Outcomes of cutaneous squamous cell carcinoma of the head and neck with parotid metastases.

Introduction: Cutaneous squamous cell carcinoma of the head and neck (cHNSCC) metastatic to the parotid has a moderate risk of recurrence despite multimodality treatment. Immunosuppression is associated with lower rates of long-term cure. Our aim was to review outcomes of current management in a tertiary centre with a view to targeting future strategies.

Methods: A retrospective review of clinico-pathological data and outcomes for patients with metastatic cHNSCC involving the parotid gland, undergoing radical surgery and adjuvant radiotherapy during 2000-2014 was conducted. The Kaplan-Meier method was used to determine time-to-event outcomes.

Results: One hundred and thirty-two patients met the inclusion criteria. Median follow-up was 5.0 years. Five-year overall (OS), cancer-specific (CSS) and progression free survival (PFS) were 44% (95% Confidence Interval (CI) 34-53%), 64% (95% CI 52-74%) and 37% (95% CI 28-47%) respectively. Locoregional control (LRC) was 68% (95% CI 55-77%) at 5 years. Immunosuppressed patients fared worse (compared with immune-competent) with five-year OS, CSS, and PFS of 14% versus 53% (HR = 3.19; 95% CI 1.91-5.34), 40% versus 71% (Hazard Ratio (HR) = 2.92; 95% CI 1.38-6.19) and 10% versus 46% (HR = 2.51; 95% CI 1.52-4.14) respectively. On multivariate analysis, immune status strongly predicted OS (P < 0.001), CSS (P = 0.003), DMFS (P < 0.001) and PFS (P < 0.001), but not LRC. Largest lymph node size was the only significant factor predictive for LRC on multivariate analysis (P = 0.02).

Conclusions: Despite multimodality treatment metastatic cHNSCC involving the parotid shows moderate rates of recurrence. Immunosuppressed patients with this disease have a particularly poor prognosis, demonstrating lower rates of CSS with similar rates of LRC compared to their immunocompetent counterparts.