The 20 Best Thyroid Cancer Doctors in The United States

Find the Top Thyroid Cancer Experts and Specialists

Last Updated: 04/28/2026

Save doctors for later
Sign Up
Not sure about your diagnosis?
Check Your Symptoms
Already have a doctor?
Find A Second Opinion

MediFind found 12289 doctor with experience in Thyroid Cancer near The United States. Of these, 9299 are Experienced, 2159 are Advanced, 684 are Distinguished and 87 are Elite.

Location
LocationClose
12,289 providers found
    Marcia S. Brose
    Elite in Thyroid Cancer
    Elite in Thyroid Cancer

    Jefferson Torresdale Hospital

    10800 Knights Road, 
    Philadelphia, PA 
    Languages Spoken:
    English
    Accepting New Patients

    Marcia Brose is an Oncologist in Philadelphia, Pennsylvania. Dr. Brose is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Medullary Thyroid Carcinoma, Papillary Thyroid Cancer, and Anaplastic Thyroid Cancer. Dr. Brose is currently accepting new patients.

    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    UT MD Anderson Cancer Center

    210 Ashville Ave # 408, 
    Cary, NC 
    Languages Spoken:
    English
    Offers Telehealth

    Ramona Dadu is an Endocrinologist in Cary, North Carolina. Dr. Dadu is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Anaplastic Thyroid Cancer, Thyroid Cancer, Medullary Thyroid Carcinoma, Papillary Thyroid Cancer, and Thyroidectomy.

    Megan R. Haymart
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine

    Domino's Farms

    24 Frank Lloyd Wright Dr Ste 1300, Lobby C, 
    Ann Arbor, MI 
    Languages Spoken:
    English
    Offers Telehealth

    Megan R. Haymart, MD is Professor of Internal Medicine with an appointment in the Division of Metabolism, Endocrinology, and Diabetes at the University of Michigan. She holds the Nancy Wigginton Endocrinology Research Professorship of Thyroid Cancer and is Director of Thyroid Cancer Research at the University of Michigan. Dr. Haymart received her medical degree at Johns Hopkins University School of Medicine and completed her internal medicine residency at Johns Hopkins Hospital. She then completed a fellowship in endocrinology, diabetes, and metabolism at the University of Wisconsin. She has been faculty at the University of Michigan since 2009.Dr. Haymart has a history of NIH-funded research focused on optimizing thyroid care delivery. She is a health services researcher who primarily studies thyroid cancer care across the disease continuum: from the diagnosis of a thyroid nodule to cancer survivorship. In recognition of her research, she received the American Thyroid Association’s Van Meter Award for outstanding contributions to research on the thyroid gland (2017), the University of Michigan’s Jerome Conn Award for Research Excellence (2017), membership to American Society for Clinical Investigation (2018), the AACE Hossein Gharib Education Lectureship Award for exemplary contributions to an individual profession or area of expertise (2021), and the inaugural AACE Endocrine Care Innovation Award in recognition of her team’s outstanding body of work focused on clinical outcomes or health care delivery (2025).Dr. Haymart is actively involved in improving research infrastructure at the University of Michigan. This includes her roles as Assistant Director of Data Solutions for AI & Digital Health Innovation, faculty support for MICHR, and co-Director of Patient’s First. She also devotes time to mentoring junior faculty and trainees resulting in her receipt of the MICHR Distinguished Clinical and Translational Research Mentor Award (2021) and the Women in Thyroidology and American Thyroid Association Woman of the Year Award (2021) for promoting the advancement of women, both within the organization and field. Dr. Haymart is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Thyroid Nodule, Papillary Thyroid Cancer, Thyroidectomy, and Hormone Replacement Therapy (HRT).

    Are you looking for a specific type of Thyroid Cancer?

    Common conditions include: Anaplastic Thyroid Cancer, Follicular Thyroid Cancer, Papillary Thyroid Cancer

    Learn about our expert tiers
    Linwah Yip
    Elite in Thyroid Cancer
    Surgical Oncology | General Surgery
    Elite in Thyroid Cancer
    Surgical Oncology | General Surgery

    University Of Pittsburgh Physicians - Endocrine Surgery

    3601 5th Avenue, Falk Medical Building, Suite 6B, 
    Pittsburgh, PA 
    Languages Spoken:
    English
    Accepting New Patients
    Offers Telehealth

