Dr Ranil Perera shows how the three main types of skin cancer can be recognised, how to manage suspicious lesions, and when to refer

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Read this article to learn more about:

  • how to assess and diagnose malignant melanoma, squamous cell carcinoma, and basal cell carcinoma
  • how to monitor lesions
  • when and how to refer.



A large number of consultations in primary care are for skin conditions. It is thought that in 2006, 12.9 million people (24% of the UK population) visited their GP with a skin complaint.1

Given the large number of skin lesions that they see, many GPs fear that they will miss a potentially cancerous lesion.

This article offers practical help in identifying and managing the main types of skin cancer (malignant melanoma, squamous cell carcinoma, and basal cell carcinoma) and refers practitioners to some helpful recent guidance.

1 Malignant melanoma: what to look out for

Malignant melanomas account for more deaths than the other skin cancers combined. The prevalence is increasing in adults aged 25–49 years and it is now the second most common cancer in this age group.2 Malignant melanomas are typically asymmetrical with border irregularity, colour variation, and a large diameter (see Figure 1, below). GPs should follow the weighted 7-point checklist (see Box 1, below).3

Figure 1: Melanomas with characteristic asymmetry, border irregularity, colour variation, and large diameter
Melanomas with characteristic asymmetry, border irregularity, colour variation, and large diameter

Box 1: Weighted 7‑point checklist for assessment of pigmented skin lesions8

Major features of the lesions (scoring 2 points each):

  • change in size
  • irregular shape
  • irregular colour.

Minor features of the lesions (scoring 1 point each):

  • largest diameter 7 mm or more
  • inflammation
  • oozing
  • change in sensation.
  • NICE (2015). Suspected cancer: recognition and referral. NICE Guideline 12. Available at: www.nice.org.uk/guidance/ng12 Reproduced with permission.

2 Malignant melanoma: take a clinical history and assess risk factors

When taking a history, highlight the following risk factors:1,4

  • naevi—(either multiple benign naevi or presence of dysplatic naevi) most significant risk factor
  • first-degree relative with melanoma
  • immunosuppressant use5
  • sun-bed use
  • a history of blistering sunburn
  • presence of freckles
  • blond or red coloured hair.

3 Malignant melanoma: assess for signs of sun damage

Assessing for signs of skin-related damage is important as exposure to solar UV radiation is a risk factor for development of melanoma.6 The presence of solar lentigines, commonly known as age spots or liver spots, indicates that a person has taken too much sun for his/her skin type. Other signs of sun damage include:

  • rhomboid-like structures forming on skin, especially the neck
  • uneven pigmentation
  • damage to areas of skin with darker pigmentation
  • solar elastosis—vertical creases, deep wrinkles, and loose or sagging skin
  • melasma
  • actinic keratoses.

If there is uncertainty over the extent of sun damage, be sure to compare areas of high exposure with low (i.e. face with buttocks).

4 Malignant melanoma: monitor for change

Low suspicion lesions can be monitored for 8 weeks using the 7-point checklist (see Box 1, above). Ideally, measurements should be taken with a ruler and a photograph taken (see Figure 2, below).3

Figure 2: Monitoring malignant melanoma
Monitoring malignant melanoma
  • Pigmented papule on the proximal arm with asymmetry, irregular border, and red, brown, and black colour variation
  • National Cancer Institute website: visualsonline.cancer.gov

5 Malignant melanoma: metastasis is possible

Remember that malignant melanomas can metastasise locally as well as to any organ (see Figure 3, below).

Figure 3: Metastatic melanoma
Metastatic melanoma

1 Squamous cell carcinoma: what to look out for

Squamous cell carcinomas (SCCs) typically occur on sun-exposed areas. Exposure to UV radiation is the most common cause of SCC. Invasive squamous-cell carcinomas usually occur on the head and neck.

Squamous cell carcinomas are characterised by papules or plaques that are firm, skin-coloured or pink, and smooth or hyperkeratotic. Ulceration may be present and patients may report that the lesions are itchy, bleed when traumatised, and are non-healing.7 Consider a suspected cancer pathway referral (for an appointment within 2 weeks) for people with a skin lesion that raises the suspicion of SCC (see Figure 4, below and Box 2, below).8

Figure 4: Squamous cell carcinoma
Squamous cell carcinoma

Box 2: Squamous cell carcinomas

  • Squamous cell carcinomas present as keratinising or crusted tumours that may ulcerate. Non-healing lesions larger than 1 cm with significant induration on palpation, commonly on face, scalp or back of hand with a documented expansion over 8 weeks, may be squamous cell carcinomas and an urgent referral should be made.
  • Squamous cell carcinomas are common in patients on immunosuppressive treatment, but may be atypical and aggressive. In patients who have had an organ transplant who develop new or growing cutaneous lesions, an urgent referral should be made.
  • In any patient with histological diagnosis of a squamous cell carcinoma made in primary care, an urgent referral should be made.

