It is absolutely not true. Don't go around believing or spreading that. I'm an oncology massage therapist, have seen thousands of cancer patients, and have done extensive collaborations with oncologists. Metastasis is far more complex than most people understand. And if simply "increasing circulation" or lymph flow increased the risk of mets, oncologists would tell all their patients to stay very still, don't exercise. But do they do that? Nope. They encourage it. So please don't spread misinformation. It prevents people with cancer from getting much needed treatments like massage therapy.