Megavoltage radiotherapy using water bolus in the treatment of Kaposi's sarcoma

Endemic Kaposi's Sarcoma

Kaposi's sarcoma (KS) is a common neoplasm in Eastern and central Africa reflecting the spread of human gammaherpesvirus-8 (HHV-8), now considered a necessary causal agent for the development of KS. The endemic KS subtype can follow an aggressive clinical course with ulcerative skin lesions with soft tissue invasion or even bone or visceral involvement. In the latter cases, a thorough imaging work-up and better follow-up schedules are warranted. As KS is a chronic disease, the therapeutic goal is to obtain sustainable remission in cutaneous and visceral lesions and a good quality of life. Watchful monitoring may be sufficient in localized cutaneous forms. Potential therapeutic modalities for symptomatic advanced KS include systemic chemotherapies, immunomodulators, immune checkpoint inhibitors, and antiangiogenic drugs.

Clinical implementation of a wide-field electron arc technique with a scatterer for widespread Kaposi's sarcoma in the distal extremities

A novel wide-field electron arc technique with a scatterer is implemented for widespread Kaposi's sarcoma (KS) in the distal extremities. Monte Carlo beam modeling for electron arc beams was established to achieve <2% deviation from the measurements, and used for dose calculation. MC-based electron arc plan was performed using CT images of a foot and leg mimicking phantom and compared with in-vivo measurement data. We enrolled one patient with recurrent KS on the lower extremities who had been treated with photon radiation therapy. The 4- and 6-MeV electron arc plans were created, and then compared to two photon plans: two opposite photon beam and volumetric modulated arc with bolus. Compared to the two photon techniques, the electron arc plans resulted in superior dose saving to normal organs beneath the skin region, although it shows inferior coverage and homogeneity for PTV. The electron arc treatment technique with scatterer was successfully implemented for the treatment of widespread KS in the distal extremities with lower radiation exposure to the normal organs beyond the skin lesions, which could be a treatment option for recurrent skin cancer in the extremities.

An Update on Kaposi's Sarcoma: Epidemiology, Pathogenesis and Treatment

Kaposi’s sarcoma is an angioproliferative neoplasm which has undergone considerable epidemiologic change since the original description by Moritz Kaposi in the late 1800s. This opportunistic neoplasm gained widespread notoriety within the US during the height of the AIDS epidemic, where it was frequently found co-occurring with opportunistic infections. With the advent of modern antiretroviral therapies, as well as an increasing number of individuals on immunosuppression for autoimmune disease or organ transplantation, the landscape of the immunocompromised individual has changed. It is now important for clinicians to be mindful of Kaposi’s sarcoma manifesting in a growing variety of clinical contexts.

Evaluation of treatment plans using various treatment techniques for the radiotherapy of cutaneous Kaposi's sarcoma developed on the skin of feet

The purpose of this study was to investigate the plan qualities of various treatment modalities for the radiotherapy of cutaneous Kaposi's sarcoma developed on the skin of the foot. A total of six virtual targets were generated on the skin of the foot in CT images. Five types of treatment plans were generated using photon beams (PB), electron beams (EB), high‐dose‐rate (HDR) brachytherapy with a Freiburg flap applicator, intensity‐modulated radiation therapy (IMRT), and volumetric‐modulated arc therapy (VMAT) techniques. Plans for each of the six targets (single‐target plans) and also for the combined target consisting of the six single targets combined (multitarget plans) were generated. Dose‐volumetric analysis was performed for the targets and normal tissues. The averaged conformity index (CI) and homogeneity index (HI) values for each single target using PB, EB, HDR, IMRT, and VMAT techniques were 1.97, 2.39, 1.60, 4.60, and 0.80 and 1.05, 1.11, 1.52, 1.04, and 1.04, respectively. For the multitarget, the CI values were 3.99, 5.08, 1.38, 1.95, and 0.84, and the values of HI were 1.10, 1.36, 1.43, 1.06, and 1.04, respectively. The averaged mean doses to normal tissue were 2.5, 2.7, 3.6, 1.7, and 2.9 Gy for single‐target plans, and 21.3, 14.6, 14.2, 14.3, and 13.0 Gy for the multitarget plans, respectively. The VMAT demonstrated dosimetric advantages and better treatment efficiency over other techniques for the radiotherapy of multifocal skin disease of the feet.

PACS number: 87.55.dk

Treatments for classic Kaposi sarcoma: a systematic review of the literature

BACKGROUND

Treatment guidelines are lacking for classic Kaposi sarcoma.

OBJECTIVE

We sought to review the evidence on efficacy of treatments for classic Kaposi sarcoma.

METHODS

Articles published in English or French in MEDLINE, Trip, Cochrane Library, and Pascal databases from 1980 to December 2010 were screened. Studies reporting at least 5 patients treated for histologically confirmed classic Kaposi sarcoma were selected. Primary outcome was a decrease in the number or size of lesions or of lymphedema. We reviewed 26 articles matching the inclusion criteria for methodologic quality, classifying them according to World Health Organization criteria.

RESULTS

The percentage of patients with a 50% or greater decrease in lesions was 71% to 100% for pegylated liposomal doxorubicin, 58% to 90% for vinca-alkaloids, 74% to 76% for etoposide, 93% to 100% for taxanes, 100% for gemcitabine, 97% for the combination of vinblastine and bleomycin, 71% to 100% for interferon alfa-2, 43% for thalidomide, and 12% for indinavir. For local treatments, a decrease of 50% or greater was achieved in 62% of lesions for intralesional vincristine, 50% to 90% for intralesional interferon alfa-2, 56% for imiquimod, and 25% for nicotine patches. A complete response was attained in 60% to 93% of lesions with radiotherapy.

