The role of lasers in managing melanoma and near-melanoma is very narrow in scope.
“For the most part, there is not a big role for light-based technologies or any kind of laser in melanoma management because melanoma is typically a surgical disease,” E. Victor Ross, M.D., director of laser and cosmetic dermatology at Scripps Clinic in San Diego, tells Dermatology Times. “Surgery is the mainstay of treatment.”
Unlike a basal cell carcinoma or an early squamous cell carcinoma, “where the likelihood of distant metastasis is very small, melanoma or even melanoma in situ (MIS) are potentially devastating,” says Dr. Ross, in a post-presentation interview on lasers from the Melanoma 2017 meeting, held in Coronado, Calif., in January.
According to Dr. Ross, atypical appearing pigmented lesions should not be treated with a laser.
“If a lesion appears at all unusual, a biopsy should be performed prior to any laser intervention,” he says.
Nonetheless, patients with early melanoma in-situ lesions may benefit from lasers.
“Published articles support lasers to ablate some of these lesions, particularly perhaps in older patients where the lesions normally grow very slowly and surgery is more risky,” Dr. Ross says.
For example, an 88-year-old patient might have MIS (lentigo maligna) that develops into lentigo maligna melanoma, but one should consider the risk within the context of the patient’s overall health.
“The older the patient, the less likely that the balance of their life is going to be affected by an early pre-melanoma, and in these cases one can use the CO2 laser to vaporize the lesion off of the skin, especially if close follow-up is available,” Dr. Ross says.
When employing a CO2 laser, the lesion is first numbed with local anesthesia.
“The goal is to actually eradicate the lesion, so this means using several passes with the laser,” Dr. Ross says. During the single 15-minute session, “you are treating to the point where you do not see any more pigment. This is a reasonable endpoint.”
A second potential role for lasers is treating in-transit metastases, whereby a person has a true invasive melanoma that is spreading locally.
“The patient may have multiple nodules not too far away from the original melanoma,” Dr. Ross says. “Sometimes for palliative care, it is not unreasonable to vaporize those lesions as well.”
As with early MIS lesions, a CO2 laser is employed using the same protocol and endpoint, although multiple nodules can take up to 30 minutes to treat in a single session. A follow-up session six to eight weeks later may also be warranted.
A third potential indication for lasers is treating MIS with a Q-switched Nd:YAG or Q-switched alexandrite laser, in concert with the topical cream imiquimod.
The pigment-specific laser is used first, typically at 4 or 5 J/cm2, with a 3 mm spot.
“Just treat to the point where there is immediate whitening of the pigment or erythema, then stop,” Dr. Ross says. Imiquimod is then applied five times a week for about six weeks.
“Obviously, if the cell is not pigmented, you are going to miss those cells,” Dr. Ross explains. “Hence, these are more last resort treatments, where the impact of a wide excision might be prohibitive, given the patient’s general condition or anatomic location.”
In an otherwise healthy patient, though, surgery is still the gold standard, and any laser intervention carries a risk of recurrence of MIS, and even development of invasive melanoma.
Indications and advice
For all three laser indications, patient age and general health are paramount.
“If the patient is older and less healthy, they may not outlast the pre-melanoma, so you might not want to do something heroic that will leave a large scar,” Dr. Ross says.
For instance, if someone has an enlarged MIS on their face and is 94 years old, coupled with poor congestive heart failure and the likelihood of that person living beyond four months is slim, performing major surgery that may deform the face is simply not reasonable.
“You can circumvent such a procedure by considering laser or doing nothing at all,” Dr. Ross says.
Frequent patient follow-up for re-evaluation every three months after the final session of treatment is key for all three indications.
Also, these patients often have other providers, including an oncologist.
“Sometimes, I am referred a patient because the patient is not a good surgical candidate,” Dr. Ross says. “However, laser is not a first-line therapy in most cases.”
A possible downside of laser is that if the lesion is not completely eradicated, the lesion will become even more atypical.
“But the greatest advice is not to use a laser on a lesion that has any clinical atypical features,” Dr. Ross notes. “By treating that lesion with a laser, there is some potential that the lesion might actually become worse. Hence, do not treat with a laser a pigmented lesion that looks unusual, without first conducting a biopsy.”
Dr. Ross is encouraged that lasers can eventually assume a larger role in treating melanoma, assuming some co-therapies are developed.
“The challenge with melanoma and MIS, unlike other diseases which we treat with lasers, is that we have to have perfection in destroying every cell, not just a piece of the lesion,” he says. “At this time, lasers play more of a role in palliative care.”
Disclosure: Dr. Ross reports no relevant financial disclosures.