Exclusion criteria would include systemic retinoid treatment or systemic chemotherapy within the past six months; indices of very high mortality risk within 3 years (history of invasive noncutaneous malignancy within the past five years or metastatic cutaneous malignancy, or of other severe medical problems e.g. end-stage cardiac disease); known allergy or severe irritation reaction to tretinoin or the cream vehicle; special conditions predisposing to NMSC that may not be generally applicable (xeroderma pigmentosum, basal cell nevus syndrome, major organ transplant recipient, known arsenic exposure, PUVA photochemotherapy, mycosis fungoides, or prior or current radiation therapy involving the face, ears, or area of prior skin cancer), and likely inability to comply with the requirements of the trial as judged by the investigator. Incompetent patients and pregnant or nursing patients will be excluded