Why does it matter whether cancer trials report results separately for men and women?

Cancer treatments — including chemotherapy regimens and immunotherapy — do not affect men and women identically. Women tend to experience higher rates and more severe forms of toxic side effects from many standard cancer treatments. Without sex-disaggregated trial data, oncologists cannot accurately counsel women on their individual risk profile, cannot make dose adjustments based on sex-specific pharmacokinetics, and cannot identify subgroups of patients who respond better or worse to particular treatments. When clinical trials pool results across sexes without reporting separate analyses, the averaged findings may systematically underrepresent women's actual risk of harm from treatment — meaning clinicians and patients are working from an incomplete picture.

What is the SAGER guideline and why did it fail to improve reporting?

The Sex and Gender Equity in Research (SAGER) guidelines were introduced in 2016 to provide researchers with a framework for incorporating sex and gender analysis into research design, conduct, and reporting. The George Institute findings show that Australian cancer trial reporting has actually declined since 2016, with sex-based analyses falling from 44% to 22% — a halving of an already modest baseline. The guidelines did not achieve their goal. Research equity experts point to weak enforcement mechanisms: SAGER is a recommendation, not a requirement, and peer reviewers and journal editors have not consistently applied it as a condition of publication. Journals and trial registries have not made sex-disaggregated reporting a mandatory submission criterion. Guideline adherence in research publishing depends on enforcement, and enforcement has been inadequate.

Australian cancer trials are failing women on sex-disaggregated data

What just happened

A study led by The George Institute for Global Health, published in Research Integrity and Peer Review, has examined how Australian cancer randomised controlled trials report sex and gender differences — and found that rather than improving, reporting has significantly worsened.

The study analysed 128 Australian cancer trials published between 2014 and 2024. In 2016, the SAGER guidelines — Sex and Gender Equity in Research — were introduced internationally, with the explicit goal of improving how biological sex and gender are incorporated into research design and reporting. The George Institute’s findings show what happened after those guidelines:

Sex-based analyses in Australian cancer trials fell from 44% to 22% — a halving
Sex and gender consideration in study design dropped from 21% to 14%
Sex-disaggregated results decreased from 21% to 12%
Only 14% of trials reported sex breakdown in abstracts
Fewer than 2% reported adverse event data separately by sex
Only 11% discussed whether results could be generalised across sexes

Lead author Dr Vikneswary Batumalai and senior author Professor Mei Ling Yap (both George Institute / UNSW Sydney) identified this as a failure at the level of research culture, peer review, and journal standards — not just individual researcher choice.

The both-and

Why sex differences in cancer treatment are clinically real

The decline in reporting matters because the underlying biology it is meant to capture is clinically significant.

Women experience different — often worse — toxicity profiles from several of the most widely used cancer treatments. In immunotherapy, women have higher rates of severe immune-related adverse events including colitis, hepatitis, and pneumonitis. In chemotherapy, women generally achieve higher plasma drug concentrations at equivalent weight-based doses due to differences in body composition, fat distribution, and drug metabolism pathways — which translates to higher rates of toxicity at standard doses. Hormonal interactions, cardiac toxicity profiles, and peripheral neuropathy rates also differ meaningfully between sexes for specific agents.

This is not a peripheral concern. It affects how dose modifications are made, how toxicity risk is communicated to patients before treatment, and how side effects are managed during treatment. A clinical trial dataset that does not report these findings by sex is a dataset that has actively discarded information relevant to individualised care.

A guideline with no teeth

The SAGER guidelines did not arise from nowhere. They were introduced in response to decades of documented evidence that women were systematically excluded from early-phase clinical trials (a legacy of thalidomide-era reproductive risk concerns that persisted long past their justification), that trial populations skewed male, and that results were applied to women without adequate validation in female-specific populations.

The guideline’s failure to improve Australian cancer trial reporting over nearly a decade of operation points to a structural problem, not an awareness gap. Researchers are aware of the SAGER guidelines — they were published across major journals and adopted as a recommendation by multiple scientific bodies. What has not occurred is any consequential enforcement: peer reviewers do not routinely reject manuscripts for non-compliance, journals have not made sex-disaggregated reporting a condition of publication, and trial registries have not required it as a registration criterion.

Recommendations without enforcement are not mandates. The George Institute study makes the implicit argument that voluntary compliance is insufficient.

The international dimension

Australian cancer trial reporting does not exist in isolation. The George Institute study involved collaboration with Imperial College London and institutions in India — suggesting the problem extends beyond Australian research culture. The SAGER guidelines are international in scope; their underperformance in Australian cancer research likely reflects a more widespread failure to translate guideline adoption into reporting practice.

This is relevant because Australian oncologists and GPs who draw on the international cancer evidence base — and all do — are working with a literature that systematically under-reports sex-specific findings. The data gap is not Australian-specific; it is embedded in the evidence base itself.

My two cents

This research lands differently depending on where you are in relation to cancer treatment.

If you are a patient currently receiving cancer treatment, or considering a treatment decision, the practical question this research raises is simple: what is known about how this treatment affects women specifically — its toxicity profile, the typical side effect burden, and whether the dose I am being offered has been calibrated for a patient with my body composition and metabolism?

In most cases, your oncologist will be working from pooled trial data and clinical experience rather than sex-specific trial subgroup analyses, because those analyses frequently do not exist in the published record. That is not a criticism of your treating team. It is a description of the limitation they are operating within.

Asking the question still has value: it prompts discussion about what is known, what is uncertain, and how monitoring for side effects will be approached. It also surfaces information — about what to watch for, what to report, and at what threshold dose adjustments are considered — that might otherwise be communicated incompletely.

The research finding itself is not a reason for alarm about any specific treatment decision. Cancer treatment involves weighing harms and benefits under uncertainty; that is always true. What the George Institute study documents is that the uncertainty is larger than it should be — and that the tools available to reduce it, if applied consistently, have not been.

Verdict: yes — worth knowing about.

Sources cited

The George Institute for Global Health — Australian cancer trials report worsening sex-difference data (8 July 2026). https://www.georgeinstitute.org/news-and-media/news/australian-cancer-trials-are-getting-worse-at-reporting-sex-differences-putting-patients-at-risk
Research Integrity and Peer Review — Sex and gender reporting in Australian cancer trials (2026). Published by BioMed Central. https://www.georgeinstitute.org/news-and-media/news/australian-cancer-trials-are-getting-worse-at-reporting-sex-differences-putting-patients-at-risk