nonmelanomas _______ have higher mortality rates than melanomas
The most common cancer type overall in the United States is ____________ skin cancer
_____________are usually tan or black in color
In late stage disease, __________ tend to ulcerate and have a rolled border on examination
___________ are not usually treated with radiation because they are radioresistent
Control rates for stage 1 basal cell carcinoma are approximately ___%
Clark method for classifying melanoma is based on _____________
Depth in invasion
write 3 statements appropriate for increasing public awareness reguarding the precentage of skin cancer
pay attention to any new or existing skin markings
avoid excessive exposure to uv light
early diagnosis & early treatment is important
List 3 functions of the skin
regulation of body temperature
barrier between the body and the enviroment
provides receptors for stimuli like heat, cold and touch
Epstein-barr virus is an etiologic factor for ______________
Melanocytes are found in the ____ layer of the skin
Cells most sensitive to radiation are located in which layer of the epidermis?
Frequent visits to the tanning bed increases risk of developing _______________
Nonmelanoma type skin cancer are not usually seen in children. One possible reason is:
Nonmelanomas are a result of long term exposure to UV rays
Lentigo maligna is a histologic type of melanoma characterized by
Growth in a radical pattern with a tan or black color
What role does immunotherapy play in the management of melanoma?
Immunotherapy attempts to take advantage of this response and gives the immune system a boost to help fight the disease
List the expected side effects of radiation therapy for non melanoma skin cancers
Typical fx: 40-50 Gy total (2 Gy fx's)
Erythema @ 20Gy
Dry Desquamation @ 30 Gy
Wet Desquamation @ 40 Gy
depth of invasion 4 cm
Pxd dose 90%
What electron energy?
A patient has a non melanoma located on the lower eyelid. Discuss positioning & field arrangements.
Electron therapy with careful protection of the lens
Full internal eye shield could be inserted & field shaping by thin lead cut out placed directly on the skin
Likely, the lesion is small enough to be covered by an extendable, round Lucite cone.
Combination of couch & gantry angle to achieve parallel relationship between the surface & horizontal axis of the beam
When a lesion on the external surface of the nose is treated, a lead shield should be placed into the nostril. Breifly explain why
The lead shield protects the underlying mucosa from residual radiation. Wax behind the shield will further protect the mucosa closest to the septum, from secondary radiation from electron/lead interaction