The effect of CO2 laser excision on local tumor recurrence.

This study was undertaken to determine the effect of CO2 laser surgery on the incidence of local recurrence following tumor recurrence and to study the effect of "sterilization" of the operative site on this phenomenon. Sixty Fisher 344 rats were implanted with R323OAC mammary carcinoma. Animals were anesthetized with intraperitoneal pentobarbital, and all tumors were completely excised at 21 days postimplantation. The animals were randomized into groups of 12 as follows: Group S underwent excision with the scalpel. Group E underwent excision with electrocautery (Bovie, Valley Labs, Boulder, CO). Group L and LV underwent excision with the Sharplan 733 CO2 laser (Laser Industries, Israel) (TEMoo, 125-mm handpiece, 25-W continuous wave). Group LV wounds were then "sterilized" by using the laser defocused to a 5-mm spot size and gently heating the site without producing blanching or charring of the tissues. Primary tumor size was 2.0 +/- 0.5 cm and was similar in all groups. Animals were observed for recurrence for 33 days postoperatively. Mortalities were excluded from analysis. Tumors recurred in 7/9 (78%) in group S, 5/11 (45%) in group E, 4/10 (40%) in group L, and only 1/12 (8%) in group LV. All results are significant at P less than 0.05. The CO2 laser is an effective surgical adjunct to reduce local tumor seeding and recurrence. This effect is enhanced by "sterilizing" the surgical site with the defocused laser beam.