Advances in radiation therapy offer additional options treat skin cancer with increased accuracy.
Your skin is the body’s largest organ. It helps to control body heat and stores water and fat for the body. It also protects your body from infection, injury, heat and ultraviolet (UV) radiation. There are two main layers of the skin, the epidermis or the top layer and the dermis or bottom layer. The epidermis is mostly made of flat cells called squamous cells and just below them are round cells called basal cells. Melanocytes are scattered in between the basal cells and produce pigment when the skin is exposed to ultraviolet (UV) radiation. The deeper dermis has many types of tissue such as glands, blood vessels and lymph vessels.
Skin cancer is the most common of all cancers. More than 68,000 Americans will be diagnosed with melanoma (cancer of the melanocytes) and another 48,000 will be diagnosed with an early stage of the disease that only affects the top layer of the skin. In addition, more than 2 million cases of basal cell or squamous cell skin cancer will be diagnosed in the United States every year. Melanoma is the most serious of all the skin cancers because it can spread to other parts of the body. Basal cell, squamous cell and less common forms of non-melanoma skin cancers seldom spread to other parts of the body.
Both non-melanoma and melanoma skin cancers are treatable with surgery, chemotherapy, photodynamic therapy, immunotherapy and radiation therapy. Which options will produce the best outcome in your situation depends on the type of skin cancer you have, its location and whether or not it has spread.
Your Surgical Oncologist, Plastic Surgeon or Dermatologist may recommend a simple excision to remove your skin cancer. This is typically done under local anesthetic. There are several techniques to choose from depending on whether the cancer is located in a sensitive or highly visible area such as your face.
The different techniques share the same goal: to remove the growth along with margins of normal skin around it to improve the likelihood that all cancerous cells are removed and to help prevent a recurrence.
Most chemotherapy drugs for early stage basal and squamous skin cancer are applied in the form of a lotion. For Melanoma and more advanced stages of basal and squamous cell cancer, more powerful drugs are distributed via the bloodstream or in pill form to destroy cancerous cells. Photodynamic Therapy (PDT) is a type of chemotherapy where the drug is activated by a light source such as a laser. PDT is only used for early stage skin cancer. The drugs are injected intravenously or rubbed onto the skin in the affected area. Cancer cells absorb these drugs more quickly than normal cells and maintain the drugs for a longer period of time. When the light source is aimed at the tumor, it activates the drugs and kills the cancer cells.
Immunotherapy uses certain drugs to boost your body’s own immune system so it can better fight the melanoma. Some are administered via an injection while others are introduced to the bloodstream intravenously or topically through creams or gels. Each of these immunotherapy drugs can be used alone or in conjunction with surgery, traditional chemotherapy or radiation therapy.
Although radiation therapy is not typically used to treat the original site of skin cancer, it can be used in combination with surgery to destroy any remaining cancerous cells and to help prevent a recurrence. Radiation therapy is also an option for cancer patients for whom surgery is not an option and for those who previously had surgery and whose cancer has returned or spread to the lymph nodes. Radiation therapy can be used to help shrink tumors, preserve function, alleviate pain and control symptoms.
There are different forms of radiation therapy that can be used for skin cancer. External Beam Radiation Therapy (EBRT) is used primarily for advanced stage skin cancer and melanoma that may have spread into the lymph nodes and High Dose Rate (HDR) Brachytherapy is used for early stage basal and squamous cell tumors.
3D-Conformal Radiation Therapy and Intensity-Modulated Radiation Therapy (IMRT) are two forms of External Beam Radiation Therapy. During 3D-Conformal treatments, a device called a “multi-leaf collimator” will shape the individual radiation beams to “conform” to the shape of your tumor according to the data and instructions it receives from the system computer. IMRT uses thousands of radiation “beamlets” from many different angles to deliver a single dose of radiation. The intensity of the “beamlets” can change during the treatment session to modulate the dose, so that the tumor receives a very precise high dose of radiation, while minimizing damage to surrounding, normal tissue.
Before each session, a Radiation Therapist will carefully position you on the treatment table using a body immobilizer for precise body placement. Image guidance will be used to confirm the location of the tumor before the therapy begins. During your treatment sessions, the radiation delivery system will revolve around you, delivering the radiation according to the plan set by your Radiation Oncologist. Each treatment session lasts from 10 to 30 minutes. . If radiation is your primary form of treatment, you will be scheduled for five sessions a week for five to six weeks. If it is used in adjuvant to surgery, you will be treated for three to four weeks. The sessions are pain-free and require no sedation so you can return to your normal activities right away.
With High-Dose Rate (HDR) Brachytherapy, a computer-controlled machine sends the radioactive isotopes through a special delivery handle that looks like a flat hammer. The flat surface is placed against the skin during the treatment. The overall treatment time at the tumor site is 10 to 20 minutes. Your treatment plan may require one session or multiple sessions. After each session there is no radioactive material remaining in the body. You are free to resume normal activity with either treatment.