    Linwah Yip, MD, FACS, is an associate professor in the Department of Surgery, Division of Endocrine Surgery at the University of Pittsburgh School of Medicine, chief of the Division of Breast and Endocrine Surgery, and program director for the University of Pittsburgh  Endocrine Surgery Fellowship. She specializes in thyroid and parathyroid disease/cancers, adrenal tumors, and functional pancreatic tumors. She studies how molecular testing can optimize diagnosis and treatment for thyroid cancer patients and leads the UPMC VHL Alliance Comprehensive Clinical Care Center.Dr. Yip is board-certified in general surgery. She received her medical degree from the University of Chicago Pritzker School of Medicine, Chicago. Dr. Yip completed surgical residency training at Northwestern University in Chicago and the University of Florida Health Sciences Center in Jacksonville, Fla., and surgical oncology research and clinical fellowships at the University of Texas MD Anderson Cancer Center and UPMC. Dr. Yip is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Nodule, Thyroid Cancer, Papillary Thyroid Cancer, Thyroidectomy, and Parathyroidectomy.

    Bryan Haugen
    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    University Of Colorado Hospital Authority

    1635 Aurora Ct, 
    Aurora, CO 
    Languages Spoken:
    English

    Bryan Haugen is an Endocrinologist in Aurora, Colorado. Dr. Haugen is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Anaplastic Thyroid Cancer, Follicular Thyroid Cancer, Thyroidectomy, and Hormone Replacement Therapy (HRT).

    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    David H. Koch Center For Cancer Care At Memorial Sloan Kettering Cancer Center

    530 E 74th St, 
    New York, NY 
    Languages Spoken:
    English
    Offers Telehealth

    Robert Tuttle is an Endocrinologist in New York, New York. Dr. Tuttle is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Papillary Thyroid Cancer, Follicular Thyroid Cancer, Thyroidectomy, and Gastrostomy.

    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    Ohio State Martha Morehouse Outpatient Care

    2050 Kenny Rd, 
    Columbus, OH 
    Languages Spoken:
    English

    Matthew Ringel is an Endocrinologist in Columbus, Ohio. Dr. Ringel is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Papillary Thyroid Cancer, Medullary Thyroid Carcinoma, Follicular Thyroid Cancer, and Thyroidectomy.

    Christian Nasr
    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    Banner - University Medicine Diabetes And Endocrinology Institute

    1441 North 12th Street, Floor 2, 
    Phoenix, AZ 
    Languages Spoken:
    English, Arabic, French
    Accepting New Patients
    Offers Telehealth

    Exercise and Music. Dr. Nasr is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Papillary Thyroid Cancer, Diabetic Neuropathy, Thyroid Nodule, and Thyroidectomy.

    Jochen H. Lorch
    Elite in Thyroid Cancer
    Hematology | Oncology
    Elite in Thyroid Cancer
    Hematology | Oncology
    675 N St Clair St Ste 21-100, Galter Pavilion, 
    Chicago, IL 
    Experience:
    32+ years
    Languages Spoken:
    English
    Offers Telehealth

    Jochen Lorch is a Hematologist and an Oncologist in Chicago, Illinois. Dr. Lorch has been practicing medicine for over 32 years and is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Anaplastic Thyroid Cancer, Thyroid Cancer, Medullary Thyroid Carcinoma, Adenoid Cystic Carcinoma, and Thyroidectomy.

    Eren Berber
    Elite in Thyroid Cancer
    General Surgery
    Elite in Thyroid Cancer
    General Surgery

    Cleveland Clinic Main Campus

    9500 Euclid Avenue, 
    Cleveland, OH 
    Languages Spoken:
    English, Turkish
    Offers Telehealth

    Eren Berber is a General Surgeon in Cleveland, Ohio. Dr. Berber is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Hyperparathyroidism, Pheochromocytoma, Thyroidectomy, and Parathyroidectomy.

