Rationalizing Optimal Timing for Adjuvant Hormone Therapy for Patients with Breast Cancer: Impact on Limited Resource Countries

Abstract

Modern day cancer chemotherapy is complex and involves multiple drugs given either sequentially or concurrently, as an adjuvant or neo-adjuvant. Besides the concentration of the drug, timing, duration and sequencing of individual drugs in combination with other similar agents play a vital role in the final therapeutic outcome. This study constitutes an exhaustive overview of current knowledge of timing and sequencing, specifically of Tamoxifen, based on tumor’s hormone receptor status, as part of a comprehensive treatment plan. It has become apparent that inappropriate timing or sequencing can be detrimental. On the other hand, appropriate timing and sequencing of Tamoxifen, based on breast cancer cell-biology, pharmacokinetics and pharmacodynamics of drugs, the body’s homeostatic response to drugs; surgery and radiation, yield huge benefit for locoregional control, long-term survival and reducing complications in patients with breast cancer. Conclusion : A rational plan for use of Tamoxifen has been recommended, based on this study; for optimal therapeutic benefit. It has also been suggested that in receptor “unknown cases”, it is beneficial to prescribe Tamoxifen, since 75% of breast cancers are likely to be estrogen receptor positive and side effects can be minimized with planned vigilance.