Ethnic Differences in Brain Tumour Survival Raise Questions

Liam Davenport

November 16, 2021

White British individuals with malignant brain tumours are more likely to die within a year than those from several other ethnic groups, according to a large-scale analysis that is the first of its kind for England.

Researchers looked at data on over 24,000 patients diagnosed between 2012 and 2017, finding that one-year survival was 16% better among people of Indian ethnicity than those categorised as White British.

Survival was also 30% better for people from groups classified as ‘other ethnic’, and was 17% better among people whose ethnicity was recorded as ‘other White’. Patients with an unknown ethnicity had 19% better one-year survival than those identified as White British.

The research, presented at the 2021 NRCI Festival on November 9, indicated that, statistically, survival among patients with a Bangladeshi, Pakistani, Chinese or Black African or Caribbean ethnicity was no different from that in White British patients.

"Brain tumours are under-researched compared with other cancers and, until now, no study has investigated the impact of a person’s ethnicity on brain tumour survival using information on patients in the whole of England," said study presenter Hiba Wanis, MPhil, a PhD student in the Centre for Cancer, Society & Public Health at King’s College London, UK, in a press release.

She continued: "It is probably too early to speculate on what may lie behind these differences, but a number of factors may be involved."

"These include how early people ask their doctors about symptoms, how early in the disease a diagnosis is made, better reporting, lifestyle and cultural factors, deprivation, tumour characteristics and behaviour, and treatment options."

Ms Wanis said in her presentation that further analyses will examine the degree to which potential risk factors play a role in survival, "including understanding the accuracy of death registration for patients from ethnic minority groups."

"This new study is not only the first to investigate the impact of ethnicity on brain tumour survival but also the first to consider the different types of brain tumours across patients in England," commented Michael Jenkinson, Chair of the NCRI Brain Group and professor of neurosurgery and surgical trials at the University of Liverpool, UK.

He noted that recent improvements in the "quantity and quality of data" allowed the researchers to perform a detailed analysis, the results of which "help to fill in the gaps in what is currently an under-researched area of cancer."

"However, further research is needed to consider other factors that may play a role in these differences, such as a patient’s lifestyle and how early they received their diagnosis."

"Once explored further, the findings could be vital for doctors to provide appropriate information to patients on their prognosis," said Prof Jenkinson.

Ms Wanis began by highlighting that approximately 11,000 people are diagnosed with primary brain tumours in the UK every year, with data from England for 1995–2017 showing increasing incidences for the most common brain tumours, such as grade 4 glioblastomas.

As the impact of ethnicity on primary malignant brain tumour survival is "not clear", the researchers set out to examine this using "improved and detailed" data from the National Cancer Registration and Analysis Service (NCRAS).

They gathered information on primary malignant brain tumours, including gliomas, primary central nervous system lymphomas and unclassified malignant neoplasms, diagnosed in adult’s resident in England between 1 January 2012 and 31 December 2017.

The team combined the NCRAS data with that from Hospital Episode Statistics, the Office for National Statistics, Cancer Waiting Times data collection, the Systemic Anti-Cancer Therapy Dataset and the Radiotherapy Data Set.

Specifically, they obtained information on the patients’ demographics, socioeconomic status and medical history, as well as their tumour characteristics and management, and their route to diagnosis.

A total of 24,319 patients were included in the analysis, with ethnicity data available for 95.7%. Of those, 85.5% were White British, 1.3% were Indian, 0.8% Pakistani, 0.1% Bangladeshi, 0.4% Black African, 0.4% Black Caribbean, 0.2% Chinese, and 4.2% any other White. A further 2.8% were from other ethnic groups.

Just over half (53.3%) of the patients were aged 65 years or over, and 58.0% were male.

The most commonly represented area of the country was the South East, accounting for 16.8% of patients, followed by the North West, which accounted for 13.6%. Almost half (46.2%) of patients were from the two least deprived quintiles of socioeconomic deprivation.

The most common diagnosis was glioblastoma, identified in 60.7% of patients, and 53.2% of patients presented as an emergency. The vast majority of patients (83.9%) did not have any comorbidities.

Radiotherapy plus chemotherapy and surgery was used in 23.0% of patients, followed by surgery and radiotherapy in 10.4%, while 34.9% of patients received no treatment at all.

Ms Wanis and colleagues found on unadjusted analysis that, compared with White British people, people from Indian, Pakistani, Black African, any other White and other ethnic groups had better survival, while patients with an unknown ethnic status fared worse.

These relationships largely disappeared after adjusting for age. However, many of the associations became significant with further adjustment for sex, socioeconomic deprivation, comorbidities, tumour morphology, route to diagnosis and treatment received.

Compared with White patients with malignant brain tumours, those from an Indian background had significantly better survival on the fully adjusted analysis, at a hazard ratio of 0.84 (p=0.025).

Individuals from any other White groups also had better survival than White British patients, at a hazard ratio of 0.83 (p<0.001), as did those from other ethnic groups, at a hazard ratio of 0.70 (p<0.001).

Patients with an unknown ethnic status also had better survival than White British patients, at a hazard ratio of 0.81 p<0.001).

Ms Wanis noted, however, that the study has a number of limitations, including that there is an overlap between adult and childhood brain tumours, and a lack of detailed data on recurrences and secondary glioblastoma.

"The combination of ethnic groups with smaller numbers also makes it "difficult" to interpret the results," she said.

The study was funded by NHS England, 100,000 Genomes Project, cancer programme

No relevant financial relationships declared.

NCRI Festival: Abstract 3437. Presented November 9.

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