Pediatric melanoma: Occurrence is rare, yet most common type of skin cancer in children
It is estimated that there are approximately 400 new cases of melanomas diagnosed annually in the U.S. among those aged younger than 19 years. Melanoma is the most common type of skin cancer that occurs in children, according to St. Jude Children’s Research Hospital, as approximately 7% of all cancers diagnosed in children aged between 15 years and 19 years are melanomas. On a brighter note, the majority of melanomas are diagnosed early on and are highly curable.
HemOnc Today asked Alberto Pappo, MD, director of the solid tumor division at St. Jude Children’s Research Hospital, about the risk for melanoma in children, the different types that occur and the different treatment options that exist for the pediatric population of melanoma patients.
Question: How common is melanoma in children? What are the most recent statistics suggesting?
Answer: Melanoma can occur in children and we do not know exactly why this happens. It depends on how melanoma is defined. The term melanoma in pediatrics has been applied very broadly to a variety of different diseases. One is the typical melanoma that we normally find in adults. There is another type of melanoma in pediatrics (the most common type) called spitzoid melanoma. This type of melanoma has a different natural history and treatment recommendation than that of the regular conventional melanoma that we see in adults.
Q: What are the risk factors in children?
A: There is a very small percentage of children who do have predisposing factors. For example, there are children who are born with very large moles on their backs — this is a very rare disease called giant congenital melanocytic nevus. About 5% of these children develop melanoma, usually within the first 10 years of life. We also know that patients who have been treated with immunosuppressants such as chemotherapy or a renal transplant have a higher incidence for developing moles or nevi and eventually may be at increased risk for developing melanoma. There are also genetic conditions that are associated with an increased risk for developing melanoma, but these are extremely rare. One of these is called xeroderma pigmentosum and these patients usually go on to develop carcinomas but a small number of these patients may develop melanoma. Also, survivors of hereditary retinoblastoma are at increased risk for developing melanoma. The other interesting thing about children who develop melanoma within the first two decades of their life is that many of them have similar traits that we see in adults with melanoma — a lot of these children have had a history of sunburns, they usually have light complexion, red hair and a lot of freckles. But the question of why this happens at the age of 14 and not at the age of 40 — we do not have an answer for this. We conducted a genomic analysis of pediatric melanoma here at St. Jude (the first comprehensive genomic analysis on pediatric melanoma in the world) and we were unable to identify the exact reasons why younger patients develop melanoma. We were, however, able to confirm that if a child develops a conventional melanoma just like the one seen in adults, the genomic profile of the tumor is almost identical to that seen in adults, including evidence that ultraviolet radiation plays a role in the disease.
Q: What are the best prevention measures for children?
A: There are primary and secondary prevention measures which include regular use of sunscreen to prevent sunburns. The sunscreen should be broad spectrum and at least 15 SPF. There is little evidence that anything above 50 SPF has more protective effects. Sun care products need to be broad spectrum, meaning they should be efficacious against UVA and UVB rays. Also, even when a product is water-resistant, this does not mean it should be applied only once. No more than a couple of hours should pass between applications, especially if one is sweating and is in and out of the water. Between 10am and 2pm, children should avoid direct UV rays, but this does not usually happen. For small infants younger than 6 months of age, usually no sun at all is best. They can be at the beach, but they need to be covered, have on a hat and their neck and upper extremities should be covered. It is better to avoid sunscreens on babies younger than 6 months old because they can get significantly more exposure to the chemicals in sunscreens when compared with older patients.
Q: What types of treatments are available for children with melanoma?
A: This depends on the type of melanoma, but in general if the pediatric patient has typical melanoma, we follow the adult treatment guidelines. There have been no specific trials of melanoma treatment in children. Unfortunately, a lot of the drugs that are currently being studied in adults are not available in children. With the study we conducted at St. Jude showing that a subset of melanomas in children are exactly the same as in adults, we believe that clinical trials should be made available for younger patients particularly adolescents. However, there are a variety of approved therapies in adults that we can apply to pediatric patients such as interferon, which we have been using at St. Jude for many years, as well as other targeted treatments such as BRAF inhibitors and immune treatments such as check point inhibitors. However, we have no direct access to new therapies being tested in adults.
Q: What is the prognosis like for children with melanoma?
A: Pediatric melanoma that is diagnosed after the age of 10 years is very similar to that in adults. This means most will be diagnosed at a relatively early stage and the chance for cure is normally very good — I would say more than 90% of children with melanoma are expected to be cured of their disease. However, prognosis is directly related to the stage of the disease, and if the melanoma has metastasized to lymph nodes or distant metastases, then the outcomes are very poor — anywhere between 10% to 50%.
Q: What is your advice for pediatricians in terms of being vigilant for melanoma during office visits? Is this something that should be included in well-child visits if it isn't already?
A: If a child has a mole, the parent should bring this up to their pediatrician. The classical ABCDEs of melanoma that we see in adults are not exactly the same in children. Routine visits with physical exams are routinely recommended by the American Academy of Pediatrics. I emphasize discussion of preventive measures at each office visit, especially during the summer when families are going to the beach. Physicians should listen to parents. If there is a mole that the parent is concerned about that has changed in size or has had bleeding or ulceration, then listen to them and refer them to a dermatologist. In pediatrics, the vast majority of cases are identified by parents bringing up their concern to their primary care physician. The main reason for checking regularly for melanoma is that this is one diseases that if caught early, chances for survival are significantly high, but if caught late, these chances are significantly less. The earlier it is caught, the less needs to be done surgically and the less the chances are of the tumor spreading to other parts of the body.
Q: Do you have any final thoughts for our readers?
A: It is worthwhile to bring up that when a patient is diagnosed with melanoma in a pediatrician’s office that the family ask to specify the type of melanoma, in particular whether it is spitzoid melanoma. Because, again, the therapeutic implications and how aggressive we are in treating this type is significantly different from conventional melanoma. At St. Jude for example, if a spitzoid melanoma has spread to the lymph nodes, we are not being as aggressive anymore in terms of complex surgeries and giving interferon as we have in the past because we have learned that these tumors have a much more indolent and benign clinical behavior. We still do not know why this is so, but we at least know this and we are tailoring our therapies based upon the type of melanoma we are seeing. We do not treat any melanomas the same as we did 10 years ago.
Disclosure: Pappo reports no relevant financial disclosures.
Alberto Pappo, MD can be reached at St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105; email: email@example.com.