Clinician scientist Carolyn Lee, MD, PhD, has made it her mission to prevent skin cancer from ending the life of a person who has already beaten a death sentence. Lee sees patients in Stanford's new High-Risk Skin Cancer Clinic who have an increased risk of developing skin cancer—those who are post-transplant; immune suppressed; extremely fair skinned; or otherwise prone to developing skin cancers at an accelerated rate.
"I would hate to see someone who's been waiting for a heart or lung transplant finally get it, only to then battle an aggressive skin cancer that's fundamentally preventable," said Lee, a clinical instructor in dermatology. "These patients should come in and see us early for frequent monitoring and individualized treatment."
As a transplant center with high volume and recognized outstanding results, Stanford follows a large population of post-transplant patients who are immune-suppressed. This group is at an increased risk of skin cancer because the medications they rely on to prevent organ rejection decrease their body's innate defenses against cancer; some of those medications can also be carcinogenic. For these patients, the risk of squamous cell carcinoma increases approximately 60- to 100-fold. The risk of basal cell carcinoma increases about 10-fold, and the risk of melanoma increases three- to four-fold. These patients also tend to develop more simultaneous skin cancers that can also be more aggressive in their development as malignancies.
"We know the worst case scenario, and understand how quickly some of these non-melanoma skin cancers can develop and how aggressive they can be," said Lee, who presents the most challenging cases at a monthly, multidisciplinary Tumor Board. There, dermatologists, radiation oncologists, medical oncologists, dermatology and head and neck surgeons, pathologists and dermato-pathologists work together to formulate personalized treatment plans.
Because post-transplant patients also tend to have a higher rate of recurrence, "close surveillance is our most useful tool," said Lee. "We treat skin cancers early and aggressively. We want to catch pre-cancers and treat them as soon as we can to prevent them from becoming skin cancers. If some pre-cancers escape and become skin cancers, then we want to treat those as quickly as possible at the earliest stages."
Advanced, individualized treatment
Treatment plans are individualized, taking into account a patient's age, exposure to the sun and skin cancer history. Patients who are transplanted at a young age haven't yet accumulated the sun damage that might predispose them to skin cancer. But they will be immunosuppressed for a longer time, putting them at increased risk. Patients transplanted later in life, after years of possible sun exposure and damage, have to be vigilant about their skin sooner as a result of their combined years of sun exposure and subsequent ultraviolet-induced skin damage.
Many of the frontline treatments used at the High-Risk Skin Cancer Clinic are less commonly available elsewhere. For patients with numerous pre-cancers that are not well defined, dermatologists at Stanford's specialty clinic use topical field treatments to address a large area of skin at one time. This allows them to treat pre-cancerous lesions that are not yet visible, but that are still there on a microscopic level. Some of these treatments include topical 5-Fluorouracil and photodynamic therapy, or PDT.
Topical 5-Fluorouracil is a form of skin-directed chemotherapy that targets cells that are dividing too quickly, resulting in their death and causing inflammation. That inflammatory response also recruits the immune system and helps eliminate remaining abnormal cells. In photodynamic therapy, a light source targets areas of skin that have been treated with a photosensitizer.
When these broad treatments alone are not sufficient, Lee and other dermatologists at the High-Risk Skin Cancer Clinic use chemowraps, which combine topical chemotherapy with occlusive bandaging to enhance both efficacy and healing. This therapy is particularly good for arms and legs that have sustained extensive sun damage and results in numerous pre- or early cancers. Acitretin, an oral Vitamin A derivative, also has been shown to decrease the number of pre-cancers in transplant recipients.
Surgery is one of the mainstays for treatment of aggressive skin cancers. Lee consults with dermatology surgeons, Sumaira Aasi, MD, and Tyler Hollmig, MD, who have advanced training in skin-preserving Mohs Surgery. During a Mohs procedure, the surgeon uses a microscopic analysis of tissue samples from the suspicious area of skin to determine that the margins of the sampled area are clear of cancer before closing up the incision. If the margins are not clear, the surgeon can continue to remove cancerous cells, layer by layer, to spare as much healthy skin as possible.
"This technique conserves healthy tissue, which is especially important when working on the head and neck and around vital structures such as the eyes, ears, nose and mouth," said Lee. "Mohs surgery has excellent cure rates and is currently the most effective way to treat non-melanoma skin cancers."