This overview outlines the most common types of skin cancer and the treatment options available for each one.
This first in a two-part series on skin cancer gives an overview of the most common types and outlines the main treatment options. Part 2, to be published next week, discusses the causes of and risk factors for skin cancer, highlighting those people who are most at risk and the importance of early diagnosis.
Citation: Alexander RL (2012) Skin cancer 1: main types of skin cancer and treatment options. Nursing Times [online]; 108: 29, 18-20.
Author: Rachel Louise Alexander is Macmillan skin cancer clinical nurse specialist, dermatology and plastics outpatient department, the Ipswich Hospital Trust.
- Scroll down to read the article or download a print-friendly PDF including any tables and figures
- Read part 2 of this series here
Skin cancer is the most common type of cancer in humans. In the UK incidence levels are currently 19.2 per 100,000 people for malignant melanoma alone (Cancer Research UK, 2011). Effective and efficient referrals should be made to a dermatology consultant in acute care for expert opinion on worrying lesions.
The current national cancer waiting-time targets in England and Wales apply to malignant melanoma and squamous cell carcinoma (SCC) but exclude basal cell carcinoma (BCC), Bowen’s intraepidermal squamous cell carcinoma and other precancerous skin lesions. Patients suspected of having a skin cancer should be referred urgently through the two-week GP referral route (National Institute for Health and Clinical Excellence, 2012).
Around 97% of skin cancers are epithelial in origin and are either BCC or SCC, collectively known as non-melanoma skin cancers (NMSCs) (Bath-Hextall et al, 2008).
Basal cell carcinoma
BCC is defined as a slow-growing, locally invasive, malignant epidermal skin tumour that mainly affects people with light-coloured skins and originates from basal cells of the epidermis (Bath-Hextall et al, 2008).
Subtypes of BCC described by Bath-Hextall et al (2008) include:
- Superficial (Fig 1) - a well demarcated, scaly, red, minimally indurated plaque that, at times, can mimic a papulosquamous rash, such as psoriasis, or single patch;
- Multifocal - potentially more aggressive than other forms of BCC;
- Morphoeic (scarring) - this is the most invasive type of BCC;
- Ulcerated (Fig 2);
- Pigmented (Fig 3) - this is often confused with melanoma;
- Cystic (Fig 4);
- Nodular (Fig 5).
Sixty per cent of BCCs diagnosed in the UK are nodular, presenting as a pearly papule with telangiectasias (raised areas through which dilated vessels may show) throughout (Bath-Hextall et al, 2008).
BCCs are generally treated with surgery although superficial ones can be treated with cryotherapy.
An alternative treatment for superficial BCC is imiquimod (Aldara). This offers a topical, non-invasive, patient-administered modality, expanding options for treating skin cancers. Benefits include less patient discomfort, favourable cosmetic outcome and documented efficacy against BCC. In addition, patients who are unsuitable for surgery (that is, those who are older, anticoagulated or who have implanted cardiac pacemakers) would benefit from this non-invasive topical therapy. It can also be used as an adjunct to surgery, such as excision, and allows clinicians to combine immunological-based treatment with surgical intervention.
Imiquimod works by stimulating innate and cell-mediated immune pathways, which are critical components of the body’s defence mechanisms against both viruses and tumours, and has been shown to be an excellent treatment choice for selected skin malignancies (Sapijaszko, 2005). It is appropriate for patients who are able to apply treatment effectively themselves or for those with carers who can apply treatment to areas that may be difficult for patients to reach themselves.
Another treatment, accessed via consultant referral, is photodynamic therapy (PDT). In PDT, the lesion is prepared by removing overlying crust and scale. A photosensitising agent is applied to the lesion and a margin of surrounding skin, and is left to absorb for three hours. The lesion is illuminated by light of an appropriate wavelength to activate the photosensitiser, producing targeted tumour destruction. Occasionally, the photosensitising agent may be given intravenously. More than one lesion may be treated in a session and the treatment can be repeated. Non-melanoma skin tumours including BCC, SCC, Bowen’s disease and actinic (or solar) keratosis can all be treated in this way (NICE, 2006).
If surgery is the treatment of choice for BCC, then, once clear histological margins are achieved, the treatment is complete. Patients can then be discharged back to their GP with sun-protection advice and BCC literature encouraging them to take measures against skin cancer in the future.
Squamous cell carcinoma
SCCs are generally more aggressive than BCCs and originate in the skin cells that produce keratin. Unlike BCC, which has no reported precursor lesions, SCC has two principal precursor lesions: actinic keratoses (Fig 6) and Bowen’s disease (intraepidermal carcinoma) (Fig 7), described as SCC in situ (Bath-Hextall et al, 2008). Fig 8 shows SCC of the retroauricular region and Fig 9 shows SCC of the lower lip.
The potential for SCC to metastasise can range from 0.5% to 40% depending on the subtype (Bath-Hextall et al, 2008). Veness (2007) outlined high-risk factors related to SCC (Box 1).
Box 1. High-risk factors related to SCC
- Large size (>2cm)
- Thick or deeply invasive lesion (>4mm)
- Incomplete excision (<4mm)
- Recurrence of SCC at original SCC site
- High-grade or desmoplastic lesion
- Presence of perineural invasion
- Presence of lymphovascular invasion
- Located near the parotid gland (ear, temple, forehead, anterior scalp
- Immunosuppressed state (such as transplant recipient)
Note: patients often have multiple high-risk factors present
Source: Veness (2007)
SCCs are treated primarily with surgery; when clear histological margins are satisfactorily achieved and individual risk factors of the skin cancer are known, practitioners can establish follow-up recommendations. Follow-up appointments ensure regular skin and lymph-node examinations can be carried out as a means of detecting possible disease recurrence.
