RATES of cancer are rising among women under 50 in Scotland despite medical breakthroughs which have seen cervical cancer virtually eradicated for the youngest age groups.

The latest annual incidence report by Public Health Scotland (PHS) found that rates of breast cancer in women aged 35 to 39 increased by 25% over the past decade, with diagnoses of colorectal cancer in younger people climbing for both sexes - but most steeply in females.

The findings are in line with trends being seen in developed countries around the world.

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In the UK as a whole, over the past 20 years, cancer incidence has been rising twice as fast in the under-50s compared with the elderly for reasons that scientists do not believe can be fully explained by traditional causes such as obesity, alcohol and smoking.

A £20 million international research trial recently got underway which will spend the next five years investigating what has gone wrong, including the whether ultra-processed foods, air pollution and the overuse of antibiotics is leading to carcinogenic disruptions of the microbiome - the trillions of bacteria in the gut which are influenced by everything from what we consume to whether a baby is delivered naturally or by C-section.

The work, funded by Cancer Research UK and the Bowelbabe Fund - set up by the late BBC presenter Dame Deborah James, who was diagnosed with bowel cancer aged 35 - is being led in the UK by nutrition scientists Professor Tim Spector and Professor Sarah Berry.

The overall study is spearheaded by cancer scientists in the US, with research arms also located in India, France and Italy to seek out a “global solution to a global crisis”.

Overall cancer incidence rates have increased among women under 50, but the change is less clear in men  (Image: PHS) The PHS report notes that the age-standardised cancer incidence rate for women under 50 in Scotland increased by 6.5% between 2012 and 2022, from 123 cancers per 100,000 population to 131 per 100,000 population.

Over the same period, the rate in males "remained fairly constant".

For all types of cancer combined, women aged 30 to 34 in Scotland have seen their rates of of the disease increase by 28% over the decade, with those aged 35-39 and 40-44 experiencing increases of 19% and 11% respectively.

For breast cancer, diagnosis rates have increased by 25% in women aged 35-39 - with 144 new cases in 2022.

Colorectal cancer has seen a sharp increase over the past decade for both men and women under 50.

Rates of colorectal cancer among 50 to 74 year olds - who are eligible for screening - have fallen slightly compared to 2022 (Image: PHS) Both men and women under 50 have seen colorectal cancer rates increase (Image: PHS)

Overall, for both sexes combined, incidence is up by 30%.

For some age groups the increase has been particularly pronounced.

Females aged 30-34 have seen their bowel cancer rate surge by 127%, compared to 67% for men, and by 26% for women aged 40-44 compared to a 10% increase for men.

PHS said this was "worthy of note" but that "no definitive cause for the increased incidence in younger people has been identified".

Scotland offers routine bowel cancer screening in the NHS to people aged 50 to 74, but in other parts of the world - including Australia and the US - the age threshold has been reduced to 45 to reflect the growing incidence among younger people.

However, the actual number of cases still remains comparatively low.

In 2022, a total of 259 cases of colorectal cancer were detected among under-50s in Scotland - up from 157 in 1998, but still far short of the 2,368 diagnosed in the 50-74 age group.

Confirmed cases of cervical cancer (dark purple) have almost disappeared for young women, with cases of 'carcinoma in situ' - a risk factor for cervical cancer - also falling steeply since HPV vaccination was introduced (Image: PHS) The PHS report also highlighted the impact of the HPV vaccination service on cervical cancer.

Since the vaccine - which was initially rolled out to all schoolgirls aged 12 to 13 in 2008 and is now offered to all S1 pupils - the incidence of cervical cancer in the 20-24 age group has fallen from more than eight per 100,000 in 2005 to less than one per 100,000 from 2018 onwards.