Ridley-Tree Cancer Center has met the highest standards of the American Society for Radiation Oncology (ASTRO) and APEx (its Accreditation Program for Excellence) by receiving a second four-year re-accreditation for radiation oncology services.
ASTRO is the world’s premier radiation oncology society, which recognizes facilities that deliver exceptionally safe, high-quality care to patients. The comprehensive and rigorous voluntary accreditation process focuses on the functions of the entire radiation oncology team, and how well safety, quality, and adherence to patient-centered care are prioritized.
“This re-accreditation by the most important professional body in our field shows that Ridley-Tree’s Radiation Oncology Department is truly dedicated to providing our patients with the highest level of care,” said Dr. W. Warren Suh, medical director, Radiation Oncology Department.
In 2017, Ridley-Tree Cancer Center was the second facility in California to earn this accreditation, ahead of several major academic cancer centers. Currently, Ridley-Tree is one of 23 facilities in the state with APEx accreditation, and the only one on the Central Coast, to secure this achievement.
Each center seeking APEx accreditation must have its policies and procedures evaluated using objective, verifiable expectations for performance in radiation oncology. It must demonstrate a commitment to high standards of safety and quality, and prove it practices patient-centered care by promoting effective communication, coordinating treatment, and engaging patients and their families as partners in care.


