Brain tumour diagnoses among Irish adults up 35% in 30 years

Seán McCárthaigh

The incidence of brain tumours in Irish adults has increased by over a third in the past 30 years, although survival rates have also improved significantly over the same time period, according to the findings of new research.

The study by researchers from the Royal College of Surgeons in Ireland and several hospitals also found females with brain tumours have better survival rates than males.

It also revealed that survival rates decline with increasing age when a brain tumour is first diagnosed.

“The increasing incidence and improved survival suggests that growing numbers are living longer and surviving beyond their initial brain tumour diagnosis,” the study observed.

It analysed details of over 13,100 cases of primary brain tumours among those aged over 15 years between 1995 and 2019 which were recorded on the National Cancer Registry in Ireland.

There were 1,799 cases in the five years between 1995 and 1999 compared to 3,590 in a similar period between 2015 and 2019.

Adjusting to account for the age of patients, the study said the incidence rate of brain tumours in Ireland increased from 79.2 per 100,000 population in 1995-1999 to 107.2 per 100,000 population for 2015-2019 – an increase of 35.4 per cent.

The rate of increase was even higher for most types of brain tumour except astrocytic tumours which decreased by 36.4 per cent over the same period.

Females accounted for 51.9 per cent of all cases of brain tumour compared to 48.1 per cent of males.

The median age for the diagnosis of a brain tumour was 60-64 years.

Around a third of all patients were diagnosed with the most aggressive brain tumour subtype known as a glioblastoma, while 25 per cent had the least aggressive type know as meningiomas. Approximately a quarter of all brain tumours were also “unclassified”.

The study found the five-year survival rate increased from 39 per cent for those with brain tumours diagnosed between 1995 and 1999 to 48 per cent for those diagnosed between 2015 and 2019.

The five-year survival rate for females at 52 per cent was significantly higher than that for males at 36 per cent.

However, survival rates decrease with increasing age when a brain tumour is diagnosed.

Five-year survival rates for those aged 20-44 years at diagnosis is 73.5 per cent compared to 26 per cent for those aged over 65.

Patients who received surgery, radiotherapy or chemotherapy also had improved survival outcomes compared to those who did not receive any interventions.

The study, which is published in the Irish Journal of Medical Science, showed 47 per cent had surgery to remove the tumour, while 36.2 per cent underwent some form of oncology treatment within 12 months of diagnosis of the brain tumour, and 19.8 per cent had radiotherapy.

Survival rates were also higher for all tumour types compared to glioblastoma.

The authors of the study said the increased incidence of brain tumours in Ireland since 1999 is likely due to a variety of factors, including improvements in diagnostics, treatment advances and cancer registrations.

They noted that other research had found links between increased incidence and other factors, including ageing populations and higher socioeconomic status.

Researchers said their findings about improved survival rates mirrored international trends of longer survival in Western Europe and Pacific regions compared to South-East Asia and Africa.

However, they pointed out that increased survival rates also lead to increased burden on healthcare services.

The study acknowledged that patients with a brain tumour in Ireland often experience difficulties accessing specialist rehabilitation services.

It noted the relatively young median age when people are diagnosed with a brain tumour, with over half still of a working age.

The authors said their findings would have wider relevance for neuro-oncology services in the Republic and would assist in prioritising the supports required.

“Such resources are essential for those who are living with functional difficulties in their survivorship journey,” they added.