To confirm reports that
skin cancer can be prevented with
retinoid treatment, a three-year controlled prospective study was conducted of oral
isotretinoin in five patients with
xeroderma pigmentosum who had a history of multiple cutaneous basal cell or
squamous cell carcinomas. Patients were treated with
isotretinoin, 2 mg/kg per day for two years, and then evaluated for an additional year without using the
drug. Before, during, and
after treatment, biopsy specimens of all suspicious lesions were examined, and
skin cancers were removed surgically. The patients had a total of 121
tumors in the two years before treatment. During two years of treatment with
isotretinoin, there were twenty-five
tumors, with an average reduction in
skin cancers of 63 percent (p = 0.019). After use of the
drug was discontinued, the
tumor frequency increased a mean of 8.5 times over the frequency during treatment (p = 0.007). Although all patients experienced mucocutaneous toxic effects, and abnormalities in
triglyceride levels, results of liver function tests, or skeletal findings occurred in some, high-dosage oral
isotretinoin was effective in the
chemoprophylaxis of
skin cancers in patients with
xeroderma pigmentosum.