Sick Kids

Annual mammography screenings aren't the best option for female survivors of some childhood cancers: U of T study

geoff.vendeville — Wed, 10 Jul 2019 14:59:40 +0000

Annual mammography screenings aren't the best option for female survivors of some childhood cancers: U of T study

geoff.vendeville Wed, 07/10/2019 - 10:59

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Current Ontario guidelines recommend survivors of some childhood cancers undergo both an annual mammogram in addition to an MRI, but a U of T study found little added benefit compared to having an MRI alone (photo by Choja/iStock via Getty Images)

Rebecca Biason

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Breaking Research

Ontario Impact

Institute of Health Policy Management and Evaluation

Cancer

Graduate Students

Hospital for Sick Children

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Sick Kids

Female survivors of childhood cancers who have been treated with thoracic radiation, such as survivors of Hodgkin’s lymphoma (HL), have a higher risk of developing breast cancer later in life compared to the general population.

To mitigate this risk, current guidelines in Ontario recommend that female HL survivors undergo annual mammography and MRI screenings starting at age 30, the same for all high-risk women.

However, Lauren Tessier and Jill Furzer (left), PhD students at the Institute of Health Policy, Management and Evaluation (IHPME), led a recent study that suggested mammographic screening in addition to MRIs for this group is a costly strategy that provides limited additional benefits in preventing cancer compared to having an MRI alone.

“Mammograms are not as sensitive as MRI in their ability to look for new tumors, especially in women under age 50, and there is often a low compliance rate in this population of women,” said Tessier.

“Our findings show that the guidelines should be more specific to an individual’s specific risk profile and that survivors of pediatric HL would likely benefit from starting screening earlier than age 30.”

What started as a course project for Furzer and Tessier’s graduate studies in health services research at IHPME grew into a study on real-world applications that was recently published in the Journal of the National Cancer Institute.

Furzer and Tessier conducted their study by modifying an existing breast cancer natural history model for HL survivors with a high risk of developing breast cancer. This model starts with HL survivors at age 25, who are then simulated through different screening strategies starting at either age 25 or 30 and include MRI, mammogram or both. If breast cancer is detected, the life expectancy and quality of life of these individuals and the associated health-care costs were calculated based on the frequency of screening, the timing of cancer detection and the cost of treatment.

In their findings, Furzer and Tessier found that screening with both an MRI and mammogram at age 30 is, on average, more expensive and less effective than screening using MRI only. They also found that at age 25, adding an MRI to mammography screening also added significant costs without a meaningful change in a survivor's life expectancy or quality of life.

“Within cost-effectiveness analysis in health care, there is also a value judgement,” adds Furzer. “We are trying to determine what treatments or screening strategies provide value in terms of quality adjusted life years for these patients, while also ensuring system sustainability in terms of public funding for these services.”

Senior author and assistant professor at IHPME Petros Pechlivanoglou notes that this kind study is important for the field of pediatric oncology as a whole.

“In pediatric oncology there are positive effects in the short term because we prevent children from relapsing in their disease. However, it has been recognized by many that there are long-term implications that can be treatment related,” says Pechlivanoglou, who is also a scientist in child evaluative sciences at the Hospital for Sick Children. “That is why studies like this are useful in estimating the long-term effects over a lifetime for childhood cancer survivors, including costs to the health system.”

With the study’s finding that cancer screening guidelines would benefit from some revisions, especially for HL survivors, Furzer and Tessier point out that any call for change from the status quo, especially in health care, can be tough.

“There can be a strong emotional reaction when talking about cost in health care,” says Furzer. Tessier agrees: “It is not our goal to only focus on costs, but to create a better health-care system and outcomes for everyone who uses it now and in the future.”

Redefining infant brain tumours to improve treatment

sgupta — Fri, 29 May 2015 16:26:23 +0000

Redefining infant brain tumours to improve treatment sgupta Fri, 05/29/2015 - 12:26

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“I’m hoping this will create a paradigm shift in the way we approach childhood brain tumours, ” says Professor Huang, with student Jonathon Torchia

Katie Babcock

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Katie Babcock

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“There is no benefit in giving radiation, ” says Annie Huang. “Radiation can have devastating effects.”

For years there was little hope for children diagnosed with rhabdoid brain tumours.

Infants with the rare disease would undergo surgery, chemotherapy and sometimes radiation, but these treatments had toxic side effects and often failed.

Now researchers from the �ؿ�ζSM have discovered how to categorize these tumours, allowing for more targeted treatment of this deadly disease.

In a recent study in The Lancet Oncology, Professor Annie Huang and PhD candidate Jonathon Torchia, from U of T's department of laboratory medicine and pathobiology, identified three categories of patients with rhabdoid brain tumours. They also studied the effectiveness of surgery, chemotherapy and radiation on this disease.

Their research shows that one group of patients can be effectively treated with surgery and chemotherapy, while the other two have a lower survival rate.

“Until 15 years ago these tumours were considered to be untreatable and almost universally fatal. Now we can identify children who have an increased chance of survival and who would benefit from surgery and chemotherapy,” said Huang, a neuro-oncologist and senior scientist at The Hospital for Sick Children.

The team also discovered that a second group of patients had higher survival rates with intensive chemotherapy and stem cell transplants, while a third group of patients had a high death rate regardless of treatment.

