Episode 186 - Early Onset Cancer with Professor Dorothy Keefe
Australians in their 30s and 40s are experiencing unprecedented rates of at least 10 different cancers. Between the year 2000 and 2024, for 30- to 39-year-olds, early onset prostate cancer increased by 500%, pancreatic cancer by 200%, liver cancer by 150%, uterine cancer by 138%, and kidney cancer by 85%.
Australia is a world leader when it comes to bowel cancer and, again since the year 2000, the rate of bowel cancer in 30- to 39-year-olds has increased by 173%, and the stage the cancer is at when diagnosed is often advanced. DNA mutations in young onset colorectal cancer are very specific, including those involving mismatch repair genes and the P53 tumour suppressor gene, suggesting particular factors or exposures might be implicated.
Although the cause for young onset cancer is not known, experts believe environmental toxin exposures maybe interacting with specific vulnerable genes to cause malignant changes. A person with nonvulnerable genes exposed to the same toxin would be unaffected. The Human Exposome Project is documenting and studying these exposures and encompasses environmental factors as well as lifestyle and their connections and interactions in an attempt to explain the causes of different diseases.
Other factors considered relevant to the increased onset of young cancers may include:
Childhood obesity and increasing obesity in young adults
Alteration of the microbiome through antibiotic use and eating ultra processed foods, as well as through caesarean section. Being borne by caesarean section could result in the acquisition of a microbiome different to those born vaginally. Interestingly, E coli colonisation of the colon at an early age may be relevant in this respect by way of exposure to colibactin, a potentially mutagenic bacterial toxin produced by E coli.
Microplastic exposure including polychlorinated biphenyls (PCB’s) and poly fluroalkyl substances (PFAS), which are found in nonstick cookware, food packaging and some cosmetics. These have been referred to as “forever chemicals” because of their very long environmental persistence.
Thinking about this emerging problem, I was curious to learn more about the trending incidence and to seek advice regarding how we should be counselling our patients regarding appropriate recommendations for the age of entry to cancer screening programmes.
It was a very special honour to have Prof Keefe from Cancer Australia accept my invitation to be a guest on the Podcast. Prof Keefe is the CEO of Cancer Australia and an honorary Clinical Professor in the School of Medicine at the University of Adelaide. She has enjoyed an illustrious career as a Medical Oncologist and Professor of Cancer Medicine and has a special interest and expertise in gastrointestinal toxicity of cancer treatment, supportive care in cancer, and both medical leadership and health reform.
Her pedigree of publications, awards and commendations is enviable and her commitment to improving cancer outcomes through her clinical work, professorship and role at Cancer Australia is exceptional. I am so pleased we can welcome her to the podcast.
References
Professor Dorothy Keefe. researchers.adelaide.edu.au
Cancer Australia. www.canceraustralia.gov.au
Why Is Early Onset Cancer on the Rise? National Cancer Institute. Cancer.gov
Early-Onset Cancer. canceraustralia.gov.au
The Alarming Rise of Early-Onset Colorectal Cancer. Markey, Srinath. www1.racgp.org.au
The Latest Research on Why So Many Young Adults Are Getting Cancer. Piersol. mskcc.org
Dr Norman Swan, ABC. (July 7th, 2025)