The Effect of Pulsed Dye Laser on Basal Cell Carcinomas

Overview

Basal cell carcinoma (BCC) is the most common skin cancer in the United States, with approximately 800,000 cases diagnosed annually. Pulsed dye laser (PDL) successfully treats cutaneous vascular lesions, such as port wine stains and hemangiomas. BCCs contain abundant abnormal vasculature that could serve as a treatment target for PDL. The objective of this study is to determine the histologic and clinical response of BCCs to PDL as a new form of treatment.

Why Use Pulsed Dye Laser Treatment on Skin Cancer?

Lasers are sources of high intensity light that can be accurately focused into small areas with very high energy. Lasers can produce light in the visible (400 nm to 700 nm) and infrared spectrum ( > 700 nm) by exciting a particular laser medium and emitting a photon of light when the medium returns to its stable state.

Figure 1:
Pulsed Dye Laser (595 nm)

Pulsed Dye Laser (PDL) is a type of laser invented in the 1980's that is used to treat vascular lesions. The VBeam is the newest generation of pulsed dye laser. It emits yellow light in the visible spectrum (595 nm.) Vascular malformations, such as telangiectasias, vascular birth marks, and port wine stains, can be treated with lasers because hemoglobin specifically absorbs light at particular wavelengths in the visible spectrum (418, 542, 577 nm.) Thus, abnormal blood vessels can be selectively targeted by the pulsed dye laser and coagulated, without causing damage to the surrounding tissue.

Basal cell carcinoma (BCC) is the most commonly diagnosed skin cancer in the United States. BCCs are tumors of the deepest layer of the epidermis (the basal cell layer). BCCs can penetrate down into the dermis and destroy underlying structures if not treated early. BCCs, like any other tumor, require and recruit abnormal microvasculature for growth. Certain histologic subtypes of BCC are often clinically described as having telangiectasias. By specifically targeting this vasculature using PDL, the tumor growth could be decreased or even eliminated.

Various treatment options for BCCs exist, such as electrodessication and curettage, cryosurgery, topical treatments such as Aldara and 5-fluorouracil, elliptical excision, and Mohs surgery. We hope to demonstrate PDL as a new potential, efficacious, non-surgical method of treating basal cell carcinoma.

Study Methodology

Figure 2: Outline of Treatment Protocol

Recruitment

PDL Treatment

Surgery

Histology

 

1. Recruitment: We studied ten patients with eighteen biopsy-proven BCCs on the trunk and extremities. The BCCs could be any low-risk histologic subtype. These subtypes included superficial and nodular type BCCs.
2. Pulsed Dye Laser Treatment: Each patient received four PDL treatments at minimum two week intervals. At each laser visit, the selected treatment area and four millimeters of normal skin were assessed, demarcated, photographed, and treated with PDL at the following parameters: wavelength of 595 nm, energy of 15 J/cm², pulse length of 3 ms, no dynamic cooling mode, and 7 mm minimally overlapping spot size.
3. Surgical Removal: Two weeks after the final laser treatment, the BCC and the 4 mm margins of skin treated with PDL were surgically removed as standard of care. The surgical removal was performed as a disk excision. The tips were also removed, and wound was repaired with a complex linear closure.
4. Histology: The excised skin tissue was examined using hematoxylin and eosin (H&E) stains for the histologic response of BCC to PDL treatment. Complete response is defined as no histologic evidence of disease after complete sectioning of the tumor. No response is defined as histologic evidence of BCC in the excised tissue.