“Our research shows us that current, highly punishing and intensive therapy is not effective in this third group of patients, and they urgently need new types of therapeutics to change their low survival rates,” said Huang. “For all groups, we believe that there is no benefit in giving radiation. Radiation can have devastating effects, especially in this disease where the majority of children are very young.”

Usually diagnosed in children under two to three years, these fast-growing brain tumours are often found in the cerebrum and the cerebellum – both of which are critical for normal intellectual and physical development. While doctors in other countries sometimes treat patients older than three years with brain and spine radiation, Canadian doctors have been hesitant to do the same because of its toxic side effects. They’ve been investigating how to treat brain tumours without using radiation, particularly in younger children.

Sylvie Boucher, the mother of a child treated for a rhabdoid tumour, is thankful that her son avoided radiation. “My son is going to be 10. Because he avoided radiation he’s in the fourth grade in a bilingual school and he’s doing very well. I’m very thankful to Dr. Huang and the team at SickKids.”

Since these tumours are rare, Huang started a global collaborative network to collect enough samples for her study. She began this process in 2001 when she was a post-doctoral fellow, and it has grown into a network called the Rare Brain Tumour Consortium, which has recently launched a web-based registry.

With the help of the consortium, she and her team analyzed the genetic makeup of 259 tumour samples from 37 international institutions – the largest study conducted in this area.

“We’ve had tumours and tumour cells sent to us from Budapest, Israel, Pakistan, Thailand, Australia, Hong Kong and many other far-flung countries – it’s amazing what we can achieve together with such global reach and collaboration,” said Huang.

Next the team plans to develop a trial to test new drugs and ways of delivering therapy. One promising treatment is to offer patients long-term maintenance chemotherapy, and to use chemotherapy delivered directly to the brain and spine to prevent relapse.

“This study allows clinicians to immediately make more informed treatment decisions,” said Torchia, the first author of the study. “We now know we need a more targeted approach for patients with low survival rates.”

Huang added, “I’m hoping this will create a paradigm shift in the way we approach childhood brain tumours. It will make us look at malignant brain tumours, particularly those affecting very young children, as a medically treatable disease for which radiation is not always necessary.”

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Surprising results from study of siblings with autism

sgupta — Thu, 29 Jan 2015 15:38:20 +0000

Surprising results from study of siblings with autism sgupta Thu, 01/29/2015 - 10:38

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Professor Stephen Scherer (photo courtesy the Faculty of Medicine)

A new study led by researchers at the �ؿ�ζSM and The Hospital for Sick Children (SickKids) turns scientific prediction on its head.

Contrary to what was expected, researchers found that siblings with autism spectrum disorder often carry very different genetic mutations. And the news has been making headlines around the world. (Read the Globe and Mail article; read the article in Time magazine; Read the New York Times article; read the article in The Guardian.)

The study, published in the January 26 online edition of Nature Medicine, is the largest whole genome sequencing study in autism and one of the largest on any disorder to date. The research highlights the fact that there is significant genetic diversity in autism; it also emphasizes the need to do whole genome sequencing on patients in order to see their complete genetic picture.

“We already knew that there are many differences between autism cases, but our recent findings firmly nail that down. It shows that a full assessment of each individual’s genome is needed to determine how to best use knowledge of their own genetic makeup for autism treatment,” said Dr. Stephen Scherer, a professor of molecular genetics and director of the McLaughlin Centre at U of T. He is also a senior scientist and director of the Centre for Applied Genomics at SickKids.

The study finds that siblings with autism spectrum disorder often carry different genetic mutations. This image shows the global positioning of genetic variations across the chromosomes in unidentified individual with autism.

Researchers analyzed the DNA of 85 families which each have two children with autism, with a total of 170 individuals with autism. Using the revolutionary technology of whole genome sequencing, they found genetic mutations that were previously missed using techniques like exome sequencing and microarrays, which only look at parts of the DNA.

“We believe each child with autism is like a snowflake; one is unique from another. Surprisingly, our research found that in more cases than not, even siblings can have two different ‘forms’ of autism,” said Scherer. “This research has larger implications for the field of genetics. This means we cannot just look at parts of the DNA if we want to fully understand the underpinnings of autism and other disorders – we need to analyze the entire genome.”

The data collected for this study is an important first step in a much larger international initiative by Autism Speaks in collaboration with Google. The project, called MSSNG, is being led by Scherer and his team. The goal is to sequence the genomes of 10,000 families with autism, and store all the data in an open-source research platform – Google Cloud Platform – so it is accessible to researchers around the world. Data from this project is the first to be stored in the MSSNG project cloud, and this is the first time ever that research data is being made broadly available in a cloud-based platform for scientists to share and work from.

“By using the cloud to make data like this openly accessible to researchers around the world, we’re breaking down barriers in a way never done before,” said Robert Ring, chief science officer of Autism Speaks and co-author on the paper. “As always, our goal at Autism Speaks is to accelerate scientific discovery that will ultimately improve the lives of individuals with autism at home and around the world.”

This study not only underscores the importance of whole genome sequencing as a diagnostic tool for autism but also for other common complex diseases, said Dr. Bartha Knoppers, Canada Research Chair in Law and Medicine and director of the Centre of Genomics and Policy at McGill University.

“The cloud-based platform for researcher access from all fields is exemplary,” Knoppers said.“We can only hope that the importance of this approach will be recognized by policymakers and health care systems.”

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