Actinic Keratosis The Earliest Form of Skin Cancer
What is Actinic Keratosis?
Actinic keratosis (AK) is one of the most common skin conditions seen in the adult population. The risk factors in developing AKs include Ultraviolet (UV) exposure, fair skin (light colored skin, eyes and hair), advancing age, as well as immunosuppression such as seen in organ transplant patients.
Actinic keratosis represents a visible clue that patients received sufficient damage to the skin to cause alterations in the DNA structure. The risk of progression of AK to invasive squamous cell carcinoma (SCC) has been estimated to occur in about 8% of cases. Approximately 60% of SCCs develop from AK, and the incidence of AK is continually increasing. An estimated 60% of predisposed individuals aged 40 years and older have at least one AK. All AKs deserve our attention and treatment, since they are the earliest clinically recognizable manifestation of SCC. The DNA changes in AK are very similar if not identical to those seen with invasive SCC. Actinic keratoses are an early form of squamous cell carcinomas .
What does Actinic Keratosis look like?
Actinic keratoses are predominantly found on the sun-exposed surfaces of the face, scalp, ears, neck, chest, arms and hands. Visually, AK presents as a skin-colored, lightly pigmented, or reddish rough area. It is generally less than a 1/2 inch in diameter and is frequently better appreciated by touch than by visual examination. It is very important to note that sun damage is not only localized to the areas of visible AK but rather to the whole region.
Successful treatment of AK rests on the choice of appropriate therapeutic modality, patient selection, and practical, ongoing treatment management. The choice of therapy depends on the medical status of the patient, the lesion location and number, as well as characteristics (e.g. size, duration, and growth pattern). Dermatologist skills and experience, is important in prevention, diagnosis and management of AK.
What are the treatment options for Actinic Keratosis?
There are several treatment options currently available for AK, including local destruction, topical drug therapy and light based modalities. Locally destructive measures include cryosurgery (liquid nitrogen spray), curettage (scraping), chemical peels, dermabrasion, laser surgery, electrosurgery, and excision. These methods are specialized, office-based and well suited to treat individual lesions (i.e. cryosurgery, curettage, electrosurgery, or excision) or extensive diffuse disease (i.e. chemical peels, dermabrasion, or laser ablation).
Topical, non-ablative drug therapy includes 5-fluorouracil (5-FU – Efudex®), imiquimod (Aldara®) and photodynamic therapy (PDT).
5-FU (Efudex®) interferes with the DNA synthesis, creating unbalanced growth and death of the abnormal cells. Its effect is greatest in more rapidly dividing cells. Depending on the frequency of use, the side effects of Efudex® are considerable and despite initial success, there is significant change of AK recurrences.
Since the immune system plays an important role in the development of AK, Aldara® has been used to treat AK and even early forms of other cancers. Aldara®, when applied to the skin, locally stimulates the immune system enhancing its ability to destroy abnormal cells. It appears that the enhancement of the immune system to recognize abnormal cells plays a role in lower AK recurrence rates over time.
Photodynamic therapy is based on the activation of a photosensitizer by visible light (laser- or non-laser sources) to create particles that selectively destroy abnormal cells. The photosensitizer is applied to the skin (face, chest or hands) and allowed to penetrate into the abnormal cells. When exposed to special light, the interaction between the particles and the light creates particles that destroy abnormal cells.
Many of the treatment are frequently combined in an effort to provide the best chances for improvement. It is important to note that actinic keratoses are not just a cosmetic problem or dry skin. They are a visible evidence of DNA alteration and an increased risk of more dangerous skin cancers.