Combined Medical Treatment
In refractory OSSN cases, various chemotherapeutic agents can be used sequentially or as a combined treatment. Di Pascuale et al. reported a case of OSSN that responded to MMC treatment. However, due to intolerance to further topical MMC, treatment was continued with IFN-α2b until complete resolution of the tumor was acheived. Topical MMC has been used before IFN-α2b in an attempt to reduce the length of IFN-α2b treatment. In a case reported by Huerva et al., complete resolution of an extensive OSSN tumor was achieved after two cycles of MMC and 75 days of topical IFN-α2b. Lack of treatment efficacy with MMC and successful tumor management with 5-FU has been reported. The suggested mechanism for the differential response was the difference in the mode of cytotoxic action of 5-FU and MMC, with MMC inhibiting DNA synthesis and 5-FU affecting both DNA and RNA. However, due to the fact that MMC exerts its chemotherapeutic effect for a long time, the chemotherapeutic effects of 5-FU and MMC in cases of sequential treatment may be additive.