S Rourk, BS1; Ghazal S Daher, MD2; Jenna R Schwartz, BA1; Anne K Shurtz, MS3; Kendall K Tasche, MD2; Daniel L Price, MD2; Kathryn M Van Abel, MD2; Linda X Yin, MD2; Eric J Moore, MD2; 1Mayo Clinic Alix School of Medicine; 2Department of Otolaryngology- Head and Neck Surgery, Mayo Clinic; 3Department of Quantitative Health Sciences, Mayo ClinicIntroduction: Pleomorphic adenomas (PA) are the most common benign pathology of the parotid gland and are well known for their ability to recur with incomplete resection. In the era of enucleation recurrence rates neared 35%, but in modern surgical practice the recurrence rate has declined to an estimated 1-3%. In this study, we aim to explore the recurrence rate of PA for residents of a single county from 1976-2022 and describe any potential factors associated with recurrence.
Methods: All patients diagnosed with PA from 01/1976-12/2022 in a single county were identified using a public health record linkage system which allows for all health care records of residents to be reviewed over their lifetime or duration of residence in the county. Patients who had their first occurrence of PA in this county were followed for recurrence. Patients who had their first tumor diagnosed elsewhere or prior to 1976 that presented due to recurrences were included as a separate cohort. Inclusion criteria included pathologic diagnosis of PA through FNA or surgical pathology. Presentation was defined as palpable mass or incidental imaging finding. Incidence was calculated per 100,000 person years and were directly standardized to the total United States population from the 2020 United States Census. Kaplan Meyer survival estimates and plots were calculated to summarize the time until recurrence of PAs.
Results: 251 patients were identified from 1976 to 2022 with a primary occurrence of PA in this county. Of these patients, 7 had recurrences with a rate of recurrence of 2.3% at 10 years and 6.6% at 40 years. The average time to recurrence was 11.2 years with a median follow-up of 12.7 years. When compared to the nonrecurrent cohort, patients with recurrence were more likely to have tumor spillage in surgery (33.3% vs 3.5%), have less extensive surgery (0% total parotidectomy vs 7%), be female (71.4% vs 54.9%), and were diagnosed at a younger age (39.4 vs 51.6 years). The median tumor size for patients with recurrence was 1.6 cm, compared to 2 cm for the nonrecurrent cohort. No patients experienced malignant transformation.
Out of the 7 patients with recurrence, one patient had re-recurrence for a total of 9 recurrent tumors. 5 patients had multifocal disease at recurrence and all but one received surgical treatment for these recurrences. One patient (multiple re-recurrences) received radiation treatment for their recurrent disease.
Conclusion: While PAs still exhibit a relatively low recurrence rate, most recurrences occur more than a decade after initial diagnosis. Our study demonstrates a higher recurrence rate than estimated averages at 20-40 years (4.1-6.6%). Factors potentially contributing to recurrence include tumor spillage and younger age at initial diagnosis. This data supports the need for future studies that evaluate long-term follow-up and recurrence rates of PAs.