    Maria Papaleontiou
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine

    Domino's Farms

    24 Frank Lloyd Wright Dr Ste 1300, Lobby C, 
    Ann Arbor, MI 
    Languages Spoken:
    English

    Maria Papaleontiou, MD, is an Associate Professor of Internal Medicine with an appointment in the Division of Metabolism, Endocrinology and Diabetes, and a Research Associate Professor at the Institute of Gerontology, at the University of Michigan. Prior to starting her internal medicine residency at Saint Peter's University Hospital in New Jersey, she spent several years conducting clinical research on aging at Weill Cornell Medical College in New York City. She completed her endocrinology fellowship at the University of Michigan, where she subsequently joined the faculty in 2013. She is a recipient of Fulbright and Howard Hughes Medical Institute scholarships. Her clinical practice focuses on thyroid diseases and thyroid cancer, as well as geriatric endocrinology.Dr. Papaleontiou is also a health services researcher in the field of thyroidology and aging. Her research focuses on evaluating the risks of thyroid hormone overtreatment and misuse in older adults, understanding the role of providers and patients in thyroid hormone use and misuse and how it relates to patient outcomes in the aging population, as well as the role of age and comorbidity in thyroid cancer decision-making. Her ultimate goal is to develop tools to tailor thyroid disease treatment to older adults by translating research findings into effective strategies and interventions to improve the care of older adults and reduce patient harm. She has received funding from the National Institute on Aging, the Claude D. Pepper Older American Independence Centers, the University of Michigan Biology of Cardiovascular Aging Core and the Elizabeth Caroline Crosby Research Award. She serves on multiple national committees including at the American Thyroid Association (ATA), the Endocrine Society, the American Association of Clinical Endocrinology and the North American Society for Interventional Thyroidology. She has served as Co-Chair for the ATA’s Annual Program Committee (2021-2022), Chair of the ATA’s Women in Thyroidology (2022-2023) and Vice-Chair for AACE's Thyroid Disease State Network (2022-2023). She is an Associate Editor for Endocrine Practice, and serves on the Editorial Boards for Thyroid and BMC Endocrine Disorders. Dr. Papaleontiou is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Thyroid Nodule, Hypothyroidism, Thyroidectomy, and Hormone Replacement Therapy (HRT).

    Douglas W. Ball
    Elite in Thyroid Cancer
    Endocrinology | Radiology
    Elite in Thyroid Cancer
    Endocrinology | Radiology

    Johns Hopkins Outpatient Center

    601 North Caroline Street, Floor 7, Floor 7, 
    Baltimore, MD 
    Languages Spoken:
    English
    Offers Telehealth

    Dr. Douglas Ball is an associate professor of medicine at the Johns Hopkins University School of Medicine. He holds a joint appointment in oncology. His areas of clinical expertise include diagnostic radiology, endocrine oncology, thyroid cancer and thyroid diseases. Dr. Ball earned his M.D. from the George Washington University School of Medicine. He completed his residency at the University of Pittsburgh-Presbyterian University Hospital and performed a fellowship in endocrinology and metabolism at Johns Hopkins. His research interests include medullary thyroid cancer, differentiated thyroid cancer and anaplastic thyroid cancer. Dr. Ball is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Medullary Thyroid Carcinoma, Thyroid Cancer, Anaplastic Thyroid Cancer, and Papillary Thyroid Cancer.

    Snehal G. Patel
    Elite in Thyroid Cancer
    General Surgery
    Elite in Thyroid Cancer
    General Surgery

    Emory Saint Joseph's Hospital Campus

    5673 Peachtree Dunwoody Road, Fl6, 
    Atlanta, GA 
    Experience:
    16+ years
    Languages Spoken:
    English, Gujarati 
    Offers Telehealth

    Snehal Patel is a General Surgeon in Atlanta, Georgia. Dr. Patel has been practicing medicine for over 16 years and is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Papillary Thyroid Cancer, Thyroid Nodule, Thyroidectomy, and Parathyroidectomy.

    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    Carlos Fernandez-Del Castillo MD

    15 Parkman St, 
    Boston, MA 
    Languages Spoken:
    English

    Gilbert Daniels is an Endocrinologist in Boston, Massachusetts. Dr. Daniels is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Follicular Thyroid Cancer, Thyroid Nodule, Papillary Thyroid Cancer, and Thyroidectomy.

    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    UT MD Anderson Cancer Center

    1515 Holcombe Blvd, 
    Houston, TX 
    Languages Spoken:
    English
    Offers Telehealth

    Anita Ying is an Endocrinologist in Houston, Texas. Dr. Ying is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Multiple Endocrine Neoplasia Type 2, Multiple Endocrine Neoplasia, Papillary Thyroid Cancer, and Thyroidectomy.

    Erich M. Sturgis
    Elite in Thyroid Cancer
    Otolaryngology | Surgical Oncology
    Elite in Thyroid Cancer
    Otolaryngology | Surgical Oncology

    Baylor College Of Medicine - Otolaryngology

    1977 Butler Blvd, Ste E5.200, 
    Houston, TX 
    Languages Spoken:
    English
    Accepting New Patients

    Dr. Erich M. Sturgis is a Professor of Head and Neck Surgery and Deputy Chair in the Bobby R. Alford Department of Otolaryngology - Head & Neck Surgery. His surgical practice is focused on thyroid cancer, sarcomas of the head and neck region, and melanoma/non-melanoma skin cancers. He has devoted much of his academic career to HPV-related oropharyngeal cancer and working to broadly disseminate the message of preventive HPV vaccination. Dr. Sturgis is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Head and Neck Squamous Cell Carcinoma (HNSCC), Human Papillomavirus Infection, Gastrostomy, and Thyroidectomy.