LIMITATIONS

Eligible trials were of poor quality. The lack of standardized classification of disease activity and clinical outcomes precluded the comparison of studies.

CONCLUSION

The evidence for efficacy of any particular intervention is of low quality and does not support recommending any particular therapeutic strategy. Further studies are required and it will be important to standardize the assessment of disease activity and clinical response.

Results of Radiation Therapy for Treatment of Classic Kaposi Sarcoma

Background:

Classic Kaposi sarcoma (CKS) is a vascular neoplasm that primarily affects men of Mediterranean and Ashkenazi Jewish descent. A variety of therapeutic options exist, and choice of treatment depends on clinical form and stage, as well as lesion location and size; options include surgical excision, intralesional interferon α-2b, local or extended field radiotherapy, and chemotherapy.

Objective:

The aim of this study was to review the outcome of radiation therapy in the treatment of CKS at a single institution.

Methods:

This retrospective study reviewed patients who receive radiation therapy for histologically confirmed CKS between 1994 and 2006.

Results:

Sixteen patients were reviewed; the mean age at diagnosis was 74 years, and 13 patients were male. Fifteen patients (94%) presented with leg lesions, and two patients (12.5%) presented with arm lesions. The most commonly prescribed radiation dose was 30 Gy in 15 daily fractions of 2 Gy. All lesions responded to treatment, with a complete response rate of 88% and a partial response rate of 12%. Toxicity was limited to grade I dermatitis (four patients) and grade II dermatitis (two patients).

Conclusion:

Radiation therapy is an effective treatment modality for CKS and is associated with minimal toxicity.

The conversion of air splints to provide buildup bolus in the treatment of extremities with skin involvement

An alternate method for bolusing superficial skin lesions of extremities during photon beam treatment was reviewed. Emergency first-aid air splints were filled with water and used as bolus in the treatment of a Kaposi's sarcoma of the leg. Large parallel-opposed 6-MV photon beams were employed. Sheets of bolus were placed under the air splint bolus to ensure coverage of the posterior skin surface. Computerized tomography was performed demonstrating conformity of the air splint bolus to the leg. A diode measurement verified adequate dose to the skin. The results confirm that by adding water to an emergency first-aid air splint to use as bolus was practical, reproducible, and aided in the accurate delivery of a homogenous dose to the skin surface of involved extremities.

Dosimetric considerations of water-based bolus for irradiation of extremities

The dosimetry of high-energy photon beams in the treatment of superficial lesions occurring in extremities was examined. Large parallel-opposed fields with different photon beam energies were used. The extremity was immersed in water contained in a commercially available plastic wastebasket. The water bolus serves to even out the surface irregularities of the extremities and to remove the skin sparing effect. A polystyrene block was placed at the floor of the wastebasket to ensure that the extremity was encompassed in the radiation fields. The photon beam energies considered were 4 MV, 6 MV, 10 MV, and 24 MV. The results show that the dose distributions are more homogeneous with higher photon beam energies. The isodose lines are more constricted at mid-plane for low energy photon beams. Higher energy photon beams, 10 MV and up would be preferable for the treatment of superficial lesions of the extremities immersed in water bolus contained in a typical wastebasket size.

Radiation therapy for non-AIDS associated (classic and endemic African) and epidemic Kaposi's sarcoma

PURPOSE

A retrospective analysis of patients with non-AIDS and AIDS-related Kaposi's sarcoma, who were treated with radiation therapy.

METHODS AND MATERIALS

Between 1978 and 1992, 56 patients with one of the three major types (classical, endemic, epidemic) of Kaposi's sarcoma received radiation therapy as their sole treatment modality. Extent of fields, daily fractionation, and total dose were applied on a clinical basis. These lesions received superficial x-ray therapy, Co-60 teletherapy, or 6-8 MeV electron beams. Field sizes depended on extent of the lesion. Total dose administration ranged from 8-12 Gy in one exposure, or a total of 24-30 Gy fractionated over 2-3 weeks.

RESULTS

The majority of patients responded to radiation therapy. Symptomatic relief was achieved in 80-100% of patients irrespective of the type of Kaposi's sarcoma, treatment modality, or schedule. Side effects were tolerable in all but three patients with epidemic type Kaposi's sarcoma, who developed severe mucositis.

CONCLUSION

Radiotherapy is the most useful mode of palliative treatment for all forms of Kaposi's sarcoma in southern African patients.

Comparison of dose distribution by means of bolus versus water bath phantom techniques in treatment of cutaneous sarcoma of an extremity

Cutaneous involvement by Kaposi's sarcoma (KS) is frequently diffuse, requiring large field irradiation. Selective tissue compensation techniques, accomplished with either a 1.5 cm bolus cast or water bath phantom, are compared. Dosimetric determinations were performed using 6 MVX with bone heterogeneity corrections. Application of 1.5 cm bolus effectively eliminated dose buildup and provided tissue compensation equivalent to water bath phantom technique. Treatment of other cutaneous malignancies, such as angiosarcoma, requiring higher total doses, should be accompanied by dosimetric evaluation, because cutaneous and midline dose inhomogeneity may result in a significant total dose differential over the target volume. Application of 1.5 cm bolus improved accuracy in treatment positioning, eliminated concerns regarding infection control in AIDS-related KS, and provided dose homogeneity comparable to the more standard water bath phantom technique.