Department of Surgery »  Faculty »  Emeritus Faculty »  Orlo Clark, M.D.

Orlo Clark, M.D.

Professor Emeritus of Surgery
Division of General Surgery

Contact Information

Campus Box 1674
University of California, San Francisco
1600 Divisadero St.,
San Francisco, CA 94143-1674
Clinic:  (415) 353-7687
Voice: (415) 885-7616
FAX:    (415) 885-7617
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  • 1959-63, Cornell University, B.A., Zoology
  • 1963-67, Cornell University, M.D., Medicine
  • 1967-68, University of California, San Francisco, Intern, Surgery
  • 1968-70, University of California, San Francisco, Resident, Surgery
  • 1971-72, University of California, San Francisco, Senior Resident, Surgery
  • 1972-73, University of California, San Francisco, Chief Resident, Surgery
  • 1970-71, Hammersmith Hospital, London, Royal Postgraduate M, Endocrine Surgery
  • 1995, Harvard School of Public Health, Unknown,  2 week Program for Clinical Chiefs
  • American Board of Surgery, 1974
  • UCSF Helen Diller Family Comprehensive Cancer Center
  • Thyroid and other endocrine neoplasms

Dr. Orlo H. Clark is Professor of Surgery at UCSF and specializes in endocrine surgery, thyroid cancer and other endocrine malignancies. He is certified by the by the American Board of Surgery.  Dr. Clark specializes in Endocrine Surgical conditions; specifically treatment of disorders of the thyroid and parathyroid, as well as, adrenal and endocrine pancreas.  He utilizes minimally invasive surgical techniques and open operations with intraoperative parathyroid hormone assay and intraoperative magnification.

Dr. Clark attended Cornell University and Cornell Medical School.  He completed his surgical training and residency at UCSF.  He also did a year Fellowship at the Royal Postgraduate Medical Center in London in Endocrine Surgery, and joined the UCSF faculty in 1973.  He continues to teach medical students, residents, and fellows and has received the Lim Thomas Award and Excellence in Teaching Award distinguishing his outstanding teaching accomplishments at UCSF.  He is also recognized as one of the best surgeons in America by several publications, such as Leading Health Professionals of the World and America's Top Doctors.

Dr. Clark was the previous Chief of Surgery at Mt. Zion Medical Center and the Vice Chair of the Department of Surgery.  Dr. Clark is recognized as a leader in his field both nationally and internationally.  He has been the President of the American Association of Endocrine Surgeons, the American Thyroid Association, the International Association of Endocrine Surgeons, and is currently President Elect of the Pacific Coast Surgical Association.  He is an honorary member of the German Surgical Society, the Turkish Endocrine Surgical Society, the Asian Endocrine Surgical Society, and received a Docteur Honoris Causa (Honorary Doctorate) from Poitier University.  Dr. Clark has authored and co-authored over 300 journal manuscripts, chapters, and books. Highly respected by his peers, Dr. Clark was named to the list of U.S. News "America's Top Doctors," a distinction reserved for the top 1% of physicians in the nation for a given specialty.

Besides a busy and successful clinical practice, Dr. Clark is actively involved in research focusing on what makes thyroid and parathyroid cancers grow and spread to other areas of the body.  He also investigates the genetic basis of familial thyroid cancer.  Dr. Clark is currently a principle investigator and co-investigator on several clinical trials concerning  improving the care of patients with thyroid cancer.

  1. Park JW, Zarnegar R, Kanauchi H, Wong MG, Hyun WC, Ginzinger DG, Lobo M, Cotter P, Duh QY, Clark OH. Troglitazone, the peroxisome proliferator-activated receptor-gamma agonist, induces antiproliferation and redifferentiation in human thyroid cancer cell lines. Thyroid. 15: 222-31, Mar/2005.
  2. Shen WT, Wong TS, Chung WY, Wong MG, Kebebew E, Duh QY, Clark OH. Valproic acid inhibits growth, induces apoptosis, and modulates apoptosis-regulatory and differentiation gene expression in human thyroid cancer cells. Surgery. 138: 979-84; discussion 984-5, Dec/2005.
  3. Caron NR, Tan YY, Ogilvie JB, Triponez F, Reiff ES, Kebebew E, Duh QY, Clark OH. Selective modified radical neck dissection for papillary thyroid cancer-is level I, II and V dissection always necessary? World J Surg. 30: 833-40, May/2006.
  4. Triponez F, Wong M, Sturgeon C, Caron N, Ginzinger DG, Segal MR, Kebebew E, Duh QY, Clark OH. Does familial non-medullary thyroid cancer adversely affect survival? World J Surg. 30: 787-93, May/2006.