Skin Cancer

Overview of skin cancer

With the escalating growth of industrialization throughout the world, two major phenomena have been observed. These are global warming and ozone depletion. Both the phenomena are directly impacting the human body. The part of the body that is most affected in both cases is the skin. Inhabitants of tropical, sub-tropical, arid and semi-arid regions who are subjected to extremely hot climatic conditions throughout the year are more prone to skin diseases than people living in other parts of the world. In recent years, the most alarming form of skin disease has been “skin cancer”.

It is necessary to note that skin cancer not only affects adults and aged people, but they are also prevalent among children who are subjected to equally adverse climates. Recent epidemiological studies by the World Health Organization (WHO) suggest that further depletion of the ozone layer by about 10% will give rise to 3,00,000 non-melanoma and 4500 melanoma skin cancer cases in the upcoming years.

What is skin cancer?

Skin cancer is the medical condition in which abnormal and proliferative growth of skin cells occurs. In general, there are three main types of skin cells namely- squamous cells, basal cells, and melanocytes. Abnormal growth of melanocytes gives rise to melanoma type skin cancer, while the abnormal growth of basal cells and squamous cells lead to non-melanoma type skin cancer. In the initial stage, the disease is not so severe. But in the more advanced stages of skin cancer, the malignant cells spread to the other parts of the body (metastasis) and may affect the Central Nervous System at the end stage. Usually, skin cancer is manifested through flesh-colored lesions on the epidermis and mucosal layers. The extent of pigmentation varies from one person to another.

What causes skin cancer?

The various causes of skin cancer are described below-

• Exposure to sun rays (particularly the harmful Ultraviolet rays of the sun) for a long time on a regular basis
• Unprotected exposure to ultraviolet rays, X-rays or other ionizing radiations during radiotherapy or chemotherapy (for treatment of existing diseases)
• Frequent use of Ultraviolet lamps, tanning beds or other artificial sources of ultraviolet radiations
• Exposure to sun rays between 10 AM-2 PM when the intensity of sunrays is strongest
• Having more than 100 abnormal moles (also called atypical moles) in the body
• Having blisters or sunburns for a long time
• Ancestral history of skin cancer (may increase risks of xeroderma pigmentosum)
• Reduced use of sunscreens and other protective accessories like hats, ultraviolet-sunglasses, full-sleeved aerated clothes and a few more
• Having blonde hair, fair skin, and freckles
• Loss of function of melatonin pigments (protects the body from sunburn) due to certain existing diseases
• Medications like RetinA, sulfa drugs, tetracyclines and diuretics that progressively damage the immune system of the body
• Activities like surfing, skiing, and swimming that increase exposure of skin to sun-rays reflected from sand, water and snow
• Having HIV infection or pancreatic cancer
• History of skin cancer or other skin diseases

What are the main warning signs?

Skin cancer is mistaken for benign moles in the initial stage. Hence proper knowledge of the following symptoms of skin cancer is necessary-

• Mild to severe pigmentation
• The appearance of moles and spots that gradually increase in number with the progress of the disease
• Inflammation and reddish (or brownish) patches on the skin
• Irritation and itching of the skin
• Abnormal growth of existing moles (may turn into malignant tumors)
• Change in color and texture of moles
• Spread of cancerous moles and tumors into the deeper layers of the skin (dermis)
• The appearance of reddish or flesh colored itchy moles that cause irritation and itching
• Extreme tenderness of the affected skin and moles
• Burning sensation when the moles are accidentally rubbed or scratched
• Fever, dizziness, loss of appetite and nausea
• The appearance of scaly whitish flakes on the skin
• The appearance of fluid-filled reddish lumps in some cases

What are the different types of skin cancer?

Skin cancer is broadly categorized into two types- melanoma and non-melanoma skin cancer. The following section discusses melanoma skin cancer.

Melanoma is the type of skin cancer that originates primarily in the melanocytes and spreads to other parts of the body in the advanced stages. It has two subtypes-

• Amelanotic melanoma: In this type of skin cancer, the skin cells do not produce melanin pigment. The skin lesions are usually flesh-colored and are therefore not easily identified. They are asymmetric and have an almost invisible pigmented edge.
• Melanotic melanoma: This type of skin cancer is characterized by the production of melanin by the skin cells. Prominent pigmentation is observed in this case.

Now we shall discuss the non-melanoma type skin cancers. The following categories have been identified so far-

• Basal cell carcinoma: In this type of cancer the skin lesions appear in the deepest layer of the epidermis. This originates in the basal cells and gradually spreads to other skin cells as well.
• Squamous cell carcinoma: This type of cancer involves the squamous epithelium present in the middle and outer skin layers.

A few other types of skin cancer are discussed below-

• Merkel cell carcinoma: It is also called neuroendocrine carcinoma and is characterized by bluish-red nodules on the face, neck, and head.
• Kaposi sarcoma: Here, the malignant cells develop from the linings of lymph nodes and blood vessels.
• Cutaneous lymphoma: It involves the lymphocytes and can appear anywhere on the skin.

What diagnostic tests are necessary?

The following diagnostic tests are normally recommended for the treatment of skin cancers-

• Blood test (to check levels of lactate dehydrogenase)
• CT scan (to examine the soft tissues)
• Chest X-ray (to check for spread of cancer to the lungs)
• Biopsy (especially lymph node biopsy)

Treatment & Prevention

The treatment of skin cancers mainly depends on the type and stage of cancer. There are several treatment modalities such as radiation therapy, surgery, chemotherapy, targeted therapy, cryosurgery, photodynamic therapy (PDT), and immunotherapy or biologic therapy.

The photodynamic therapy makes use of a kind of laser in order to eliminate the cancer cells and prevent their further proliferation. The biologic therapy helps to boost the immune response of the body to fight cancer. The cryosurgery involves the freezing of the cancerous cells by means of liquid nitrogen.

In some cancers (such as basal cell carcinoma) topical ointments and creams are also prescribed for superficial lesions. The drugs such as imiquimod and fluorouracil are used for the topical application.

Prevention of the cancer is mainly by limiting sun exposure. Various precautions can be observed in order to limit the sun exposure. Some of the precautions are the application of sunscreen before stepping out, wearing protective clothing, use of hats and protective sunglasses etc.  Avoiding intentional UV tanning or indoor tanning by means of tanning beds, sunlamps, tanning booths etc. should also be avoided.

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