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Meet Our Physicians

Ravikumar Vasireddy, M.D.

Dr. Ravikumar Vasireddy is a medical oncologist who specializes in medical oncology and hematology. Dr. Vasireddy is a board certified medical oncologist and hematologist and is licensed to practice in Ohio, Oklahoma, and Maryland. Dr. Vasireddy specializes in the care of persons diagnosed with cancer: including lung cancer, breast cancer, mediastinal tumors, and cancer of unknown primary site.

Board Certifications include: American Board of Internal Medicine; American Board of Internal Medicine – Medical Oncology; American Board of Internal Medicine – Hematology

Dr. Vasireddy’s clinical expertise includes: Lung Cancer; New Cancer Treatments; Thymoma; Mediastinal Tumors; Control of Side Effects and Physical Problems Caused by Cancer and Cancer Treatments.

Dr. Vasireddy has been practicing medicine in the Muskogee, Oklahoma area for many years now and is well known in the community. Trained in both India and the United States, Dr. Vasireddy received his medical degree from Kakatiya Medical College, Kakatiya University, Warangal, India. He served his internship at MGM Hospital in Warangal and then completed residency programs in pathology and dermatology at Kakatiya Medical College and Gandhi Medical College, Hyderabad, India. He also trained in dermatology at the University of Wales, Cardiff, UK. Dr. Vasireddy worked in various medical positions and as a consultant in India before serving an internal medicine residency at Prince George’s Hospital, Cheverly, Maryland. He received his specialty training in oncology and hematology at the University of Cincinnati, Cincinnati, Ohio. Dr. Vasireddy’s memberships include The American Society of Clinical Oncology and The American Medical Association.

Dr. Vasireddy is Chief Medical Oncologist at Landmark Medical Center in Muskogee, Oklahoma.

Joshua Garren, M.D.

Joshua Garren, MD., Chief Radiation Oncologist at Landmark Medical Center, is an award winning, board-certified radiation oncologist, from the world-renowned Lahey Clinic in Boston where he led the radiosurgery program for over eight years.

His research career began in the Brown University MD/PhD program. His research on minimizing the side effects of radiation has been presented and supported internationally. He received his neurosurgery training at NYU Medical Center, where he worked on the first radiosurgery system in New York. Dr. Garren’s interest in health care for the disadvantaged began at the Harvard/Brown MD/MPH program. He has worked with Doctors of the World and has received a fellowship from the Albert Schweitzer Foundation.

Dr. Garren has been voted one of Boston’s top doctors by his peers in each of the past four years. Prior to joining Landmark, Dr. Garren was named to the first US News and World Report list of top doctors in the United States.

Dr. Garren speaks English, French and Russian. During his free time, he coaches his five budding young soccer stars, Daniel, Ariella, Maya, Jonathan and Shira Garren.

Dr. Garren is Chief Medical Oncologist at Landmark Medical Center in Muskogee, Oklahoma.