Guide: Non melanoma skin cancer
- Non-melanoma skin cancers (NMSC) are the most common cancers in Australia.
- Solar radiation is the major cause.
- Over 434,000 people are treated for one or more non-melanoma skin cancers in Australia each year.
- GPs play a pivotal role in the early detection and management of NMSC.
- The first opportunity for treatment is the best strategy to achieve cure.
- Uncomplicated small tumours are best removed by an elliptical excision with a 3mm margin for BCC and 4mm margin for SCC. The wounds should be closed by primary suture.
- Caution should be used in the management of tumours on the face including the ears, lip and around the eyes — consider referral.
- It is important to be aware of guidelines for referral.
- Consider opportunistic screening with a total-body cutaneous examination in all patients over the age of 40.
- Education in sun-smart behaviour is vital.
- Protection against solar radiation is recommended. Where possible, shade areas should be provided or sought when outdoors. Protective clothing should be worn because it provides the best means of photo-protection.
- Broad-spectrum sunscreens with an SPF of 15 or greater may be used as an adjunct to sun avoidance and together with other sun-protective measures.
Squamous cell carcinoma (SCC)
- Second most common skin cancer in Australia.
- Erythematous squamoproliferative lesions that may grow over months.
- Commonly tender on palpation.
- Occur predominantly in areas that have been heavily exposed to sunlight (head and neck, limbs and upper trunk).
- Up to 1% of SCCs may metastasise, with a greater risk of secondary spread occurring in lesions on the ear, lower lip and scalp.
- SCC behaves more aggressively in patients with chronic lymphocytic leukaemia.
- Patients on long-term immunosuppressants are at increased risk of developing both primary SCCs and metastatic disease.
Basal cell carcinoma (BCC)
- Slow growing invasive epithelial tumours, arising from the basal layer of the epidermis.
- The most common skin cancer.
- Fifty percent of lesions occur on the head and neck,30% on the upper trunk and the remainder on the limbs.
- May present as a pearly papule, a crusted or haemorrhagic ulcer, an erythematous scaly plaque or an infiltrating scar-like plaque (morphoeic BCC).
- Occasionally a BCC may be pigmented, resembling a melanoma.
- Metastasis is exceedingly rare, but can cause extensive local destruction if left untreated.
3 Types: a. Solar keratosis
- Erythematous and hyperkeratotic lesions.
- Commonly found on chronically sun-exposed skin (most frequently on the dorsal hands, forearms, face and, in balding men, the scalp).
- Vary in size from 2 to 20 mm in diameter and commonly occur as multiple lesions (field change).
- Usually asymptomatic, occasional stinging.
- Prevalence high in older men, and organ transplant recipients.
- Clinical variants include atrophic, hyperkeratotic/hypertrophic, pigmented and lichenoid keratoses.
- May occasionally develop a secondary cutaneous horn.
- Represent intraepidermal keratinocyte dysplasia but the potential for malignant transformation in an individual lesion is low.
b. Bowenoid keratosis
- Likely there is a histological continuum of keratinocyte dysplasia from solar keratosis to invasive SCC. The continuum includes Bowenoid keratosis and Bowen’s disease (see below).
- May have a slightly thicker erythematous base than a solar keratosis.
c. Squamous cell carcinoma in-situ (Bowen’s disease)
- Presents as a well-demarcated, slowly expanding, erythematous and scaling plaque (which can be mistaken for psoriasis or dermatitis).
- Usually asymptomatic, but ulceration can occur.
- There are multiple lesions in 10% to 20% of cases.
- Occur anywhere on the skin but is most common in sun-exposed areas, especially the lower leg.
- The risk factors are solar damage, arsenic exposure, ionising radiation, psoralen and ultraviolet A (PUVA) therapy, immunosuppression and oncogenic human papillomavirus infection.
- An untreated lesion has a 3% to 8% risk of progression to invasion. The risk is higher for genital lesions.
- Diagnosis can be confirmed by punch or shave biopsy.
Consider referral to a specialist such as a dermatologist, plastic surgeon or radiation oncologist in the following situations:
- Uncertainty of diagnosis
- Any doubt about appropriate treatment
- A tumour larger than 1cm
- Frequent multiple tumours e.g. organ transplant patients, Gorlin’s syndrome
- Recurrent tumours, despite treatment
- Incompletely excised tumours, especially when complete excision may be difficult
- Tumours in technically difficult sites such as the ear, tip or nose or eyelid
- Recommended treatment beyond the skills of the practitioner
- Anticipation of difficulty with technique or anatomy
- SCC on the lip or ear
- Infiltrating or scar-like morphoeic BCC, particularly on the nose or around the nasolabial fold (where there may be a problem in determining tumour extent & depth)
- Cosmetic concerns e.g. lesions of the upper chest and upper arms where there is potential for keloid scarring
- Areas where palpable regional lymph nodes are suggestive of metastatic spread of SCC, especially head and neck, axilla and groin
- Organ transplant and other chronically immunosuppressed patients (refer to organ transplant clinics)
- When the GP will be unavailable for regular follow-up, especially for SCC
Squamous Cell Carcinoma
- Surgery is the treatment of choice.
