Editor'S comment.

Dr. Jyotsna Potdar reports an occurrence of breast cancer in a patient who was on Tibolone treatment for five years. It was an observational study of 50 women on Tibolone therapy for a period of six months to five years. Cause-effect relation between Tibolone treatment and breast cancer cannot be derived from such an uncontrolled /observational study. However, the Million Women Study has concluded that current use of Tibolone significantly increased RR (1.45 [1.25-1.68], P<0.0001) and was associated with an increased risk of incident and fatal breast cancer.[1] Use of Tibolone for treating vasomotor symptoms in breast cancer survivors is also contraindicated as an interim analysis of the LIBERATE trial found a 40% increase in the risk for breast cancer recurrence with Tibolone.[2] Isolated spontaneously reported cases of adverse drug reaction generated early signals that may get established or refuted by larger case control studies or randomized double-blind placebo-controlled clinical trials. McPherson and Hemminski point out the importance of recording rare adverse events during efficacy trials, as they might be early signals of true drug-related adverse events.[3] Spontaneous reporting will continue to be an important tool for identifying rare adverse reactions which are sometimes difficult to identify in premarketing clinical trials.[4]