[478] Metastatic Melanoma to the Parotid Gland: Different Clinical Outcomes Based upon the Presence of Known or Unknown Primary

Thomas J Lawrence, Stephen Y Lai, Roland L Bassett, Victor G Prieto. University of Texas MD Anderson Cancer Center, Houston, TX

Background: Melanoma metastatic to the parotid gland has been reported to have a better prognosis in those cases in which there is an unknown primary site. The current study was designed to study all cases of metastatic melanoma to the parotid gland at a single cancer center over a 10-year period to assess possible differences in clinical outcomes.
Design: Surgical pathology reports were reviewed from January 2002 through December 2011. Follow-up information was obtained through the institutional electronic medical record. Patients were classified as having known (MKP) or unknown primary (MUP) tumors and the latter further subclassified as primarily presenting or not with a parotid metastasis. Disease-free survival (DFS) and overall survival (OS) were analyzed for all three groups.
Results: In all, 129 patients were identified as having a metastatic melanoma to the parotid gland or a parotid lymph node. 117 of 129 (90.7%) patients had MKP and 12 (9.3%) had MUP. Median follow-up for all patients was 2.1 years.

Patients with Metastatic Melanoma to the Parotid Region (N=129)
 % of Total Patients (n)Alive with Dz (n)Alive Dz Free( n)Death with Dz (n)Death without Dz (n)
MKP90.7% (117)20.5% (24)32.4%(38)43.5% (51)3.4% (4)
MUP, Initial Parotid Metastasis (n=8)6.2% (8)25% (2)62.5% (5)12.5% (1)0
MUP, Subsequent Parotid Metastasis (n=4)3.1% (4)25% (1)75% (3)00

Statistical comparison for p-values by log-rank tests show that the MKP group had significantly worse OS and DFS from the time of surgery than the MUP group (p=0.02 and p=0.01, respectively). Comparison of all three groups shows a statistically significant longer DFS(p=0.04) and a trend toward longer OS(p=0.06). These data indicate a better prognosis for those patients with MUP metastatic to the parotid region.

Conclusions: The results of this study suggest that patients who have MUP metastatic to the parotid have longer OS and DFS from the time of parotid metastasis as compared to those patients who experience a parotid metastasis from MKP. Patients experienced a survival advantage regardless of whether the patient presented with a parotid mass or subsequently following a presenting initial metastasis from another site.
Category: Dermatopathology

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 53, Tuesday Morning


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