Total and Spot Electron Beam (TSEBT/SPOT EBT)
Conventional Radiation Therapy
Radiation therapy uses X-rays and electrons to treat the skin. In fact, the mycosis fungoides variant of CTCL may have been the first type of cancer treated with radiation therapy only a few years after X-rays were discovered at the end of the 19th century. Today, radiation therapy can be used to treat individual CTCL lesions (local) or the entire skin surface (total skin). Types of X-rays suitable for treatment of the skin include low orthovoltage X-ray and electron beam is also used. Orthovoltage X-ray can effectively treat recurrent lesions, but its penetration to underlying tissues (blood vessels, muscles, bone marrow) can prove to be a distinct disadvantage if more widespread disease is evident. In contrast to conventional X-rays, electron beam therapy delivers radiation primarily to the layers of involved skin and spares the deeper tissues and organs any radiation effects. In current CTCL care, local x-ray therapy is employed for treatment of isolated skin tumors or ulcerated plaques that don’t respond to other treatments. Orthovoltage X-ray therapy has been gradually replaced by electron beam treatment in many centers.
Electron beam effectively penetrates the superficial portions of the skin (epidermis and dermis). Thus, electron beam therapy (EBT) is extremely effective in clearing most problematic skin manifestations of CTCL. Total skin electron beam therapy (TSEBT) is often reserved for the CTCL patient with extensive skin surface involvement or those that may have proven resistant to less aggressive therapies.
EBT is delivered by experienced radiation oncologists in collaboration with dermatologists and oncologists specializing in the treatment of CTCL. The addition of maintenance PUVA or systemic therapies following TSEBT may reduce disease recurrence.
Acute side effects can include a skin burn/irritation that is much like a moderate to severe sun burn (worse in patients who burn but do not tan when exposed to sun), deep tanning (in those who tan after sun exposure), itching and fatigue. Although these acute side effects are occasionally severe, they are self-limited if appropriate supportive therapy is administered in a timely fashion. Long-term side effects can include generalized dry skin and permanently decreased secretion of sweat and oil on much but not all of the skin, scattered dilated blood vessels (telangectasias), pigmentation changes, and partial or complete scalp hair loss which is more severe in males with signs of thinning hair than in females. A curious side effect is the re-growth of pigmented hair in those who have already gone gray or white and is usually not a source of complaints.