During a course of radiotherapy, patients can expect to see erythema of the skin as part of an acute radiotherapy reaction characterised by desquamation, oozing, crusting of the lesion and increased skin pigmentation. This is usually at its peak by about two to four weeks after radiotherapy and patients should be consented for this and reassured that this is temporary and reversible.
It is recommended that patients are followed up at the skin / radiotherapy clinic. However, some patients may visit their GP who may prescribe antibiotics although, most commonly the skin reaction is not as a result of infection.
Following the acute reaction phase the appearance of the lesion improves, as healed skin grows below. Commonly observed late adverse side effects, seen over subsequent months or years, may include skin de-pigmentation, skin atrophy, telangiectasia and hair loss within the treatment site. These effects are variable and acceptable to most patients if consented properly .
Further information regarding management of radiation skin reactions can be found in the Patient Care topic area.
In the differential diagnosis of a skin lesion, the lesion could be benign or malignant and the malignant lesion could be primary or secondary.
- Benign naevus
- Haemangioma of the nose; for example, ala nasi or tip of nose. These are often unpleasant, bleeding, quite bulky benign tumours that cause concern to the patient and are difficult to treat with surgery as cosmesis is often poor.
- Sebaceous cyst
- Peyronie’s disease; this condition is the development of benign plaque-like lesions within the corpora spongiosa and cavernosum which causes the male patient to have pain on erection and often means that intercourse is not possible because the plaques cause deviation of the penis when erect.
- Epidermal cyst
- Basal cell papilloma (seborrhoeic keratosis)
- Vascular angioma
- Actinic keratosis. This is rarely treated with radiotherapy as topical application of Ibuprofen gel is highly effective.
- Bowen’s disease or squamous cell carcinoma in situ. Cases which are referred for radiotherapy include painful, bleeding lesions which are non responsive to other forms of treatment.
- Erythroplasia of Queyrat; a form of plaque on the glans penis.
- Paget’s disease; this can be skin cancer overlying the nipple and must be treated very seriously as this condition is always associated with breast cancer. Pagets disease of other sites may be benign and therefore should be closely observed.
Malignant Tumours – Primary
- Basal cell carcinoma; malignant tumours that arise in the basal cell layer of the epidermis.
- Squamous cell carcinoma; tumours which arise from squamous cells in the epidermis.
- Lentigo maligna; this is often melanoma in situ which consists of malignant cells which do not show invasive growth and can remain in this non-invasive form for years. It is normally found in the elderly (peak incidence in the sixth to ninth decade), on skin areas with high levels of sun exposure.
- Lentigo maligna melanoma (LMM); this is sometimes called Hutchinson’s melanoma. It usually presents on skin that has had long and frequent sun exposure, such as the face. LMM is characterised by a new mole or brownish patch which spreads flat and outwards. This form of melanoma is slow growing, but may eventually start to grow rapidly and then may ulcerate if left untreated.
- Kaposi’s sarcoma; a tumour caused by Human herpes virus 8 (HHV8) The lesions commonly present as nodules or blotches that may be red, purple, brown, or black, and are usually palpable or raised. They are typically found on the skin, but spread elsewhere is common, specifically to the mouth, gastrointestinal tract and respiratory tract. Growth can range from very slow to fast, and can be associated with significant mortality and morbidity. Nowadays Kaposi’s sarcoma is often seen in patients with HIV but it can also be endemic in patients of Mediterranean or Arabic origin.
- Cutaneous T-cell lymphoma (CTCL); a cancer of the T-lymphocytes which mainly affects the skin. It is caused by the uncontrolled growth of a type of T cells within the skin. Common types of CTCL are mycosis fungoides or Sezary syndrome. Other types of cutaneous lymphoma can be well differentiated and slow growing. Local superficial radiotherapy is a highly effective means of treating these skin lymphomas and even though they appear as separate skin nodules, they can be well controlled and the patients lifespan is unaffected .
- Merkel cell tumour; a rare, highly malignant tumour of the skin, occurring in the dermis and subcutaneous tissues from the Merkel’s cells located in the basal layer of the epidermis. The primary tumour presents as a small, non-ulcerated, painless, bluish red, intradermal nodular mass, often located in sun-exposed areas of the skin. They commonly present on the head and neck region, often on the scalp but they can occur anywhere on the body [2, 7, 8, 9].
- Amelanotic melanoma; A form of melanoma in which the malignant cells (melanocytes) do not make the pigment melanin. Amelanotic melanomas may be pink, red, or have light brown, tan, or grey at the edges and are usually detectable only on close examination of the skin.
- Angiosarcoma; A type of cancer that arises in the lining of blood vessels. This type of tumour tends to be aggressive, recur locally and can spread widely. It can originate anywhere in the body but is well known to arise in skin, soft tissue, liver, breast, spleen, bone, lung and heart.
- Lymphangio sarcoma (also know as Stewart-Treves Syndrome); this is a rare malignant tumour which often occurs as a result of prolonged lymphoedema, following radiotherapy treatment for breast cancer. The sarcoma first appears as a bruise mark or a tender skin nodule. It progresses to an ulcer and finally develops extensive necrosis involving the skin and subcutaneous tissue. It metastasises quickly .
- Atypical fibroxanthoma (AFX); this is a tumour that occurs primarily in older patients after the skin of the head and neck has been damaged significantly by sun exposure and/or therapeutic radiation. Clinically, lesions usually are suggestive of malignancy because they arise rapidly (over just a few weeks or months) in skin in which other skin cancers have been found and treated.
- Melanoma – primary and secondary; a malignant tumour of melanocytes which are found predominantly in skin but also in the bowel and the eye (uveal melanoma). It is one of the rarer types of skin cancer but causes the majority of skin cancer related deaths. Primary melanomas are usually removed by the surgeon whereas secondary melanoma link skin deposits may be suitable for treatment with superficial radiotherapy.
Malignant Tumours: Secondary
- Bone metastases from primary site, commomly breast cancer, lung cancer, colon cancer, prostate cancer, pancreas cancer, or malignant melanoma. These painful bone secondaries can be treated using orthovoltage therapy X–Rays, resulting in excellent palliation for the patient.
Other Conditions that may be treated with superficial or orthovoltage radiotherapy:
- Aneurysmatic bone cyst
- Langerhan’s cell histiocytosis
- Vertebral haemangioma
- Aggressive fibromatosis (also termed villonodular fibromatosis)
- Keloid scars (over production of scar tissue often seen in Afro-Caribbean’s but also in other races) 
- Heterotopic new bone formation; orthovoltage therapy can prevent this from occurring if given immediately pre-operatively prior to the hip replacement operation or a few hours post-operatively.
Information regarding treatment regimes for both benign and malignant conditions can be found in the Dosage and Fractionation topic area.