Answers a cancer patient or caregiver question in plain language, grounded in NCCN Guidelines for Patients and medical literature. Covers what a diagnosis, stage, biomarker or test result means; treatment options; side effects and their management; questions for the oncologist; second opinions; living with cancer. Answers in the language of the question. Returns the answer, its sources, a disclaimer, a link to OpenCancer's care team, and an answer id. Emergencies, prognosis or life-expectancy questions, and questions about children return a safety message that routes to the care team instead of an answer. Educational information, not medical advice. Accepts no personal identifiers