Wednesday, August 05, 2015

Thousands diagnosed with brain tumors last year (but only about half are reported)

Thousands diagnosed with brain tumors last year (but only about half are reported)

Joel's comments: 
The article below notes that cancer registries are developed to collect data on malignant tumors and generally do not collect data on non-malignant (sometimes called benign) tumors. Since about half of primary brain tumors are non-malignant, these tumors are often not monitored by public health surveillance systems (e.g., Canada).
The U.S has a Central Brain Tumor Registry (CBTRUS): "a resource for gathering and disseminating current epidemiologic data on all primary brain tumors, benign and malignant, for the purposes of accurately describing their incidence and survival patterns, evaluating diagnosis and treatment, facilitating etiologic studies, establishing awareness of the disease, and ultimately, for the prevention of all brain tumors." However, "CBTRUS makes no representations or warranties, and gives no other assurances or guarantees, express or implied, with respect to the accuracy or completeness of the data presented." There is a good reason for this disclaimer which appears on the CBTRUS home page.

Tumor registries are useful in monitoring disease incidence only to the extent that all procedures are well implemented. Registries are highly dependent upon reporting agencies (e.g., hospitals) to do an accurate and complete job in reporting tumors to the registry. Registry data  typically suffer from numerous problems. "Users must be aware of diverse issues that influence collection and interpretation of cancer registry data, such as multiple cancer diagnoses, duplicate reports, reporting delays, misclassification of race/ethnicity, and pitfalls in estimations of cancer incidence rates." (Izqierdo, JN, Schoenbach, VJ. The potential and limitations of data from population-based state cancer registries. AmJ Public Health. 2000;90:695-698. URL:

Hardell and Carlberg (2015) recently reported that brain cancer rates have been increasing in Sweden based upon the Swedish National Inpatient Registry but not according to the Swedish Cancer Registry. Based upon their results they "postulate(d) that a large part of brain tumours of unknown type are never reported to the Cancer Register ... We conclude that the Swedish Cancer Register is not reliable ..."

Thousands diagnosed with brain cancer last year

Gillian Slade, Medicine Hat News, August 4, 2015

There were 2,900 newly diagnosed cases of brain cancer in 2014 based on the Canadian Cancer Statistics Reports between 2010-2014.

The cancer surveillance system does not capture all primary brain tumours. 

“I would approximate that the actual number of new cases is about double that reported here,” said Faith Davis, professor and vice-dean school of public health, University of Alberta who will be helping to create a brain tumour registry.

It would help to identify whether there is an increase of brain tumours in some parts of the country, whether mortality is increasing or not, and whether survival outcomes are similar in different regions, said Davis. It would also tell how well we are doing in diagnosing and treating the disease.

“I’ve been involved with brain tumour surveillance probably since about 1990. I was involved with the feasibility studies and the work that resulted in the development of the centre brain tumour registry in the United States,” said Davis.

The brain tumour foundation of Canada, recognizing some gaps in the system, asked Davis to look at the feasibility of creating a brain tumour surveillance system in Canada.

While clinicians see and treat all primary brain tumours the standard cancer surveillance reporting system only records brain tumours that are malignant, which is only about 50 per cent of brain tumours, said Davis.

Currently clinicians can’t get information on the full patient population so they don’t know the health outcomes of the full patient population. They can’t study the full spectrum of the disease because they don’t have information on it.

“As a population scientist, population researcher, I can’t with confidence look at the patterns of some tumours because those tumours may have malignant and non-malignant tumours in that same category,” said Davis. “It restricts our ability to understand what causes the tumour and understand how well we are doing providing services to these patients.”

Davis is awaiting a decision on funding to compile a registry of non-malignant brain tumours in Alberta. She is working with the Canadian Cancer Registry system. Each province has its own system funded under provincial healthcare. 

Tweaking of this electronic system will be needed for it to accept data on non-malignant brain tumours. Staff will be trained about tumours to review and code information accurately so data can be extracted.

It will take about 18 months to get the data in the systems. At that stage Davis hopes to be able to publish the first “almost pan-Canadian report on primary brain tumours”. 
“We’re hoping three years,” said Davis. 

This will include data from Ontario, Quebec, B.C. Alberta and Manitoba, representing 90 percent of the brain cancers reported in Canada.


Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

Electromagnetic Radiation Safety

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