Here's some of the data I have:

Prevention of Second Primary Tumors with Isotretinion (13-cis-retinoic acid) (9/20/1990):

Results: There were no significant differences between the two groups (medication & placebo) in the number of local, regional or distant recurrences of the primary cancers. However, the isotretinion had significantly fewer second primary tumors. After a median follow up of 32 months, only 4% of the isotretinion group had SPT's as compared with 12% of the placebo group.

Conclusions: Daily treatment with high doses of isotretinion is effective in preventing SPT's in patients who have been treated for SCC of the head and neck, although it does not prevent recurrences of the original tumor.

The other studies I have involve more than one agent -- interferon and 13-cis-retinoic acid.

-Brett

Base of Tongue SCC. Stage IV, T1N2bM0. Diagnosed 25 July 2003.
Treated with 6 weeks induction chemo -- Taxol & Carboplatin once a week followed with 30 fractions IMRT, 10 fields per fraction over 6 more weeks. Recurrence October 2005.