Dear OncoLink "Ask The Experts,"
Can a person with Xeroderma Pigmentosa (XP) use radiation therapy to treat melanoma?
Carolyn Vachani RN, MSN, AOCN, OncoLink's Medical Correspondent, responds:
There are a few issues here. For starters, melanoma is not very sensitive to radiation , meaning radiation does not usually work very well against melanoma cells. Radiation may be used on occasion to treat an isolated spot, such as a local recurrence in someone with stage III disease, or a metastatic lesion in the brain.
That being said, there are several issues to consider regarding giving radiation to someone with XP. XP is a condition in which patients have an abnormal sensitivity to ultraviolet (UV) light, thus putting them at very high risk of developing skin cancers like melanoma. These patients are unable to effectively repair DNA damage. However, radiation therapy is not comprised of UV light, but rather of high-energy x-rays, which are a different type of ionizing radiation included in the electromagnetic energy spectrum. So from this standpoint, it seems that radiation would be ok in XP patients -- in theory. In practice, however, most radiation oncologists would avoid using radiation in XP patients unless absolutely necessary. Radiation therapy can cause skin burns or blisters in an average non-XP patient, and the fear is that these side effects could be far worse in a patient with XP.
Given the other, (likely) more effective treatments available for melanoma, radiation therapy should probably be avoided in patients with underlying XP.
Nov 2, 2012 - Mice with an inactivating mutation in the melanocortin 1 receptor gene, which controls pigment production, have a phenotype similar to red hair/fair skin in humans; these mice have an increased risk of melanoma, even in the absence of ultraviolet radiation exposure, which may act by a mechanism of oxidative damage, according to a study published online Oct. 31 in Nature.
Oct 30, 2014
May 9, 2012