Sporadic cutaneous angiosarcomas: a proposal for risk stratification based on 69 cases

Area of Science:

• Dermatopathology
• Surgical Pathology
• Oncology

Background:

• Cutaneous angiosarcomas are traditionally considered high-grade lesions.
• Histologic features and grading have historically played no role in prognostication.
• Angiosarcomas have been excluded from the American Joint Committee on Cancer staging system.

Purpose of the Study:

• To determine if a combination of histologic and clinical parameters can differentiate indolent from aggressive cutaneous angiosarcomas.
• To analyze 69 cutaneous angiosarcomas not associated with lymphedema or prior radiation therapy.

Main Methods:

• Analysis of clinical features: patient age, location, size, depth, and focality.
• Study of histologic features: growth pattern, nuclear grade, necrosis, cell type, inflammatory infiltrate, and mitotic rate.
• Stratification into low-risk (n=41) and high-risk (n=28) groups based on necrosis and/or epithelioid features.

Main Results:

• Univariate analysis identified older age, anatomic site, necrosis, and epithelioid features as correlating with increased mortality.
• Multivariable analysis associated high-risk group (HR 4.07, P=0.0004) and age >70 (HR 2.79, P=0.012) with increased mortality.
• Tumor depth correlated with local recurrence risk (P=0.048); high-risk group showed significantly worse prognosis (3-year survival 24% vs. 77%).

Conclusions:

• A combination of clinical and histologic features allows stratification of angiosarcoma patients into two distinct risk groups.
• These risk groups are strongly associated with marked differences in clinical course and prognosis.
• Features are most useful in tumors less than 5 cm; importance diminishes with increased tumor size.