WebMD doctor Harold Burstein gives advice:

“Cancer patients, like others with chronic health problems, require regular, ongoing health delivery. Cancer patients typically receive chemotherapy or radiation therapy treatment on fixed schedules, such as daily radiation treatment for 5 weeks, or chemotherapy treatment every 2 weeks, and so forth. Disruptions in the scheduling and delivery of cancer treatment can interfere with optimal treatment outcomes….
Question: What should cancer patients actively being treated do right now?

The short term needs of the patient will differ depending on the tumor type, the treatment, and the available medical resources…”

WebMD