An Overview of Skin Cancer

Introduction

Skin cancer includes 2 large groups: cutaneous melanoma and nonmelanoma skin cancer (NMSC).

At the start of the 21st century, melanoma remains a potentially fatal malignancy accounting for 75% of all deaths from skin cancer. At a time when the incidence of many tumour types is decreasing, melanoma incidence continues to increase. Although most patients have localized disease at the time of the diagnosis and are treated by surgical excision of the primary tumour, many patients develop metastases.

Nonmelanoma skin cancer (NMSC) is the most common form of cancer in the world and approximately 40% of all malignancies. The incidence of nonmelanoma skin cancer has increased since the 1990s, but its mortality rate has decreased.

The following are major environmental risk factors for NMSC:

• frequent exposure to ultraviolet (UV) in fair skinned individuals
• immune suppression, and increased life longevity.

The prevalence of skin cancer cases is approximately 5 times higher than the prevalence of breast or prostate cancer and higher than the prevalence of all other cancers. Australia has the highest incidence of skin cancer in the world, and NMSC is the most commonly diagnosed cancer in Australia.

Aims of the module

• To gain an understanding of the differing clinical presentations of skin cancers.
• To appreciate the need for diagnosis of pigmented lesions without delay when a diagnosis of melanoma is suspected.
• To gain an understanding of the appropriate margins needed for clearance in primary excision and wider local excisions to prevent incomplete tumour removal and recurrence.
• To appreciate the need for prevention and the identification of at risk groups with respect to the management of non-melanoma skin cancers which are occurring at an epidemic rate with rising incidence and present a huge treatment burden to our health services.
• To gain an understanding of staging for melanoma and SCC.
• To gain an understanding of high risk sites for SCC and BCC and the effect on prognosis.
• To have a limited understanding of other less common skin cancers such as the aggressive Merkel Cell Carcinoma and Kaposi’s sarcoma, and the group of patients at risk of these tumours.