Pulsed-dye laser and retinoic acid delay progression of oral squamous cellcarcinoma: A murine model

Objectives/Hypothesis: This study examined the role of the pulsed-dye laser (PDL) at 585 nm coupled with retinoic acid at therapeutic (5.0 mg/kg) and nontherapeutic (0.5 mg/kg) doses to delay the progression of cancer with a two-hit approach. The existing vasculature is selectively targeted by the l aser, whereas retinoic acid inhibits future angiogenesis, Study Design: Ran domized, prospective study in a murine model. Methods: Twenty-five athymic nude mice were inoculated with oral squamous cell cancers on six flank site s and randomly divided into five groups: 1) control subjects, 2) treatment with 0.5 mg/kg retinoic acid CRA 0.5), 3) treatment with 5.0 mg/kg retinoic acid (RA.5.0), 4) treatment with RA 0.5 + PDL, and 5) treatment with RA 5. 0 + PDL, The PDL groups received irradiation after inoculation. The retinoi c acid was administered daily. The tumors were counted and measured for 14 days. Results: The control group developed visible tumors in 50% of the ino culation sites at 3 days compared with 3 days (RA 0.5) and 4 days (RA 5.0) for the retinoic acid groups and 9 days CRA 0.5 + PDL) and 10 days (RA 5.0 + PDL) for the laser treatment groups. There was no tumor growth until day 7 in the RA 5.0 + PDL group. The tumor volume was statistically different b etween the treatment groups. Conclusion: This study demonstrated the superi ority of a single treatment with the PDL coupled with retinoic acid to dela y the progression of cancer when compared with treatment with retinoic acid alone, thus introducing a novel strategy in cancer control.