Radiation Therapy for Skin Cancer
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What is Skin Cancer?
- The skin is the body’s largest organ. Its job is to protect internal organs against damage, heat and infection. The skin is the organ most exposed to ultraviolet (UV) radiation and other forms of damage from the environment.
- About 90 percent of skin cancers are associated with damage from ultraviolet (UV) radiation from the sun.
- More than half of our life-time UV exposure occurs after the age of 40, so continued skin protection is very important.
- As the skin becomes damaged, it may develop into precancerous lesions. The risk of an actinic keratosis lesion transforming to skin cancer is very small. However, the risk is higher for patients who have many of them on their skin.
- Skin cancer is the uncontrolled growth of cells that make up the skin. Skin cancer can come from specific types of cells: basal cells, squamous cells, pigment cells (melanocytes), or other accessory skin cells.
- Any new growth or change in appearance should be evaluated by a physician for possible skin cancer. Worrisome signs include the ABCDE mnemonic:
- Asymmetry: Normal freckles are typically symmetrical from side to side, but skin cancers may look different on one side than the other side.
- Border: irregular, blurry, or jagged edge.
- Color: Normal moles are typically just one color, but skin cancer may vary in color or hue from area to another, with shades of black, brown, tan, blue, red or white.
- Diameter: Areas larger than a pencil eraser (1/4 inch or 6 millimeters).
- Elevation: Normal moles are typically flat and flush with skin, but skin cancers may be raised above the surrounding skin, and have an uneven surface.
- More than 2 million people will be treated for skin cancer in the United States this year, and more than one in five adults may develop skin cancer during their lifetime.
Types of Skin Cancer
Broadly, skin cancers can be divided into melanoma and non-melanoma skin cancers (NMSC). However, each specific type can have distinctive features.
Basal cell carcinoma (BCC)
- Basal cell carcinomas are the most common type of skin cancer, accounting for almost 75 percent of all new skin cancer diagnoses.
- BCC develops from cells located deep in the epidermis, which is the outermost layer of the skin.
- They usually occur on sun-exposed areas, such as the nose and the ears but can be anywhere on the skin. They can even develop in areas that are never exposed to the sun.
- Individuals at highest risk are those with fair skin, and light hair and eyes, who had early, intermittent, intense exposure to sun usually resulting in a sunburn.
- Basel cell carcinomas are typically slow growing tumors, which can be very destructive locally but rarely spread (metastasize) to other parts of the body.
Squamous cell carcinoma (SCC)
- Squamous cell carcinoma is the second most common type of skin cancer.
- These skin cancers develop from squamous cells located in the middle layer of the epidermis, which is the outermost layer of the skin.
- Similarly to basal cell carcinoma, sun/UV light exposure is the most common risk factor. They can also arise in areas of previous trauma, scars, burn injuries or inflammatory conditions.
- They can be either slowly-growing or rapidly-growing tumors, they can invade surrounding structures, and they may spread (metastasize) to other parts of the body.
- Melanoma is not as common as basal cell and squamous cell carcinoma, but it is still the sixth most common malignancy among all other cancers.
- These cancers develop from skin cells called melanocytes that produce brownish or reddish pigment (melanin), which gives skin its color.
- Sun and UV light exposure, particularly if combined with having fair or light skin color, is the most common risk factor.
- This is the most serious type of skin cancer, because it can be very aggressive and spread rapidly to other parts of the body.
Other skin cancers
- Merkel cell carcinoma: These cancers develop from cells in the skin that allow us the sensation of touch (called tactile receptors). They are located in the dermis, which is the deeper layer of the skin. They can be quite aggressive and are more likely to spread to other parts of the body.
- Sebaceous, apocrine or eccrine cell carcinoma: These cancers develop from the different types of sweat glands, located in the skin dermis. They can behave aggressively.
Treating Skin Cancer
The treatment you receive depends on several factors, including what type of skin cancer you have, your overall health, stage of the disease and whether the cancer has spread to other parts of your body.
- Because these can be highly aggressive tumors, surgery to remove a wide area is usually the primary treatment option.
- Melanoma can spread into the surrounding lymph nodes, which are the tissue draining stations. In most instances, the surgeon will also biopsy or remove these draining lymph nodes.
- Radiation therapy is sometimes recommended after surgery for either the primary site or for the lymph nodes, if there is a concern that the surgeon might not have removed all of the disease. After surgery, it will be important to talk to a radiation oncologist to see if radiation would be right for you.
- Interferon therapy, which is a type of biologic therapy, is sometimes offered, if there is concern that your melanoma has a high risk of developing distant (metastatic) disease. You will want to talk to a medical oncologist, a doctor who prescribes chemotherapy, about these issues is more detail.
Basal cell cancer and squamous cell cancer
- These tumors are typically not as aggressive as melanoma, and there are many treatment options available.
- Surgical excision may be used, particularly Mohs Surgery (MMS), which is a special surgical approach using microscopic evaluation to map and remove all of the cancerous tissues, while preserving as much healthy tissue as possible
- Curettage and electrodessication (C and D, EDC) is typically used for smaller lesions (less than one centimeter). The cancer is dried with an electric current and removed.
