A Phase III Skin Cancer Chemoprevention Study of DFMO: Long-term Follow-up of Skin Cancer Events and Toxicity.

1Carbone Cancer Center, University of Wisconsin-Madison.
Cancer Prevention Research (Impact Factor: 4.89). 10/2012; DOI: 10.1158/1940-6207.CAPR-12-0233
Source: PubMed

ABSTRACT Decreasing the incidence of non-melanoma skin cancer (NMSC) is of great importance in regards to future healthcare services. Given the previously reported preventive effects of α-difluoromethylornithine (DFMO) in skin and colon cancer trials, we determined appropriate cause to update the clinical data on the subjects from the recently reported Randomized, Double-Blind, Placebo-Controlled Phase III Skin Cancer Prevention Study of DFMO. Our intention was to retrospectively assess the further incidence of skin cancer, other malignancies, and adverse events of patients accrued to our phase III skin cancer prevention study of DFMO. Clinical records of 209 UW Health subjects were reviewed, and 2092.7 person years of on study (884.3 person years) and post study (1208.4 person years) follow-up for these patients were assessed for new NMSC events and recurrence rates from the on study period, the post study period, and the two study periods combined. No evidence of increased significant diagnoses or serious adverse events was observed in the DFMO participants. The initially observed, marginally significant reduction (p=0.069) in NMSC rates for DFMO subjects relative to placebo continued without evidence of rebound. Event rates after discontinuation from study for total NMSCs (DFMO 0.236 NMSC/person/year, placebo 0.297, p=0.48) or the subtypes of BCCs (DFMO 0.179 BCC/person/year, placebo 0.190, p=0.77) and SCCs (DFMO 0.057 SCC/person/year, placebo 0.107, p=0.43) are listed. Follow-up data revealed a persistent but insignificant reduction in new NMSCs occurring in DFMO subjects without evidence of latent or cumulative toxicity relative to placebo subjects.

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