My mom is 72 has breast cancer that spread to her brain she is reciving hyperbaric oxygen therapy has these large knots in her upper thighs im concern?

Of course you are! The knots in her thighs could be breast cancer. It sounds like her cancer has spread to many places. The thighs aren't an area that will cause many problems, but her brain is a big concern. Have you talked to your mom about where she would like to die? That's a hard conversation, but a compassionate and loving thing to understand so you can plan together. Cherish this time with her.
Agree with earlier. Responses. I know of no connection between the large knots on her upper thighs and use of hyperbaric oxygen therapy.
Yes you have . To be concerned about your mom health, you discuss with her doctors and decide what is best for her , you and your family members and friend make her as comfortable as possible good luck .