- Curettage may be used for keratoacanthoma when the operator is skilled in the technique and tumour selection.
- Superficial x-ray therapy is used in biopsy-proven tumours when surgery is not feasible or will cause unacceptable morbidity.
Basal Cell Carcinomas
- Surgery is used in a large proportion of tumours. In most cases a simple ellipse with a 3mm margin under local anaesthetic followed with primary closure is sufficient.
- Cryotherapy is suitable for primary, well-defined, histologically confirmed, superficial tumours at sites away from the head and neck. Cryotherapy is contraindicated for morphoeic or ill defined tumours. Long-term follow-up is essential.
- Curettage is suitable for primary, well-defined, superficial or nodular tumours. It is not suitable for morphoeic or recurrent tumours. Requires supervised training in tumour selection and technique.
- Superficial x-ray therapy may be an option for biopsy-proven tumours in older people where surgery is unacceptable to the patient.
- Imiquimod suitable for biopsy-proven superficial BCC, but not on nose or around the eyes. May be suitable for nodular BCC on occasion, but requires referral for specialist opinion. Treat Monday-Friday, five times weekly for six weeks.
- Imiquimod is an immune response modifier. This treatment is patient-administered, compliance is essential. Adverse effects include brisk inflammatory reactions, flu-like effects (in 1%) and hypopigmentation. Local skin reactions (particularly erythema) at the treatment site are common and range from mild to severe. If severe, treatment can be interrupted until skin reactions resolve, without compromising long-term results.
- Imiquimod is currently categorised as B1 and should be avoided when pregnant or breastfeeding.
- Photodynamic therapy (requires specialist centre and equipment) suitable for biopsy-proven superficial or small nodular BCC but not on the nose or around the eyes.
Keratinocyte Dysplasias —solar keratosis, Bowenoid keratosis, SCC in-situ (Bowen’s disease)
- Surgery is not usually used unless there is doubt about whether the lesion is invasive SCC.
- Cryotherapy may be used for solar keratosis. There is a high cure rate, particularly with a single freeze cycle of 5-10 seconds directly to the lesion. A 3 mm margin and 30 second single freeze cycle should be used for Bowenoid keratosis or SCC in-situ (Bowen’s).
- Curettage may be used occasionally in Bowenoid solar keratosis or SCC in situ (well localised Bowen’s disease).
- Ingenol mebutate is indicated for the topical treatment of solar (actinic) keratoses in adults and is available as a clear colourless gel. For the treatment of solar (actinic) keratoses on the face and scalp, Ingenol mebutate gel 0.015% should be applied to the affected area once daily for 3 consecutive days. For the body consider a 0.05% formulation applied to the affected area once daily for 2 consecutive days.
- Imiquimod may be suitable for multiple solar keratoses. Also suitable for localised biopsy-proven Bowen’s disease. Treat three times a week for four weeks; then review prior to continuing therapy.
- 5-fluorouracil is suitable for patients who have multiple solar keratoses and localised biopsy-proven Bowen’s disease; treat twice daily for 2-4 weeks. Some irritation is needed for the preparation to be effective, but it can cause severe chemical irritation with erythema and crusting, and photosensitivity. Because of its adverse effects, experience in its use is necessary.
- Diclofenac gel may be used for multiple solar keratoses. Treat twice daily for 90 days. Can cause severe inflammation so close supervision is required. This gel is category C and should not be used whilst pregnant; it is not recommended for use in breastfeeding women.
- For field directed treatments, diclofenac, 5-fluorouracil, imiquimod, and ingenol mebutate had similar efficacy. Ensure familiarity with product information guides to application and adverse reactions.
- Photodynamic therapy may also be used for multiple solar keratoses. Also suitable for localised biopsy-proven for Bowen’s disease.
- High-risk individuals from age 40 years should be examined for NMSC opportunistically.
- Encourage skin self-examination for high-risk individuals (fair complexion, a tendency to burn rather than tan; personal or family history of skin cancer; occupational exposure to high UV levels, immunosuppressed.)
- The most common preventable cause of NMSC is UV exposure. All people, especially children, should be advised to use protective measures when UV levels are 3 or above.
|Sun protection advice||Advise all people (particularly children) to adopt protective measures — shade; broad-brimmed hats; protective clothing; sunglasses; SPF 30+ sunscreens — when UV levels ≥ 3, especially 10 am to 3 pm.|
|Skin examination||Skin examination should be preceded by relevant history. Identify skin lumps, ulcers or scaly patches, particularly growing, scarred or inflamed lesions. Consider incision, shave or excision biopsy for histology (or referral). Full body skin examination should take 2–3 minutes approx.|
|Self-examination||Advise patients to be alert for skin lesion changes.|
Adapted from: RACGP Guidelines for preventive activities in general practice 8th edition, 2012.
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