Recent Insights and Advances in the Management of Merkel Cell Carcinoma.

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine malignancy with a propensity for recurrence and a poor prognosis. Incidence of MCC is on the rise and is known to increase with advanced age, immunosuppression, and UV exposure. Merkel cell polyomavirus is implicated in the pathogenesis of virus-positive MCC and accounts for 80% of MCCs in the northern hemisphere and 25% in southern latitudes. In contrast, tumorigenesis of virus-negative MCC is linked to UV-induced DNA damage. Interplay between ubiquitous Merkel cell polyomavirus skin infections that commonly occur in healthy skin and other established risk factors, such as immunosuppression and UV exposure, remains poorly understood. Surgery and radiotherapy achieves excellent locoregional control; however, invariably, a significant proportion of patients develop disseminated disease that is incurable. Chemotherapy offers a high response rate for metastatic disease, but responses are short-lived and the impact on survival is not established. Recent advances in our understanding of the genetic landscape and immunobiology of MCC has led to investigation of novel treatments, including immune checkpoint inhibitors, which are likely to rapidly transform the way we manage these patients. We review epidemiologic, clinical, and histopathologic features of MCC; describe recent insights in MCC biology; and discuss novel therapeutic approaches.

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.

p16-positive lymph node metastases from cutaneous head and neck squamous cell carcinoma: No association with high-risk human papillomavirus or prognosis and implications for the workup of the unknown primary.

BACKGROUND: The incidence of p16 overexpression and the role of human papillomavirus (HPV) in cutaneous head and neck squamous cell carcinoma (cHNSCC) are unclear. METHODS: One hundred forty-three patients with cHNSCC lymph node metastases involving the parotid gland were evaluated for p16 expression by immunohistochemistry. The detection of 18 high-risk HPV subtypes was performed with HPV RNA in situ hybridization for a subset of 59 patients. The results were correlated with clinicopathological features and outcomes. RESULTS: The median follow-up time was 5.3 years. No differences were observed in clinicopathological factors with respect to the p16 status. p16 was positive, weak, and negative in 45 (31%), 21 (15%), and 77 cases (54%), respectively. No high-risk HPV subtypes were identified, regardless of the p16 status. The p16 status was not prognostic for overall (hazard ratio, 1.08; 95% confidence interval [CI], 0.85-1.36; P = .528), cancer-specific (hazard ratio, 1.12; 95% CI, 0.77-1.64; P = .542), or progression-free survival (hazard ratio, 1.03; 95% CI, 0.83-1.29; P = .783). Distant metastasis-free survival, freedom from locoregional failure, and freedom from local failure were also not significantly associated with the p16 status. CONCLUSIONS: p16 positivity is common but not prognostic in cHNSCC lymph node metastases. High-risk HPV subtypes are not associated with p16 positivity and do not appear to play a role in this disease. HPV testing, in addition to the p16 status in the unknown primary setting, may provide additional information for determining a putative primary site.

Salivary duct carcinoma: Treatment, outcomes, and patterns of failure.

BACKGROUND: Salivary duct carcinoma is rare, with distinct morphology and behavior. We reviewed our institutional experience with salivary duct carcinoma, aiming to characterize clinical behavior and treatment outcomes. METHODS: All salivary duct carcinomas treated curatively between 1999 and 2010 were reviewed. Overall survival (OS), locoregional control, distant control, and patterns of failure were analyzed. Multivariate analysis identified predictors of OS. RESULTS: Fifty-four patients with salivary duct carcinoma (parotid gland = 49; submandibular gland = 5) were included in the analysis. Fifty-three patients underwent primary surgery, and 48 (89%) received postoperative radiotherapy (RT; median dose = 60 Gy). Median follow-up was 5.7 years. The 5-year OS, locoregional control, and distant control were 43%, 70%, and 48%, respectively. Nine local (6 involving facial nerve), 10 regional, and 28 distant failures were identified. Multiple pathologic involved lymph nodes (pN2b/N2c) predicted reduced OS (hazard ratio [HR] = 3.6; p = .02). CONCLUSION: Distant recurrence is common. Presence of pN2b/N2c disease is associated with reduced OS. Local recurrence frequently involves the facial nerves. © 2015 Wiley Periodicals, Inc. Head Neck 38: E820-E826, 2016.