Key clinical point: Although local transdermal therapy with 4-hydroxytamoxifen was associated with low systemic exposure, it was not as effective as oral tamoxifen in suppressing proliferation in the ductal carcinoma in situ (DCIS) lesions of the breast.
Major finding: Posttreatment Ki67 labelling index was significantly higher in the transdermal 4-hydroxytamoxifen gel vs oral tamoxifen treatment group ( 3.3%; 80% CI 2.1%-4.6%), with the value exceeding the noninferiority margin of 2.6%. Grade 2 adverse events were reported by five patients in both groups.
Study details: Findings are from a phase 2 study including 107 patients with DCIS of the breast who were randomly assigned to receive oral tamoxifen or 4-hydroxytamoxifen gel treatment for 4-10 weeks, of which 90 patients completed the treatment and underwent surgery.
Disclosures: This trial was sponsored by the US National Cancer Institute. Some authors declared receiving grant funding from various sources or holding a patent.
Source: Khan SA et al. Presurgical oral tamoxifen vs transdermal 4-hydroxytamoxifen in women with ductal carcinoma in situ: A randomized clinical trial. JAMA Surg. 2023 (Oct 23). doi: 10.1001/jamasurg.2023.5113