    Prasanna Santhanam
    Elite in Thyroid Cancer
    Elite in Thyroid Cancer

    Johns Hopkins Bayview Medical Center

    Baltimore, MD 
    Languages Spoken:
    English, Gujarati , Hindi, Tamil
    Offers Telehealth

    Dr. Prasanna Santhanam received his M.B.B.S. from B.J. Medical College and his M.D. from N.H.L. Municipal Medical College. He completed a residency in internal medicine, Joan C Edwards School of Medicine, Marshall University and a fellowship in endocrinology, diabetes, and metabolism at Joan C Edwards School of Medicine, Marshall University. He underwent additional training in nuclear medicine, at the Department of Radiology and Radiological Sciences at Johns Hopkins University School of Medicine, to pursue his research and clinical interests in nuclear medicine and molecular imaging of endocrine glands and disorders. His clinical interests include thyroid disorders, endocrine neoplasms, and research focus on metabolic and molecular imaging of endocrine tissues and predictive analytics in metabolic disorders. Dr. Santhanam is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Thyroid Cancer, Follicular Thyroid Cancer, Papillary Thyroid Cancer, Anaplastic Thyroid Cancer, and Thyroidectomy.

    Joanna Klubo
    Elite in Thyroid Cancer
    Endocrinology
    Elite in Thyroid Cancer
    Endocrinology

    Johns Hopkins Community Physicians, Inc

    5255 Loughboro Rd Nw, 
    Washington, DC 
    Languages Spoken:
    English, Polish

    Joanna Klubo is an Endocrinologist in Washington, Washington, D.c.. Dr. Klubo is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Thyroid Nodule, Hypothyroidism, Thyroidectomy, and Hormone Replacement Therapy (HRT).

    Nazanene H. Esfandiari
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine
    Elite in Thyroid Cancer
    Endocrinology | Internal Medicine

    Domino's Farms

    24 Frank Lloyd Wright Dr Ste 1300, Lobby C, 
    Ann Arbor, MI 
    Languages Spoken:
    English
    Offers Telehealth

    Nazanene H. Esfandiari, MD, is a Clinical Professor of Internal Medicine with an appointment in the Division of Metabolism, Endocrinology and Diabetes (MEND). Dr. Esfandiari received her medical degree from the University of Bordeaux in France, completed internal medicine residency in France and at UMASS Memorial Health Center in Massachusetts, and then completed fellowship in endocrinology at the University of Michigan. She joined the faculty at the University of Michigan in 2003. She was inducted into Clinical Excellence Society at the University of Michigan in 2014. She is the MEND Service Chief, Co-director of Hospital Intensive Insulin Program (HIIP) and Assistant Chief for the Inpatient Endocrine Consult.Dr. Esfandiari’s practice focuses on thyroid cancer, thyroid disorders, post bariatric care, and diabetes. She is also interested in medical education and is the Co-director of the Endocrine Sequence at the University of Michigan Medical School. In addition, Dr. Esfandiari has served in several national committees at the Endocrine Society and American Thyroid Association (ATA). Dr. Esfandiari is rated as an Elite provider by MediFind in the treatment of Thyroid Cancer. Her top areas of expertise are Thyroid Cancer, Follicular Thyroid Cancer, Anaplastic Thyroid Cancer, Gastric Bypass, and Thyroidectomy.

    Ilan Gabriely
    Distinguished in Thyroid Cancer
    Endocrinology | Internal Medicine
    Distinguished in Thyroid Cancer
    Endocrinology | Internal Medicine

    Reading Hospital Endocrinology & Diabetes Center Wyomissing

    1001 Reed Ave, Ste 402, 
    Wyomissing, PA 
    Languages Spoken:
    English

    . Dr. Gabriely is rated as a Distinguished provider by MediFind in the treatment of Thyroid Cancer. His top areas of expertise are Low Blood Sugar, Hyperparathyroidism, Thyroid Cancer, and Anaplastic Thyroid Cancer.

    Showing 1-20 of 12,289

    Last Updated: 04/28/2026

    What is the definition of Thyroid Cancer?

