Radiotherapy of Benign Disease
Radiation therapy was once widely used in the treatment of benign diseases. Leer et al (1996) reported that in 1948, at the Rotterdam Radiotherapeutic Institute, 3348 benign disorders were irradiated compared with 857 malignant tumours. Early therapeutic applications of radiation in Australia included the treatment of ringworm (Johnson, 1954).
Benignity can be defined in a couple of ways. When discussing tumours, benignity implies an inability to metastasise or invade neighbouring tissues (i.e. non-malignancy). Radiotherapy is commonly used in the treatment of benign intercranial tumours such as meningiomas. More generally speaking, benign is a label to describe conditions that are not life threatening. In some radiotherapy centres, more than 10% of patients are treated for non-malignant conditions.
Within the radiation therapy literature, the meaning of benign varies: reviews of benign treatments often omit benign tumours, but include potentially life threatening abnormalities such as arteriovenous malformations. This post explores a selection of benign (that is, non-malignant) conditions for which radiation therapy is still used clinically in treatment.
Radiation therapy has been used a treatment for cerebral arteriovenous malformations, abnormal connections between arteries and veins, which can result in a variety of neurological symptoms (e.g. dizziness and confusion). Radiation induces an inflammatory response in the vessel walls of the malformation with ultimate thrombosis, progressively obliterating the malformation (Ogilvy, 1990).
Dupuytren’s contracture is a connective tissue disorder which causes a contracture of the palmar fascia, which can result in fingers bent towards the palm (unable to be straightened). Radiation therapy has been used to treat early stage Dupuytren’s contracture, with minimal acute toxicity (Seegenschmiedt et al., 2001). Ledderhose’s disease, or plantar fibromatosis, is a similar condition that involves the thickening of the plantar fascia (in the foot), and has also been treated with radiation therapy (Seegenschmiedt et al. 2008).
Graves’ Ophthalmopathy is an auto-immune disorder causing inflammation in the orbits, which commonly presents as a retraction of the eyelids. A report by Bradley et al (2008) reviewed 14 studies (5 observational and 9 randomised clinical trials) covering over 1500 patient cases, evaluating clinical response (generally positive), complication incidence (no reported radiation induced malignancy and cataracts developing in approximately 10% of cases in observational studies). The most common dose was 20 Gy delivered over 10 fractions.
Radiation therapy can be employed prophylactically after hip arthroplasty or spinal cord injury for the prevention of heterotopic ossification, the formation of bone within soft tissue. It is hypothesized that osteoprogenitor cells, which can differentiate into osteoblasts (in bones) or chondrocytes (incartilage), is particularly radiosensitive (Balboni et al., 2006).
A keloid is an overgrowth of collagen within scar tissue, resulting in a lesion or nodule that can be accompanied by discomfort. Keloid scars are particularly refractory to therapeutic modalities other than radiation therapy, which has been used as a treatment since 1906 (Botwood et al., 1999). Electron beam irradiation has offered high control rates with minimal side effects (Maarouf et al., 2002).
Meningiomas are benign tumours originating in the brain and spinal cord meninges and represent approximately 15-20% of all central nervous system neoplasms (Miralbell et al., 1992). Radiation therapy is often employed as a treatment either following or in lieu of surgical resection, which is the treatment of choice for accessible meningiomas.
Pterygium is a benign growth of the conjunctiva which can be treated using radioactive strontium-90 plaques (or applicators), sometimes combined with surgical excision.
Trigeminal neuralgia is a neuropathic disorder characterized by debilitating pain from the trigeminal nerve, for which radiation therapy is used as a second-line treatment modality (Karam et al., 2014). Treatment involves the delivery of a high dose (e.g. 70 Gy) using small fields (e.g. 5 mm) focused on the trigeminal nerve/
- Balboni TA, Gobezie R and Mamon HJ, 2006. Heterotopic ossification: pathophysiology, clinical features and the role of radiotherapy for prophylaxis. International Journal of Radiation Oncology Biology Physics, 65(5): 1289-1299.
- Botwood N, Lewanski C and Lowdell C, 1999. The risks of treating keloids with radiotherapy, The British Journal of Radiology, 72: 1222-1224.
- Bradley EA, Gower EW, Bradley DJ, Meyer DR, Cahill KV, Custer PL, Holck DE and Woog JD, 2008. Orbital radiation for Graves Ophthalmopathy: a report by the American Academy of Ophthalmology, Ophthalmology, 115(2): 398-409.
- Johnson A, 1954. A note on the early use of radiotherapy in skin diseases in Australia, Australasian Journal of Dermatology 2(3): 149-152.
- Karam SD, Tai A, Snider JW, Bhatia S, Bedrick EJ, Rashid A, Jay A, Kalhorn C, Nair N, Harter KW, Collins SP and Jean W, 2014. Refractory trigeminal neuralgia treatment outcomes following CyberKnife radiosurgery, Radiation Oncology, 9: 257.
- Maarouf M, Schleicher U, Schmachtenberg A and Ammon J, 2002. Radiotherapy in the management of Keloids: clinical experience with electron beam irradiation and comparison with x-ray therapy, Strahlentherapie und Onkologie, 178(6): 330-335.
- Micke O and Seegenschmiedt MH, German Working Group on Radiotherapy of Benign Diseases, 2002. Consensus guidelines for radiation therapy of benign diseases: a multicenter approach in Germany, International Journal of Radiation Oncology Biology Physics, 52(2): 496-513.
- Miralbell R, Linggood RM, de la Monte S, Convery K, Munzenrider JE and Mirimanoff RO, 1992. The role of radiotherapy in the treatment of subtotally resected benign meningiomas, Journal of Neuro-Oncology, 13: 157-165.
- Ogilvy SC, 1990. Radiation Therapy for Arteriovenous Malformations: A Review, Neurosurgery, 26(5): 725-735.
- Seegenschmiedt MH, Makoski H-B, Trott K-R and Brady LW, 2008. Radiotherapy for non-malignant disorders: contemporary concepts and clinical results. Springer, Berlin, Germany.
- Seegenschmiedt MH, Olschewski T and Guntrum F, 2001. Radiotherapy optimization in early-stage Dupuytren’s contracture: first results of a randomized clinical study, International Journal of Radiation Oncology Biology Physics, 49(3): 785-798.
- Trott K-R and Kamprad F, 2005. Estimation of Cancer Risks from Radiotherapy of Benign Diseases, Strahlentherapie und Onkologie, 182(8): 431-436.