Paul Walfish

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     Paul G. Walfish received his MD from the University of Toronto before completing his residency in Internal Medicine. Walfish was then awarded a McLaughlin Foundation Fellowship and furthered his clinical studies in endocrinology at Harvard Medical School. Upon his return to Canada, Walfish joined U of T’s Department of Medicine as a clinical teacher and founded the Department of Nuclear Medicine at Mount Sinai Hospital in 1965. He was appointed full Professor in 1982, and became Professor Emeritus in the Departments of Medicine, Paediatrics, Laboratory Medicine and Pathobiology and Otolaryngology — Head and Neck Surgery in 2002.

     Walfish’s early-career research on carbohydrate and lipid metabolism, and the establishment of a method to measure lipoproteins, insulin, cortisol, growth hormone and thyroid hormones laid the foundation for the discovery of a new way to detect congenital hypothyroidism (CH) — a condition that affects approximately one in 3600 infants and can be easily treated with daily medication — by measuring thyroid hormones in a small blood sample taken by heel prick from a new born baby a few days after their birth. The heel prick test had been pioneered by American Microbiologist Dr. Robert Guthrie to detect phenylketonuria, which is also known as PKU. Walfish and Dr. Jean Dussault in Quebec, pioneered the new application for the test to detect CH.

     “This was an advance because if you didn’t recognize a newborn having an underactive thyroid problem — preferably before 1 month of age — it was too late,” says Walfish, who is also a clinician-scientist at Mount Sinai Hospital. “Detecting congenital hypothyroidism meant we could help at-risk babies receive treatment well before they began to show symptoms, and prevent them from the extensive brain damage and mental retardation associated with the disease.”

     Between 1978 and 1983, Walfish helped Ontario become one of the world’s first jurisdictions to establish a province-wide newborn screening program for congenital hypothyroidism using the heel prick test. The test is now used in every developed country across the globe. Newborn screening using the heel prick test has saved millions of babies around the world from CH-related developmental disabilities. In Ontario, newborn screening is now used to diagnose at least 29 rare diseases, helping infants receive early treatment and achieve healthier outcomes.

     While working on newborn screening, Walfish was the first to recognize the classical clinical features of postpartum painless thyroiditis syndrome and to describe its clinical course, frequency and management. When babies were found to have suspicious heel-prick test results, Walfish and his team recalled their mothers to see if they had their own thyroid problems. It was found that some of the mothers had a painless overactive thyroid problem, but follow-up testing revealed the condition could spontaneously resolve itself. As well, Walfish and his team have also detected many other causes that may contribute to developing postpartum painless thyroiditis syndrome, which is likely a manifestation of an underlying susceptibility to an autoimmune condition. 

     In 1976, Walfish, in collaboration with Professor Harry Strawbridge of the Department of Laboratory Medicine and Pathobiology as well as the head of Mount Sinai Hospital’s Department of Laboratory Medicine and Pathology and the Director of the Michener Institute for Applied Health Sciences, was instrumental in introducing fine needle aspiration biopsy to North America to detect thyroid cancer early. This development helped people with benign nodules avoid unnecessary surgery. Though the technique was already being used in Europe, there was concern in Canada and the United States about the possibility of implanting cancer into the needle tract. Walfish and his team disproved this idea, helping the fine needle biopsy become the number one test in the world for examining thyroid nodules.  

     Walfish also pioneered the use of a blood biomarker called Thyroglobulin to distinguish which patients need radioactive iodine treatment. Prior to this finding, a patient’s age or a tumour’s size determined the need for radiation. Walfish and his team proved that measuring Thyroglobulin in a person’s blood and combining that information with data from a neck ultrasound could more accurately assess a person’s individual risk. The finding has saved many patients with low-risk thyroid cancer from being hospitalized for treatments that have a potential for serious side effects and has become the new standard of care.

     Walfish has also broadened his focus to other kinds of biomarkers, including biomarkers for oral cancer. In collaboration with the Department of Otolaryngology — Head and Neck Surgery’s Professor Ranju Ralhan, he identified a protein called S100A7 which can help determine the aggressiveness of an oral dysplastic lesion, predict which lesions might lead to cancer and identify patients who would benefit from early intervention.

     Over the course of his career, Walfish has also established a database of all of the thyroid cancer cases he has treated. He has followed the patients through the years to find new information about the disease and how it responds to treatment. He has also authored more than 300 publications including peer-reviewed journal articles and book chapters.                     

“It’s always been my goal to translate findings from the research bench to the patient’s bedside. To find that your work is reliable, accurate, and has been reproduced by other clinicians and scientists is all you can ask for. The highest goal that you can have is to be able to help a human being.”

     Walfish’s work has been recognized by a number of organizations. He was elected Fellow in The Royal Society of Medicine in England’s Endocrinology Section in 1986. In 1990, Walfish was appointed to the Order of Canada for his work establishing the newborn screening program for congenital hypothyroidism. Five years later, he was named the first recipient of the Council Award from the College of Physicians and Surgeons of Toronto. Walfish was also honoured by the March of Dimes with a 2001 Jonas Salk Prize. The next year, he was presented with a 50th Anniversary Jubilee Medal on the Reign of Queen Elizabeth II. Walfish later became the first Canadian to receive the Paul Starr Award fro the American Thyroid Association and was presented with the Canadian Medical Association Medal of Service and the Sidney H. Ingbar Distinguished Lectureship Award of the American Thyroid Association. In 2008, Walfish was appointed to the Order of Ontario. In 2009, Walfish was recognized again by the American Thyroid Association with the John B. Stanbury Medal in Thyroid Pathophysiology. He is also an Emeritus Fellow of the Canadian Academy of Health Sciences and a recipient of the Queen Elizabeth II Diamond Jubilee Medal. 

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