A new study finds that sex and gender reporting in Australian cancer clinical trials has worsened despite global guidelines, with potentially serious consequences for patients.
Women with cancer may not have the same chance of cure or quality of life as men - yet fewer than 2% of Australian cancer clinical trials report results separately for men and women. Women are also more likely to experience severe side effects from cancer treatment, including from immunotherapy and chemotherapy, but without this data, clinicians have no way of knowing whether a treatment's safety or effectiveness profile applies equally to their patient.
A new study from The George Institute for Global Health, published in Research Integrity and Peer Review, reviewed 128 Australian cancer randomised controlled trials published between 2014 and 2024 and assessed how well they reported sex and gender of participants, which is known to influence cancer incidence, treatment response and outcomes.
The findings are stark. Not a single trial defined how participants' sex or gender was determined. Only 14% reported a sex or gender breakdown in the abstract. And rather than improving after the introduction of international Sex and Gender Equity in Research (SAGER) guidelines in 2016, several critical measures went backwards.
Sex-based analyses dropped from 44% of trials before the guidelines to just 22% after. Consideration of sex and gender in study design fell from 21% to 14%. The proportion of trials presenting results disaggregated by sex declined from 21% to 12%.
"When clinical trials don't report data separately for men and women, we lose critical information about safety and effectiveness. We know women experience higher rates of severe side effects from cancer treatments including immunotherapy and chemotherapy, yet fewer than two per cent of the trials we reviewed broke down adverse event data by sex. That's not a minor reporting gap. That's information clinicians need to make informed decisions for their patients.
By:Dr Vikneswary Batumalai
Lead author, The George Institute for Global Health
Biological sex influences how tumours develop, how the body processes drugs and how patients respond to treatment. Research has identified sex-related differences in the effectiveness and toxicity of immunotherapy, chemotherapy, targeted therapy and radiotherapy across multiple cancer types.
Gender, the social and structural context in which people live, also shapes cancer outcomes through factors including health-seeking behaviours, access to care, caregiver roles and psychosocial support. Conflating sex and gender, or failing to report either, makes it impossible to determine whether observed differences stem from biology or social context.
The study found that only 11% of trials discussed whether findings could be generalised across sexes and genders, and not one trial offered a rationale for omitting sex or gender analysis, a basic requirement under the SAGER guidelines.
"These findings tell us that voluntary guidelines are not enough. Journals endorsing the SAGER guidelines made virtually no difference to reporting quality in practice. What we need are funding mandates, stronger editorial enforcement and genuine investment in researcher education. Sex and gender need to be built into study design from the very beginning, not treated as an afterthought at the point of publication.
By:Professor Mei Ling Yap
Senior author, The George Institute for Global Health
The study also tested whether journal endorsement of the SAGER guidelines made a difference. It did not. Of the 94 post-guidelines studies, 54% were published in journals that formally endorsed SAGER, yet reporting practices were virtually identical to those in journals that did not.
Australia's policy environment compounds the problem. A 2017 analysis found that eight of the country's top ten national health funding agencies had no policies on sex- and gender-specific reporting in research.
The authors call for stronger editorial compliance mechanisms, mandatory reporting requirements from funding bodies and investment in researcher education to ensure sex and gender considerations are embedded from study design through to publication.
