Sana Ghaznavi, MD, FRCPC

 

The Thyroid Foundation of Canada (TFC) is very excited to announce the winner of the 2023 TFC Research Award. Congratulations to Dr. Sana Ghaznavi, Clinical Assistant Professor, Division of Endocrinology & Metabolism, at the University of Calgary.

Dr. Ghaznavi is an academic endocrinologist whose practice focuses on the management of thyroid nodules and thyroid cancers. She completed her medical school at the University of Alberta, an endocrinology fellowship at the University of Calgary, and a thyroid cancer fellowship at Memorial Sloan Kettering Cancer Centre in New York city. She now works as a clinical assistant professor within the Division of Endocrinology & Metabolism, at the University of Calgary, with a cross appointment to the Department of Oncology.

Dr. Ghaznavi’s research project is titled “Exploring limitations in the current standard of care for thyroid hormone replacement therapy in thyroid cancer survivors”.

The annual TFC research award provides researchers with an opportunity to be granted a one-year award of $50,000. This grant is provided by TFC and is administered with support from the Canadian Society of Endocrinology and Metabolism (CSEM).

Exploring limitations in the current standard of care for thyroid hormone replacement therapy in thyroid cancer survivors

Ghaznavi et al.

Lay Summary

Background: When patients are diagnosed with thyroid cancer, the main treatment is to surgically remove the thyroid. While this cures most patients of their thyroid cancer, it creates a new problem, because the patient now lacks a thyroid gland. The thyroid gland normally makes two types of thyroid hormones, called T4 and T3. Most patients without a thyroid are treated with a daily pill containing only T4 (known as “levothyroxine” or “Synthroid”). For most people, their body can convert the T4 to T3 hormone as needed. Doctors adjust the dose of thyroid medication by looking at a thyroid blood test called TSH. Some patients have trouble converting T4 to T3 and so report ongoing hypothyroid symptoms, such as fatigue, weight gain, brain fog, and mood changes, even when they are on a dose of thyroid medication that results in a normal TSH. This creates a dilemma for patients and their doctors because while their blood work is normal, they continue to feel unwell.

One approach to treat this problem is to use T3 pills together with T4 pills, to mimic what happens in a normal thyroid gland. This approach is called “combination therapy”. Many patients are becoming interested in combination therapy, which they may hear about online or from other care providers like naturopaths. However, most endocrinologists do not prescribe combination therapy, partly because the effectiveness and safety of combination therapy is not entirely known, and there has never been a randomized controlled trial comparing combination therapy to T4 pills alone specifically in patients without a thyroid. 

Proposed research study:
We propose conducting an online questionnaire with approximately 150 thyroid cancer patients who are on thyroid hormone pills and 150 doctors that treat these patients across Canada. The questionnaire will use a scientific approach called a discrete choice experiment (DCE), which comes from health economics research, but is being used more often in health care settings. DCE is based on the economics concept of “opportunity cost”, which means that when we select one option, we give up or trade–off something else that we value in return.

A real–life example of opportunity cost is discovering that your favorite movie is about to come on right when you’re about to go to sleep. On the one hand, if you stay up, you will get to enjoy your favorite movie, but the opportunity cost, the thing you would have to give up, is an extra two hours of sleep. You may choose to watch the movie if the next day is a holiday, but you may choose to skip the movie and instead go to bed, if the next morning you have to be up early for an important meeting. By changing the scenario slightly each time we ask you the question of whether you will stay up to watch the movie, we discover the factors you consider in making that decision, and the relative importance of each factor.

In the context of this research study, we are going to conduct a DCE with patients and doctors to compare the relative importance of different factors when deciding whether to use T4 pills alone or combination therapy. Examples of factors that patients and doctors may use in deciding whether to use combination therapy or LT4 monotherapy include severity of hypothyroid symptoms present, how effective each treatment approach is in improving hypothyroid symptoms for this patient, the severity and types of side effects experienced from the pills, the cost of the pills, and the doctor’s expertise and comfort level prescribing and monitoring each treatment type.

Implications for patients with thyroid disorders:
This study will improve our understanding of how doctors and patients think about the risks and benefits of combination therapy, and what each group considers important when deciding on a thyroid hormone strategy. Equally importantly, we believe it will help doctors and patients understand one another’s perspectives better and thus improve the therapeutic relationship. The current study is part of a broader research program that aims to develop a personalized treatment approach for patients requiring thyroid hormone pills after their thyroid is removed. As our research team made up of both thyroid cancer patients and thyroid cancer doctors, we believe it is important to create a treatment approach that combines both scientific evidence and patients’ values and preferences, and ultimately leads to better shared decision making between doctors and patients. In the next phase of our research (not included in the scope of this grant), we plan to do the first randomized controlled trial of levothyroxine versus combination therapy in thyroid cancer patients. This RCT will compare how effective and safe both treatment approaches are. This type of scientific evidence, combined with the current study, drives the change to medical guidelines, and thus, physician prescribing practices. It also helps us personalize the thyroid hormone strategy for an individual patient, to better their quality of life and well–being.