"Being male or female might be a more important determinant of health, illness, and response to treatment than is known." "The Lancet is calling for researchers to enrol more women into clinical trials of all phases, and to plan to analyse data by sex, as a matter of routine."

Awareness that gender can influence the prevalence, diagnosis, drug efficacy and tolerance and surgical outcome in a number of diseases is increasing.  Better understanding of gender/sex differences has resulted in the improvement in the diagnosis and treatment outcomes of heart disease in women.  For example, it is now recognized that women do not show the classic symptom of severe chest pain associated with a heart attack. In women the symptoms may be shoulder pain, fatigue, breathlessness, nausea and vomiting - and ECG readings may be atypical. Knowledge of this difference has led to better and quicker diagnosis of heart attacks in women.

It is agreed that there is a big gap in the understanding and knowledge of gender differences and the impact that gender specific dosing can  have on drug treatments. Professor Ray Powles CBE of the Cancer Centre London Parkside states: "There is a huge potential blind-spot in optimizing effectiveness and toxicity of drugs in routine clinical practice. Gender differences have been largely ignored in relation to the design, conduct and analysis of testing new drugs, and this might lead to under or over dosage of patients.  Understanding this might improve treatments for both sexes for future drugs after approval for public use...."  

Current clinical practice for almost all drug treatments defines the dose to be given simply on the size of the patient and does not take into account potential differences relating to gender and it would be a surprise if the dose of a drug, even if adjusted for size, would always be the same for men and women.  Women are generally smaller, but their surface area is not representative of their size compared with men, because the total body water is different.  There is a difference in fat tissue ratio, and the hormone matrix is different, particularly relating to pre-puberty, menarche and the menopause. There is also a difference in the metabolism and the enzymes in men and women.

"This may be particularly important in cancer treatment because trials that have led to approval determine the starting doses of the schedule, and are the same for men and women.  As successive courses are given there is a dose adjustment relating to toxicity, particularly using blood counts, leading to patients receiving an individualized biological dose. But the first two or three courses may be critical in getting on top of the cancer and it could easily be that either men or women are being under-dosed at this point" stated Professor Powles.  Click here to read the Lancet editorial.