2 Squamous cell carcinoma: remember the 3 Ss

  • Speedy—SCCs can grow rapidly1 (more than 1 cm in 1 month)
  • Spreading—SCCs have a greater (although still small) risk of spreading, 1 compared with basal cell carcinomas (BCCs), especially in people who are immunosuppressed3
  • Serious—SCCs are amenable to treatment but because they can metastasise, they need prompt referral to secondary care under the 2-week rule.3

1 Basal cell carcinoma: when to refer

Basal cell carcinomas are the most common form of skin cancer.1 They are slow growing3 (approximately 2–3 mm per year) and invade locally (see Figure 5, below).1 When a BCC is suspected, consider routine referral.8

Figure 5: Basal cell carcinoma, superficial and ulcerated
Basal cell carcinoma, superficial and ulcerated

Although BCCs very rarely metastasise, they can cause local tissue invasion and destruction,1 particularly on the head and neck, so should be referred urgently if this is a concern. If there is overlying scale, consider the possibility of a squamoproliferative process and refer under the 2-week rule. Most BCCs should be routinely referred as non-urgent.

2 Basal cell carcinoma: what to look out for9

  • Basal cell carcinomas are usually painless
  • They may present as a scab that bleeds occasionally and does not heal completely
  • Some basal cell carcinomas are very superficial and look like a scaly red flat mark
  • Others have a pearl-like rim surrounding a central crater
  • Overlying telangiectasia
  • At latter stages, skin erosion occurs producing a 'rodent ulcer'.

3 Basal cell carcinoma: history and risk factors

When taking a history highlight the following risk factors:1,9

  • cumulative UV light exposure
  • trauma to the affected area
  • smoking
  • immunosuppression—particularly following renal transplant
  • people with freckles or with pale skin and blond or red hair
  • premalignant lesions and past history of non-melanoma skin cancer.

Empower patients in skin cancer prevention

With an increasing prevalence of skin cancer it is imperative that diagnoses are made early so patients have the best possible outcomes. This article will hopefully provide a reminder to facilitate this. For ongoing professional development the Primary Care Dermatology Society (PCDS) website provides useful support with guidance and diagnostic dermatology tables

In general practice prevention is always an important focus and it is important to educate patients on how they can reduce their individual risk of developing skin cancer. Patient information leaflets on sun protection and self-examination of moles that could help empower patients are also available from the PCDS.


  1. Schofield J, Grindlay D, Williams H.Skin conditions in the UK: A health care needs assessment. Nottingham: Centre of Evidence Based Dermatology, University of Nottingham, 2009. Available at: www.nottingham.ac.uk/research/groups/cebd/documents/hcnaskinconditionsuk2009.pdf
  2. NICE. Melanoma: assessment and management. NICE Guideline 14. NICE, 2015. Available at: www.nice.org.uk/guidance/ng14
  3. NICE website. Clinical knowledge summaries. Skin cancer—suspected. June 2009. cks.nice.org.uk/skin-cancer-suspected (accessed 3 September 2015).
  4. Bataille V, de Vries E. Melanoma—part 1: epidemiology, risk factors, and prevention BMJ 2008; 20 (337): a2249.
  5. Olsen C, Knight L, Green A. Risk of melanoma in people with HIV/AIDS in the pre- and post-HAART eras: a systematic review and meta-analysis of cohort studies. PLoS One 2014; 9 (4): e95096.
  6. Markovic S, Erickson L, Rao R et al. Malignant melanoma in the 21st century, part 1: epidemiology, risk factors, screening, prevention, and diagnosis. Mayo Clin Proc 2007; 82 (3): 364–380.
  7. Alam M, Ratner D. Cutaneous squamous-cell carcinoma. N Engl J Med 2001; 344: 975–983.
  8. NICE. Suspected cancer: recognition and referral. NICE Guideline 12. NICE, 2015. Available at: www.nice.org.uk/guidance/ng12
  9. Baxter J, Varma S. Facial basal cell carcinoma.BMJ 2012; 345: e5342.