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Researchers look at pulsed-dye lasers as possible "next generation" treatment of basal cell carcinoma (BCC).
Dr. Tannous still supports surgical excision or Mohs micrographic surgery as the standard of care for skin cancers; however, she has completed one study and is in the process of completing two other research studies exploring the best methods to use pulsed-dye lasers for BCC.
Her work, presented last fall at the American Society for Dermatologic Surgery annual meeting in Chicago, showed a 92 percent clearance rate for small BCCs measuring less than 1.5 cm in diameter treated with pulsed-dye laser alone.
The current study treated 14 patients with a total of 23 lesions, all on the trunk or extremities, measuring 0.5 cm to 7 cm in diameter. All but two patients received four treatments in two- to four-week intervals.
Tumors less than 0.7 cm showed 100 percent clearance and lesions up to 1.4 cm showed 92 percent clearance upon histologic exam. Larger carcinomas had less favorable results, with 22 percent clearance after pulsed-dye laser treatments.
"Pulsed-dye lasers can specifically heat the blood, because it is absorbed by the hemoglobin and destroys the blood vessels.
"BCC is rich with blood vessels, and we got this idea to cut down the blood supply and treat them selectively, inducing necrosis, and that's why we get good efficacy," says Dr. Tannous, chief Mohs micrographic surgeon, Veterans Administration Hospital, and staff dermatologist, Massachusetts General Hospital, Harvard Medical School, Boston.
As a Mohs surgeon, Dr. Tannous says she first began observing the high number of vessels associated with BCCs under confocal microscopy, which allows visual inspections in vivo into the blood vessels.
"The imaging of blood vessels is more apparent in vivo than on regular histology," Dr. Tannous tells Dermatology Times.
The pilot study focused on four treatment sessions, "but we may not need that many and have yet to determine the optimal number," she says.
One patient only completed a single session and another, just three. However, clearance rates were similar to those who finished all four.
"It is still experimental, but at least I know it works," Dr. Tannous says, unlike other lasers she is still studying.
Beyond the pulsed-dye laser
Other lasers may also prove effective, but remain even more experimental than pulsed-dye lasers for BCC treatment, she says.
Older research has ruled out CO2 and Er:YAG lasers because of their destructive nature and scarring.
"My hope is for good clearance rates in a scar-less fashion. A lot of work has to be done to determine whether pulsed-dye lasers leave a scar, but it is promising," Dr. Tannous says.
Other skin cancers, including squamous cell carcinomas and melanomas, are not indicated for pulsed-dye laser treatment.
"Melanoma is life-threatening and should not be touched except with surgery, because the parameters are so uncertain," Dr. Tannous says, adding that SCC fails to have as many blood vessels to target as well.
Pre-cancerous lesions are also not an indication for pulsed-dye lasers for similar reasons.
Actinic keratoses (AK) are even more superficial than most BCCs, and Dr. Tannous says standard photodynamic therapy (PDT) is better because it is effective to prevent AK lesions from becoming cancer.
The risk of scarring and pigment changes is low with PDT, but temporary minor pain is one adverse effect that applies to all patients.
"It can provide good cosmetic results with minimal scarring, but pigmentary risk depends on skin type. Patients at highest risk for skin cancer are light-skinned individuals, so pigment is not a big issue," she says.
"We use a lot of modalities for treatment of skin cancer," Dr. Tannous says.
"You can grade them by which has the highest efficacy, but sometimes depending on the patient situation, including how many skin cancers the patient has or how much sun damage the patient has, it all factors into deciding which modality to use. Sometimes we go for something less invasive like PDT, because it is more suitable for the patient," she says.