Oncology Support Staff

Sarah Buenviaje

Sarah Buenviaje, O.N.P.

Sarah received her B.S. in Nursing from University of Southern California in 1992 and earned her M.S.N. in the Oncology Nurse Practitioner program at UCLA Medical Center in 1996. She has been practicing as an Oncology Nurse Practitioner since 1996 with Diablo Valley Oncology and Hematology Medical Group located at the California Cancer and Research Institute in Pleasant Hill. DVO specializes in comprehensive, cutting edge treatment of all forms of cancer and blood disorders. Sarah serves on the Professional Advisory Board for the Cancer Support Community in Walnut Creek.

michelle rooney

 Michelle Frankland, N.P.

Michelle received her B.A. in Psychology from Gonzaga University in Spokane, Washington in 1998 and her M.S.N. in the Family Nurse Practitioner program from Samuel Merritt College in Oakland, California in 2002. She is an Oncology Certified Nurse and has been practicing as a Nurse Practitioner since 2004 with DVO. Michelle serves on the Professional Advisory Board for the Cancer Support Community in Walnut Creek and serves on the Board of the local melanoma foundation, SCARF, as a medical advisor. Michelle takes great interest in the role exercise and nutrition play in the prevention and management of cancer and has published a review article on the subject in the Clinical Journal of Oncology Nursing.

 Mariya Ryazantseva, N.P.

Mariya received a Bachelor’s of Science degree in Neurobiology from University of California in Davis, CA in 2012. She then earned her Masters of Science in Nursing degree from Boston College William F. Connell School of Nursing in Massachusetts. Mariya moved back to Northern California and practiced at a primary care community clinic where she managed complicated, multiple-disease states of patients. In 2016, Mariya joined Diablo Valley Oncology and Hematology Medical Group to pursue her passion for oncology.  She is instrumental in facilitating our patient education and survivorship programs. Mariya enjoys getting to know her patients, helping them understand their disease and seeing them through their journey. Mariya is fluent in English, Russian and semi-fluent in French. 

Alison Ryan, NP

Alison Ryan, P.A.

Alison received her B.S. in Nutrition Science from California Polytechnic State University in San Luis Obispo, CA.  She then earned a M.S.in Nutrition Science from Tufts University in Boston and completed her dietetic internship at Tufts-New England Medical Center. She became a Registered Dietitian in 2005. Alison practiced as a clinical dietitian at California Pacific Medical Center, Stanford Hospital, and Stanford Cancer Center in Palo Alto for a combined eleven years providing oncologic and surgical nutrition care and counseling. She authored a book chapter in Oncology Nutrition for Clinical Practice published by the Academy of Nutrition and Dietetics in 2013. Alison returned to school to become a Physician Assistant, enrolling in Stanford’s Primary Care Associate Program, and completed her degree in 2017. Alison is excited to combine her background in nutrition with her medical training to provide comprehensive cancer and nutritional care to patients at Diablo Valley Oncology/Hematology Medical Group.


Shannon Chakedis, NP

Shannon received her B.S. in Biology from Ohio State University in Columbus, Ohio in 2006 and earned her R.N. degree from Case Western Reserve University in Cleveland Ohio in 2008. She immediately began her oncology and hematology nursing career at Ohio State University Comprehensive Cancer – James Cancer Hospital and Solove Research Institute and continued at the University of California, San Diego Medical Center where she gained inpatient and outpatient experience caring for oncology/hematology and bone marrow transplant patients.  In 2015, Shannon completed a Master of Science degree in Adult Gerontological Primary Care Nurse Practitioner from Case Western Reserve University. For two years, she worked as an Oncology Nurse Practitioner at Ohio State University Comprehensive Cancer Center. Shannon joined Diablo Valley Oncology and Hematology Medical Group in 2019. 

We are proud to have our Oncology Support Staff on our great team.