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The Role of UV Radiation in Basal Cell & Squamous Cell Carcinomas. Mary Maloney, MD, FAAD Director of Dermatologic Surgery University of Massachusetts Medical School. Associated with a substantial risk of metastasis. Account for approximately 20% of non-melanoma skin cancers.
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The Role of UV Radiation in Basal Cell & Squamous Cell Carcinomas Mary Maloney, MD, FAAD Director of Dermatologic Surgery University of Massachusetts Medical School
Associated with asubstantial risk of metastasis. • Account for approximately 20% of non-melanoma skin cancers. • Total dose of UV radiation is directly related to the development of squamous cell carcinoma. Sequence of Events Thought to Occur After UV Irradiation of the Skin Cell with Functional p53 Premalignant cell with dysfunctional p53 Premalignant cell with dysfunctional p53 Cell with Functional p53 UV UV One p53 mutation UV Two p53 mutations UV One p53 mutation No apoptosis; growth of abnormal cell population Apoptosis Apoptosis Actinic keratosis Uncontrolled cellular proliferation Uncontrolled cellular proliferation Squamous Cell Carcinomas Carcinoma in situ Source: Alam M, Ratner D. Cutaneous Squamous-Cell Carcinoma. N Engl J Med, 2001; 344(13): 975-83.
Carcinogenesis in Basal Cell Carcinoma • UV-B radiation • Absorbed by DNA • Forms Pyrimidinedimers • Causes mutations in suppressor genes p53 and Patched-1 • UV radiation is involved in the mutations of the Hedgehog/Patched/Gli intercellular signaling pathway genes • Leads to basal cell carcinoma UVR
Facing a Skin Cancer Epidemic • Nonmelanoma skin cancer is the most common cancer in the US. • Evidence exists of a 3-fold increase in the incidence of nonmelanoma skin cancer between 1994 and 2006. • While the incidence has been quoted as a million new cases each year, Rogers’s paper out this month puts the incidence at 3.5 million new cases each year. Rogers HW, et al., Incidence Estimate of Nonmelanoma Skin Cancer in the US, 2006, Arch Dermatol. 2010:146(3):283-287.
The Role of Tanning Beds • Those who use tanning beds are 2.5 times more likely to develop squamous cell carcinoma and 1.5 times more likely to develop basal cell carcinoma Karagas MR et al. Use of Tanning Devices and Risk of Basal Cell and Squamous Cell Skin Cancers. J of the NCI. 2002: 94 (3):224-226
Is There a Role of Age at Tanning? YES • For each decade younger the subject was at first use of a tanning device. • The odds ratio for SCC increased by 20%. • The odds ratio for BCC increased by 10%. Karagas MR, et al. Use of Tanning Devices and Risk of Basal Cell and Squamous Cell Skin Cancer. J of the NCI. 2002;94(3):224-226.
Karagas MR, Stannard VA, Mott LA, Slattery MJ, Spencer SK, Weinstock MA. Use of Tanning Devices and Risk of Basal Cell and Squamous Cell Skin Cancers. J Natl Cancer Inst. 2002; 94(3):224-26.
At What Cost? • This set of tumors is the least expensive to treat (when compared to such tumors as stomach, lung, breast, and melanoma). • Because of the sheer number of tumors, non-melanoma skin cancers are the 5th most expensive set of tumors to treat overall in the Medicare population. Rogers HW, Incidence Estimate of Nonmelanoma Skin Cancer in the US, 2006. Arch Dermatol. 2010;146(3):283-287.
Stronger Regulations Are Needed • To protect the public health, the FDA should: • Ban the use and sale of tanning devices in the US • Or at a minimum, • Reclassify tanning devices to the strongest possible category; • Ban tanning bed use by minors • Require informed consent for all consumers; • Require posted warning statements; • Implement and enforce labeling recommendations from the TAN Act; and, • Enforce additional state regulations.
We must decrease the incidence of skin cancer • Thank you • Questions?