Squamous Cell Carcinoma

Squamous Cell Carcinoma

  • Definition
  • Causes
  • Diagnosis
  • Treatment

Definition

A squamous cell carcinoma (SCC) is a type of skin cancer. There are two main types of skin cancer: melanoma and non-melanoma skin cancer. SCC is a non-melanoma skin cancer, and is the second most common type all skin cancers.

F25: Large cutaneous SCC of the scalp
Large cutaneous SCC of the scalp

Causes

Overexposure to ultraviolet (UV) light is the main cause of non-melanoma skin cancer. UV light comes from the sun, as well as from artificial tanning sunbeds and sunlamps. SCCs can occur anywhere on the body, but are most common on areas that are exposed to the sun such as your face, head, neck and ears. Squamous cell carcinomas can also develop in skin damaged by other forms of radiation, in burns and persistent chronic ulcers and wounds and in old scars.

Those with the highest risk of developing a squamous cell carcinoma are:

  • Immunosuppressed individuals (i.e. HIV+, leukaemia, lymphoma, taking methotrexate or azathioprine, etc.).
  • Patients with transplants (kidneys, liver, pancreas, etc.).
  • People with pale skin who burn easily and rarely tan.
  • Those who have had a lot of exposure to the sun (i.e. fishermen, farmers).
  • People who have used sun beds or have regularly sunbathed.
  • Patients with skin conditions like albinism or xeroderma pigmentosum.

Diagnosis

The clinical appearance of these lesions is most of the times enough to characterise them. Your doctor will refer you to the OMFS H&N Surgeon for any lesion that looks abnormal on your face. Direct inspection or use of dermoscopy (looking at the lesion with a special magnifying glass) is often enough to diagnose the lesion.

SCCs can vary greatly in their appearance, but most of the times present as scaly or crusty raised areas with an ulcerated or inflamed base. They can also appear as ulcers that occasionally bleed.

Rarely, a skin biopsy might be needed to confirm the diagnosis.

Treatment

SCCs are curable, but some of them tend to spread (metastasize). Most commonly, they spread to the lymph glands of the surrounding areas (regional lymph node metastases).  In the case of facial and scalp SCCs, this mainly refers to the intraparotid and neck lymph glands. Very rarely, in some neglected or aggressive cases, they can metastasize in other parts of the body.

Treatment can be challenging and complex when SCCs appear in difficult areas, such as the face. Your OMFS H&N surgeon will ensure that he adequately removes the skin cancer and reconstructs the wound respecting appearance and cosmesis.

Surgery is the first line treatment for skin SCCs. Any other treatment options should be carefully considered only when surgery isn’t possible

Surgery with a predetermined margin is the main treatment for non-melanoma skin cancers. It involves removing the cancerous tumour and some of the surrounding skin (around 3-4mm, or more, depending on the type and the area).

The surgery is usually done under local anaesthetic. Once the SCC has been removed, the surgeon will reconstruct the wound. That might be as simple as closing the wound primarily with few stitches, but in the majority of cases, when it comes to the face, more complex reconstruction is needed to achieve the best cosmetic result. This is done in the form of a local skin flap or a skin graft

Local skin flaps

A local skin flap is mobilising skin from areas adjacent to the defect, in a planned and often geometrical way, in order to facilitate wound closure under no tension and place the scars in the least visible areas (particularly important when it comes to the face). There are several types of skin flaps, and your OMFS H&N surgeon will discuss the options with you.

Skin graft

A skin graft is a piece of skin taken from another part of the body and transferred in the area of the wound defect. It gradually takes its blood supply from the tissues at the bed of the wound. It can be full thickness (contains the epidermis and all of the layers of the dermis) or split thickness (contains the epidermis and part of the dermis). When a split thickness skin graft is harvested (usually from the upper inner arm, the thigh, or the buttock) it leaves a graze that heals on its own in few weeks. On the other hand, harvesting a full thickness skin graft allows closure of the donor site in a straight suture line. Full thickness skin grafts are most commonly used in facial skin reconstruction. Donor sides include the neck, around the ear, and the forehead.

Neck dissection: When the SCC has spread to the regional lymph glands, a procedure to remove them is undertaken. This includes the removal of the lymph nodes in the neck, and occasionally it is combined with a parotidectomy (removal of the parotid salivary gland and the lymph nodes that it contains). This is done when the skin SCC has spread from the face or scalp. This also provides access to blood vessels for microvascular reconstruction, in case the defect after the primary cancer excision is significant.

Other treatments include:

  • Radiotherapy: Surgery and radiotherapy are the two modalities that are supported by strong medical evidence in the treatment of cutaneous SCCs. However, radiotherapy is expensive and time consuming, and is mainly reserved for patients that cannot have surgery.
  • Curettage and cautery (mainly for diagnostic purposes and not as definitive treatment)
  • Combination of surgery and adjuvant radiotherapy: In advanced and difficult cases of cutaneous SCC, a combination of surgery and radiotherapy is employed. This is particularly the case when the SCC has spread in the regional lymph glands.

The treatment used will depend on size and location of the SCC you have. Because facial skin cancer is in a difficult area of the body, your treatment should be carried out by a surgeon experienced is excision and reconstruction of such lesions.

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