Patients should be educated on the importance of self-examination and given leaflets about SCC, as well as sun-protection advice, to reduce the risk of further skin cancer. Adjuvant therapy in the form of radiotherapy is sometimes needed for identified high-risk SCC to reduce the risk of local recurrence. As previously mentioned, some people may benefit from using PDT for their particular SCC (NICE, 2006).
Of all types of skin cancer, cutaneous malignant melanoma causes the most concern because of its significant morbidity and mortality. Melanoma is a malignant tumour developing from pigment-forming cells. Its incidence has steadily increased over the last 30 years; it is now the most common form of cancer in young adults and is responsible for 80% of deaths related to skin cancer (Calianno, 2011). There are nearly 12,000 new cases of malignant melanoma in the UK each year (11,767 diagnosed in 2008) (Cancer Research UK, 2011).
Superficial spreading melanoma, nodular melanoma and lentigo maligna melanomas make up 90% of all diagnosed malignant melanomas. Acral lentiginous melanoma and a few very rare types together make up the other 10% (Cancer Research UK, 2012). Types of malignant melanoma include:
- Superficial spreading malignant melanoma (Fig 10) - the most common type, which is most often seen on the trunk or legs and can appear as a new or existing mole;
- Nodular malignant melanoma (Fig 11) - can appear as blue or red and typically occurs as a new mole;
- Lentigo maligna melanoma (Fig 12) - about one in 10 melanomas (10%) are this type. It is most common on the face, and in people who have spent a lot of time outdoors. It grows very slowly;
- Acral lentiginous malignant melanoma (Fig 13) - rare and occurs on peripheral extremities. It is commonly seen on the palms, soles or nails of people with darker skin;
- Acral amelanotic (without colour) malignant melanoma (Fig 14) - as amelanotic melanomas are atypical and lack pigmented presentation, health professionals need to be vigilant to detect any atypical changes in any mole.
Diagnosis is ultimately made by biopsy. Usually an excision biopsy is taken with a potential follow-up re-excision if indicated. This first excision is performed to determine the presence and stage of the melanoma. In the early phase of growth, the tumour is limited to the dermo-
epidermal junction, which is the area of tissue that joins the epidermal and the dermal layers of the skin. The tumour can become invasive as it progresses and proceeds to grow vertically, entering the dermal layer and gaining potential access to other dermal structures.
The commonly used system to assess patient prognosis is the tumour, lymph-node and metastasis staging tool, developed by the American Joint Committee on Cancer (Marsden et al, 2010).
Malignant melanoma has the invasive potential to metastasise via the lymphatic and haematological pathways. Regular outpatient surveillance allows all patients with a melanoma diagnosis to attend for lymph node and skin examination to detect any concerns. Patients should be encouraged to communicate any concerns clearly to health professionals, and to carry out self-surveillance in between outpatient visits.
Primary cutaneous melanoma is treated with surgery; Marsden et al (2010) contains full recommendations on treatment. There is also clear guidance on the wider local excision margins of melanoma, which depends on Breslow thickness (Table 1).
Sentinel lymph-node biopsy (the first lymph nodes to which cancer is likely to spread from a primary tumour) is offered to eligible patients, which adds to prognostic information about the melanoma and also allows nodal involvement to be detected early, enabling efficient surgical intervention.
Localised metastatic melanoma (Fig 15) is of great concern. Individual lesion excision, carbon dioxide laser therapy and chemotherapy creams (diphencyprone) all have a role in controlling local disease, with very close monitoring.
Skin cancer is the most common type of cancer in humans. In this article, BCC, SCC and melanoma have been identified; all have their own levels of risk to the patient.
Identification of skin lesions by the patient, followed by assessment in primary care by the GP then referral to secondary care to see a dermatology consultant (if indicated via the two-week wait pathway) are essential for early assessment of suspected skin cancer.
Patient information relating to skin self-examination, as well as sun protection advice, is key in preventing new lesions or identifying them early.
- Skin cancer is the most common type of cancer
- Patients suspected of having skin cancer should be referred urgently through the two-week GP referral route
- Basal cell carcinoma can be treated with surgery, cryotherapy, imiquimod or photodynamic therapy, depending on patient circumstances
- Squamous cell carcinomas are generally more aggressive than basal cell carcinomas and are treated mainly with surgery
- Malignant melanoma causes the most concern because of its significant morbidity and mortality
Bath-Hextall F et al (2008) Interventions for preventing non-melanoma skin cancers in high risk groups. Cochrane Database of Systematic Reviews; Issue 4; CD005414.
Calianno C (2011) Influencing melanoma prevention. Dermatology dilemmas. The Nurse Practitioner; 36: 3, 6-10.
Cancer Research UK (2012) Types of Melanoma.
Cancer Research UK (2011) Skin Cancer - UK Incidence Statistics.
Marsden J et al (2010) Revised UK guidelines for the management of cutaneous melanoma 2010. British Journal of Dermatology; 163: 238-256.
National Institute for Health and Clinical Excellence (2012) “Referral Advice” Recommendation Details.
National Institute for Health and Clinical Excellence (2006) Photodynamic Therapy for Non-melanoma Skin Tumours (Including Premalignant and Primary Non-metastatic Skin Lesions).
Sapijaszko MJA (2005) Imiquimod 5% cream (Aldara®) in the treatment of basal cell carcinoma. Skin Therapy Letter.com.
Veien NK, Nielsen M (undated) An Atlas of Clinical Dermatology. D@nderm.
Veness MJ (2007) High-risk cutaneous squamous cell carcinoma of the head and neck. Journal of Biomedicine and Biotechnology; 80572.