Journal of Clinical and Aesthetic Dermatology

AUG 2017

An evidence-based, peer-reviewed journal for practicing clinicians in the field of dermatology

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of this form of radiation therapy may be cumbersome for the physician and patient, as many treatment sessions must be administered within a short period of time. an even more cumbersome form of brachytherapy is low-dose- rate brachytherapy during which a patient is confined in a lead-coated chamber for up to 64 hours while the brachytherapy is being administered. although this has been used effectively for the treatment of keloids, it is now rarely used due to its inconvenience. 24 an easier form of brachytherapy is hdR superficial or surface-conforming brachytherapy during which the catheter is fixed externally onto the skin. this form of brachytherapy is helpful for long keloids. Kuribayashi et al 25 studied 36 keloids with a median length of 8.5cm treated with excision followed by hdR superficial brachytherapy using an iridium-192 source. the applicator was fixed to the skin with a spacer, and the keloids on high-tension sites were treated with 20Gy in four daily fractions, while keloids in other areas were treated with 15Gy in three daily fractions; there was a 9.7-percent recurrence at 12 months. hdR superficial brachytherapy can be advantageous over electron beam radiotherapy for keloids with uneven surfaces, as the applicator can be molded to the surface of the skin so that there are no variations in the distance between the skin surface and radiation source. 25 COMPLICATIONS the acute skin side effects of temporary erythema are seen in almost all patients during the first 7 to 10 days after treatment and are related to the total dose of radiation that is given. the late side effects are observed weeks later and include pigmentary changes that are generally temporary and mild. the late side effects are related to the dose given per session or fraction (table 2). 9,10,19,26 in order to reduce the chances of these side effects, it is important to use an emollient and a steroid ointment after radiation, reduce the single dose of irradiation per fraction while keeping the total dose unchanged, or lengthen the irradiation interval. 10 as patients with darker skin types are more prone to developing keloids, it is important to note that pigmentary changes were found most commonly in types 5 and 6 african american individuals. 23 Recurrence of keloids treated with postsurgical radiation was found to be significantly increased in subjects who developed the keloid after infection and those with a family history of keloids. 6 as keloids are a benign skin condition, there is a question of whether radiotherapy is an appropriate modality for treatment. a review of the literature by ogawa et al in 2009 26 yielded a total of five cases of carcinogenesis associated with radiation therapy for keloids: fibrosarcoma, basal cell carcinoma, thyroid carcinoma, and breast carcinoma. in each of these cases, it is unclear whether an appropriate dose of radiation was used or if there was adequate protection of surrounding tissues. as such, the authors concluded that radiation is useful if sensitive tissues, such as the mammary gland or 14 JCAD JOURNAL OF CLINICAL AND AESTHETIC DERMATOLOGY august 2017 • volume 10 • number 8 R e v i e w TABLE 1. types of radiotherapy T YPE MECHANISM OF RADIATION DEPTH OF PENETRATION ADVANTAGES DISADVANTAGES electron beam electrons delivered via linear accelerator X-Ray (photon) beams Radioactive source emitting gamma rays delivered via catheter Radioactive source emitting gamma rays delivered via catheter superscial/ orthovoltage 2–6cm 5mm/2cm inserted into target tissue Fixed onto skin high-dose-rate (hdR) interstitial brachytherapy • treats superscially without damage to underlying structures • Can treat broad area of skin without radiation dose drop-off • treats superscially without damage to underlying structures • inexpensive and easy to use involves less normal tissue Good for long keloids and uneven surfaces hdR superscial (surface conforming) Brachytherapy • Cannot use on curved surfaces • need linear accelerator dose of radiation drops off at periphery so have uneven dose delivery total dose must be delivered in short time frame total dose must be delivered in short time frame TABLE 2. Complications of radiotherapy POST-RADIATION TREATMENT RELATED TO COMPLICATION T YPE acute (within 7–10 days after radiation) total dose of radiation given erythema, edema, desquamation, ulceration, necrosis late (weeks to months after radiation) dose of radiation given per session or fraction pigmentary changes (hypo- or hyperpigmentation), atrophy, alopecia, telangiectasias

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