domingo, 25 de noviembre de 2018

Eyelid Cancer

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By Liji Thomas, MDReviewed by Afsaneh Khetrapal, BSc

Eyelid cancers refer to the several types of malignant cell growth on the eyelid. Whatever the type, the tumor is graded by the differentiation seen in the cells, and the rate of proliferation. Basal cell carcinomas and squamous cell carcinomas are the most frequent. Cancers which do not belong to these groups are rare but occur with a six-fold increased incidence in elderly white patients.

Types of Eyelid Cancer

The main categories of cancers occurring on the eyelids are:

Basal Cell Carcinoma

This accounts for approximately 85% of all tumors occurring on the eyelid, especially common on the lower eyelid. The eyelids account for 16% of basal cell carcinomas in the body. The condition is more often seen in adults. However, younger people are not exempt from it. Skin exposure to the sun or ultraviolet radiation puts one at a higher risk for this type of skin cancer.

The overwhelming majority of basal cell tumors are noduloulcerative while superficial tumors and infiltrative tumors are significantly less common on the eyelids. Tumors of this type rarely spread to nearby or distant organs, either through blood or the lymph nodes. They are treatable, therefore, with a good prognosis.

Squamous Cell Carcinoma (SCC)

This comprises only 5 out of 100 eyelid tumors, but may follow a precancerous condition. It may be caused by chronic skin damage related to sun exposure. Some common precursors of SCC are Bowen’s disease or actinic keratosis. This type of eyelid cancer is more aggressive than basal cell tumors, and metastasis is more common. Spread occurs to the eye socket (local spread), to the local lymph nodes, or to distant organs. If caught early and excised completely, the patients have a good prognosis. Lifelong follow-up is required because of the relatively high risk of recurrence or of new tumors.

Sebaceous Gland Carcinoma (SGC)

This type of cancer arises from the sebaceous glands in the eyelid - these produce the fatty substance called sebum to lubricate the eyelid skin. It also accounts for less than 5% of eyelid tumors, but is more likely to occur in older people, and especially in older women. The most common site is the upper eyelid because of the large number of Meibomian glands here. It may behave aggressively, and its multifocal nature in some cases makes it a challenge to treat conservatively. Recurrence rates, as well as metastasis rates, are higher with this form of eyelid cancer. It is often diagnosed late because it mimics more benign conditions such as a chalazion or blepharitis.

Malignant Melanoma

This tumor arises from the melanocytes of the skin, and uncommonly occurs on the eyelids (in less than 1 in 100 patients).

B-cell Lymphomas

Several lymphomas may appear first as primary eyelid tumors, but are extremely rare.

Symptoms and Signs

A tumor of the eyelid may appear to be a mild inflammation of the eyelids, called blepharitis. In some patients, the eyelids in the affected site may fall out.

Diagnosis and Treatment

Eyelid tumors are diagnosed based on their clinical features and an excisional biopsy. The tumor is removed and sent for pathologic examination under a microscope.

Surgical Methods

Surgical Excision

This is the most commonly implemented surgical method. It involves the removal of a wide margin of healthy tissue. Since basal cell carcinomas are mostly indolent, they respond well to this form of therapy. In patients who are not fit for surgery of this type, cryotherapy or irradiation is used. These are, however, associated with higher recurrence rates.

Mohs Surgery

This is a specialized conservative form of tumor excision which involves microdissection of the eyelid layer by layer. At each step the excised tissue is examined by a pathologist so as to detect the point at which excision may be stopped. It is available only at some centers.

Curettage and Electrodissection

This is suitable for some small and superficial basal cell carcinomas of the eyelid. Heat is delivered through an electrode to cauterize cancerous tissue and arrest bleeding at the same time. The necrotic tissue is then curetted.

Orbital Exenteration

This refers to the complete removal of all the contents of the orbit if a tumor spreads into the eye socket.

Non-surgical Methods

Non-surgical methods to deal with eyelid cancer include the following:

Cryosurgery

This is a form of tissue removal by freezing it using liquid nitrogen or other sources of intense cold. It is followed by higher recurrence rates compared with adequate surgical excision.

Eyelid Irradiation

This is used to remove recurrent tumors or tumors which extend throughout the eyelid. It is also suitable for those tumors whose excision would leave too large a defect. Sick or frail patients may also be considered fit for irradiation instead of surgical excision. It is also used postoperatively in patients with SCC and perineural spread. When radiation is used as exclusive therapy, it is associated with higher recurrence rates.

Laser Removal

This is sometimes used to remove small cancers.

Surface Chemotherapy

This involves the application of chemotherapeutic drugs on the eyelid tumor is rarely used.

Eyelid Reconstruction

This may be required if there is a cosmetic defect in the eye as a result of the surgery.