Stopping tamoxifen peri-operatively for VTE risk reduction: a proposed management algorithm.

Tamoxifen is a selective oestrogen receptor modulator used in pre-menopausal oestrogen receptor positive breast cancer patients as adjuvant endocrine treatment. Increased risk of venous thrombo-embolism with the use of Tamoxifen is well known from published literature. This risk further increases in patients undergoing surgical procedures of high risk involving prolonged period of immobilization, therefore withholding Tamoxifen treatment in the immediate peri-operative period should be considered as a risk reducing measure. In the absence of nationally agreed guidelines on the safe duration for stoppage of treatment in the pre and post operative period without worsening cancer prognosis, operating surgeons and individual trusts have adopted their own guidelines based on individual experience. From the available evidence in the literature on the VTE risk assessments based on age, operative procedure and pharmacokinetics of the Tamoxifen drug we would like to propose a working algorithm for selecting the right patient group and safe treatment stoppage durations. These proposed guidelines are formulated taking all the risk factors of VTE, operative risks, pharmacokinetics of the drug and chemotherapy risks into consideration. With this guidance, we aim to help surgeons across different specialities in the decision making process through a structured evidence based approach.