Total Parotidectomy May Benefit Patients With Cutaneous Squamous Cell Carcinoma or Malignant Melanoma With Metastasis to the Parotid Superficial Lobe
The optimal extent of surgical resection is unclear in patients with parotid superficial lobe lymph node metastasis from cutaneous squamous cell carcinoma and malignant melanoma. In a single-institution retrospective review reported in JAMA Otolaryngology Head & Neck Surgery, Thom et al found that total parotidectomy may benefit such patients, since metastasis to the deep lobe is common.
The study involved 65 adults from the Mayo Clinic in Minnesota who underwent total parotidectomy and neck dissection for metastatic cutaneous squamous cell carcinoma (n = 42) and malignant melanoma (n = 23) involving the parotid superficial lobe between 1994 and 2010.
Frequency of Deep Lobe Metastasis
In total, 11 patients (26%) with cutaneous squamous cell carcinoma and 3 patients (13%) with malignant melanoma also had parotid deep lobe metastasis and 13 (31%) and 6 (26%) had cervical node metastasis. Thus, overall, 22% of patients had metastasis to the parotid deep lobe in addition to the superficial lobe, and 29% had metastasis to cervical nodes.
On univariate analysis, neck metastasis (odds ratio [OR] = 4.10, P = .05) and N2 vs N0 neck disease (OR = 4.80, P = .05) were significant risk factors for metastatic spread of cutaneous squamous cell carcinoma to the parotid deep lobe. Analysis of risk factors for metastatic spread to the parotid deep lobe in patients with malignant melanoma was not performed since only three patients had deep lobe metastasis.
Worse Outcome With Deep Lobe Involvement
Parotid-area local control rates were 93% in the squamous cell carcinoma group and 100% in the malignant melanoma group. For squamous cell carcinoma patients without vs with parotid deep lobe involvement, 5-year rates were 92% vs 89% for local control (P = .69), 88% vs 78% for locoregional control (P = .35), and 76% vs 36% for distant disease control (P < .01). Parotid deep lobe metastasis was a significant risk factor for distant metastatic disease (hazard ratio [HR] = 5.35, P = .02), disease recurrence (HR = 3.49, P = .03), death from disease (HR = 3.73, P = .04), and death from all causes (HR = 2.89, P = .02).
Among patients with malignant melanoma, 6 (26%) developed locoregional recurrence in the neck and 11 (48%) developed distant metastatic disease. The three patients with deep lobe metastasis all had regional recurrence in the neck within 10 months after surgery, with deep lobe metastasis being a significant risk factor for locoregional failure (P < .001).
The investigators concluded: “Metastatic [cutaneous squamous cell carcinoma and malignant melanoma] to the parotid superficial lobe also involve [lymph nodes] in the parotid deep lobe and neck in a significant and almost equal number of patients. Parotid deep lobe metastasis from cutaneous malignancies portends a poor prognosis. Therefore, patients with superficial parotid gland metastasis should be considered for management with not only neck dissection and adjuvant therapy but also deep lobe parotidectomy.”
Kerry D. Olsen, MD, of Mayo Clinic Medical School, is the corresponding author for the JAMA Otolaryngology Head & Neck Surgery article.
The study authors reported no potential conflicts of interest.
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