Types of Skin Cancers
By far the most common type of skin cancer is basal cell carcinoma. Fortunately, it's also the least dangerous kind - it tends to grow slowly, and rarely spreads beyond its original site. It commonly occurs on the limbs and face, especially on the nose, eyelids and upper lip. Though basal cell carcinoma is seldom life-threatening, if left untreated for a long time, it can invade deep beneath the skin and erode the underlying tissue and bone, causing serious damage (particularly if it's located near any vital structures such as the eye).
Squamous cell carcinoma is the next most common kind of skin cancer, frequently appearing on the lower lip, face, or ears. Squamous cell carcinoma on the lips and in the intraoral cavity can be related to cigarette or pipe smoking. These cancers can be of different ‘grades’, with some types exhibiting more aggressive growth with higher incidences of recurrence and spread. This is the skin cancer that may spread to distant sites, including lymph nodes and internal organs such as the lung and liver. Squamous cell carcinoma can become life threatening if it's not treated.
A third form of skin cancer, malignant melanoma, is the least common, but its incidence is increasing rapidly, especially in the Sunshine State. Australia has one of the highest incidences of Melanoma in the world, with Queensland leading the national tally. Malignant melanoma is also the most dangerous type of skin cancer. If discovered early enough, it can be completely cured. If it's not treated quickly, however, malignant melanoma may spread throughout the body and is often deadly. The prognosis of Malignant Melanoma is based on its depth of invasion, so early detection is the key. Changes in the colour, shape or border of a mole can be an early sign of melanoma, as well as itching, ulceration or bleeding. New moles should always be checked by your GP or a skin specialist.
Diagnosis & Treatment
Skin cancer is definitively diagnosed by either a punch biopsy (removing part of the growth) or an excisional biopsy (removing all of the growth). The specimen is then sent to the laboratory and the cells examined under a microscope. It can be treated by a number of methods, depending on the type of cancer, its stage of growth, and its location on your body.
Most skin cancers are removed surgically. If the cancer is small, the procedure can be done quickly and easily, in an outpatient facility or the surgeon’s office, using local anaesthesia. The procedure may be a simple excision and direct closure, which usually leaves a scar. These scars are often prominent for the first six to eight weeks before fading into a fine line. The risks of surgery are low for this simple procedure and the benefit is an instant cure if completely excised.
All specimens excised are sent for histopathological examination by a pathologist. These are expert specialists who analyse microscopic features of the skin structures and cells. They are able to determine the type of skin cancer and also whether adequate margins have been taken around the cancer. If any component of the cancer has been left behind or the excision margins are close (also known as an ‘involved margin’ or ‘close margin’ respectively), a second procedure is required to take out more tissue to ensure that no cancer cells have been left behind. Inadequate excisions, if left untreated, often leads to high rate of cancer recurrence in the same area, usually within the first few months after the initial excision. On the other hand, a complete excision of a skin cancer often results in a cure.
Other possible treatments for skin cancer include cryotherapy (freezing the cancer cells with liquid nitrogen), radiation therapy (using ionising radiation), topical chemotherapy (anti-cancer creams applied to the skin), and Mohs surgery, a special procedure in which the cancer is shaved off one layer at a time.
All of which has its own place and suitable for specific types of cancer at specific sites. For example, Cryotherapy and anti-cancer creams are only effective on superficial skin cancers limited to the very top layer of the skin. Despite the fact that these are non-surgical treatments, they may still leave a scar. To find out which treatments are most suitable for you, please discuss your options with your surgeon.
Reconstructive Surgery is often required for skin cancers which are too big to be excised and directly closed, or skin cancers in areas of the body where there isn’t a lot of skin laxity. Most commonly, techniques used to reconstruct small to moderate sized skin cancers on the limbs and face are local flaps or skin grafts. A Local Flap repair is where a geometrically designed pattern is made adjacent to the defect (where the cancer had been cut out), so that the defect can be closed using available laxity in the nearby skin. This technique is very often used on the nose (e.g. a Bilobe Flap), on the face (e.g. a Rhomboid flap or V-Y advancement flap) or the forehead (e.g. an A-T flap or H-flap).
There are two types of Skin Grafts: Split Thickness Skin Graft (or STSG), and Full Thickness Skin Graft (or FTSG). STSG is where a shaving of skin is taken from a ‘donor site’ (commonly from the thigh). This is then placed and secured into the defect with sutures or staples. The donor site often heals with simple dressings within 10-14 days. The wound on the donor site are similar to a gravel rash; it can ooze blood stained fluid through the dressings and be ‘stingy’ in the first 3-5 days. This is the most common method of skin grafting for lower legs, as well as some scalp defects. The donor site is often left with a permanent but very faint patch of discolouration.
FTSG is where a full thickness piece of skin is cut out from the body (donor sites are usually the upper inner arm, behind or in front of the ear, lower neck or the groin). This skin is then sewn into the defect, sometimes with a pressure dressing (also known as a ‘tie-over’). The donor site is left with a straight line scar which is barely visible after 2 months.
With any skin graft, there is always the risk of graft failure, where all or part of the skin graft fails to ‘take’ on the raw surface. This could be due to a variety of causes, such as infection in the wound, bleeding under the graft, swelling in the area, or too much movement under or around the graft. When grafts fail, they undergo a slow necrosis, where the graft will firstly turn yellow and sloughy, then black before falling off like a scab. Majority of the time, the wound will continue to heal itself slowly over 4-6 weeks; it is only in very rare instances where another graft is required to help healing of the wound.
More commonly, grafts ‘take’ with very little failure, which is usually around the rim where surrounding skin movement prevent graft edges from adhering. Grafts first appear blue to purple in colour, then it becomes very thin and appear pinkish red (due to the in-growth of underlying blood vessels into the graft). Grafts take up to 2 weeks to heal and 8 weeks to ‘settle’, by which time it should be a faintly discernible patch that can be easily camouflaged with a thin layer of foundation or tinted sunscreen.
If the cancer is very big, or if it has spread to the lymph glands or elsewhere in the body, major surgery may be required. The different techniques used in treating extensive skin cancers can be life saving, but they may leave a patient with less than pleasing cosmetic or functional results. Depending on the location, size and severity of the cancer, the consequences may range from a small but unsightly scar to permanent changes in facial structures such as your nose, ear, or lip.
In such cases, no matter who performs the initial treatment, the plastic surgeon can be an important part of the treatment team. Plastic and reconstructive surgeons have a wide array of reconstructive techniques - ranging from re-arranging local tissue to a complex transfer of tissue flaps from elsewhere on the body. With reconstructive surgery, we are able to repair damaged tissue, fill-in tissue defects, rebuild body parts, and restore most patients to acceptable appearance and function.
The Aim of any skin cancer surgery has two components:
- To adequately remove the cancer
- Then to reconstructing the defect to achieve both good cosmetic and functional outcomes.
The important point to note is that the earlier a skin cancer is detected and treated; the operation required is usually a lot simpler.