Patient-controlled transdermal 4-hydroxytamoxifen (4-OHT) vs. oral tamoxifen: A systematic review and meta analysis

There has been a number of studies looking into an alternative mode of therapy for the treament of breast cancer via 4-hydroxytamoxifen (4-OHT) transdermal administration.This systematic review aims to compare the safety and efficacy of a transdermal 4-OHT local therapy and oral tamoxifen (oral-T) on the treatment of ductal carcinoma in situ breast cancer. Through a systematic search of health science databases, eligible trials were located and the end points assessed were Ki-67 labeling index, concentration of 4-OHT in breast adipose tissue (ng/g) and plasma (ng/ml). Revman 5.3 version was used to perfom the meta-analysis. Three trials were identified (n=103), while only two were included for meta analysis. The mean difference between the two studies included were 0.40 and -10.58. Overall the I² value was 89.0%, (Tau² =53.86) and the differences between the two trials were statistically significant p=0.002. The meta analysis of the randomized controlled trials showed that the use of local transdermal therapy of 4-OHT gel is more safer than oral-T. However, due to the limited number of studies, the potential use of 4-OHT topical transdermal therapy for the treatment of breast cancer could not be concluded for healthcare professionals.