Treatment of superficial basal cell carcinoma and squamous cell carcinoma in situ with a high-energy pulsed carbon dioxide laser.

BACKGROUND: High-energy pulsed carbon dioxide (CO2) lasers have been used extensively to resurface wrinkled and photodamaged skin with a low risk of scarring. Results of histological studies demonstrate precise ablation depths in treated skin with minimal thermal damage to underlying tissue. Our objective was to determine if a pulsed CO2 laser could effectively ablate superficial malignant cutaneous neoplasms (superficial multifocal basal cell carcinoma [BCC] and squamous cell carcinoma [SCC] in situ).

OBSERVATIONS: Thirty superficial neoplasms (17 BCCs and 13 SCCs) and their surrounding 3-mm margins were treated with either 2 or 3 passes of a pulsed CO2 laser (500 mJ, 2-4 W) using a 3-mm collimated handpiece. The treated areas were subsequently excised and evaluated histologically by serial sectioning at 5-micron intervals for residual tumor at the deep and lateral margins. Average patient age was greater for those with SCCs than for those with BCCs (76.5 vs 56.7 years; P = .001). The average tumor thickness of SCC in situ was significantly greater than that of superficial BCC (0.57 vs 0.34 mm; P = .01). All (9 of 9 patients) BCCs were completely ablated with 3 passes, and residual tumor in the deep margins was seen in 5 of 8 patients treated with 2 passes of the pulsed CO2 laser (P = .005). Incomplete vaporization of the SCC depth was seen in 3 of 7 patients treated with 3 passes and in 2 of 6 patients treated with 2 passes. Those SCCs incompletely treated were significantly thicker than those completely ablated (0.65 vs 0.41 mm; P = .01). Positive lateral margins were seen in 1 BCC and 3 SCC specimens.

CONCLUSIONS: Pulsed CO2 laser treatment can be effective in ablating superficial BCC. Treatment of the neoplasm and a minimum of 4-mm margins with 3 passes (500 mJ, 2-4 W) is recommended for complete vaporization using this laser system. Because 3 passes did not completely ablate all SCC in situ, use of this modality alone is not recommended for treatment of thick or keratotic lesions. No direct comparison of efficacy can be made with other destructive modalities that have not been evaluated with comparably sensitive histological techniques. Further study is needed to establish any cosmetic advantage of pulsed CO2 lasers over other destructive modalities for treatment of superficial malignant neoplasms and long-term cure rates.