Our Physicians

Nine doctors who never back down.

The experience and caliber of our oncologists are key factors in determining our patients’ success. We are able to attract and retain superior physicians because we have access to the latest research and treatment techniques. It’s the best cancer care in the country, right here at Green Bay Oncology.


Gerald K. Bayer, M.D.
Medical Oncology
Internal Medicine
Jules H. Blank, M.D.
Hematology
Medical Oncology
Internal Medicine
David L. Groteluschen, M.D.
Medical Oncology
Internal Medicine

Anthony J. Jaslowski, M.D., FACP
Hematology
Medical Oncology
Internal Medicine
Matthew L. Ryan, M.D.
Hematology
Medical Oncology
Internal Medicine
Thomas J. Saphner, M.D., FACP
Medical Oncology
Internal Medicine

Michael J. Volk, M.D.
Hematology
Medical Oncology
Internal Medicine
Ruth Warren, DO
Medical Oncology
Internal Medicine
Jerry Mitchell Winkler, M.D.
Hematology
Medical Oncology
Internal Medicine