Radiation Induced Skin Reactions Flashcards
(36 cards)
Effects of Acute Radiation Skin Reactions
- Physical discomfort and pain
- Itching
- Difficulty with movement of a limb or ambulation
- Sleep impairment
- Difficulty with wearing clothing
Severe Skin Reactions
• May have a dose limiting impact on treatment or treatment breaks may be required
Late Skin Reactions
- May occur months to years after treatment
* Can result from extracellular matric alterations and the deposition of collagen during the healing phases
Reactions Directly From Radiation
- Occur most frequently within the first four weeks of treatment
- Epidermal regeneration, healing and resolution occurring within three to five weeks following treatment
- Complete healing can take up to three months
Physiology of a Reaction
- Radiation accelerates the destruction of basal cells
- End result is inflammation, epidermal cell apoptosis and a reduction and alteration in normal epithelial stem cells
- Collagen formed is immature or insufficient (doesn’t meet demands of normal wound healing)
Transient Erythema
- May occur within hours of commencing treatment within the treatment field
- Due to capillary dilation in the dermis and oedema as a result of increased vascularity and obstruction
- Red and warm skin surface, may have a rash-like appearance
Other Changes in the Skin
• Changes in pigmentation, interrupted hair growth, changes to the sweat and sebaceous glands
Hyperpigmentation
- Melanin cells migrate to more superficial layers of the epidermis due to increase cellular destruction
- May appear as a moderate tan
- Occurs after two to four weeks of treatment
- Normal Skin tone returns within three months following the last radiation treatment
Dose Relation to Reaction
• Total hair loss within the radiation field can occur with doses higher than 55 gray
o May take two to three months to regrow following treatment
• Sweat and sebaceous glands may be permanently destroyed after a cumulative dose of 30 Gy
o Leads to reduction in skin lubrication and increase in dryness and pruritus (itchy skin)
Repair Following Acute Injuries
- Normal tissue repair caused by the migration of epithelial cells from the basal membrane through homeostatic stimulation, proliferation and cellular differentiation begins 10 – 14 days following treatment
- Migration of these cells across the irradiated field is improved with a moist wound healing environment (shown to heal wounds 50% faster than a non-moist wound healing environment
Types and Severity of Acute Skin Reactions
- Many patients don’t experience noticeable changes within first two weeks with a daily fraction of 1.8 – 2 Gy
- When cumulative dose reaches 20Gy – patient may experience dryness, pruritus, flaking of the skin or dry desquamation
- At doses exceeding 30Gy – extra capillary cell damage may occur, resulting in increased capillary blood flow and oedema
- At doses 40-60 Gy – if severe, there is epilation leading to moist desquamation including arterial thrombi, fibrinous exudate, oedema and considerable pain
Desquamation
Sloughing of the epithelium with potential exposure of the dermal layer of skin
Factors increasing Risk of Moist Desquamation
- Friction
- Skinfolds
- Use of bolus material (as it increases skin dose)
- Addition of chemotherapy
Moist Desquamation
- Dermis is exposed
- The treatment field is moist and tender with oozing and leaking of serous fluid
- Light or heavy exudate and crusting may be present
Treatment Related Risk Factors for Acute Skin Reactions
- Location of the treatment field (e.g., head and neck, breast, axilla, perineum, skinfolds)
- Large volume of tissue being treated
- Total dose of radiation
- Larger fraction size (>2Gy / fraction)
- Accelerated fractionation treatments
- A longer treatment duration
- The type of energy resulting in a higher skin dose
- Use of tangential fields
- Use of tissue equivalent or bolus material
Patient Related Risk Factors for Increased Skin Reaction
- Areas of thin o smooth epidermis
- Areas of skin-to-skin contact
- Previous lymphocele aspiration
- Areas of compromised skin integrity within the treatment field (burns, lesions, existing surgical incisions, scars, planned postoperative radiation)
- Presence of comorbidities (e.g., diabetes, renal failure)
- Poor Nutritional Status
- Older Age
- Inclusion of drug therapy (e.g., chemotherapy)
- Patient race and skin routine
Radiation Recall Dermatitis
- An acute inflammatory response in a previously irradiated treatment field following the administration of an inciting systemic drug
- Most frequently associated with MV radiation
- Can also occur within the mucosa, muscles and organs
- Appears as dermatitis but can range from a mild erythema or a pruritic rash to a severe exfoliative dermatitis
Late Effects
- May be identified as persistent, non-healing skin reactions
- True late radiation-induced changes may take months or years to develop, become progressive and vary in severity
- May appear as transient oedematous changes, hyperpigmentation, hypopigmentation resulting from the destruction of melanocytes and telangiectasia
Telangiectasia
- Appears as reddened spider like veins close to the skin surface within the treatment fields
- Caused by damage to and stretching of the small vessels
Late Effects are Associated with:
- Larger total treatment dose and volume of irradiated tissue
- A dose per fraction > 2 Gy and higher daily dose
- Other therapies including chemo
- Patients age and general medical condition
- Comorbidities (e.g., diabetes, collage vascular disorders)
- Individual genetic factors
- Radiation fibrosis
- Atrophy
Advantages of Preoperative Radiation
- Smaller treatment volumes and radiation fields, lower radiation doses (less tumour cell hypoxia), surgery being performed on more normal blood vessels (fewer hypoxic and radioresistant cells
- Been shown to reduce risk of recurrence in soft tissue sarcoma and improve survival rates in rectal cancer
Disadvantages with Preoperative Radiation
- Increased wound complications
* Difficulties associated with interpreting postsurgical pathology specimens
Advantages of Postoperative Radiation
- Lower risk and fewer short term wound complications
* Access to a full pathology report
Disadvantages of Postoperative Radiation
- Needs for a larger radiation treatment field and volume (need to encompass the original tumour volume prior to surgery)
- Concern that treatment may be compromised if there is a wide surgical disruption of tissues
- Risk of enhanced late toxicity
- Higher risk of fractures (in patients with sarcoma)