Dr Siwillis is the former head of the Nakuru Regional Cancer Centre (NRCC) and is among Kenya’s most highly trained oncologists working outside of Nairobi. She is extensively trained in radiation and chemotherapy for various cancers, including treating tumors in the breast, cervix, head and neck, and the gastrointestinal tract – the most common forms of cancer in Kenya. At NRCC, Siwillis has supervised the establishment of one of Kenya’s first regional radiotherapy treatment centre, and led the hospital to introduce multidisciplinary consultations, focus on impact-oriented research, and streamlined patient care. Having worked at several different hospitals, in both urban and rural areas.
Dr Siwillis brings a unique perspective to cancer care through strengthening regional and sub-regional health facilities, to improve cancer management in urban and rural areas of Kenya. She has worked closely with the National Cancer Institute of Kenya (NCI-K) and the National Cancer Control Program (NCCP) where she played a key role in rolling out the Kenya National Cancer Screening and Treatment Guidelines as well as in the analysis of the National Cancer Registry (NaCaRe) Data 2021/2022 that culminated to The Status of Cancer in Kenya report that was launched in February 2023. She has been a prominent voice in raising cancer awareness across Kenya through continuous medical education (CME), health talks, clinical camps, and TV shows.
Dr. Siwillis is an advocate of quality and affordable cancer care for all patients. She is also a member of several national and international professional cancer bodies including the Kenya Society of Hematology & Oncology (KESHO), Kenya Medical Association (KMA), European Society of Medical Oncology (ESMO), European Society of Therapeutic Radiation Oncology (ESTRO), America Society of Clinical Oncology (ASCO), International Society of Pediatric Oncology (SIOP), Africa Radiation Oncologist Group (AFROG) and Africa Organization of Research and Training in Cancer (AORTIC).
Dr Siwillis also has interest in research, having attended and presented papers at both local and international conferences and has made several publications to her name. She is a nominee recipient of the International Visitors Leadership Program (IVLP on Demand) on “Cancer Care in the U.S”, which is the most prestigious Exchange Program by the United States Department of State. She also serves as an adjunct lecturer at the Egerton University department of Internal Medicine.