Medical Services

Meet the Providers

Christopher Spencer, MD, MS

Radiation Oncologist Christopher Spencer, MD, is board-certified in Radiation Oncology and is the Director of Radiation Oncology at Phelps County Regional Medical Center (PCRMC). Dr. Spencer brings over four years of radiation oncology experience to the cancer services team.

Dr. Spencer graduated with his medical degree from Saint Louis University School of Medicine and completed his residency at Washington University School of Medicine/Barnes Jewish Hospital where he served as Chief Resident from 2014-2015.

Dr. Spencer is skilled in all areas of radiation oncology and has special interests in head and neck cancer, stereotactic radiation (SRS and SBRT), intensity modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT) and brachytherapy.

To learn more about Dr. Christopher Spencer, please visit or call the PCRMC Radiation Oncology Department at 573-458-7500.

Stephen Richard Toothaker, MD

Stephen Richard Toothaker, MD is board-certified in Medical Oncology and Hematology and brings 14 years of experience to the PCRMC cancer services team. Dr. Toothaker completed his residency in Internal Medicine at Maine Medical Center in Portland, Maine and completed a fellowship in Oncology and Hematology at the University of Rochester/Strong Memorial Hospital in Rochester, New York.

Dr. Toothaker is skilled in Medical Oncology and Hematology and specializes in bone marrow biopsy. Dr. Toothaker trained in a lymphoma specialty healthcare facility and is experienced in conducting medical research.

Tezo Karedan, MD

Medical oncologist and hematologist Tezo Karedan, MD, earned her medical degree from Odessa State Medical University in Odessa, Ukraine.

She completed her residency training in internal medicine at Trivandrum Medical College at the University of Kerala, India, and at McLaren Regional Medical Center at Michigan State Unversity in Flint, Michigan. She completed a clinical fellowship in hematology and oncology at the University of Louisville in Louisville, Kentucky.

Dr. Karedan has been practicing for three years and has special interests in oncology, hematology and immunotherapy.

Jinna Lisenbe, AGPCNP-BC

Jinna Lisenbe, AGPCNP-BC, is the nurse practitioner in Radiation Oncology at the Delbert Day Cancer Institute. Lisenbe completed her Master of Science in Nursing (MSN) from St. Louis University in 2014 and is certified as an Adult-Geriatric Primary Care Nurse Practitioner.

Lisenbe is furthering her education by working towards becoming certified as a Radiation Oncology Nurse as well as an Advanced Oncology Certified Nurse Practitioner. Lisenbe has special interests in patient education, health promotion and disease prevention.

Becky Witham, FNP

Witham received her MSN from Maryville University in 2014 and her BSN from Kaplan University in 2012. Witham worked as a nurse in the PCRMC Bond Clinic oncology/infusion room for four years, and after completing a nurse practitioner program, returned to practice at PCRMC. She has special interests in colon, lung and pancreatic cancers as well as hematology.