Oncology Support Staff

Sarah Buenviaje, O.N.P.

Sarah Buenviaje

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 Frankland, N.P.

michelle rooney

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. 

 Cyndi Schultz, N.P.

Cyndi received her first degree as a Bachelor of Arts in Psychology from the University of California in Santa Barbara. Shortly after graduation she pursued a Bachelor of Science in nursing, graduating with Cum Laude Honors.  Cyndi then received a Masters of Nursing and Family Nurse Practitioner degree from Maryville University in St. Louis, Missouri  in 2015. She worked as a registered nurse in Las Vegas, Nevada from 2010 to 2015, when she moved to Northern California. She began practicing at a oncology and hematology clinic where she assisted in the care of chronic and acute health problemsIn 2017, Cyndi joined Diablo Valley Oncology and Hematology Medical Group to pursue her passion for oncology. Cyndi strives to connect with each patient and make each one feel comfortable during their visits. 


Tinrin Chew, R.D., C.S.O.

Tinrin ChewTinrin Chew is a registered dietitian, who is Board Certified Specialist in Oncology Nutrition. She is recently certified in Adult Weight Management. Tinrin graduated from University of Hawaii and completed her internship at Detroit Medical Center in Michigan. Subsequently, she spent 8 years working as a clinical dietitian at Detroit Medical Center; during that time, she garnered her expertise in digestive issues, heart disease, diabetes and weight management. Tinrin is an oncology dietitian with Diablo Valley Oncology / Hematology Medical Group. She also has a private practice providing nutrition consultation in Lafayette. Tinrin is a regular speaker at the Wellness Community and Bay Area Tumor Institute, and is involved in many local cancer support groups and education programs. She has been co-leading “Navigating through Chemotherapy and Nutrition” at John Muir Medical Center. She contributed a nutrition chapter to “Chemotherapy Survival Guide” published last year and co-authored a chapter to “Nutrition Issues in Cancer Care” for health care professionals.

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