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Kaposi's Sarcoma
   (KS) is commonly treated with radiation as noted below

ks_purple2.jpg (10906 bytes)

ks_dose_chart.gif (15854 bytes)

literature review of radiation in the treatment of KS

typical purple appearance of Kaposi's Sarcoma skin lesions

other pictures of KS: back, foot, legs, skin
for more on KS go here

Radiation therapy is the most widely used local therapy for the treatment of KS. Most irradiated lesions regress with treatment, but regrowth, often in 4-6 months, is common. Radiation therapy provides effective palliation of cosmetically disturbing lesions or localized bulky symptomatic disease at any site.

Electron beam therapy, which has limited penetration beyond the dermis, is effective for superficial lesions and generally provides good cosmetic results. Initially, raised lesions flatten, lesion size may decrease, and a violaceous lesion generally changes to a tan-brown, hyperpigmented spot. Genital KS associated with pain, difficulty with urination, or psychologic discomfort may be well palliated with electron beam therapy without significant toxicity.

Conventional beam irradiation is a good choice for deep or bulky lesions. No standard dosing schedule for radiation can be recommended. Responses have been seen with dosing schedules ranging from single doses of 800 cGy to fractionated schemes with total doses exceeding 4,000 cGy.The optimal radiation schedule and dose are defined by the goals of therapy. A randomized, prospective trial of three radiation doses and schedules (40 Gy in 20 fractions, 20 Gy in fractionated doses, or a single 8 Gy dose) observed a greater time to treatment failure and the least residual cutaneous pigmentation for lesions treated with 40 Gy.

Radiation therapy is effective in treating oral cavity lesions, but because of the significant risk of radiation-induced mucositis, this therapy should be reserved for symptomatic disease. To minimize the morbidity of oral cavity irradiation, patients should be aggressively pretreated for local fungal and herpetic infections, and prescribed use of an antibacterial mouthwash.

Edema secondary to lymphatic obstruction may be palliated with radiation, but the benefit is often short-lived and may be complicated by brawny induration, fibrosis, or ulceration, particularly in previously irradiated fields. With the exception of patients with very limited survival expectations, radiation therapy for symptomatic visceral KS is not recommended.

 

Radiation therapy for AIDS-related Kaposi's Sarcoma.

  Int J Radiat Oncol Biol Phys. 1990 Sep;19(3):569-75.

Source

Department of Radiation Oncology, University of California, San Francisco 94143.

Abstract

Between March 1982 and October 1987, 375 fields in 187 patients with AIDS-related Kaposi's Sarcoma were treated in the Department of Radiation Oncology at the University of California in San Francisco (UCSF). Field sizes ranging from 2 x 2 cm to total skin received doses of 8 Gy in a single fraction to 15-40 Gy in 5-10 fractions. Seventy-four percent of the patients have died. Response to treatment was achieved in over 90% of treated fields, with a median time to progression of 21 months and an actuarial freedom from relapse at 6 months of 69% (97 patients alive). There was no difference in outcome regardless of the fractionation regimen used. Severe reactions were noted in 17% of treated fields, but this incidence was significantly lower when a single fraction of 8 Gy was used (p less than 0.001). Radiation therapy plays an important palliative role in this devastating disease. This review supports the use of a single 8 Gy fraction for all Kaposi's Sarcoma lesions of the skin. Further data regarding single fraction therapy for lesions of other sites are needed.

A randomized prospective trial of radiation therapy for AIDS-associated Kaposi's sarcoma

IJROBP 1993;27:1057

: The optimal dose of radiation in the treatment of AIDS-associated Kaposi's sarcoma has been controversial based on previous nonrandomized retrospective studies.

: Seventy-one cutaneous AIDS-associated Kaposi's sarcoma lesions were randomly assigned to 1 of 3 radiation dose regimens-8 Gy in 1 fraction, 20 Gy in 10 fraction. and 40 Gy in 20 fractions. Lesions were measured prior to and following treatment. Complete resolution of palpable tumor was considered a complete response, regardless of residual purple pigmentation. Reduction in palpable tumor to less than 50% of pretreatment area was considered an objective response. Less than 50% reduction in tumor size was considered a nonresponse.

: Complete response was higher with 40 Gy (83%) and 20 Gy (79%) than with 8 Gy (50%). Absence of residual purple pigmentation was greater (p = .005) with 40 Gy (43%) than with 20 Gy (8%) or 8 Gy (8%). Lesion failure was lower (p = .03) with 40 Gy (52%) than with 20 Gy (67%) or 8 Gy (88%). Median time to failure was 43 weeks with 40 Gy, 26 weeks with 20 Gy, and 13 weeks with 8 Gy (p = .003).

: Fractionated radiotherapy to higher total doses resulted in improved response and control of cutaneousKaposi's sarcoma. This dose-dependence should be considered in determining the optimal radiotherapeutic regimen for individual patients treated for epidemic Kaposi's sarcoma.