Squamous cell carcinoma (SCC) refers to the second most prevalent skin cancer after basal cell carcinoma, characterized by an abnormal growth of the squamous cells on the skin. SCC is not life-threatening but can cause serious complications if allowed to enlarge and spread to other body parts. A large percentage of SCCs are curable if they are arrested early.
Cancer may manifest in any part where squamous cells are in the body. These places include the ears, lips, back of the hand, and scalp because these areas are often exposed to the sun. It can also grow in other areas of the body, such as the genitals, bottom of the foot, and mouth.
SCC may occur in the form of an open sore, rough-looking skin, raised growth with a depression at the centre, and scaly, red patch. Sometimes the lesion may bleed, itch, or crust over, especially in skins exposed to the sun.
Also Known As
- Cutaneous squamous cell carcinoma (cSCC)
Causes & Risk Factors
The leading cause of SCC is exposure to the sun’s ultraviolet radiation or from agents that can damage an individual’s DNA, such as indoor tanning lamps and beds.
Risk factors that may predispose an individual to SCC may include:
- Use of tanning beds
- Excessive sun exposure
- Skin cancer that may recur
- Conditions such as Bowen’s disease and actinic keratosis
- Genetic disorders such as xeroderma pigmentosum because of the disease’s sensitivity to sunlight
- Weak immunity such as in leukemia or lymphoma patients who are taking immune-suppressing medications
- History of sunburns, especially during childhood which can cause SCC in adulthood. Sunburns in adulthood can also cause SCC
- Fair-skinned people because more skin pigmentation offers more protection from the damage caused by UV radiation. Besides, having light-coloured eyes and red or blond hair can predispose an individual to SCC
Signs & Symptoms
The signs and symptoms of SCC may include:
- Firm, red node
- Pruritus (itchy skin)
- Lesion that is enlarging
- Scaly, crusting, sore lesion
- A red or rough sore in the mouth
- Raised wart-like patch on the genitals
- A lesion growing on an old ulcer or scar
- An open sore resulting from a rough, scaly, lip patch
The eye doctor will initially diagnose SCC based on clinical suspicion when a lesion appears, especially in individuals highly at risk. The doctor confirms the diagnosis by having an incisional biopsy and histopathological or microscopic examination. The biopsy distinguishes BCC from other cancers that look the same. The individual’s history of previous cancer or skin lesion is taken.
The individual undergoes a complete ophthalmic examination, which may include assessing for proptosis and ocular motility. The doctor also assesses facial sensation, and regional lymph node palpation. The lesion is examined for its periocular skin and general appearance. The doctor also checks for eyelid malposition or whether the eyelid architecture is distorted. Other assessments may include skin ulceration, telangiectasias, and loss of eyelashes.
Treatment of squamous cell carcinoma is aimed at eliminating the tumors and preventing them from metastasizing.
SCC is primarily managed through surgery. The surgeon ensures the lesion is excised entirely while observing margin control. However, there is the challenge of clinically determining the margin of the tumor due to less defined edges. Radiation therapy can be used after incision surgery in case all the cancer was not eliminated. Other types of surgery may include:
- Imiquimod which is used to treat extensive superficial lesions
- Cryotherapy (extreme cold) which is used to treat early, small, differentiated tumors
- Photodynamic therapy (applies drugs and laser) is used for multiple or large tumors who cannot undergo surgery
- Curettage and electrodesiccation can also be used to treat thin SCC lesions and those measuring less than 1 cm across
- Mohs surgery is preferred for lesions with the risk of recurrence. The procedure can also be used for lesions with poorly defined edges or those larger than 2 cm across. It is used for tumors that spread along the nerves and located under the skin. Patients with cancer on the face or genital area can also benefit from Mohs surgery. Surgeons use Mohs surgery after incision surgery has failed to remove all of the cancer
SCC that presents with large tumors can be eliminated via radiation therapy. Radiation therapy is particularly useful in patients with lesions in hidden areas like the ears, eyelids, or nose where excision surgery is impossible. It is also used if the nerves are involved and in recurrent cancers after surgery and are too large for surgical removal. However, radiation therapy is usually not suitable for younger patients due to risk of long-term complications.
Other Types of Treatment (For Advanced SCC)
The following may be used to treat advanced SCC:
- Systemic chemotherapy or targeted therapy drugs is used for SCC that has spread to distant organs or lymph nodes
- Lymph node dissection removes regional lymph nodes in enlarged or hard lesions. It may be followed by radiation therapy
- Immunotherapy which uses drugs like cemiplimab for advanced SCC lesions that cannot be addressed by surgery or radiation therapy
Prognosis & Long-Term Outlook
Squamous cell carcinoma has an excellent prognosis if treatment is sought early enough. Most people survive because treatment is often effective. However, the lesions that metastasize, such as those found close to the lips and ears, can turn fatal.
Prevention & Follow Up
Prevention of SCC may include:
- Avoiding tanning beds because they emit UV rays
- Sunscreens which can protect an individual against sun exposure
- Regularly checking the skin for new skin growths and consulting a doctor promptly to report the changes
- The individual wearing protective clothing, which include wide-brimmed hats, pants, and long-sleeved shirts
- Avoiding sun exposure, such as minimizing outdoor activities (especially in the middle of the day), staying under the shade, and sunbathing