Volumetric modulated arc therapy (VMAT) for extensive skin field cancerisation (ESFC) – exploring the limits of treatment volumes with a case series of backs

Abstract

Skin field cancerisation arises from prolonged sun exposure and increases with age. Multiple areas of the skin can be involved resulting in poor quality of life and cosmesis and even death. The long-term efficacy of traditional treatments such as topical creams is disappointing. Volumetric modulated arc therapy (VMAT) is a relatively new radiation technique that allows the definitive treatment of large convex fields. Extra dose can also be delivered simultaneously using a boost technique to proven areas of macroscopic invasive disease. In what we believe is the first publication of its kind, we present a retrospective case series of 15 patients with 21 areas treated with VMAT to the back. Treatment is feasible but areas of skin cancerisation over 800 cm2 should not be treated in one course but broken into smaller fields separated by adequate breaks. Care should be taken when treating large areas of the spine as pancytopenia may result and routine blood counts between treatment courses should be considered. More research is warranted to confirm the dose and efficacy outcomes, but this technique may represent a new therapeutic option for patients with extensive skin field cancerisation of the back.

Circumferential volumetric modulated arc radiotherapy of the lower legs–a technique described in a case of disseminated superficial actinic porokeratosis

“…Prolonging the break until resolution is an option rather than ceasing treatment. Difficulties in completing the prescription were expected as the PTVs were both over the 800cm 3 limit suggested by Wong et al 12 3. Tape measurement at 15cm superior from the medial malleolus showed the most change compared with more inferior levels.…”

“…3. The PTVs were larger than the size when breaking up the PTV into smaller for sequential treatment is advised 12 .…”

Radiotherapy, Utilizing Volumetric Modulated Arc Therapy, for Extensive Skin Field Cancerization: A Retrospective Case Series Assessing Efficacy, Safety, and Cosmetic Outcomes at 12 Months After Treatment

“…Our case series also suggests that radiotherapy is potentially a durable salvage option following previous treatment failure. One explanation for its efficacy is that VMAT technique can deliver targeted doses to target volumes up to a depth of 5mm, thus including skin appendages, such as sweat glands and hair follicles, potentially alleviating sanctuary sites for malignant keratinocytes [ 14 ].…”

Wide‐field radiation therapy for skin cancerisation – Have we forgotten what we learned?

“…Areas treated for over a 1000 cm 2 have been documented in this setting using VMAT (Volumetric Modulated Arc Therapy). 5 Highly conformal RT delivery modalities, such as VMAT, do not represent RT with different biological effects, but merely a technological advance in delivery. It allows the use of megavoltage photons tangentially to treat skin, with the ability to optimise dose distribution using inverse planning.…”

“…Despite the lack of evidence, there has been recent enthusiasm and promotion from a minority of Australian radiation oncologists (RO) and groups for recommending long course (5–6 weeks) RT in the setting of the so‐called skin field cancerisation (SFC), an as yet not well‐defined entity which includes areas of chronically ultraviolet exposed skin exhibiting a spectrum of changes that may include multiple AKs, IEC and invasive KC. Areas treated for over a 1000 cm 2 have been documented in this setting using VMAT (Volumetric Modulated Arc Therapy) 5 …”