- Cryosurgery is also used for small lesions that are not deep (this is called superficial). The cancer cells are frozen and eventually rub off naturally.
- Laser surgery can be used for superficial lesions. This is when cancer cells are destroyed by laser beams.
- Radiation therapy is an effective treatment often used for skin cancers where surgery or other localized therapies might cause functional or cosmetic defects.
- Photodynamic therapy (PDT) is primarily used in the treatment of actinic keratosis. It uses a drug that is very sensitive to a special kind of light. This drug is topically applied to the lesion. When exposed to that special light, the drug produces a chemical reaction that kills the cancer cells.
- Topical therapy is an application of a drug cream (Imiquimod or 5-FU) over the tumor. These drugs then locally kill the cancer cells.
- Sometimes a combination of approaches may be used, such as surgical excision followed by radiation therapy, if there is a concern that the surgeon may not have completely removed all of the tumor.
What is Radiation Therapy?
- Radiation therapy is the use of various types of radiation to safely and effectively treat cancer and other diseases.
- Doctors called radiation oncologists use radiation therapy to kill tumors, to control tumor growth and to relieve symptoms.
- Radiation therapy works by using X-rays or electrons to damage the genetic material or other critical components of cancer cells. This damage limits the cancer’s ability to reproduce. Radiation can sometimes stop the blood supply to cancers, which also kills the cancer cells. When these cancer cells die, the body naturally eliminates them.
- Normal cells are also affected by radiation, but they are better able to repair and heal the damage caused by radiation therapy than can most cancer cells.
- Radiation therapy treatments are noninvasive and painless, much like receiving an X-ray. You should be able to go home after treatment and will not need to stay in the clinic.
External Beam Radiation Therapy for Skin Cancer
- External beam radiation therapy involves a series of outpatient treatments to accurately deliver radiation therapy to the cancer, or the area from which the surgeon previously remove the tumor, and/or to the draining lymph nodes. The radiation will only be directed to the specific area of concern.
- Treatments are usually given every day, Monday through Friday, and may take anywhere between one and six weeks, depending on how large the cancer is and where it is located. Each treatment itself only takes a few minutes, but it may take half an hour to park, get checked in and set up on the treatment machine.
- Before starting radiation, you will undergo a radiation “planning” session where the radiation treatment team creates a way to set your treatments up accurately on a day-to-day basis. This may require imaging in the treatment position, typically with a CT scan. The radiation oncologist then works with his or her treatment team to “prescribe” the radiation treatment.
- Tailoring each of the radiation beams allows doctors to target more of the cancer cells while sparing nearby organs.
- Skin cancer is often treated with superficial forms of radiation therapy. That means the radiation penetrates only a short distance below the surface, giving more radiation to the skin cancer while keeping it away from underlying organs.
- More about external beam radiation therapy.
Potential Side Effects and Patient Care During Treatment
Patient care during treatment
- The side effects you might feel will depend on the part of your body being treated, the dose of radiation given and whether you also receive other treatments like chemotherapy.
- Fatigue is the most common side effect, often described as an overall “blah” feeling. Feeling tired often starts in the middle of the treatment course and may last several weeks after your last radiation session.
- Nearly all patients will experience redness and moistness of the skin, similar to brisk sunburn. After treatment ends, the skin will form a protective scab and new, healthy skin will develop underneath it. This healing may take several months.
- You may also notice some minor skin discoloration and darkening where the radiation was aimed. This should fade over time.
- If your tumor is located on your scalp, you will also likely lose your hair in the area treated. Your hair may grow back, but it might not have the same texture or thickness.
- Side effects are different for everyone. Your radiation oncologist and nurse will follow you closely during treatment and ask you and your family members about any symptoms. Medications may be prescribed to make you more comfortable.
- Please do not delay in talking to a radiation oncologist or oncology nurse about any side effects or concerns about treatments. They want to help you and your caregivers to be as comfortable as possible.
Patient care during treatment
- In most cases, you can continue your everyday activities such as moderate exercise and work. However, it’s important to also take time to rest as coping with cancer can be exhausting.
- Your treatments may be easier with good support from family, friends and neighbors. You may want to consider asking your doctor or nurse about support groups in your area that may also help.
- It is important to follow the doctor’s orders and ask a lot of questions. There are no silly questions; often the treatment team has heard similar questions.
- You and your family should ask the doctor if it’s safe for you to drive.
- It is important to tell your doctor about any medications you are taking to make sure they are safe to use during radiation therapy. This includes any vitamins or other dietary supplements.
- Try to eat a balanced diet. Your doctor, nurse or dietician can help suggest foods if you are having trouble eating or if food tastes funny.
- Try to treat the area exposed to radiation with special care. This includes staying out of the sun, avoiding hot and cold packs and cleaning the area with warm water and mild soap (such as baby shampoo). Also check with your radiation oncology about any lotions and ointments before using them to make sure they are safe on skin exposed to radiation.
- In the long term, it is especially important to use sun block over the area that received radiation. It is also a good practice to apply sun block any area exposed to the sun.