    Thyroid cancer is a cancer that starts in the thyroid gland. The thyroid gland is located in the front of your lower neck.

    When should I see a Thyroid Cancer doctor in The United States?

    There are various reasons why you may want to see a specialist, such as: 

    • Your primary care provider recommends it. 
    • Your condition requires expert knowledge and specialized care. 
    • Your symptoms persist or worsen despite treatment. 
    • You need specialized testing or procedures. 
    • You want a second opinion.  

    What should I consider when choosing a Thyroid Cancer doctor in The United States?

    It’s important to see a provider with expertise in your specific condition. Each provider profile in MediFind’s doctor database includes information on which conditions they treat, years of experience, research contributions, languages spoken, insurance plans accepted, and more.  

    How does MediFind rank Thyroid Cancer doctors in The United States?

    MediFind’s rankings are based on a variety of data sources, such as the number of articles a doctor has published in medical journals, participation in clinical trials and industry conferences, as well as the number of patients that provider sees for a given condition. Note that MediFind’s provider database is not based on user reviews, and providers do not pay to be included in the database. 

    What types of insurance are accepted by Thyroid Cancer doctors in The United States?

    Most profiles in MediFind’s doctor database include a list of insurance plans accepted by that provider. However, it’s a good idea to contact the provider’s office to make sure they still accept your insurance, then doublecheck by contacting your insurance plan to confirm they’re in network. 

    How can I book an appointment online with a Thyroid Cancer doctor in The United States?

    MediFind offers direct scheduling for certain providers using the “Request Appointment” button on that provider’s profile. If the schedule option is not available for a provider, tap the red “Show Phone Number” button on their profile to get their contact information. If you prefer to find providers who offer online scheduling, select “Schedules online” under the “Availability” category of the filter feature on the left side of the Thyroid Cancer doctor search results page. 

    Why is it important to get a second opinion from a different Thyroid Cancer doctor?

    Second opinions are an opportunity to confirm a diagnosis and its root cause, learn about alternative treatment options, or simply gain peace of mind. Many people, especially those with serious diagnoses, get second opinions so they can understand all their options and make informed decisions, so don’t hesitate to get one if you have any doubts or need more information or clarification regarding your care. Note that some insurance plans require second opinions, while others don’t cover second opinions, so be sure to confirm with your insurance provider first.   

    How can I prepare for my appointment with a Thyroid Cancer doctor in The United States?

    Prepare for your appointment by gathering the following items: 

    • Copies of medical records (dating back at least one year) 
    • Your medical history, including illnesses, medical conditions, surgeries, and other doctors you see 
    • Family history of disease 
    • List of current prescription drugs, over-the-counter medicines, vitamins, and herbal remedies or supplements including names and doses 
    • Allergies to medications, food, latex, insects, etc.  
    • List of questions and concerns 
    • Your insurance card 

    You might also contact the provider’s office to see if they offer transportation or childcare services or if you’re allowed to bring a loved one for support or to take notes during your visit. 

    What questions should I ask my Thyroid Cancer doctor?

    Here are some sample questions: 

    • Can you explain in simple terms what this condition is and how it’s treated? 
    • What symptoms or side effects should I watch for? 
    • What tests will be involved, and when can I expect results? 
    • Are there other specialists I need to see? 
    • What’s the best way to reach you if I have follow-up questions? 

    How can I learn about the latest clinical trials and research advances my Thyroid Cancer doctor may know about?

    MediFind’s Clinical Trials tool asks you a series of questions to help you narrow down your search by health condition, age, gender, location, how far you’re willing to travel, and more. Each question you answer filters down the number of trials until you find the ones that are most relevant to you. 

    MediFind’s Latest Advances tool features summaries of recent articles published in medical journals. We use cutting-edge technology to scour medical publication databases for the latest research advancements on any given condition, then we simplify this information in a way that’s useful and easy to understand. 

    Can I filter my search to show male or female Thyroid Cancer doctors in The United States?

    Look for the filter feature on the left side of the Thyroid Cancer doctor search results page. Select “Female” or “Male” under the “Gender” category to search for female or male providers exclusively. If the “Any” option is selected, it will pull results for both male and female providers. 

    Can I filter my search to find a Thyroid Cancer doctor that offers video calls?

    Look for the filter feature on the left-side of the Thyroid Cancer doctor search results page. Select “Offers telehealth visits” under the Availability category to search for providers who offer virtual appointments (video calls). 

    Reviewed on: 11/11/24  

    By: MediFind Medical Staff 

    Read more about our Content Policy