New laser technology packs punch for pigmented lesions

Research studies Dr. Chan reviewed a number of studies conducted in the Orient over the past few years while speaking at the recent American Academy of Dermatology annual meeting. He outlines results of a couple of studies that could be considered somewhat unexpected.

The Q-switch is the traditional laser of choice for the treatment of pigment problems such as freckles and age spots. Dr. Chan says although the results are generally good, for darker-skinned patients, there is a high risk of increased hyperpigmentation afterwards.

Dr. Chan says he worked on a study several years ago supporting that result.

"That study basically showed that a long pulse 532 is as effective as the Q-switch 532 in the reduction of lentigines in a dark-skinned patient, but in terms of complications, the Q-switch 532 was associated with a high risk of post-inflammatory hyperpigmentation."

Dr. Chan says, "Effectiveness is one issue; the other issue is complications. For any cosmetic procedure, if you treat somebody and then they develop increased pigmentation afterwards, they will not thank you. They will be very upset."

'Pivotal controversy' Another message Dr. Chan wants to get across is what he calls the "pivotal controversy" over whether one should use lasers to remove moles.

"The laser is effective in removing moles, but the question remains, whether using the laser to remove the mole could lead to increased melanoma. Nobody knows.

"There are people who feel one should never use a laser to remove a melanocytic nevus in case the nevus has already gone nasty," he says.

Dr. Chan says this is one instance in which ethnic differences appear to make a difference in treatment choices. He notes that if one looks at the available data, the risk of melanoma is substantially higher in Caucasians than in Asians or Africans. Therefore, he says, one needs to define the ethnic group one is treating and whether one should use a laser in that ethnic group to treat such congenital melanocytic nevi.

"If you compare the Osaka (Japanese) Cancer Registry with the Italian registry - and they compared those two because Italians have a darker skin type as compared to Anglo-Saxons - there is literally a 50 to 100 times difference in the number of melanoma."

According to the Osaka registry, between 1964 and 1995, 2.45 melanoma cases were reported annually for every 100,000 men and 2.04 cases for every100,000 women, on average. According to the Italian registry, 10.04 melanoma cases were reported for every 100,000 men and 13.09 for every 100,000 women.

That indicates that the incidence of melanoma is not related simply to a person's skin tones, but to the ethnicity of the person.

Dr. Chan says melanoma encountered in the Asian race tends to be acral in nature, and while he would avoid using a laser on an acral lesion or if there is any other risk of melanoma, he would treat facial congenital melanocytic nevi on an Asian patient and expect to get excellent results, but would forewarn the patient's parents of the potential risk.