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.