From East Tennessee Medical News: Clinically Speaking
By Jessica L. Vinsant, MD, General Surgeon, Premier Surgical Associates
Skin lumps, bumps and lesions is a big subject – so let’s focus on skin cancers. Three common kinds of skin cancers are Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), and Malignant Melanoma (MM).
Nonmelanoma Skin Cancers
Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) are the most common types of malignant neoplasms in the world and the incidence is rising each year. An estimated 1 in 5 Americans will be affected by a nonmelanoma skin cancer during their lifetime. After a patient’s initial diagnosis of BCC or SCC, the risk for development of an additional skin cancer is estimated at 35% in 3 years and 50% in 5 years.
Basal Cell Carcinoma is slow-growing with no precursor lesion. BCC commonly infiltrate, but rarely metastasize. There are four distinct growth patterns: nodular, pigmented, cystic and superficial.
Squamous Cell Carcinoma has higher mortality rate than BCC. It does have a precursor lesion: actinic keratoses. The first site of metastasis is usually the regional lymph nodes. Patients commonly present with palpable scaling lesions that become ulcerated centrally and have raised edges.
Because most SCC occur on the sun-exposed surfaces of the head and neck, sunlight is thought to be a major causative factor. People who are especially susceptible include those with fair skin, blonde hair, and blue eyes. Other risk factors include patients with compromised immunity (transplant patients, lymphoma, leukemia, autoimmune diseases); those who have occupational and environmental exposures to arsenic, organic hydrocarbon, ionizing radiation, and cigarette smoke; and people with chronic conditions of the skin, such as ulcers, infections, and poorly-healing wounds.
Treatments
Treatment options of nonmelanoma skin cancer includes field therapy techniques such cryotherapy, topical fluorouracil, electrodessication and radiation. Radiation is highly effective for preserving wide areas of skin in the head and neck region, and for treating areas at high risk for recurrence after extensive surgical excision. Another treatment option is standard surgical excision. The needed margin of resection is generally one that is histologically free of carcinoma.
An alternative surgical approach to standard surgical excision is Moh’s Microgrpahic Excision (MME). It has a high rate of local tumor control with the use of horizontal frozen sections, which is continued until clear margins are obtained. This technique is very good for high-risk patients and for anatomic areas where it is important to preserve as much tissue as possible (around the eyes, ear, nose, mouth).
Malignant Melanoma
Only 4-5% of all skin cancers are malignant, but they cause the majority of deaths from skin cancer. Melanoma is the 8th most common cancer in the US and the incidence is rising faster than any other type of cancer. Lifetime probability of developing melanoma is 1 in 57 for males and 1 in 81 for females. Melanomas more commonly arise on the lower extremities in women and on the trunk and head and neck in men. The median age of diagnosis is 45 to 55 years old.
Highest risk population is individuals with fair complexion who receive intermittent doses of UV radiation that results in severe sunburns. Factors that increase the risk of developing melanoma include: dysplastic nevus syndrome, xeroderma pigmentosum, a history of non-melanoma skin cancer and a family history of melanoma. Individuals with congenital nevi have an increased risk for melanoma proportional to the size and number of nevi. Giant congenital nevi (1 in 20,000 newborns) carries a lifetime risk of 5-8%.
Four major types of melanoma:
- lentigo maligna melanoma– 10%- older individuals with sun-damaged skin; appears as a flat, darkly pigmented lesion with irregular borders and a history of slow development; prognosis is generally better than for other types.
- superficial spreading melanoma– 70%- most common histologic type; initially appear as a flat, pigmented lesion growing in a radial pattern.
- acral lentiginous melanoma– 5%- confined to the subungal areas and the glabrous skin of the palms and soles. Most common histologic variant in African Americans. Overall prognosis is poor.
- nodular melanoma– 15%- worst prognosis, early vertical growth pattern.
Unknown Primary
Nodal or distant mets may be the first evidence of melanoma (less than 2% of all melanoma cases and less than 5% of all cases of metastatic melanoma). Work up should include: histologic review of all previously removed skin lesions, inquiry into skin lesions that resolved without treatment, and inspection of areas that may have been previously missed (scalp, external auditory canal, oral and nasal mucosa, nail beds, genitalia, anal canal, and the eye). Melanoma is one of the most frequent tumors that metastasizes to the GI tract.
Surgery for Malignant Melanoma
The fundamental principle in the management of primary melanoma is to resect the tumor and minimize the risk for local recurrence. Management is based primarily on thickness and ulceration (ulceration indicates a significantly worse prognosis). For MM on the fingers and toes, amputation is required. Lymphoscintigraphy is a procedure where a radioactive colloid is injected into the skin and then a gamma camera is used to identify the sites of uptake (sentinel lymph nodes).
Recurrence of MM
“Local recurrence” is defined as tumor appearing in skin or subcutaneous tissue within 5cm of the primary wide excision site. Local recurrence is treated with surgical resection to attain histologically clear margins. Isolated hyperthermic limb perfusion involves the use of cannulation of the principle extremity artery and vein, a tourniquet, and hyperthermic perfusion with L-phenylalanine mustard or another chemotherapeutic agent.
Skin cancers are a pervasive problem throughout the world. Encourage patients to do regular skin self exams and use the A-B-C-D-E method of observation – look for moles and spots that change in asymmetry, border, color, diameter and evolve. Early detection and diagnosis plays an important role in the treatment of these malignancies
About Dr. Vinsant:
Jessica L. Vinsant, MD, is a general surgeon with Premier Surgical Associates Tennova North Knoxville and Physicians Regionals offices. Premier Surgical is the Knoxville area’s largest surgical group, performing general, vascular, bariatric, breast and laparoscopic procedures.